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TRANSCRIPT
KR0100950
KAERI/RR-2052/99
711 tf 9l7|ftO| £ t f
Research of Developing and
Processing Technology of New
Visual and Optical Materials
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PLEASE NOTE THATALL MISSING PAGES ARE SUPPOSED TO BE
BLANK
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TiOCl2
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£ # £ TiO2# °)-g-^M ^^-«LS S^J^Tiq- CR39/TiO2
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colloid -8-^l-i- 1 me4^1 ^ 7 ^ ^ Si Si 4 . ^r^, PMMA/TiO2
- iv -
CR39/T1O2
V.
TiO2
Fe2O3, ZrO2 ^
oil ^
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a- SiO:?,
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- v -
SUMMARY
I . Project Title
Research of Developing and Processing Technology of New Visual and Optical Materials
II. Objective and Importance of the Project
In order to use functional ceramic powders as the dispersant in an optical
polymer to be multi-functional, the ceramic powders should be homogeneously
ultrafine and structurally stable. TiC>2 material of various ceramics is very applicable
for the multi-coating and high refractive index of an optical lens. Thus, to give the
functions of UV light protection and high refractive index to the plastic optical lens,
it should be fabricated after the chemical mixing of TiC>2 powder with plastic lens
material, or the organic solution homogeneously dispersed with TiO2 particles should
be coated onto the surface of the lens. Here, TiC>2 powder for the dispersion in an
organic coating solution for a lens should be naturally synthesized with very small
particles. On the other hand, ultrafine TiO2 powder with good dispersion ability has;
been utilized due to long durability as the inhibitor for stress corrosion cracking of
the steam generator in a nuclear power plant, and as a component in cosmetic and
paint materials. Therefore, it can be said that the applications of the ultrafine TiO2
powder are multifarious in the industries.
Up to now, it is well known that the crystal structures of TiO2 are classified into
anatase and rutile structures corresponding to the stable phases in low and high
temperatures, respectively. To apply TiO2 to practical utilizations, it must consist of
the rutile phase alone instead of the anatase phase, where the latter can be easily
photo-degraded with changes in color. However, the development of TiO2 material
has been theoretically carried out in universities in Korea and all the ultrafine TiO2
-vi -
powder required is still mostly imported from Japanese and Germany companies.
Therefore, in the case that all the ultrafine T1O2 powders with the rutile phase
required for the industries are imported, if the mass production of ultrafine TiO2
powder using self-developed technology can be accomplished, the import
alternations as well as the solution of technology dependency will be possible. This
would also be very helpful to development in the domestic industry.
The objective of this project is to develop a coating solution with the dispersed
TiC>2 particles after synthesizing ultrafme TiO2 powder for high hardness as well as
UV light protection of an optical plastic lens, with utilizing the Chinese technology
of optical plastic company (OPC) of Jilin University, JangChun. In other words,
through the project to carry out developing the synthesizing as well as the dispersion
technology for ultrafine T1O2 powder, and to co-work internationally with the OPC
of Jilin University in China, the fabrication technology for the multi-functional
optical plastic lens with the dispersion of TiC>2 particles is developed and the other
applications of the ultrafine TiCh powder are studied. Therefore, it can be said that
the enhancement in research ability and the globalization of science and technology
in our country will be possible from this international corporations with China.
IE. Scope and Content of the Project
Synthesis, dispersion, and coating technology of ultrafine TiC>2 powder for the
protection of UV light and the optical plastic material with a high refractive index
have been developed with the following scope and content of the project.
-Development of a synthesis technique for ultrafine TiC"2 powder to support the
plastic lens with UV light protection and a high refractive index.
-Development of a dispersion technique for ultrafine TiCh powder to improve the
characteristics of ceramic/polymer composite material and to overcome the
limitations (low refractive index and low hardness) of a plastic lens (CR39) with
a low price.
-For an optical plastic lens, on the Korean side the rutile TiC>2 particles with sizes
-VII -
of 20 ~ 50 nm should be dispersed in an aqueous or organic solution, while on
the Chinese side the new coating solution should be developed using them for
hard-coating.
IV. Result of Project
Crystalline T1O2 powder with rutile phase for the plastic lens material was
prepared by the homogeneous precipitation process at ambient or low temperatures
(HPPLT) simply using heating and stirring of an aqueous TiOCb solution with
appropriate Ti4+ concentrations prepared diluting T1CI4 in a 1 atmosphere, and the
process was optimized controlling the reaction rate, reaction pressure, and amount of
H2O and alcohol. Also, the transparent TiCh thin films and CR39/TiO2 composite
lens were fabricated using dispersed TiO2 particles in aqueous or organic solutions;.
The research results are as follows:
Crystalline T1O2 precipitates were directly formed by the transformation of
TiOCb to TiO2 using OH" supported from H2O, without hydrolyzing it to Ti(OH)4.
This may be due to the crystallization of an unstable intermediate product, TiO(OH)2,
to TiCVxt^O in a highly acidic HCl solution. The crystalline TiC>2 precipitates witli
pure rutile phase formed between room temperature and 65 °C, whereas TiCh
crystalline precipitates with anatase phase started to form at temperatures higher than
65 °C. Precipitates with pure anatase phase formed at lOCTC. Here, the formation of
stable TiC>2 rutile phase at room temperature to 65 °C is probably due to be slowly
performed in this condition, although TiCh with the rutile phase thermodynamically
forms at higher temperatures. Also, with the increase in the reaction temperature, the
rapid reaction rate might result in the formation of stable TiC>2 anatase phase.
The mono-dispersed TiC-2 ultrafine particles with diameters of 40 ~ 400 nm wen;
obtained from an aqueous TiOCl2 solution with an appropriate Ti4+ concentration by
the homogeneous spontaneous precipitation process. The process was carried out
under conditions in the ranges of 17 ~ 230 °C to prevent complete H2O evaporation
- viii -
and to make it freely or to prevent it thoroughly. The precipitation of TiC>2 ultrafine
particles by the reaction of TiOCk with H2O occurred easily and rapidly when a
sufficient amount of H2O was supplied. With the spontaneous hydrolysis of TiOCk,
which means the natural decrease of pH in the aqueous TiOCl2 solutions, all the
mono-dispersed precipitates were crystallized with anatase or rutile TiC>2 phase
during the reaction regardless of various conditions. TiO2 precipitate with pure rutile
phase was fully formed at temperatures below 6 5 ^ , which did not involved the
evaporation of H2O, and above 155°C, which was available by suppressing it. TiC^
precipitate with rutile phase including a small amount of anatase phase started to
form in the intermediate temperatures above 70 °C showing the full formation of
anatase above 95 °C under the free evaporation of H2O. However, in the case of
completely suppressing H2O evaporation at temperatures above 70 °C, TiO2
precipitate with anatase phase that had already been formed by the rapid reaction was
folly transformed with the reaction time into the precipitate with rutile phase by the
vapor pressure of H2O. Therefore, it can be thought that these crystallization
behaviors of TiC>2 precipitates such as the formation of rutile phase around room
temperature would be caused due to the existences of capillary pressure between the
agglomerated needle-shaped particles or ultrafine clusters, together with the slow
reaction rate.
Crystalline T1O2 ultrafine powder was prepared in an aqueous TiOCb solution by
HPPLT, i.e., simply heating the solutions below 70 °C and compared with the
precipitations in aqueous TiO(NC>3)2 and TiOSC>4 solutions. The formation and
transformation of TiC>2 precipitates with the rutile phase even at ambient
temperatures was thought to be due to the presence of capillary forces among the
primary particles. The rutile TiC>2 phase precipitated in aqueous TiOC^ and
TiO(NC>3)2 solutions, but the anatase T1O2 phase precipitated in the aqueous TiOSO4
solution. If the amount of SO42" ions increases in the aqueous TiOC^ solution, the
primary particle shape changes from acicular to spherical, and the crystal structure
also changes from rutile to anatase phase. Hence, the existence of SO42" ions in the
aqueous TiOCb solution make the preferential growth of the acicular primary
- ix-
particles suppressed, resulting in spherical or round primary particles with the
anatase phase by lessening the capillary force between them. Also, it seems that the
weakened capillary force between the spherical primary particles was still as high as
that for the formation of T1O2 precipitates with the anatase phase in HPPLT.
The ultrafine TiO2 powder by HPPLT was well dispersed with sizes of 20 ~ 50
nm in the n-butyl alcohol solution. The mixture of TiCh particles with silica sol,
corresponding to 1.0 wt.% SiC>2 in a 99 wt.% (TiC>2 + H2O) aqueous solution was
coated with a 40 ~ 50 nm thickness on the substrate. The optical transmittance of a
CR39/TiC>2 composite lens with an increase in the addition of the ultrafine TiO?
powder decreases gradually although T1O2 particles were well dispersed in the
n-butyl alcohol solution. Thus, it can be thought that it is appropriate to add 0.3 mL
of 1.0 g TiCh/lOOO mL n-butyl alcohol solution to the CR39 solution for the
CR39/TiO2 composite lens with an optical transmittance of more than 90 %. In
summary, good CR39/TiC>2 homogeneous composite lenses are available with
various optical transmittances according to amounts of ultrafine TiC>2 powder added
to them. Also, to solve problems such as spots or cracks in the CR39/TiO2 composite:
lens, ultrafine TiC>2 powder was partly added to the composite using CH2CI2 solvent
with a low boiling point of 44 °C when using n-butyl alcohol. As a result, a good
CR39/TiO2 composite lens with an optical transmittance of more than 90 % at an
amount of 1.0 mL of TiO2/CH2Cl2 1000 mL colloidal solution. On the other hand,
PMMA/TiO2 composite thin films were also prepared with the same method above
using a spin coater and their optical and microstructural properties were investigated.
It was confirmed that PMMA/TiC>2 composite thin films also showed a similar
transmittance like the CR39/TiC>2 composite lens.
V. Proposal for Applications
Ultrafine TiC>2 powder with a good dispersion ability can be applied in various
fields such as UV light protection, organic/inorganic composites, and filler material
in the fields of tire making, cosmetics and paint. Also, with HPPLT (homogeneous
- x -
precipitation process at ambient or low temperatures), the new method developed in
this project, it is possible to apply the fabrication technique of TiC^ powder to the
syntheses of ultrafine SiC>2, Fe2C>3, and Z1O2 powders, etc. It was well recognized
that TiO2 dispersion in a nano composite and a photocatalyst for recovery of precious
metals from the wastewater and decomposition of organic materials in various T1O2
applications have good characteristics. Therefore, the project plan to utilize our
excellent results will be prepared in a short time. In addition, industrialization of the
synthesis and dispersion technology of ultrafine TiC^ powder through technology
transfer to small business groups will be actively driven forward.
-xi -
CONTENTS
Chapter 1. Introduction I
Chapter 2. A state of the art on ceramic powder preparations 5
Section 2-1. Status of industrial technology — 8
Section 2-2. Status and optical properties of T1O2 20
Chapter 3. Results and discussion 31
Section 3-1. Approaches 31
Section 3-2. Synthesis of rutile TiO2 ultrafine powder by HPPLT 34
Section 3-3. Preparation of coated T1O2 films using Ti-precursor and dispersed
TiO2 sol 96
Section 3-4. Preparation of plastic lens using TiO2 coating sol 117
Section 3-5. Application of ultrafine TiO2 powder to the EL device 141
Section 3-6. Preparation of PMMA/TiO2 composite by spin coater 160
Chapter 4. Achievements and Contributions 179
Section 4-1. Achievements 179
Section 4-2. Contributions 189
Chapter 5. Proposal for applications 197
Chapter 6. References 204
Appendix
-XI I -
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7} S!l4. S^^-^l TiO2 1 271 * l l#f :£ ^ 3015 ~ 17 nm l 3 7 ] ^ ] 7 ^ 1 ? ) A>-g-s)ji §1^. 2^ol]fe xf V<y ofl
-§-s] 31 Si t-fl TiO2
<So]xlfe BaTi037l-
TiO2 ^r
TiO2
l 5Ufe * ^
514. ^ 4 ^ ^ ^ ^ ^ 7
71- -4
- 25 -
TiO2
TiO2
: lOOOM/T, %)
1989
3172
3080
97.1
1991
3387
2913
86.0
1993
3721
3127
84.0
1995
3894
3466
89.0
1996
4124
3589
87.0
TiO2
: 1000M/T)
M ft §O^HX|Q^
1995
1210
940
785
416
3351
2002
1442
1142
1185
627
4396
1995-2002
2.5 %
2.8
6.1
6.0
4.0
1995-2002
232
202
400
211
1045
SCM Chemicals
- 26 -
T1O2
: 1000M/T)
Ell O| JE|
?l EF
f[ 31
1995
1944
684
441
282
3351
2002
2550
957
532
357
4396
1995-2002
4.0 %
4.9
2.7
3.4
4.0
199572002
#7h§f
606
273
91
75
1045
SCM Chemicals
TiO2
-*]-•§-) Millennium Chemicals
-97V1 <>)$• A 1 ^ ^ 1 TiO2
(1998^
Company
Dupont
Millennium Inorganic Chemical
Tioxide
Kronos
Kerr-McGee
Kemira
Ishihara
7|E^
Capacity (M/T)
98
71
59
45
38
30
20
83444
- 27 -
TIO2
: 1000M/T, %)
Dupont
Tioxide
SCM Chemicals
Kronos
4qpi<a mns^ l 6 ^ 1 S
1996-2000
108
60112-
280
4719
346
2000
1042
690617
4052754
1125
802
4681
100%
22
886472
41
15
55
-1995\1
TiO2
Company
Dupont
SCM
ishihara
Tioxide
Kerr McGee
Bayer7|EF
Kronos
Market Share (%)
39
17
15.7
12
11.50.7
2.51.6
70,000 M/T
- 28 -
Company Market Share (%)94.1
5.9
17,000 M/T
TiO2 (1996)
Market Share (%)
66
25
64
56,000 M/T
£ S
Market Share (%)33171615104
17,000 M/T
- 29 -
Company
Sachtleben (Germany)
Fuji Titanium (Japan)7| E
-S#^= (Ton)
40,000
23,000
12,000 ~ 17,000
capacity : 36,000^
: M/T)
1995
4458
3559
8017
1996
4241
4170
8411
1997
4529
5276
9805
-$2800
-$2500
$3000 (1997)
$2600 (1998. 5)
- 30 -
ifl-g-
3-1
- ^.*n ^ TiO2
- 1 TiO2 l : ^ 1 ^
£331-71 £ 4 7H--g-sfl,
TiCl4 + H20 «-» TiOCk + 2HC1
TiOCk + 2H2O «-> TiO(OH)2 + 2HC1 «-> TiO2-xH2O I + 2HC1
.s. # 4 TiCU^l- ol-g-sfsa^l^:, S-^SAl- ^ 4 TiOCk
^- pH
NH4OH2] ti>-g-^.£ <9^r Ti ^ s j - l - i : ^ ^ > i ^ ^ TiO(NO3)2
=L ^ ^ ^ ^ - H ^ : TiOCl2^
TiOCk + 2NH4OH «-» Ti-hydroxide I + 2NH4C1
Ti-hydroxide + 2HNO3 <-» TiO(NO3)2 + 2H2O
TiO(NO3)2 + H2O <-* TiO(OH)2 + 2HNO3 ^ T i O 2 • xH2O i + 2HNO3
- 31 -
- ze -
-§-[0 -1J31B00 uids ijofc ^Uta-B- f-fc-g-giff & & * t-zO!X
Z(£ON)O!X
002 ~ OST f c £ 5 l f l 'i§ to i«u 0T
^ 9"0 ~ SO'O ^
toi°r[o IT fc&ft. ^ ( s ^ f v t-V [ b ^ lo DS9
UBUIBH 'VXO/OX
life^lK \P^[O MO b£ && kIP_H0 ^ts^lt^ ta^^# l-a-^^ iv ^-b^^-fi l^^ la
T o i TOHOdad loferr^^ Had { TT-lsHalo --R'fefe-g- ^-hloP> Ib
CR395f ^ TiO2»
- 33 -
3-2 TiO2
l.
[1-4].
(TCE),
7}
^2:1-
>fet-il RF i
o]«fl
5)7]
, TiO2 ^ ^ -
TiO2
A] £7]-
200°C
T i 0 2 ^ n i ^o] ^
TiO2
£. TiO2
- 34 -
100°C °)*}2\ *1|-f # £«M 4. ^ A ^ A S . <*£ TiO2
TiO2 °d*Hr "
TiO2 ^-nsv^
n. 3.7)7}
^[14,15], ^
^ 3.711-S
Si4. S ^ t t 3 7 l f 5>fe ^^31 TiO2
3.711: 5J"^
autoclavel- <>l-8-«l-7l
1 Si4.
polymer/TiO2
r Sife Ti €S.^1, TiCl4l- ol-g-*H ^ 1 ^ TiO2
S ^4^14. S^^S . ^^*V 7A*]^ TiCUl- °1TiOrt A&^t »^SLS. ^5] Af^-s]ji o ^ 7lAV^^ 2,0]
^ A S . nfl-f- - f ^ t H ^ J TiCl4
^ i 1000
«>-g-8-7171- ^ o f l 7 j -^ 711 .1-
TiO2 ^ - ^ ^12 : 4
- 35 -
TiO 2
1 o> §>JL, ^ ^ ^ o]
TiO2 I r^- i- ^|2:*V7l ^ t b # ^ ^ S S . ^ 1 TiCUl-
^Bi 100°C 01*1-51
TiO27]-
TiOCk ^ - 8 - ^ ^ . S . ^ - B ] ^ .^-8- TiO2
71- <i^5l §Jo] ^^?>-§-ni.
2 : 3 3 S1CI4, Z1OCI2
TiO2
TiOCbol 7 )
^-AS.Ai TiOCk^ 1-4^1 wi-g-il
TiO2 ^
TiOCk ^r-8-^i^.S.^-E]
^ TiO2
- 36 -
^£r TiO2 M ^ S Q%^ f-«fl 3 ^ Ti4+ ^ S I S ^ S ] TiO(NO3)24
TiOSO4 ^r-8-^l[45,46]<$*\S. TiOCk
^ t f TiO2 3#<&-8-£ 4 * f^f-3 <§-°l£-§- ^ ^ - TiO(NO3)24
TiOSO4 f - 4 ^ ^ Ti Sl-^-# ^-g-^l £ fe SiCU, ZrOCk *r-g-«| #^1 47} <&*]
S-Si -S-§-«l-7l ^
. JE, S.4& ^e] ^XflS. ^ ^ s ^ f e TiOCb
°1^Ti
TiOSO4
2.
, Aldrich Co.,
USA)-i- 4-§-«l-^4. #*1, stock solutionO-S. A]-g-§|-7] ^ * t TiCl4 ^r-§-<^# 4
0°C ol«>s. ^ ^ * 1 ^ z ^ - ^ TiCUl- (TCsL -frx]^ #-
. TiOCk ^r-S- l ^1^°H tfl^ 7 ^ £ f Fig. 3 - 2 - H
Si4. °1nfl, TiCl4 stock solution^ ^ £ f e <g g- 2 4 2 ] ^ - i : S^§j-<^ ^ 5 M
stock solution^- 4V^°H^ 1 ^ ^
TiCl4 ^ «
- 37 -
TiCLj + H20 = TiOCk + 2HC1
o] ^711 < § o ^ ^ t}7]
-§-§H ^ ^ 1 TiO2
7} 0.35 ~ 1.2
©i >fl ^ TiOCfe stock solution^ °]
fe o] s t ock solution^ Ti4+
80 mm x
O-ring-i:
(water bath)
160°C °}^2]
SS316
6 mm7>
100 mm)1 TiOCh
^- 17
5 bar <>
mini autoclave^
, TiOCk ^ -
fe TiCLiS.^-B| ^ ^ ^ TiOCk,
(Hankook Titan Co, Korea)
TiOCl2«- °l-§-«H TiO(NO3)2l-
(Ti-hydroxide)^l
$\n Or 10
TiO(NO3)2>
TiOSO4^^-E-1 ^ « : € TiOCk
^ TiOCk
NH4C1 ^-
(lining)-i-
T1OSO4
fe AgNOs
61 %
NH4CH
Ti
TiONOs
TiOCkl-35 % H C 1 T i
A i M TiO(NO3)2
TiOCb, TiOSO4) TiO(NO3)2
50°C ol^^i
24
T\<>\
# Ti4+ 0.67
- 38 -
N03" S^r SO/" °l£r f-i- # 3 * 1 X|7l*]-7] ^ f l 0.2 ^ 1 ^ 7}^- 3.7]f- ^ f e
)3.7^4 5000
M 12
i#Sl §11511- nv7i ^ § | | H C 1 -g-o^o.^ p H 1 .
^3*1-714 1 MpH ^O] 4
TiOCk ^-§-°^^ pH ^Sj-1:
355 ion analyzer (Mettler Toledo Co.)» °]-g-§H # ^ * } ^ 1 4 . ^ iS^l ^ ^ # s : |
^ ^ ^ ^ Cu Ka radiation^- >-8-*1-fe- XRD(Rigaku D/Max-IIIc; 3 kW / 40 kV,
45 mA), Raman spectroscopy (SPEX 1403, double monochromator system with
514.5nm Ar ion laser, U S A ) J 4 TEM(transmission electron microscope)-i- °l-§-
*fo^ ^-^sl-^ja., ^J?i#^l ^Eflfe- SEM(scanning electron microscope, JEOL
ABT DX-130S; 30 kV)^:
Ti4 +
^3^r-§- ^ TiOCk
ICP-AESS
? i € ^ ^ # # 1^ 24
BET 4
3.
TiO2
stock solutionA^ A>-§-§>71 ^ t b TiCU ^-8-^j-i- ^l2:§}7l $n*] 0°C
TiCUl-
- 39 -
£. HC1 -g-«H ^ £-§• ®%^ <r 91
. ° H , TiCU stock solution^ ^ H ^ <£•%• 2,^2] «#-§- a a i s H 5M
7} SJ3EJ5- ^ $ 4 . ^7loflAi TiCl4
TiCU + H2O = TiOCk + 2HC1
. §1-7] ^ t> ^o]r^. o]^7fl nps. TiOCk stock solution-^
TiO2 ^ ^ 1 - i - <£?] #^*\^ °] stock solution^ Ti4+ <>]•€:si\
7} 0.4 ~ 1.2 M^l
TiO2 -g-1^^ ^ ^ ^ ^ 1 ^1]S«J-^^ ^}S.M, Fig. 3-2-2fe TiOCh*
>ltf. NH4OHS a}-g-, ^ # ^ ] ^ ?12:€ ^r
1000°C l
TiO2
*1, NH4OHI- o]-§-*H TiCLrl-
TiO2 ^r^- i : ^7] ^-sllA^ ^c>j
^ 1000
Fig. 3 -2-3^ NH4OHI- Af-g- j-xl ^ J I TiOCl2
4 1 H g^eJ^VSa^r ^"T-^ £- iH tfl^- XRD
B\ o\^4<#*[ TiO2 ^^^ - i r 44^13- $14. Fig. 3-2-221 ^4°H^i iL°J
^ , NH4OHI- ^l-g-tt ^J^^°flAi TiO2 l^Aov-i- °i7l ^^fi^fe. 400°C o]Aj.
- 40 -
2) ^7}$] 3L-& 1
I ^ SHE. TiOCl27> Ti
TiO2 ^ # i - ° ] *§
4s*|i?V H. Cheng f-[l]^r TiCU =r-§-^^r ol-§-t3: autoclave
£ A]oi| o|n] o>^^. 6fq.B]-^| TiO2 -#<>] ^
400°C J i 4 ±-£ ^rS^Ai t ^ ^ ^ ^ ^ - ^^-ofl^ Fig. 3-2-2
Fig. 3-2-3^1^ il?l ^ ^ ^ , TiOCk ^-§-°J|*
^ i ^ ^ 1 >id ^ ^ ^ TiO2
. Fig. 3-2-4^4-§-, °1 ^£^1^1 4^1 6l-oil c)]tt XRD q
^ ^ ^ # 1 - ^ , 0.5 °C
TiO2 ^°ll «fl^«l-
$14. ^r« , 5]f^ wV-g-^-Sl- 50°CS ^ i 13.6
4^- , °1 ^r£°fl^ 6 ^]6 AlTV f.6> 7f<i5l-^^
l j ^ ^ ) l O ] B | ^ ^ l ^ o v ^ TiO2
$14. °i s?!oflAi ioo°c, 6 *ms}
ig. 3-2-5) X-e|o) s ] ^
$14- ^ ^ ^ ^ » € ^ m - l : ^-foflfe ^r-l-8-^^ ^£7> 80°C ^4 V A^]->a -§-«5Bol m i ^ ^ ^ § ^ ^ ^ 5 > 7 l A]
fe 100^ l ^
- 41 -
100°C <>1*> ££<>1H a>-g-o) ^«-§) ^ u J - H ^ . 6 A ] # OJAJ-^
#-§- *i|3=3H H ^ 4 1 - XRD sfi^AS^-B| ^ S H Fig. 3-2-6^1
©1^, 40°C ^ 1 « H 1 ^ ^ ^ ^ ^ ^ - ° 1 ^2]X| ^^M-S .S 72 -
Fig. 3-2-6^ A
l : ^ ^ XRD ^s]-^^Ei ^-€AJ-^ ( l l O H H ^ S]^(reflection)4
^ f - f j TiO2
. 65°C ^l^oflAife ^ ^ TiO2 #°] ^ ^ S j j l H
^q-7]- 95oCi^1fe t±x\ ofq.^^1 TiO2
f - 1 TiO2 ^°
1.2 M iLtJ. fe
, 1.2 M
, ^t-g-^oi Ti4+ oi^o^ ^ £ 7 } ^ TiOCl2
Zl ^-g-°J|£- ^ ^ HC1# i«-«}7ll £)
pH
3. TiOCk ^-g-^o l )^^ -§-*fl£5] £ 3 H 4 = . ^ ^ ^ ^ o ] 6}i]2}^ 5}-I-
fr^Al^ < ^ ^ > t TiO2
SAD sflH(Fig. 3-2-
TEM
£ , Fig. 3-2-
TiO(OH)2 S f e Ti(0H)4 l- l ^ ^ l ^ l : *fl 650°C O]
TiO2 ^^^17> 1 7)<$ 2i7d$\ 65°C
Fig. 3-2-8^ 17°C
- 42 -
PH
# pH
€ ? H 4 . Fig. 3-2-9fe Fig. 3-2-6^) A1?N tfltb XRD ^
!4(primary particle)^! 3.711- Tfl^-sH 44^E ^°14 . ^
T1O2 °s!
K H.
Cheng ^-[1]°1 S-3.ft 5J*|^, ^-g-^r^l- 100°C ° H ^ J
1 TiO2
TiO2 ^^
TiO2 °J:
10 nm °l*l-5l D11-T- Dl^l^r ^ 4 ^ 4 3 .
14^451 a.711-^- 4 ^ 1 $:%5\5L $14. 65°C
TiO2 ^ # ! - £ • 4 200 ~ 400
(secondary particle)?! # £ - # ^ 3 . ^^sjSiJZ., 100°C 1 1
## l -£ r 200 ~ 5000 nm t
4=1 £ 444*11 TiO2 ^
^-1 TiO2
^ TiO27l- ^ ^ s l f e ^&£a?i (65°C o]
fe Ti4+ i i ^ £ i 4 4 ^O^. Fig. 3-2-ll<*l|^ # ^ °l-§-^ stock solution^
# ^ S l ^ ^ - g - ^ ^ l ^ S l Ti4+
ICP-AES ^IJ.2-3. ^ ^ 4 ^ iL^l 5lo14. ^^1 ^ ^ ^ V 7 f^^
0.39 ~ 0.47 M Ti4+ o)^}^ ^^^l?>-i- 48 A1?>^ .S ^ 5 ^ ^ 0.2 ~ 1.2 M Ti4+
- 43 -
ZL S£^§-
^: 150 ~ 200 mVg
°-5, TiOCktq-. 01 ^ s j T i O c i 2 ^-g-^AS-^-Ei TiO27>
fe- TiO2
65°C ^ 4 ^ ^ ^£°fl^fe of -EMl TiO2
^ TiO2
TiO2 %%
TiOCk
TiCfel-
^ § H , TiOCk ^-§-Oj|-
r *r-§-^S) pH ^Sf l - ^r-g-A]^ofl nfe} # ^ S ) - ^ Fig.
3-2-12^1 ^Hfif l^^. 100 mL2] TiOCk ^-§-^°fl 300 mL^ ( #
T i 0 Cl 2 p
] t } TiOCl2
SiPH ^ ^ r SipH
> ^ ^ H J ^ - ^ ^ 1 ^ £ pH
- 44 -
p H 1
££• # £ €(sourceW. ^r, stock solution^: ^ S ^ : nfl TiOCk^l
^1- fecil ol^J^ HC1 ^ %
^ i^^ - ^°1] TiOCl27}- TiO2S ^}3]-s]^Ai q-^fe cfsf H+°H ^«fl ^r-g-°Jj^ PH
7]- #£34-11 1- ^ Si4. atv, 371-3
Fig. 3-2-13^ S. 1 ^ ^ ^ , &-8-41 #7Hl-fe- TiOCl24
Hl -S^IS. <£-§- ^ SJfe- ^ ^
Si4. ° 1 ^ ^ TiOClz "a^l-1- l
Si4. ^ , Fig. 3-2-
4TiO2»
SI4. 37J-3 °fl^r^-^ ^ ^ ^ 7 ^ ^ ] icj-g - 0.2 m
* H ^ ^ "r &fe TiO2 ^ - ^ ^ ^r^:^ ^ ^ * ] #±^3. SX4.l ^ ^ 1 " ] - Ht-g-Al V-i- 24 A]^- OJAOV_OS ^ ^ § ^ ^ . ^ .0^1 ^ ^ a
Ti0C12 =r-S-°J! f-^^r ^f- OJH1 ^bf-^fe- Ti4+S] ^ £ f e ICP-AES
$ ^ 1 ^ ] 10
^ ^ TiOCb ^-41- tl
-^ screening S^f^l filSfl ^ # € TiO2
o) ^o]%7} v^&SLS. ^ # 3 4 . 1 § ^ ^ S , TiOCl2 ^-§-^°ll^^ TiO2
Si4. 44-H TiOC^l l - ll-
- 45 -
£.3. TiOCl27>
-§- nfl 200 £ <>ltj]s| ^ - S - ^ ^ H T T Fig. 3-2-12
TiO2 ^ ]? i#^ : ^ ^ 5 } ^ 200 £ o RHl^n] - 7]-^§}4. 4 ^ ^ , 200
pH &£] 7a
v4i4 «V )1 TiO27>
TiO2 AoVol ^ ^ s ] f e 80 ~ 100°C
PH7>
^ - 1 - ^ ^r-£-°J?^ 2 | ^ pH ?3t-i:
Autoclave*- <>l-g- r ^^^1^1 «}:-§-§-^^ pH
^ - ^ H. Cheng ^-^ ligand field t heo ry f l l ] ^^^ , TiOCl2
aciditysf ligand^l ^sfl ^B}^]fe titanium(IV) complexes [Ti(OH)nClm]2"
y\ ^r-§-°J]s] pH7f ^ A ^ OH ^ £ ^ ^ 7 f S °]*M edge-shared bondinga| 7>
^j-M-Bf^^-AS ^^=131, ^r-§-°-fl PH ^ A ^ OH ^ £
edge-shared bonding-c- ^^]s |3 i comer-shared bonding 7]-^
autoclavel- 4-§-^^l &SM- «fl, ^ ^ ^ ^ f 7 ^ ^ 2L#«H*\ 1.2 Ms] Ti4+
«l-fi1 TiOCk ^-§-^^r 4-8-1- i , aJ-§-^ ^ ^
1 ^ . 200 €
^ s ] PH
M 71 Si ^ ^ ^ ^ A H S 2 ] ^ ^ ^ # S 1 ^ ^ ^ E f l
r Si4.
4 . pH
pH
- 46 -
3.7} ^«ll stock solution?! TiOCk
°1| pH = 0.851- # f e TiOCk
50°C,
0.5
NH4OH» 7}^ pH« ^:§M
^ ^ 3-2-143- £-£: SEM
TiOCk
fe Fig. 3-2-
0.62, (C) 0.91, (D) 4.113.
pH ^ ^ (A) 0.49, (B)
, 0.913 pH ft& ^-fe TiOCh r-§-
^PJ^l-^ 3.7)7} 3= 0.2 ~ 0.4 Am
NH4OHI-
=1 TiOCk
T1O2
TG/DTA#
^s-i-3
Ti4+
T1 Si4.
TiO2 ^ ^
^€- heat flow! *1)3^ ^sJ-7]-
T1 # 4 . ^ ^ 3-2-16^
- i 464.64 458.9 eV3 ^
fe 5.7 e V ^ i Ti ^xffe
XPS
^ 31
^sJfEi TiO2
TiO-nitrate ^r-
TiOCla
#3.
. Cl'7>
Ti(OH)4 Hfe TiO(OH)2
Ti 61 %
- 47 -
¥• 10*] #
Ti ^#:3j-#°] ^f£ U # <r&q£ TiO(NO3)2
0.31 M Ti4+
3. ^ S ^ ^ ^ r ^ ^ -S -A]^ ^ ^ T i
TiO(OH)2 ^ ^ ? 1 ^ ^ - S ^4€Cr . Ti ^
TiOCk + 2NH4OH •-* Ti-hydroxide 1 + 2NH4C1
Ti-hydroxide + 2HNO3 ^TiO(NO3)2 + 2H2O
-5] acids (tartaric acid,
citric acid)# %7}
Ti4+ ^ £ » ?J-fe
^ 65°C
o.2
5} ^ €
. Ti ^ ^ ^ - i - ^l-§-*fl^£ ^ ^ ^ ^ ^ j ^ i ^ i ^«fl ^ ^ TiO27r
%<&% ^ ^ - ^ ^ , Fig. 3-2-17i JS. 1 «]:-§-^^Hl trj-^ p H
TiOCl2 -r-§-°J!2J- £ £ £ ^^71^-S ^^^]7l- ^j?i=14fe 3-
, Fig. 3-2-18°Dfe oxalic acid# Q^tf 4 ^ Ti-nitrate°fl
mol % °}
8 l > } i ^ ^ | ^ } ^ 4 m l m o l
65°C ol$>oflA- ^A^sjTg ^ ^ TiO27> ^^slSi t ) - . Oxalic acid^ %A^°) 20
mol % °HM- ^71-^1- nflofl - ^ - 1 : ^ fe#^]5f£ ^ € ^ i l 4 f e Afls^- Ti 4
- 48 -
Ti-nitrate
TiO2
. TiCUi
A] ^of ^ ^ ^ 0.5. 3 «V-g-<>ll &#•& TiOCl27f ^12:^4. ^ i ^ , Ti4+
ۥ TiOCl2 ^-g-*H>H3 ^3^71^-i; HlH^7l ^sfl ^ #^-3] TiOCb ^-8-^-ir
^ H J g ^ ^ ^ . Fig. 3-2-19TT 4.7
0.67 MS) Ti4 +
60 ~ 100
1 7 9 m2/g) 0.2 ~ 0.4
* ^ TiOCl2
o.67 M Ti4+ ^ £ ^ TiOCk
SEM 4 ^ # Fig. 3-2-20O)]
c}. Fig. 3-2-21^1
- 49 -
3 , °1 ^ t - °11 tfl^ XRD 1*H 3*1-3 17°C,
£ £^rt> f - H ^ . 5 . <>lf-<H*l TiO2 3 1 ° ]30 % ^ ^ o f l ^ s } f e O]-M-H}^HVO] s ^ - ^ ^ . ig# T i 0 2
£ s € 3#*Hl"t 400°C °R^
400TC ° l 3 H M f e
L, 650°C ^«V°11^fe ^VM-BJ-^^-o] o>3g*l-jl n o ] ^
-, S. J. Kim ^ TiOCk
65°C ol^oU^fe ^ ^ A j - TJO27]-
TiO2°] ^<>1
M 1-^ 701: ° l A o ^ ^r-
Fig. 3-2-2KC, D)s] ^ a } - ^ ^ , cf lW 0] ^ -€^ - TiO2
TiOCfct- s l ^ AM-ir ^ ^-g-0-fl^S^-Ei ^ ^ ^ ) TiO27>
? TiOCl27]- #
80°C ^l
Fig. 3-2-22i M-^-ifl^c)-. o]ifl) 80°C
p H
pH
pH ^< ] #±t}E.£. TiO2s] ^ ^ ^ r - § - ^ TiOCl2OH" o | ^ o | . ^ s j . *>^ o^t+c | . f e ^ ^ . osv =- oi4_ n}eH,
TiOCl^ 7>^^-«ill- ^ ^ f b ^ J l ^ ^ SX^-E-S. n
- 50 -
TiOCk + 2H2O = TiO(OH)2 + 2HC1 (1)
>, Fig. 3-2-22(BW
pH & ^ 3]# 3hfcS|-*l# # M « H ^HflS. pH
oj-^e}- TiOCl2 ^-§-°Jj ^ ^ A 1 ^ - ^ ^ ^ . S f e pH
^l«Vfetll c>n}.S. (2) ^31 TiO(OH)2^ l ^ S f ^ ^ ^ l ^ «ov#S]fe H2O
TiO(OH)2 + 2HC1 = TiO2-xH2O + 2HC1 (2)
S ^^*fl TiO2
- ^ si4. $ 3 , TiOCk
TiO2 ^ ^
-t- ^7>§]-JL
TiOCkl- # ^^1 ^ ^ ] 7 l ^ TiOCk ^ ^ # # &z}7\ l-e^fTfl s|j i zi
Fig. 3-2-
-f ^3}*1*1# <^# ^ sife- ^ - t - ^ a]**l-4fe *}<£•& TiOCl2 ^ ^ 1 -
Fig. 3-2-20^1^1 1-4- TiOCl2s| ^r-8-o.S. ^ l ^ s ] f e TiO2
^§} | 17 ~ 230°CV}
XRD1-
- 51 -
-f- XRD ^^^ij-S-^-El K. -N. P. Kumars ^[23]-§- <>l-g-3H
- Fig. 3-2-23i 4 4 ^ 5 3 4 . <^7l6|M 65°C <>]§r3 2 : £ ^ H X*
o]-s}2)- 155°C
^ 5 ) 3 ! $14. ^iem, 70
~ 15(TC
TiO27l- ^
TiO27|- ^
,22], 70"C
E|| 7V °a^4fe^] o] ^AJ-O. a i . ^ ^ E S - A^^O] sj^i £>^4. Fig. 3-2-24
^xflc] 37I ^^ -# a.<^^^ SEM 4^1 °14.
45]- 4 ^ - ^ : ^ ^ 3717>
120-S- ^
:71- 4^-*lT£
40^- #•%••£ ^m-i- ^S-fife 4 65
lfecfl ^ 71 ofl ^7>^ l- ll ^3X)^# 30 %Fig. 3-2-25^1 XRD ^ » 1 H il?l 53^5j 100 %
Hl ^ 4 bar ^£^1 ^ ^ ^ ^ - i : 7}^& 7}<&*\-^ *]&$ ^7}o\) 4^^i^-l-0
fe TiO2 ^
70°C «>l ofl>H ^ ° 1 ^ f e TiO2
- 52 -
, Fig. 3-2-23^ a.1?! 3*13 , 65°C
TiO27> * g ^ ^ n J
- € 65°C
! ^fe-tj-. H. Zhangsf J.F. Banfield2]
-^ *$ 14 nm ol-S-^-
:, XRD # ^ ^ 4 ^ # ^ 0 1 ^ ^ ^ j ^ a j - ^ ^ S <££ ^
*1-^(primary particle)5] 3.7]fe 3 ~ 10 nm
EL7]7\ f-^-S-fil ^ - f^ -4 as.S.[21,22] n l - ^ 741 -
tb^, N. M. Hwang ^[25-28]^ CVD ^ ^ ^ o]-g-?t 4
charged cluster^ ^Tflofl ^*!: capillary °d"^^ « 1 - ^
)-. n f ^ CVD ^-^ °11 carbon sourceS^-E-] graphite ^ 4 ^ ^ 1
diamond W ° l ^?fl ^^£]fe ^ ^ 7l^Hl^i ^ ^ ^ nlAfl^ charged cluster
diamond ^^-sl <§>$•§• -^-£«]-o|7] nfl^-ojefjl
M. Multani af-[29-31]^r PbTiOs, BaTiOs, CeO2, CuO,AI2O3 ^ 3 f 7 ^ ^ . ^ - ^ ^
fe c/a = HIH a 4 cfe 4 4 x f 4 z #°1H
. Fig. 3-2-26-S: 50°Ci^ «^s ] ^^Uo v^^-S ^ #
# TiO2 °JA1-(~ 1 ^m)5f a f 3 7 l £ l ^ ^ X - 0.3
ig. 3-2-26A) , ^^ ^(Fig. 3-2-26B)# a-^lt ^ Si4. ^ ^ i , TiOCk
^j^i^ D1^S_> cluster^ -g-
- 53 -
TiCfcfe o } ^ ^ TiO2iL4fe- ^f-'Stf TiO2^ ^ ^ ^ ^ 7 ] - c-j tfl
] TiOCk ]
cluster ,
^ ^ s ] ^ ] ^c | a f£ . cluster Sfe
(negative pressure) °1 H ^ ^ - S .
X82:€ TiOCk ^°Aa] 0.67 M Ti4+
17 ~ 230°Ci^ # ^ § ^ - # ^^§]-7m- xKff-Tfl
40 - 400 nms] 1 #3.711- £±= %^->$ TiO2
o] ^ ^ a > ^ - ^ TiOCk ^r-S-0-^0! pH
^«B ^- ^^4-, 65°C <>l«1-fe- 1- 1 ^
fe S^^-S. ^ ^ ^ $ife 155°C o
£ ^ ^ € 4 V TiO2* ^ ^ T1 ^ ^ ^ -
^ fe ^-f° l l fe 70 °C ^ H ^ B ] 4 4 ^ ^ ! ^ TiO27l- ^^S]7 l A l ^ f o l 95 °C
°fl^ ^ ^ ? b ol-M-B^ltf TiO2l "SSial, 1-S] ^ l - # ^ H ^ l ^-foD^-7] ^fl^l #3£ .3 . ^ ^ i ^ ^ ^ * > 4 ^ 1 ^ o l ^Eflsi ^ ^ A I - T i 0 2
cluster i£fe
^ ^ ^ ^ - S . TiOCk T-§-^°il^ ^ ^ TiO2
S. J. Kim ^ TiCl4S^-Ei ^ 1 ^ € TiOCk ^-g-^-l- ^ ^ « 1 70°C
°-S-*] 150 m2/g ° 1 ^ ^ y l a ^ ^ - | : £ fe f - 1 ^ TiO2
- 54 -
TiO2 -g-lH « TEM^l SADS} XRD amS-g-
\n slfe- TiO(OH)2s]- ^-^rnfl^-o] ^ ^ ^ ^ # 5 ) 8 4 . ^ 1 ^ ^ 1OOTC
T. Sugimoto
fe M. Gopal
6 ^ > § } f e t l l o)
61 PI i l j l ^ ^ ^ r S ' a ^ ^ ^ - i - 61-g-SH 4.7 M Ti4+^1 %•£§ 5>fe TiOCk
FTIRS. ^ : # ^ H 3- i « ! s s j l - Fig. 3-3-27°fl ^-Ef^^cf. 2461 E)JL 72 A]^o]]^ ^##<»1 ^-^-51 7>Bfe^o|- ^ t g ^
^ 3 % HC1 ^r-
, TiOCk ^-g-°J| MHH ^3^^ - i - ^°fl 61 P] ^ ^ #
-^-El ^ ^ ^ f e TiOCk
Fig. 3-2-28^ ^ e l 7 H Ti4+ ^£7]- S ^ ^ l TiOCk
12 A1^> ^ o > ? 1 2 : ^ TiO2 -
T i 0 2 ^^(Aldrich Co.)^l cfl^ a|-nj.
, TiOCk ^ - § - ^ ^ 1 ^ Tii4+
sjo] E l g(R)3| . A
241 c r r f ^Hs l ^ ^ r phonon scattering^ £\?tt 5JAS. TiO27 i ^ °>^^: Ti
- 55 -
°§<%°1 400 ~
TiO2 £iMr I ^ e ] ^ , ^ i iLal€ XRD
f ^ ^ S <2£ Fig. 3-2-
TiO2 ^ - I H T T 444*11^, ti]3^#S] TiO2 Sfe Ti
£, Fig. 3-2-30^ TiCU €°J|, 5 M4 0.5 M Ti4+ # ^ fe TiOCk ^r-8-^i
EBj-g. a.o] ^o ]4 . olBflt Jf^i A^O] a. TiOCh ^r-S-^ofl^ Ti4+
TiCUi #•§• 37HK$.£.«| S^^l-^o.^ ^ ^ ^ giass bottle^
^1S3*>^4. TiCU ^^°11 #°1 ^7>^<^ 4 ^ ^. ^-^°] T iCM
0.5 M Ti4+# ^fe TiOCh ^r-8-^ s£° iH fe sR> a]E.2joiiA^
-i- a o l ^ ^ ^ 1-4 # ^ ^-^1?>^- il<»lJL 514. 5 i 4 , 0.5 M
fe TiOCk ^r-g-^-i- 50°C^A-1 4 A)^> f o } 7}<g^ ^
-2-30(B)oll^ AfterS.
^S. TiO2 ^ ^ ^ 7 ] - ^
. ° H , reference i ^ M & j ^ tf] glass bottled] tfltb 3M4 . W-^^I, TiOCl2
lfe ^14 V TiO2 £D]f^)fe 15013 S
-o] T i0Cl2 ^-g-^AS^E-i w>s. TiO2 ^
^ 7ev r ^^o1"0! TiO(NO3)24 TiOSO4 ^r-g-oJ!i^£ Ti4+ <>}
S ^ § > ^ qx\ <a<H4fe ^°1 ^§s)Si4[45,46]. ^ 7 H ) A ^ TiOCl2ujo] .^^ ^-^*1 ^7>*>^ Ti ^ ^ t t dx ^ ^ A ] ^ 1 4-g-, 4
Cf o]^ol .^§] 1 7 ^ Ti ^- tb^- l - i : 61 % HNO3 -§- <Hl ^r
•i- 3 ^ * 1 ^7>t|-^ 0.67 M Ti4+ ^ £ 1 - ^fe- TiO(NO3)2 ^r-§-°J|# ^12*1-^ 4
-g- ^ 4 ^ € 4 ^ TiO2 4.^^)7} •%<%$& TiOCl2^ TiO(NO3)2
TiOSO4 ^-§-o^-5.S^B^ <*°]x}±r ^#*H TiO2s] 1 ^ 4 V ^ 4
o]nfl^ o|x}<yx} a«a:^.> Fig_ 3-2-3H j£<y 5 j ^ 5 j ) 0 9 -.
5.5 m ^^ °d^-i" ^ ^ ^ ^ ^ - ^ £ # £ 4 . °liH$ •a l-1- ° 1 ^ ^ o^^}od4SEM 3-S! 4(Fig. 3-2-32) 20 ~ 30
TiOSO4 ^r
- 56 -
TiO(NO3)2 ^-g-oJjAS^-Ei <g£ o i * } c y ^ T i O c i 2
, TiOCb, TiO(NO3)2) TiOSO4
-§r 3-f, Ti W i - I - ^ * H r ^-o]^o] C l~4 NO3"
TiO27> ^ ^ S ) J 1 , SO/" ^ ^ r ^ *fl of4E|-^^- TiO27l- ^ ^ ^ !
-°1 ^ ^ £ 1 ^ TiOSO4
TiOChS. ^ € ^ 1 ^ # - 8 - 4 -H-H«1-sa4. TiOSO4 ^-§-^ofl ^ a q o
Ti ^ ^ ^ - l - € - ^ ^ ^^^1?1 4^8-, 4 ^ 4 ^ ^ - ^«S SO42"
35% HC1
o.67 M Ti4+ ^ £ 1 - ^"fe TiOCk
70°C °l«HMfe ^"^-^ T iO^ 3 3 3 f e
TiOSO4# °l-§-«M ^)^& TiOCl24 -^efl^ TiOSO4
K #, Ti Sj-tNi- l # # # ^ ° 1 -T-^°]€-^1 ^°i] SO42" °l^r-t
i, Cl'-i- 5svfe Ti
4 . °)i:ifl, ° 1 3 ^ TiO2 3#*ll
&*= O-Ti-0 ^ t ^2 :7 l - Ti
l>7l ^«fl ^^] 7 H Ti
cfl > ^ ^ A J ^ ^ - ^ ^ ^ Table 3-2-1 i i L $ 4 .
Table 3 - 2 - 1 ^ TiCl4S.^-Bi ^ ^ TiOCl24 TiO(NO3)2, ^ie)ji TiOSO4
0.03 ~ 0.08 M^l ^-ol^.(cf, NO3", SO42")
XRD4 TEM £ ^
. TiOCk ^-§-°-H ^7>^li- \#x] ^Ti^- Cl"4 NO3" «>]£•§.
Ife ?!
, TiOCb ^r-g-0^0!] SO42"
- 57 -
Table 3-2-1. Effects of Various Additives on the Crystallinities of TiO2 Powders
from Ti Aqueous Solutions by the Homogeneous Precipitation Process at Low
Temperature.
Solutions Additives Crystallinity Shapes
TiOCI2TiOCl2TiOCI2TiOCI2TiOCI2
TiOCI2TiOCI2TiOCI2TiOSO4
TiO(NO3)2
TiO(NO3)2
TiO(NO3)2
Not addedHC!
H2SO4
HNO3
TiOSO4
TiO(NO3)2
FeSO4
CuSO4
Not addedNot added
HCITiOSO,
RutileRutile
AnataseRutile
AnataseRutile
AnataseAnataseAnatase
RutileRutile
Anatase
AcicularAcicular
SphericalAcicular
SphericalAcicular
SphericalSphericalSphericalAcicuiarAcicular
Spherical
TiOSO4
3-2-334 3-2-34).
TiO(NO3)2
Ti
TiO2
Table 3 - 2 - 1 ^
SO42"
TEM4
E1, Cl"
TiOCl2 H2SO4) FeSO4> CuSO4
°flfe S04
2-
- 58 -
TiOCk ^ -g -^ i SO42" °l£s] ^7Hr ^ 1 ^ T i 0 2 l .
fe TiO2
TiO2 ^
^ S TiOCl2°11 f ' ^ - ^ r l - 371-3H ^ ^ ^ : ^ ^ ^ ^^^1?1 4 ^ - 50
TiO2 2^1 M l - ^ | S « > J 1 , ^ € ^ 4 4 =L l ^ j ^ t TiO(NO3)24 TiOSO4
K TiOClz n -i
^Aov TiO2
TiO2 3 ;
TiO(NO3)2 ^-§-^°fl^fe f - l t f TiO27f ^3^is]^JL, TiOSOt ^§|) SO4TiO27l- ^ ^ S ] ^ 4 . H, TiOCk ^r-g-^^x-l ^^aV-g-t- ^§|) SO4
2"
SO42" °]^°] $ « ^ TiO22l n]/-11^ oj^7]. AjV*V trfl
T i 0 2
- 59 -
4.
TiOCb
^S.fe homogeneous
precipitation process at ambient or low temperatures, HPPLT) °] 5} J ! ^ ^ €r]-
7}.TiOCl2 ^-g-^-0-3.^-3 TiO27} ^ ^ A]2:S\rr ^^& ^£.^t] A}^^^ OK?}
TiOCkl-
^ s ] ^ TiO2 ^ ^ ^ 2 : 7 > nH«HA1 65°C
TiO2
TiO2
TiO2
X]2:^ TiOCb ^r-§-^°l 0.67 M Ti4+
17 ~ 230°C^Ai # 3 ^ ^ # ^^1*1-711+ xf-n-f-^1
A ! ^ 40 ~ 400-nmfii ^lf-3.7]!- ^fe ^ ^ ^ TiO2
^ ^ i ^ - g - ^ TiOCk ^-g-OJlo] pH
^sfl ^ 1 4 , 65°C 6l«>fe #£] ^
«>fe S ^ A ^ ^ ^ ^ Si^r 155°C
^ ^ * > ^ ^ ^ TiO2l- <*
^1*H ^fe Tj^-ife 70
95°C ^1^H14 ^^ *>
1 ifls} °d-^AS ^xi t § ^ ^ 444^1^-°1 &n$. ^H^ TiO2
4 4 4 , ^- ^ ^ ^ l ^ s i ^ ^ ^ A O V ^ ^ ^ ^ - 4 ^ ^-i-o]] ^ ^ .
TiOCl2a) 7^^;«114 t N < a ° i 4 ^ , ^=8"* «H-S1 2-^?l u ] ^ t> cluster SE.
- 60 -
TiO(NO3)2
TiO27l-
SO42"
T i SO42"
50°C °}*}2)
1^*11 TiO2
TiOSO4 *
Tioci2
fe TiO2
TiO2
TiO27>
, TiOCk
L, TiOSO4
TiO2
- 61 -
Making TiOCI2 SolutionSufficient H2O
hydrolysis
* * Deficient H2O (our process
hydrolysis hydrolysis
Fig.3-2-1. Schematic diagram for making aqueous TiOCb solution.
- 62 -
TiCI4 + 4NHA0H = Ti(OH)4 + 4NH4CI
R
1000°C
CD4 »
650°C
^ ^ ^ W J ^ W W U ^ A A - A
400°C
as-precipitated and driedat50°Cfor12h
i<flfMJt^1^^
_i . I , i_
20 30 40 50 60 70 80
2*theta (degree)
Fig.3-2-2. XRD patterns of titanium hydroxide (Ti0(0H)2) calcined at varioustemperatures for lhr in air. (A: anatase phase and R: rutile phase)
- 63 -
Heat-treatment for anatase phase TiO2 obtained
by heating and stirring at 100°C for 6hr
calcined at 400°C for 1hr
20 30 40 50 60 70
2*theta (degree)
80
Fig.3-2-3. XRD patterns of TiO2 anatase particles prepared from aqueousTiOCh solution heated at 100 °C for 6hr under 1 atmosphere.
- 64 -
c
20 25 30 35 40 45 50
2*theta (degree)
Fig.3-2-4. Effect of heating rates on crystalline TiO2 phase during theprecipitation from room temperature to 100 °C under 1 atmosphere.
- 65 -
650°C-1h calcined
20 30 40 50 60
2*theta (degree)
70 80
Fig.3-2-5. XRD pattern of TiO2 rutile particles prepared from aqueous TiOCksolution heated at 50 °C for 6hr under 1 atmosphere and thencalcined for lhr at various temperatures in air.
- 66 -
100 -
CDCOcc
_cQ.CD
01
co
LL.
CD
_ 3
O
40 -
20 -
0 -
0 20 40 60 80 100
Reaction Temperature (°C)
Fig.3-2-6. X-ray intensity ratios of the (110) reflection of the rutile phase tothe (101) reflection of the anatase phase for titania prepared fromaqueous solutions with the reaction temperature.
- 67 -
XE5414 MM Ski
Fig.3-2-7. TEM SAD (Selected Area Diffraction) pattern for as-precipitatedT1O2 rutile powders prepared at room temperature for 7 days under1 atmosphere.
- 68 -
/alu
e
Q .
0.00
-0.30
-0.60
-0.90
-1.20
-1 50
(A)
•
Addition of H 0
•/J
L rv .
-
Reaction Time (min.)
XQ.
0.15
0.10 -
0.05 -
0.00 -
-0.05 -
-0.10 -
-0.15 -
-0.201.0x10; 5.0x103 9.0x103 1.3x10*
Reaction Time (min.)
Fig.3-2-8. pH change of aqueous TiOCb solution at room temperature withthe reaction time under 1 atmosphere.
- 69 -
20 60 80 100
Reaction Temperature (°C)
Fig.3-2-9. Effect of the reaction temperatures on the crystallite size forultrafine TiO2 powders prepared from aqueous 0.5 M TiOCbsolution.
- 70 -
(A)
Fig.3-2-10. SEM photographs for the crystalline TiO2 powders preparedsimply by heating aqueous TiOCk solutions at (a) 50°C and (b)100 °C for 6 hr, respectively, under 1 atmosphere.
- 71 -
QL
Dilution Rate to TiOCI2 Stock Sol'n
Dilution rate= (Vol. of total sol'n) / (Vol. of TiOCI stock sol'n)
Fig.3-2-11. The productive efficiency of TiCte powders with the increase inthe amount of added H2O at 50 °C, where 4.7M TiOCb stocksolution was diluted using H2O.
- 72 -
0.6
0.3
0.2
O 300ml H2O
D 200ml H2O+100ml Ethanol
A 100ml H O+200ml Ethanol
50°C
1 , I i I . I
0 100 200 300 400 500 600
Reaction Time (min.)
Fig.3-2-12. Effect of added H2O amounts on the pH change of aqueousTiOCk solution heated at 50 °C with the reaction time under 1atmosphere.
- 73 -
100
0.67M TiOCL at 50 C for 4hrs
D_
20 40 60 80
Vol. % of Ethanol100
Fig.3-2-13. The productive efficiency for TiO2 powders with the increasing inthe amount of ethanol.
- 74 -
Fig. 3-2-14 SEM photographs of precipitated TiO2 from aqueous TiOCk with
various pH values; (a) 0.49, (b) 0.62, (c) 0.91, and (d) 4.11
- 75 -
400
Temperature (°C)
600
Fig. 3-2-15 TG/DTA curves for TiO2 powders after the filtration.
- 76 -
5x104
4x104
1x104
-HPPLTedTiO.• P-25-MT-500B
458.9(Ti4* 2p3/2)
465 460 455
Binding Energy (eV)
Fig.3-2-16. XPS spectra comparison of HPPLTed TiO2 and commercial
powders
- 77 -
0.8100 200 300 400
Reaction Time (min.)
500
Fig.3-2-17. The pH value changes of aqueous Ti-nitrate solution with the
reaction time at 50 °C and 80 °C.
- 78 -
Iqo
iCD
I2a.
100
90
80
70
60
50
40
30
20
10
0
0.31M TiO(NO3)2xH2O at 80°C for 5hrs
0.1 1 10
Mol % of Oxalic Acid to H2O
100
Fig.3-2-18. The productive efficiency of titania from Ti-nitrate with theaddition of oxalic acid at 80 °C
- 79 -
(A)
(B)
Fig.3-2-19. SEM photographs for the crystalline TiO2 powders prepared from,•4+
(A)4.7M and (B)0.67M Ti aqueous solutions at 140°C for 60 min.
- 80 -
(A) (B)
(C) (D)
Fig.3-2-20. SEM photographs for the crystalline TiO2 powders prepared from0.67M Ti4+ aqueous solution under the reaction conditions of(A)17°C for 7 days, (B)60°C for 4 hr, (C)100°C for 2 hr and(D)150°C for 1 hr.
- 81 -
20 30 40 50 60 70 80
2 * theta (degree)
Fig.3-2-21. XRD patterns for the TiO2 powders shown in Fig.3-2-20.(R:rutile, A: anatase)
- 82 -
-0.510'' 10" 10' 10' 10J 104
Reaction Time (min.)
0.75
CD
i i °-50>CL
0.25
•
\A V 6 0 ° C
80°C
(B)
34°C
-
10 10
Reaction Time (min.)
Fig.3-2-22. The pH value changes of 0.67M Ti + aqueous solution with thereaction time at various temperatures, where Fig.3-2-22(B) is anenlarged part of Fig.3-2-22(A).
- 83 -
0
has
Q.CM
oH
Rut
il
oc_o"o
"o
100
80
60
40
20
0
I
-
t . r
f¥ •J// / ;
Uncovered for 300minCovered for — A — 20min
30min\ 40minV 60minT —o—120min
LI . I . I .
40 80 120 160 200
Reaction Temperature (°C)
240
Fig.3-2-23. The volume fraction of rutile TiO2 phase formed with the variousconditions.
- 84 -
(A) (B)
(C) (D)
Fig.3-2-24. SEM photographs for the crystalline TiO2 powders prepared from0.67M Ti4+ aqueous solution under the reaction conditions of(A)85°C for 120 min, (B)115°C for 20 min, (C)115°C for 60 minand (D)115°C for 180 min.
- 85 -
-51
c
20 30 40 50
2 * theta (degree)
60
Fig.3-2-25. XRD patterns for the crystalline TiO2 powders prepared for 0.67MTi4+ aqueous solution with and without the addition of ethanolunder the reaction conditions of 115°C for 40 min.
- 86 -
(A)
(B)
(M2M2H.IN «•» 58m
Fig.3-2-26. SEM and TEM photographs for the representative rutile TiO2
powders from 0.67M Ti4+ aqueous solution; (A) by ultrasonicallystirring at 50 °C and (B) by normally stirring at 50 °C.
- 87 -
100
CDo
B"I03CCO
I •——1 ' 1 r 1 1 1 ' 1
3500 3000 2500 2000 1500 1000 500
Wavenumber (cm"1)
Fig. 3-2-27 FTIR spectra for aqueous TiOCk solutions.
- 88 -
c
E,9(R)
standard powder
241
A'(A)
0.47M
0.31 M
0.16M
200 400 600
Wavenumber (cm"1)800
Fig.3-2-28. Raman spectra for the crystalline TiO2 powders with the contentsof Ti4+ measured at room temperature after the homogeneousprecipitation at 50 °C for 4h in 1 atm.
- 89 -
(A)
(B)
Fig.3-2-29. SEM (A) and TEM (B) photographs for the TiO2 powderobtained by homogeneous precipitation process at 60 °C for 4h in1 atm.
- 90 -
1.5x105
CO
0.00 200 400 600 800 1000
Ranman Shift (cm'1)
cCD
2.0x103
1.5x103 -
1.0x103 -
5.0x102
0.0
Befor
\
. After
\
Ref.
5M TiOCI2
1\A\ ;
393
AnVim
437
0.5MTI4*
(B).
-
aqueous solution
/l 907
0 200 400 600 800 1000
Ranman Shift (cm")
Fig.3-2-30. Raman spectra for (A) TiCU and (B) aqueous TiOCb solutionwith 0.5M Ti4+ measured at room temperature before and afterthe homogeneous precipitation at 50 °C for 4h in 1 atm.
- 91 -
Fig.3-2-31. SEM photograph for the TiO2 precipitate with pure anatase phasehomogeneously obtained from aqueous TiOSO4 solution just byheating at 50 °C for 24h in 1 atm.
- 92 -
Fig.3-2-32. SEM photograph for the TiC>2 precipitate with pure anatase phaseprepared using the homogeneous precipitation process by addingcrv2~ ions to the aqueous TiOCb solution.SO4
- 93 -
(a) (b)
(c)
Fig.3-2-33. TEM photographs for the TiO2 precipitates with various amountsof SO4
2" as a seed additive; (a) 0 M, (b) 0.03 M, and (c) 0.08 M.All the precipitates were homogeneously obtained at 50 °C with (a)pure rutile phase, (b) (a large amount of rutile + a small amountof anatase) mixed phases, and (c) pure anatase phase.
- 94 -
c
c
20 25 30 35 40 45 502 * thera (degree)
Fig.3-2-34. XRD patterns for the HO2 powders in Fig.3-2-33.
- 95 -
3-3 € T i - ^ ^ ^ 1 ^ TiO2
<=fl ferroelectric
acoustic-optic devices, 7 r
S: CVD, sputtering, laser ablation, evaporation
oi7i
epitaxial growth
^ r ^ , TiO2
300 nm ^ « ] - ^ 7 . } ^ ^ ^ 7] 5} 4
. SE, TiO2fe 550 nm
fe- 2.57,
[00114 3g«8$ a o v ^ S 170o] JL [100]4
l BV nfl-f 3 4 . a t t , °1 ^ 1 : ^ 7]7}-
- 96 -
, TiO2
TiO2
electrochromic
T1O2
. 3E., TiO2fe ^-& permeativity
TiO2
, packaging
-, n-type
E), nanofiltration^:
NO2
oj)
iO2fe Si CVD, MOCVD, sol-gel^ f ^
fe 300°C 350 ~
, 600°C
51
^ 44
fe charge
f. 12^4,
l-ol 11-2. 4. a^: 71
ZL
400°C
- 97 -
£.4 ^^r ££<>IH3 ^ 1*13
° l ^ l r ^ r millimeter £ ^ centimeter
L oxyhydroxide
^ - S . ^ SAM(self-assembled monolayer)s}
biomimetic synthesis 7}^°} Slty.
SAM ^ofl ^-g-^AS^-Ei ^Vsl-l-S}-^-^ ^.o]^ ^o]tj.. o
^.S.7]- ^ ^ Fe, Ti, Sn, Zn, Zr S^r 4 € ^ ^ - i - 5 f " «
OH, -COOH, -SOsH %s) ^ ^ 7 ] # 5Hr SAM
r Si 13:^^ 71^-, glass, solid particle ^ f e
, TiO2
SAM £ f e dipping Ho
v^^-S 5 nm
nm <>1«})1- S^- TiO2/polymer/7l&
- 98 -
2.
7K SAM< 1 ^ t t TiO2
Ti
TiO2 W 3 ^ S # A]HI- 3*i|| biomemetic process^]
(negative charge)* 7}Z\B.£. 7 l t M t o l ^i«}(positive charge)TiO2
, ^ ^ ^ Sti^ 100°CoflH] S ^ ^ ^ ^ r ^^1*1-^ 3.^°\) ^ ^ ^ r S^-g- ^ « R r sol^:
^ TiO2 ^ ^ # ^la^a *r SI Til^r Fig. 3-3-loflAi
4 30 § ^ ^-g-4^^ €^1)2. -fr3}7]#-a: 80°C^ Piranha -g-^^^i 1
tb^-- n ^ ^ ^ - ^ ^ ^l^ttcf. [H2SO4 : H2O2 = 7 : 3 ]
3. Pim^oll 2 ^ , Dfl^-t-Z^f-^Kl:!)^ 2^-, #^<>H 2^-?> ^ ? ^ «fS 5
vol.% APS# %7}ffrq ^ § 1- 911 ^-^( l - f - ' a 50 cc^l 2.58 cc 98 % APSt-
^7»o)l 15 A]^> rf-nfe ^ ^ ^ - ^i^-^7lol]A^ ^1«| §|-^ negatively charged
surface!- ^ W .
4. n ^ 7]#-§-
fl 4 ^ 5 »i
5. 5 mg PSS +10 mL H2O (pH = 4) -§-°J|i #5-x}.
6. # S . ^ ^ t t ^ H>S. TiOCk ^r-g-^i ^ S 50 ~ 80°C^ S ^ ^ A - ] 2 ~ 4
?]: ^ - e 4 . ^ l ^ , 0.67 M TiOCk ^-g-^^r 15 mL TiOCk -g-°J| +90 mL H2O
75 mL HClSr 1 S r 2 M^l NaCl^r
- 99 -
7. 7}&&
8.
^ H < ^ ^ Fig. 3-3-24 £*1
negatively charge* £fe TiO2
. TiO2
TiCLi (3N, Aldrich
Co.)-§- ^f-S-^r^^. ^ ^ i , stock solution^-S. *}•%•*}?} $\& TiCU ^ - § - 0 ^ ^ : *Ha
j-71 ^«fl^ o°C <>1«1-S. 3^-trl ^ z ] - ^ TiCU*
j l ^ £ ^ t ^ TiOCh ^-8-^-i- X|2:*>SSltf. ol'fl, TiOCl4 stock solution^
^ £ f e <£& S ^ S ] <$£ a ^ * H 5.0 M ^ £ 7 f E]£^- -&}-^4. ° 1 ^ ^ ^
TiOCk stock solution-i: °}^}<^ ^Xl TiO2 ^ A J # ^ r ^7] ^«fl^fe- o] s t o c k
solution^ Ti4+ <^l^Sl ^ £ 7 > 0.67 Mo] E]£^- ^ ^ - ^ 2 ] ^ ^ - ^ # ^7}^}JL 30
^ o l ^ ^^:*1 H « V « H ^^?>-§-^ 2 : 7 ] l - ^ s 4-8-*>5a4. ^ ^ i ^ - S - ^ 50°C
Slfe- Cl" ol^r-i- ^^1*1 Xl7]t|-7] ^«B ^ ^ # S ] n]/-fl ^JEofl tcj-ej- 0.2 jifln
7]^-£ l - 5>fe PTFE ^ ^ e | o ] ^E^(Micro Filtration Systems)^ ^ ^ t -
-g-^H ^ ^ i # # 7^^7-14 5000 l ^
^ ^ > « ^ l r ^ 5O1C«H| 12 *
o]£ K-^ s -a -41- °l-8-«}^ TiO2
.7]-: laser particle size analyzer(Brook Heaven 900 plus)5. ^r
30 ^ - ^ 21-
#(SiO2 #3= 3.0
- 100 ~
& £ TiO2 £dip 3.^4: ^ A ] ^ ^ 4 . S^A] o]Aj-^£fe 5 c m / m i n o.
SEMCJEOL JEM6430F,
3.
7\. SAM ll ^ * t TiO2
^ TiO2
TiOCl2sf #3)-^ ^-S-°ll ^*llA-i ^^i*-S-ol ^ ^ ^ o. ^ 4 HC1
S-S. HCl-i- TiOCl2 ^ - § - ^ i ^-g- < 1 ^7}S}^ ^ ^ a j
^ao^°ii^ ' i ^ ^ : tfls. 5-°^#-i- ^ 1*1-7] ^n HCI7} <£•§- S ^ * M 0.67 M^ Ti4+ ^ i # ^fe- TiOCk
°JjA^ ^d^«1-^4. HC1°] ^7}s\o\ TiO2 ° d ^ ^ ^
°) positively chargel- o |£^- l - ^ ^ # S^?V 7 ] ^ - ^ ^ ^ < ^ ^ ^ > ^ o.s.
negatively chargel- ^ TiO2
TiOCb
7}t}7) *i°\}~ 3.
*& NaCl^r ^7}t
O. 1 1\/T o ] A>ol *
&., TiOCl2 ^r-8-^y\ 7] 6\ x] ig A-
°] *i pH S^l°l
. ^ € ^r-s- -r-8-
^ l ^ i TiO2 ^ ^
peeling ^4Vol ^°1
^ ° i 1 MS] NaCl °j
M- < JL 4 S . 71
^• i : pHl- ^ ° ] ^ ^
S- peeling
4 4 ^S*; ^ %7}t]
34it4.^^44
- 101 -
Fig. 3-3-3^:
. -fi-2171^-^ negative charge* ^>H H}7} fl*f| APS -g-«W 17 A1# , PEI -g-
24 *1?> ^ - e * PSS -g-«H 3 0 £ # ^ - e 4 ^ - TiOCk
1 !> APSlr
Fig. 3-3-4^ 50°C 1 -1 4 Al > -^o> s ^ € ^^°1] tfl^ XPS i
-a^- Ti ^ n ^ o ] 458.6 eV (2p3/2)°l]Ai M S I J L ^ t f l a jo .1 4 ^ peak<»] 464.5
eV (2pi/2)°n ^^ t t^ f . °1 ^ 1 - ^ Q3. TiO2°ll tfl^ reference
o] ^oflx-]^ 7l^«> cfls SAM yo
v ^ i : «>l-§-«H TiO2
TiO2 ^ - ^ ^ ^ 7 > 7] 21 10 nm <»]^
^l^: ^f-2f ^ - ^ 4 XPS
TiO2
TiO2
4 . TiO2 ^ ^
(1) MT- -g- o>^tb SOl
0.2 ~ 0.4
S ^ 4 1 : °]-§-«H TiO2 2:^1
3.7] 1- laser particle size analyzer^ ^r^
Fig. 3-3-5fe ^ ^ 5 - ^ ^ ^ ^ ^ - S ^12:^ 2.v]&n] TiO2
^r^>°] 3*1 &ji S1AM- n-butyl alcohol -g-oJ]-i: 4-§-«f^ 5 ^ ^<>l]fe 50
60 nm^l 3.7]3, ^°] 3 ^ 10 & ^^Ife °-} 25 nm^l 3.71s
- 102 -
. Fig. 3-3-6(a)^r 2 :^-^1-
^ 50 ~ 60 nrnSl W l ^ l ^ H sj-^§l
o.^ Fig. 3-3-6(b)fe 10 €• ^°1| 20 ~ 30
«-A>O.^ 20 ~ 30 nm
• •%-£ <&:
TiO2 SJ >7l- ^ - ^ ^ sols] <?1- S1- s . ^ ^ . ^ - o l ^ l $n Na2SO4^ NaPSS
^ ] : ^ TiO2 U ^ a ^ " ^ S ^ A | ^ electrostatic^ steric force
-§-<5flo] o>^s|-oi] tfl«fl <S^1- sfl 4 7>x] a ? l ^ ^ zeta potential^:
. Fig.3-3-7^ NaPSSl- ^7>^o)i n ^ zeta potential &-^r uj-BJ-ifi
NaPSSl- ^7 f^o i ^ ^ >§^-ife 3. <9=ol ^71-f-ofl tq-ef Zeta potential
sulfate o]^^r T1O2
7}7]
(2) TiO2
3.71 s. ^-^1-51^ Slfe- 2 ^#S1 #^- 7 ^ 1 1.5 wt.%
7}is}c*\ dip S^-l: ^^|*>^14. -f^l S.^-%- soH
7} $\n TiO2 f - ^ # 0.5, 1, 2, 3 wt.% ^ ^sj-A
^ ^ « | ^ S ^ ^Efll- SEMJ1S %9l# 1 ^ 1 - Fig
Fig. 3-3-8(a)fe 0.5 wt.% &t^r
sol *>*H*1 5<iol ^ : ^ * 1 - ^ ^ TiO2 ^
fe 3.0 wt.%
fe 2.0 wt.% £ l M :
- ^ # ^ si Si 4 . 44^1 , €-Dav 2.0 wt.%s.
- 103 -
Fig. 3-3-9TT «1-SI3 S] %7}%-& ^ ^ M ^sfl 2.0 wt.% TiO2°ll
0.5, 1.0, 2.0 wt.%*l € 3 W 3 S^tl : ££•§• & # $ 4*1 °14. Fig.U><?1^1- 0.5 wt.% $7Ht 1 4 3 . «Klc] ^7]-^^: ui^-
^S^S ^ ^ H H ^ c ^ ^§l-fe t q - ^ ^ ^ & $ 4 . Fig.3-3-9(c)^ 2.0Wt.% aKlc-1 ^7> ^
^ l - 1.0 wt.% ^7f«> 5 ! ^ SEM4- 4
-§-*}• nfl yfolx^ir ^ i^ ^-Sls)^ ^A^^-i i3-^*>ji ^ 1 ^ ^ - ^ s ^1.0 wt.%S. «Hr 5J 1 ^ ^ ^ f
^ 2.0 wt.%sl ^ t ^ 7 } ^ ^ 1.0 wt.%^ ^ - i - jlwM SEM^-
Fig. 3-3-10°lH M-H}^$i4. Fig. 3-3-lOi^i ilfe- H>^- ©lo ^ ^ ^ ^ ^ ^ ^ §.*« l ~ 2
Fig. 3-3-ll^r 4 ^°14. S^4^1° l l ^ ^-fe 7A^\^, nlA|)3-o|ol ^ ^ o
> j ^ ^ ^ f l ^ f-sfi of^ $^§1-3. xl^*V 30 ~ 40
4.
l- ol-§-^-<^ SAM(self-assembled monolayer) UO
VIM-^5. 10 nm
01 ^.^*> yl-nKg. ^lS§l-fe ^ ^ 4 42n 3715L ^-^Sl T i 0 2 a ^ ^ - ^ l l - ^
^ 20 ~ 30 nmS] ^ ^ ?
- 104 -
7K
positively charge!- ^ ^ APS -g-^H 17 *1#, PEI -g-^H 24 ^RV %\
PSS -8-^cfl 30 4
negatively charge*- ^ fe TiO2
. ^ f - 3 f £ # ^ ^ XPS ^a]EBj o . S 1 0 n m o]t}2) HV
^ S A M y
o
TiO2 °d^ l - a ^ - 4 « °l-8-«H 10^- ^-<LV«>^ ^ 25
^ 7A^ ^ -^ i s f^A^ ^-^>^ T1O2 M-^ sol# o]-8-
, TiO2 2wt% ^7>S]-^ S ^ ^ - sol# *)12:3M 30-40
100°C
- 105 -
Piranha &n Mm § S
Positively charged surface § S
Negatively charged surface i r S
3 ^ 1 Sol * l |s
Fig.3-3-1. Experimental procedure for TiCfe thin film.
- 106 -
[A]
Fig.3-3-2. schematic diagram for the surface treatment of substrate.
(A) process : coating process in aqueous APS or PEI solution,
(B) process : coating process in aqueous PSS solution.
- 107 -
100
CDOcm
Een
aCO
4 -
0 -
-
-
-
-__ J
r'
i
. • . . - - • - • • • - • - . - - . . . - . . . . . . .
17h APS
24h PEI
BSG-substrate
. .„>- ' • • '
200 400 600
A(nm)
800 1000 1200
Fig.3-3-3. Optical transmittance of coated T1O2 thin films using SAM method.
- 108 -
1400 1200 1000 800 600 400 200 0
Binding Energy (eV)
Fig.3-3-4. XPS spectrum for the coated TiO2 thin film using SAM method.
- 109 -
250
200
E
E
bc5 100
50
\ethanol
butanol
5 10 15 20
Ultrasonication Time (min.)
Fig.3-3-5. Mean diameter of T1O2 particle with the sonification time.
- 110 -
(a) (b)
Fig.3-3-7. TEM photograph for TiO2 particles after the sonification in n-butly
alcohol for (a) 5 min and (b) 10 min.
- 111 -
500 1000 1500 2000 2500 3000
Amounts of NaPSS (mg/l)
Fig.3-3-8. Variation of zeta potential of aqueous TiO2 solution with additions
of NaPSS.
- 112 -
Fig.3-3-8. SEM photographs for the surface of thin films with the amount of
TiO2 powder; (a) 0.5wt.%, (b) lwt.%, (c) 2wt.%, and (d) 3wt.%.
- 113 -
Fig.3-3-9. SEM photographs for the surface of TiC>2 thin films with the
amount of silica sol as a binder; (a) 0.5wt.%, (b) lwt.% and (c)
2wt.%
- 114 -
(a)
(b)
Fig.3-3-10. High resolution SEM photographs for the surface (a) and
fractured section (b) of TiCte thin film using secondary particles
dispersed in silica solution after the synthesis by HPPLT.
- 115 -
(a)
(b)
Fig.3-3-11. High resolution SEM photographs for the surface (a) and
fractured section (b) of TiCb thin film using primary particle
dispersed in silica solution after the synthesis by HPPLT.
- 116 -
3-4 * i TiO2
1.
f ^ f l 3 ^ 0 ! =lul $1JL Z]-^S| 31
7]- nfl-f JL7}°]v\
. TiO2l- ^ - ^ - ^ S i £3L^- ^ -S I - ^H 1:^1917] ^§HAife TiO27>
. a, TiO2 s^l^-^]^
- 71-7^171- $X^r ^flS-S. ° ^ ^ ^ XItf.
TiO2
- 117 -
2.
Sife
S!lfe ^ 1 5 } ^ ^ $*> ! • • § •
o>
c]
.7}$]
- 118 -
, v3£ TiO2
*r 3 51 Ji7l^ 4^4
i, £ *HHfe ^51-^^ €soil TiO2
3. ^
Ti4+ ^ £ 7 > 0.4 ~ 0.7 #?1 TiOCk "r-S-^^- 50°C^l^ 4
3.7)7} 0.2 ~ 0.4 jcanS. ^ ^ ^ ] T i 0 2
ig. 3-4-1 ^-2) . #%& ^-^>#
^71 (ultrasonic homogenizer: 4 ; a ] ^ ^ 600 watt,
^ 20 kHz)4- o]-§-*]-&4. -8-nBSfe ^ ^
xi, ^-W-^ 500 mLSf 1 gs] TiO27>
71(0.1 gfi| polyethylene glycol, 15 mLS] CH3COOH, 15 mLS] (CHs^NH, 15
mL^] ethylene glycol, 15 mL-^ ethylene diamine) 2.^- ^-7] s^^ | ] ( l g£]
Na2SiO2, 1 g 3 NaA102)» 2]-^ #J1 20^-?> S«> ^ 4A1 a ^ - 4 homogenizer
3. 1, 3, 5, 1 0 ^ - ^ ^ a^-
TiO2
4.
4 . CR39*
OPC -fi-tb^A}!. He Li Ping
- 119 -
3L, f- «i^ Hf-^-S-fe- CR39
Bl 2 ~ 3 HS1 ^ £ t ^ ^ 5 4 f ^
CR39 W ^ ! 2 t ^^s>7li4 dipping^ ^ f t s ^ , zielji multicoating*]-fe
4 . ZL SloflS ^^.^-g- 71-1-1: $&, ^#«f3L $131, 7l Ef ^-^^^£-0,1 rfl *>
T iQ 2
14 TiO2 ^ - ^ ^ n-butylalcohol ^-& CH2CI2
CR391-
^ .^ , TiO2 anl^-^111- $7}^ #$}$= CR39 SL
2.6 wt.%)7> O]P] ^yf
CR39 31s t -
(1) CR39
- 40 °C
40 °C - 40 °C
40 °C - 50 °C
50 °C - 50 °C
- 120 -
50°C - 60°C
60 °C - 60 °C 2*1
60 °C - 70 °C
70 °C - 70 °C ]
70°C - 85°C 2*1 #
85°C - 85°C 2*}?}
2*}
CH2CI2 ^ ^
(2) ^ ^ - 3
^ e l - i ^ ^ l S ^g.<y CR39°1] £- 4^1^1Ai ^^^fll-^; ^ - ^ ^ TiO2
(3)
312. 1-H Af^^ a^-3-3-2<^
(4)
-g-^1- 1.4480(at 25*0,
TiO2 £ £ # 4-§-«>^4. ° H TiO2
-"11 : CH3(CH2)2CH2OH(n-butylalcohol): ^ £ > 99.0%, M ^ - 1.3970,
C H 2 C 1 2 ( ^ 1 1 ^ € S ^ O 1 H ) : ^ £ > 99.0%, - ^ # 1.4208,,
C3H6O: ^ £ > 99.5%, ^ ^ r 1.3588
- 121 -
3.
^^Q T i 0 2
TIO2/CR39
figt§ TiO2 i ^ ^ l r ^ S ^ ^ M ^fl^- 3.JL
EL7}7\ q 0.2 ~ 0.4 m^ T ^ ^ * ££• Bfl-f -r- rt!- ^-^01^1^:
'S-Efloiojo.as £3*115.?! CR39 qsiiq-
CR39 ^^]7> 48
scattering siteS ^|-g-*l-£.S. °1 ^ ^ " # *WS}7] ^«l]Ai^ ^^71- ^ 30 ~ 50
nmS ^^1«M1 ^ s j - H ^ M . rtr?)-*\, scattering JL^
0.1 nsi 4^1» °]-§-*H ^ 4 sfe ^ 4 ^ 1 ^ , 1 nD ^^r #^«fl ^ ^ 4 CR39 *Hlfe 1.4505 olSHfetfl a]
TiO27> ^r-a-^ # S ^ H f e 3. ^ 4 f e ^ # ^ ^ 1.4520
TiO2 a^l^-^ll- ^7}z}^ nD ^ ^
<$-£: 0.0005
2
OPC |
TiO2 S^^^l7> ^7>^ CR39
45 ~ 100°CSl
Ell- «M CR39/TiO2
^ ] l 4 f e 95 %
0.0005 %£ ^ - f i 93 % %S.*H*\ 0.001 %?! ^ -<^1 ^ 50
fe n D ?!:•§•
90%
- 122 -
TiOCl2 ^-g--5>MH TiO2
TiO2 ^ 1 2 : ^ - ^ ^ ^ ^ S ^ i ^ l t l ] a>§H CR39
CR39
1.7 ^1^-AS. ^ 4 ^ 4 ^ SL-ilt- ^1-^ 514. ««>
2, 3
^ l - ^ ^ ^ # ^ ^ tfl^ofl^ ^-t)- OPC
7^514 H
- 123 -
Menorandwr.)
12 a inn 10a £
f.Amaca,
- 124 -
(Memorandum)
11.101144
2. ^12
4.
3. ^
4. €
5. TiCl.il-a.TiCb sn l^-*l l 31
< Anatase/Rutile> xi? 4 4 TT A Q % 'A] ^ m . SL ^ £\ Q 4 .
£ OPC
1998.11.02 &*M 1998.11.02 d '
- 125 -
TiO2 l -
TiO2 a ^ l ^ ^ l l - PMMA°fl
organophilic
PMMAS
-f s|^Al 0.2 ~ 0.4 p S ^ - ^ s ] ^ &fe TiO2 ^
30 ~ 50 nmS ^ - ^ ^ ^
n-butyl alcohol^
2 ^}\1
25 nm£
>^-& TiO2
TiO2 PMMAi
PMMA/TiO2
TiO27f
TiO2
^ ^ 90
Sl^- 50 mL
SX^ 10
. 2 g/L
NaA102si
-ir 1, 3, 5
24 nfl-
3-4-H
3-4-H
- 126 -
, Na2Si02 fe 1 mL
Table 3-4-1. Evaluation for dispersion stability of ultrafine TiO2 powder in
distilled water
Na2Si02
NaAIO2
1 mL
O
X
3 mL
X
X
5 mL
X
X
NaAio2t- ^
S. 3-4-2fe
>* 1, 3, 5^A0.1
^7^0, ] tn*fl
Table 3-4-2. Evaluation for dispersion stability of ultrafine TiO2 powder with
the uitrasonification time in distilled water
Na2Si02
NaAIO2
1 mL
3 mL
5 mL
10 mL
1 mL
3 mL
5 mL
i § 4 l 7(-°j- A\y}
1 min.
X
X
X
X
X
X
X
X
3 min.
X
X
X
X
X
X
X
X
5 min.
O
X
X
X
O
X
X
O
- 127 -
l ^ A i ^ ^ M l TiO2 W « ^^1^171 %n*\ ±n)*m 600 watt, 20
kHz ^sK- ^ - § - #fe a # 4
S € TiO2 3^1 M T T -n-71 Sfe
Na2Si02 S^^l l - 4 -g-s f^ ^of l fe 0.01 g/mL» TiO2
, NaA102 3 ^ ^ 1 » Af-g-fV "3 .ofl^. 10
5 mLl- ^7>^fe %°) z\^}<&^. o}^7]} ^ ^ TiO27l-
- 40mV 50mV
(2) TiO2 a n ] ^ ^ 7 > £ # £ sol-t- ol-§-?b TIO2/CR39 ^
^ 2 ^m^0!) # ^ € ^ ^ S ^ ^ ^ i ^ ^ S . ^12:€ ^ ^ ^ TiO2
71- %HlAi ^ ^ ^^Va?i s^-^^ifl S^^r oi-g.«>
^|3j-# ^]tV ^ # ^sjsl-^cf. ^ ^ , 2g/LSl TiO2
7} #<H $ife n]s]?l (301- 5L&)<% ^] 7\*} -fr71(0.1 gS] polyethylene glycol,
15 mLS] CHsCOOH, 15mL^ (CH3)2NH, 15 mL$\ ethylene glycol, 15 mL^
ethylenediamine) £ ^ *f-7) S^^l(lgS) Na2Si02, lg^j NaA102)l- 4 4 \#JL 5
TiO2 ^^>^1
100°C3, -M^€ ^.^^^1 12
-H-7] JEfe ^ - 7 l s ^ ^ l S S ^ ^^=1 TiO2
m 90 % Po1" t2:1- ^«t ^ ^ # ^ 1 wife CR39 40 mL, TiO2 0.01 g, IPP 3.0 wt.%
- 128 -
-71 A]-g-*>
(7» Polyethylene glycoKPEG)
H2O 500 mi + TiO2 l g -
10 m£ + PEG 0.1 g£] -g-d|)£ 5
$7] 9 labetfH 5 £ %•<&
?i2i ^ TiO2 £ £ £ 0.95
polyethylene glycol(JL4v, H2C)
100°C
}S #1-1 : S ^ TiO2 ^ O.Olg + (CR39+IPP3%)40M
Z. #1-2 : 3*3 TiO2 ^-nsv 0.02g + (CR39+IPP3%)40m£
#1-3 : 3.^ TiO2 ^ - ^ 0.06g + (CR39+IPP3%)40M
CH3COOH
H2O 500 m£ + TiO2 1 g -» 30^
V ^ jaHV4 -t^l] 2-2-3]. ^-^7] 9
-°flAi 100°C ^ 2 : ^ ^ 1 4 .
3 2 ^ TiO2 ^ ^ ^ 0.98 g^r <
CH3COOH 15 mil- "4JL
2. #2-1 : i a ^ TiO2 ^ ^ v O.Olg + (CR39+IPP3%)40m£
2. #2-2 : 3 ^ TiO2 ^ 0.02g + (CR39+IPP3%)40nve
3 #2-3 : SL^ TiO2 ^f lsv 0.06g + (CR39+IPP3%)40m^
13 27H
27H
12 27fl
(CH3)2NH, dimethylamine
- 129 -
H20 500 mi + TiO2 1 g -• 30£ H«Kf (CH3)2NH 15
1 100°C 3 S § > ^ 4 .
# 2 . ^ TiO2 ^ - ^ 0.98 g ^
s #3-1 : 3.^ TiO2 ^ - ^ O.Olg + (CR39+IPP3%)40m£
S #3-2 : 3.^ TiO2 ^ - ^ 0.02g + (CR39+IPP3%)40m«
fe #3-3 : 3 ^ TiO2 ^ - ^ 0.06g + (CR39+IPP3%)40me
HOCH2CH2OH, ethylene glycol
H2O 500 mi + TiO2 1 g -• 30^: 3L&5- HOCH2CH2OH 15 m^l- "4JL
7H}. ^ 57ti>j!f - 11 3.^3). ^A$7] 9 labeHl^i 5
^ - ^ l ^ 100°C ^ S ^ l - ^ 4 .
^ i S ^ TiO2 £ ^ 0.95 g^r ^ ^
#4-1 : 3 ^ TiO2 ^-^v O.Olg + (CR39+IPP3%)40m£
-* 2H>4 ^-§-4 ^ fe 27fl
#4-2 : 3.^ TiO2 ^ - ^ 0.02g + (CR39+IPP3%)40m£
- 31a #4-3 : 2 ^ TiO2 £*3: 0.06g + (CR39+IPP3%)40m£
-> H«V3ij- 2:^-4 J=L 31a 2711 1;
K ) NH2CH2CH2NH2, ethylene diamine
H20 500 m£ + TiO2 1 g -* 30^- S«V ^ NH2CH2CH2NH2 15 m«
- 130 -
ioo°cTiO2 £ ^ : £ 0.97 g^:
#5-1 : 5L*$ TiO2 ^ ^ O.Olg + (CR39+IPP3%)40m£
-> 5iHi:3f a-g-sf jf. 3 } s 2711
#5-2 : 3.^ TiO2 ^ - ^ 0.02g + (CR39+IPP3%)40m£
#5-3 : a ^ TiO2 ^ - ^ 0.06g + (CR39+IPP3%)40m«
(7]-) Na2Si02
H2O 500 m£ + TiO2 1 g -» 30£ SL& $• Na2Si02 1 g | -
atiVsl- f-Tll i ^ g - 4 1-^71 9 labeH-M 5 ^
100°C ? iS^-S l^ - .
^ 2 * T1O2 ^ - ^ ^ r 1.79 g ^
s #6-1 : S ^ TiO2 ^ ^ v O.Olg + (CR39+IPP3%)40m«
-^ 5L«V-4 2:-5-21- ^ ^IZ. 27fl
1S #6-2 : 3 ^ TiO2 ^ - ^ 0.02g + (CR39+IPP3%)40m£
-» 5L«>2l- 5 : ^ - 4 ^ fe 27fl
1S #6-3 : E3.T% TiO2 ^ - ^ 0.06g + (CR39+IPP3%)40m«
-> aavsf s-g-4 ^ ^13 27H
NaAlO2
H2O 500 m + TiO2 1 g - ^ 3 0 ^ - 5L#$- NaAlO2 1 g-§-
9
- 131 -
^ Tio2 £ ^ £ 1.8O g *
#7-1 : 3*g T1O2 ^H" O.Olg + (CR39+IPP3%)40me
#7-2 : 3 ^ TiO2 &!k 0.02g + (CR39+IPP3%)40m^
#7-3 : 3.^ TiO2 ^ - ^ 0.06g + (CR39+IPP3%)4(M
s^-2}- ^ ;$2L 27fl (12;
(7» CH2CI2, dichloromethane
CH2CI2 500 ml + TiO2 1 g -* 30^-
Z. #8-1 : S^M- ^ " ^ ^ 0.1M + (CR39+IPP3%)40m^
-> HHlr l- 2:^-4 ^- ^13 27H afl 2:
3 #8-2 : a ^ - 4 ^-^OJ) 0.2m£ + (CR39+IPP3%)40m£
-> SL^A 2 :^-4 ^ fc 2711 afl 2:
l s #8-3 : S-g-sl- ^A>°fl 0.6m£ + (CR39+IPP3%)40m£
)- S-g-^ ^ ^13 27fl 7fls
o.^ Fig. 3-4-2^11
TiO2 ^ - ^ ^ ^ - ^ ^ - B H SEM A>^1^- a.$14. ^ 2;?il-^|>H CH2CI2
TiO2
d PEG-t ^ 7 H H 43iQ 39 2-3 ^ - i : Fig. 3-4-3°ll
- 132 -
711 *]•*=• n-butyl alcohol^ CH2CI2
(M-) n-butylalcohol
TiO2# n-butyl alcohol !
10 ^-^! 2s] n)) Ai 0.2 ~ 0.4 m$\ ^ ^ TiO2 ° J ^ » 20 - 50
TiO2 €r^^r
^-S-^i TiOCki
50°CS] ^-SiAi ^ ^ f ^ A ^ , y ]S^^^ r ^ 180
0.5 g TiOz/lOOO m«. n-butyl alcohol, ^ # : 1.3970
1 g TKVIOOO mC. n-butyl alcohol, ^*L-s • 1.3965
2 g TiCVlOOO m£. n-butyl alcohol, ^ ^ r : 1.3960
CR-39 20m^ ] 1 g TiOz/lOOOra n-butyl
alcohol^ colloid #Efl 3 -8-^1-i: 0.1, 0.3, 0.6, 1, 3 met- 4 ^ ^ ^ S-g-4 ^
^715. 900 W, 28 kHz, 10* ^ O J &4M?! ^ 10^- "o^ltb ^ ^ 4^1 900 W,
39 kHzS. 10* ^ 9 i * ^ ^ 1 ^ A 1 TiO2°d l-7l- CR39°fl JL^- *
I P P 1 . ^ 2.6 - 3.0
85°C, 30* ¥<$ -
H0°C, 2 Al?> 45 * ^91 r-S-Al ?]oL ^ ^ « ) ^z^S)-^ 70°C
^ . S cleaning
Fig. 3 - 4 - 4 ^ 1 ^ ^ ^-o] TiO27l- * # £ n-butyl alcohol^
2.si ^ ^ H / l - t<H^i O.B > ^ 2 . /$% ^-o\} n-butyl alcohol^
4
- 133 -
4 4 ^ n-butyl alcohoH f t t ^
TiO2 £^M: 3 3 ^ ^ H t S f a f l ^ a t f . CR39 40 mH TiO2
0.005 g, 0.01 g # ^ "43. s ^ - 4 1 - 900 W, 28
900 W, 39 kHzS. 10£ - § ^
^ ^ r ^ 1 * V J 1 ^ 20 Afln^ 0.5
IPP1- ^7 f sH
Fig. 3-4-5^]^ il^-o] n-butyl alcohol -§-^«
<»H- S 1 ! ^o] ^ ^ ^ ^ ^ ^-2l-£7> 95 % oRVoj
t)-. ^isoil ^<y€ TiO2 "a l-71- 0.2 ~ 0.4 jraS n-butyl alcohoH
20 ~ 50 nm «1«(| ^^l1?]: 20 /an^ 0.5
- CH2CI2 -g
n-butyl alcohol -§-^4-§-4 Aov£fl3^-5. 2:tfl^ TiO2
S) ^^•^-^•^^•fr^^-AV^ < ^ ^ ^ 4 AoV^^ #°11 TiO2
Hls.^oT 44°C5. nfl-f ^ ^ CH2C121- -S-^S Aj-g-tl-^cf. TiO2
CH2C12 lOOOm^l \ # JL 10& ^<?> nH^^i ^ - ^ 1 ? 1 4 ^ - CR39
^ 0.1 mi, 1 m«, 10 mm AA %7}*}9k2-*\ ^
-§-"11 CH2CI2I
Fig. 3-4-6<>1M £ ^r Si^°l n-butyl alcohol -g-^fll-
<go]4 ^132^ l-^-^^- €Aov£ 4 4 4 ^ 1 ^ ^ - 5 - ^ , TiO2-CH2Cl2 1000 ml
colloid -g- l 1 m o]*l-l- ^71-^-fe ^Jol ^ ^ * t
n-butylalcohol -g-^1- A>-§-^1# nfl TiO2 od47> ^41
CH2C12 -g-"Hl^1fe ^ 4 4 4?fl £ # 3 S U r * l * ^°J«l-fe ^ ^ ^ «• ^.S.7> 91
4.
- 134 -
4.
TiO2
•TiO 2 £ - i H 20 ~ 50 nm
alcohol^ colloid -
-, TiCVn-butyl
n-butylalcohol
90 % <>
0.3 m£ « l ^ f
• ^isoil TiO2 CR39«^1
fe 1 g TiOz/lOOO mi n-butylalcohol
20 /an4 0.5
^iHI, Fig. 3-3-5
TiO2
n-butyl alcohol^- ^-g-^- i - "fl
CH2C121- T i o 2 £ig^r 5 2:611
TiO2-CH2Cl2 1000
colloid -g-^lr 1
TiO2 l- ^ ^
900 W, 28 kHz, 10£
900 W, 39 TiO2
I P P 1 .
85°C, 30
, 2 *i# 45
cleaning
- 135 -
(a) (b)
Fig.3-4-1. TEM photographs for ultrafine TiO2 powder (a)before and (b)after
the dispersion.
- 136 -
Fig.3-4-2. SEM fractural sections of CR39/TiO2 composite plastic lens added
ultrafine TiO2 powder organically treated using PEG.
- 137 -
Fig.3-4-3. CR39/TiO2 composite lenses with the additions of ultrafine TiO2
powder using n-butylalcohol solvent.
- 138 -
Fig.3-4-4. CR39/TiO2 composite lenses with the additions of ultrafine T1O2
powder.
- 139 -
Fig .3-4-5. CR39/TiO2 composite lenses with the additions of ultrafine TiO2
powder using CH2CI2 solvent.
- 140 -
3-5 *L EL : £ * H H ^ TiO2
notebook, cellular phone f- ^Ft|)-g- f - ^ H ^ a^^S)- , s i ^ s ) - ^ 7]
tfl fl SAl7l7)<y LCDXiquid Crystal Display)^ J L £ ^
s j ^^ c] i#^ol ^ PCS
], pager ^ # « 1 ^ ^ ^7 l^Ml f - ^ 4 ^ S ^ 1 Jfl «fl •%••%• s\^ LED
(light emitting diode)^ JL^7
EL(electroluminescence)ol2]:
i4 LED # i «l*fl It7]7]- S<a§l-JL -*0 H ^ - l mm
3M-8- ^ n -§-§-^^7f ^ ^ tj-o^t).[34-37]. o le ]^ EL
tc}-ej- a?]] A C ^ ^ D C ^ J ^ ^ ^ £ | ^ , ^ S ^ ^ ^ ^^>^1 ^so l l 4s}
M ?l^l§l-fe ^-^t^ EL (P-ELD)4
ELS ^ - ^ ^ $14[33,38]. CVDM-
1974>d Sharp^HH
EL ±*}%
, EL
- 141 -
TiO2 ^r^-t 3-§-*}$4. ;g<£*)] ^ S } £511- ^olj7 ; <$X}EL7}7} nfl-f n]^§}
°J ^-^r 2?12] #7] <^m^ll- 7}^ 3-f phosphor #°fl c) 3L#^<?1 carrier
injection^- ^ « H fl£^ ^ ^O*M- # ^ ^ ^ ^ l ^ °>^ high voltage
drive i t ^ ^9# ^7># #6J ^ $1^-^ # § phosphor ^ 4 -^-^xll^ A>O]^
-(leakage current)!- #<^ i
TiO2 &&•%: EL
AC Powder
2.
7\.
(1) Substrate^ Pattern
ELDS] ^ ^ 2 j *l*]tfl ^ ^ - ^ ^ ^ ^ § ^ r «]-fe 7]^fe £^i Bi-o] I T 0
(In2O3-SnO2)7> S ^ € flexible film-S: 4-8-*>Sl4. ^ ^ ^ ^ %%
^1*1-71 ^§f°=i ^^Aov^(7rS 0.5 cm x 43. 2 cm)f scratch
3-5-1), fil 1
30
(2)
^ ^^^1^1 phosphor
Table. 3-5-14 ^ 4 . ^sfl ^ - ^ ^ 7]^o.S s>^ JL£X}O1 polyester^]
70 %S. a ! 3 $ ^ solvent(D.M.F, M.P, S]^^l) ^ plasticizerS] 2:^^- z]-zj- 10
~ 30 %, 3 ~10 %£. 4°o^Ml ^Sf^]^^-^ , I t ^-^>ir ^\^ emulsifier 5-
%7}S. °-} 2
- 142 -
Table 3-5-1. Binder Materials Using EL Device Fabrication
Material
Polyester
N.N-Dimethyl
Formamide
N-methyl
2-Pyrrolidinons
s| q nN.N-Dimethyl
Phthalate
Company
Sam Sung Chemical Co.
Duk san Pure
Chemical Co.
Duk san Pure
Chemical Co
Sam Sung Chemical Co.
Duk san Pure
Chemical Co.
Content
70%
10-30%
10-30%
30%
3-10%
Usage
Resin
Solvent
Solvent
Solvent
Plasticizer
(3) Pasted
3 : IS)
f-7] binder^ ^^-^]tl phosphor powder(Sylvania, ZnS : Cu)i
%]^*H $ 3 . H-lM § .-f- & ^"y-s]3E^- homomixerS. ^
Sf°i phosphor pastel- ^ ^ 4 . -fr'S^lfr ^ A j ^ -rit!: -n-^l;
pasted ^|^:3-tS;S^i1Sol] ^^l-^ ^13:€ aDl^ll^ jl-n-;S^-( £) TiCfcl-
#^°1 -T- rt!: BaTiO3(High purity chemical Co., 98 %H ^-^>A]?1 ^-,
-fi-7] binderl- 2 : 1^ «l-i:S. 41^ ^-tfl^^^-S. ^ ^<^^<^ ^*>^?1
^Tfl §]-$!-2-^, agglomerate Q ^^^fy ^-^:# 4A] f 1
homomixerS- S-' 'S}'0^ ;5j<i'?!: •fr^-^/!§"s" x l \ i -n--?! ] pastel-
(4)
phosphor pasted paste U carbon paste(Dupont Co.)lr
pattern
£.3, 4^°} -8-°l^: Screen Printing^
Fig. 3-5-2fe EL£*1- ^14^: fl^:
^ ^ pattern°1 U M screen^- ^ ^ ] « 1
<H^ pastel- ^ :^¥3 i squeezes. ^
80 °CS -fi-^1^ 5.^- #^1^1 ^ 30 ^
^^i ITO film^i
screen^ <1 ^ # ^^i°fl tr)-5f ^ | # s]
printings]-^A^ printing^! film g-
- 143 -
4.
EL £*}• *H*W ^ S ^ S S ] a H a ^ - i - S ^ * M ^§}o} DTA-TG
^ , printing € ^ M S-^3 ^4 V 4 WEL71 ^ ^
(2) #71
^1S^ TiO2 -DaVol £ # € BaTiOs - f r^^l^^
HP 4192A LF Impedance Analyzer* 4-§-«H ?l7>#<a-i: 100 VS.
^Sj-#^ ^ ^ ^ 1 - 400 Hz ~ 1 MHz *M 7>^A]T '1^^ T i02
EL
100 Hz ~ 1.5 kHz^l , ^°d-^ 20 ~ 150 V 4 4 ^Sj-^l^^-^. #^^-^lfe Fig.3-5-34 £ol ^A^S|-^J 1 > ^ 4 ^ ^ ^oj.^-^.ojo.^A^ Frequency Generator
(Auto electric Model-6221)#, flS.#^-§- ^ |*H Luminometer (denshoku
NL-D1-, # ^ - ^ £ # ^ ^ - ^«f^ Multimeter(HP 3440AD1-
3.
7>. ^^"^14 DTA-TG
1 (polyester : M.P : D.M.P = 7 : 2.7 : 0.3) 1 ^mA^Ai^- o^^. DTA-TG tflo]Bf(^2:^£: 10
27 %2} -8-^fl(solvent)^ ^l#-& 313} W ^ ^7fl7j-^o^ o 25 %7>
95°C ^ g S ^ l f e ^£^7>o]| 4 ^ polyester ^ 1 $ ] 1-B]
- 144 -
, polyester!- °l-g-# EL
^ 95 °C * ] B H M ^ * > ^
80 ~ 90 °C:
-. SEM
Fig. 3-5-4fe SEM
ZnS : Cu powder3 SEM
30 /an
10 ~ 50
. Fig. 3-
phosphor
. Fig.
ITO film
path*
phosphor
^ 30 /an
. Fig. 3-5-4(c)^r
1 layers
SEM
Fig. 3-5-5fe ^-^^r-^31-
s f ^ « 400 Hz ~ 1 MHz
^-i : 100 VS.
TiO2 ^7]-^o11 K
fr^-i:( e )-& 400 8.673
BaTiO3°fl ^ 7 > ^ TiO2
TiO2 f-t°l 10%# ^ ^ ^ 1 ^TiO2 = 10 % n]n
1- ^-fe TiO27r
TiO2 10 % BaTiOs
, 1 kHz
- 145 -
A. Current Density(M/ctf) % Brightness(cd/m!)4 ^Sj-
^ ^ ^ € S H Fig.
3-5-641 4 4 ^ $ 4 . I-V ^ 9 3 # ^ 1 4 $.<&$ f ^ H 4 450 V 3 £ 4 H #fr4 t f
iHM^ ^^^ V&-& *\ CU2S4 ZnSt-EL-8- ^^ -^^ H-l] ^-^41 71?]§>JL 014. Cu2S
ZnS od4 i i }
7]
H^o] 3.7 eVS €• ?t^- 7 H £ S ZnS
SHH71- 7 l ,
- 4
£^r, TiO2s] ^ 7 } ^ 4 ^ Y-a^-^-fe ^^r BaTiOs^ ^ - f 43.36
•^ 100 V4 |^ )«LS^ TiO22l %7}% = 5% (19
= 10% (19.45 M/crf) ^ - f
BaTiOs 41 ^ 7 > ^ nl^*V TiO2
l-i- Fig. 3-5-741
30 ~ 50 VS. #7]-^-41 4 4 4 - 10.95 cd/m'-S]Si31 50 ~ 150 VS. #7}$-4) 4 4 10.95 ~ 82.32
flS.^-^^. a 7 f l o ~ 5 O
# , 50 ~ 150 Vy\x]2) $] 2 TQ a 5 ] j i 150 V o]4v2l *i] 3
7]4 ^ ^ ^ j o _ S §-7}§>ui, 1 3 ::iz-?l:4l>Mfe- <?l7l-^i^-4l tfl-i
4-§-slfe ^ 1 ^ ^ : 50 ~ 150 V$] 1 2
^-^^- ZnS : Cu
- 146 ~
ZnS4
EL i^H^S. 50 V
Cu2S
. Layer
Fig. 3-5-8^
1?! pin hole°1
shot7> tA§^- T1
7]-
ZnS : Cu %^^ ^ i %<&%<>] ^V od€ A.C. Powder
7]
81= Til ^ ^ 4 f e ^ ^ ^ * ° 1
^ ^ breakdown^
- 147 -
50
EL ^ x H fl£ ^ ¥ ^ ^ ^ - 1 - 3 3 3 - A|Z] ^ ojcf. pig. 3-5-9^ -B-^^
(-i- Fig. 3-5-HW
-: 100 1 fl
4.
^^lf '^ .S . 3-g-SH screen printing^ -f-*!- A.C. Powder EL
#•§•( £ ) ^ 400 Hzi^-i 8.67^£°H
TiO2 ^-^°1 ^ 7 > § ^ s - -a-^-irSl Hls]]2j ^ 7 > # io]nf7f TiO2 ^ ^ ° ] 10 %
# £ f . iolfetfl, TiO2 = 10 %^^Sl ^
sizes] «gx>37]-l- Sfe- TiO27]- polymer
, TiO2 %7}%o) 10 %ol^-«a ^-f BaTiO3
43.36100 V ^ ^ ^ S . ^ TiO2£) ^7>^= = 5 % (19
10 % (19.45 M/crf)
- 148 -
BaTiOsi ^7}sl v]^ TiO2
- I-V, L-V si # 3 £ 4 25°C, 100 V, 400 Hz*IM ^ ^ > ^ ^ ^ - ^ ^ f e 19.5
erf, fl^fe 42 cd/nf
45 ~ 50, 10 ~ 20
- 149 -
I.T.O Coated Film 4cm
5 cm
Fig.3-5-1. Formation of substrate pattern.
- 150 -
Resin Solvent
Binder batch
Phosphor paste
Printing
Dielectric paste
Printing
Rear electrodeprinting
EL devicefabrication
Plasticizer
ZnS: Cu+binder3:1
(BaTiO3+TiO2)+binder2:1
Fig.3-5-2. Experimental procedure of EL device fabrication.
- 151 -
Luminometer
Multimeter FrequencyGenerator
Fig.3-5-3. Block diagram for the measurement of luminescence on A.C.
powder EL device.
- 152 -
(a)
(b)
(c)
Fig.3-5-4. SEM photographs of (a) ZnS:Cu powders and (b) surface
structure,(c) interface structure by screen printing.
- 153 -
—•— TiO2—*—BaTiO3 H—*—BaTiO3H
M BaTiO3 -• BaTiO3 H- BaTiO3
H 5% TiO2i- 10%H 1 5%f- 20%
TiO2TiO2TiO2
100 400 600 1k 100k 400k 600k 1M
Frequency (Hz)
Fig.3-5-5. Dielectric characteristics by applied frequency.
- 154 -
250
200
| 150
'c
" 50
0
— — TiO2=5%-•—TiO2=10%-A— BaTiO3
50 100 150Voltage(V)
200 250
Fig.3-5-6. Current density - applied voltage characteristics in P-ELD
- 155 -
0 50 100 150 200
Applied Voltage(V)
250
Fig.3-5-7. Brightness - applied voltage characteristics in P-ELD.
- 156 -
28
24
Q 20
CD
O 16
12
CurrentDensityj 44Brightness |
42
40
43 45 49 54 56 61
Phosphor Thickness(m)
64
38 ¥CD
36 I
34
32
30
Fig.3-5-8. Brightness and current density characteristics as a function ofphosphor thickness.
- 157 -
30
25 -
20
cCD
Q 15
a 1°Current DensityBrightness
8 10 14 19 25
Dielectric Thickness(Am)
31
44
43
42
41
40
39
38
37
36
35
"E-ao
itnes
Jrig
h
LLJ
Fig.3-5-9. Brightness and current density characteristics as a function ofdielectric thickness.
- 158 -
CD
0 0.2 0.4 0.6 0.8 1 1.2
Frequency(KHz)
1.4 1.6
Fig.3-5-10. Frequency - brightness characteristics as a function of applied
voltage.
- 159 -
3-6 *1 Spin Coaterl- oj-g-^ PMMA/TiO2
0.2 ~ 0.4 fm^-S. ^ W ^ olsVW, °1# a^-s}-^- 3 - W T S 20 ~ 50 nm
SEM4 TEM-t-
CR39/TiO2 ^-^^]
TiO2#
PMMA/TiO2 ^"^-i: ^12:^-31 n ^ ^ ^ - € # TiO2
2.
Polymer/TiO2
, -§-^4- ^]^:«l-7l ^«e FEM SDEFORMS ^°a
TiO27> ^ ^ - ^ polymerl-
^ 2 f i ^ Hfe -a-2] 71^; ^0]] ^5fiHJ ; ^ ^ Ti02<q-
- 160 -
peeling S^- debonding-i- I H W I ^ S $ 4 .
DEFORM Code[17]
4.
dc _ n d2c
BC) —p,— = 0 at matrix — coating interface
—z—=h(C — Coo) at coating — environment boundary
S tit!: -S-^s] «fl^^- ^ s f l x ^ ^.xj-ij. -g-^^ ^^-^fl^(coupled
analysis)6] ^ ^ ^
71^^-Blll- ^ ^ ^ - -Bflofl ^ ^ Updated Lagrangian
- 161 -
P\
8e a dQ - 8df = 0 (1)
8o l -
- 162 -
(2)
8dB o dQ - 8df = (3)
dQ - Af = 0 (4)
da = Cp de (5)
Kd = Af (6)
= B CPB dQ (7)
Newton^
= </ + C^dk (8)
4. *JH °fl
Fig. 3-6-1-8: *H^3)^ A i W 3 3) 2:3 °1
T=Q$] tfl%i#^r 7l§AS. 1/2 (^^ -*1^ 1 radian)^: tfl^o.s. *}
^ 550 7fl, ^ ^ ^fe 612 7fl4. - M 3 7l^jzf ^ ^ ^*\ ^71]^ z]-z]- 5 m m
# , T1 /an olifloljl, ^1^-g- 50 mm £<>]7l nfl -ofl o] p,]^^
2 *H1 # tfl ^-^s. tfl^«]-^4. 4
10 mm, 7)x]^-7|| 5 mm£ 5L%*\?)3L, S ^
11- 0.1 ~ 0.5 mm£ € ^ 1 ^ ?1 14 S ^ # ^ -g-^^^|# ji
4 . -8- il ^^r 90 %, 75 %, 50 %S. SSHjq 71-f- - JL#§l-^4. #^. o]
50
= Oplasicfplastic + ^TiO2/TiO2 (10)
a.
IS. ¥SJ:4. 3 ] t H # £ - IBM PC (lOO MHz)< l 300
- 163 -
sec
Fig. 3-6-2^ &£r 19 % t = 6.1
fe **]«- r ff^. o)
71
-8- 11 Fig. 3-6-341 SLSI4.
r U-1ML
. Fig. 3-6~
fe4. Fig. 3-6-5<^lfe ^ ^ vector*
3. PMMA/TiO2
7k
TiO2 f r^ v ^ 0.67 wt% ^O]\§JL 24
PMMAl- -§-^^1 5.67 % 3 .
-spin coatert- 4-8-*
80°C, 2 Al
ball milling
^7^1-jl 24 ^R> ball milling
4-§-,
TiO2
- 164 -
spin coater(Model WS-200-4T2/RTV/ENJ)£r UV/ER J-
^ ^ 7 ] (Guided Wave Model 260 spectrum £ f e S2000 Ocean Optics
Inc. with DT 1000)1- ^~§-*r$i}. 1 ^ 3 °-£- S e ^ i ^ ^ S o f l $7>£)fe
fl^ ^ > g ) ^ > ^ ^ r ^ 1.5 w t%
5.3. ZL Sl^Hr ^^1 ^ ^ 10 Wt%»
a , n-butyl alcohol £ fe CH2CI2 •%•<%<% D]e1 € 4 ^ 1 ?1 TiCbl- PMMA
T1O2/PMMA -g-^-i- ^ 2 : ^ : 4 ^ . , spin coating H ^ A S -f
100 nm ~ 5 m ^ ^ ^ TWPMMA
« 90 % ol-S-o.S. -fr^l«l-7l ^Sfl T1O2
PMMA
7}
lfe -8-nlls.fe- CHCbl" ^tflS. Af-g-^ji tflA} a-^u]^ . 40%# CH2CI2
fe CH3COOC2H5I- ^ £ 3 ^ S ^7>^-<^ 10 wt%^ TiO27l- ^7}Q slurry*
1-^ «>^c]] ^ o ] ^ 7 1 4 Tfl^l^. ^ A J - ^ ^ i ^ - >
Fig. 3-6-6^: ^ £ ^ H H 4-§-€ Light source,
PMMA4 PMMA^r ^ ^ " € T1O2 ^-^(as-synthesized, 50°C^^ 4^1 ?>•§•?>
€ ^ H tfl?t i ^ M ^ # €• 3 W 4 . Light source^ UV ^ s)-^0!
Deuterium/Tungsten-Halogen light souncel- *H&-^$14. ° ^ 7 H ^ PMMA7]- a)
u v 4^ -^ - ^.^«VoL Safe ^ € • 1: ^r 5£*m % 7V^ TiO2
300 ~ 400 nmsi ^o] # i£* | ^ ^ 5 ) 3 1 o j ^ - ^ ^ ^ 5^4.
T1O2
Fig. 3-6-7^: 50°C^lAi 4 A ] ^ ^o> ^ - A ^ T i 0 2
Al 400°C^ 650oC°flAi 4 ^ 1 ^ 2 ] $ ^ PMMA^
1 < H ^ 1 ^ 1 ^ T i O 2 ^ - ^
£ ^- q.Ej-4 sac)-. # , 33-3-01 ^oi^of l iq-Hi- s}-n].§l-7il ^ ^ s j - ^ band tail
- 165 -
fe *ll 3-2 * H H iL<?l 3}*) 3 , HPPLT^l
10 nm ^JES. nfl-f n]
300 ~ 350 nm
Fig. 3-6-8^ TiOCk ^-g-o^4 Ti-nitrate *r-§-^ ne^ j i ^ ^ 7\T\
PMMA21
TiO2
# ^ ° 1 ^ ^ N T T x}°]7} 4^1 # -ov-§-4 TiO2 ^ • ^ • ^ 1 ^ 4 300 nm
band tail-i: ^ ^ 7A^-S. ^9llk ^r S i - ^ ^ 1 4 r Fig.
3-6-841 441-f l&4. Fig. 3-6-8-1:
diffuse scattering °1 ^"^r^ ^ * } ' ^ band tail -T-
^.^. ^.j7|.^s. 4 4 ^ ^^i, Ti-nitrate -§-^^.5.-^
71- TiOCk -g-^AS^-El ^^S: 7A 4 >11 # ^
3-6-8(A)). ^ -*1 , Fig. 3-6-8(A)4|^ 324b
90% °1AJ-£1 ^ - ^ ^ H l - ^ - ^ ^ t ^ Si4. ^1314, TiOCk -%-°^±SL^-
€ f -€ TiO2# 360°CS. <i^l5lsl-3. \+ 141 ^v4-i- ^ ^ - ^ 4 ^
1HJ-SM1?]: °^^}^\ Ai^^-S- $.%] ^-^4^.fe- ^ 4 ^ - i - ^ T=- 514. 5E, Fig.
3-6-8(B)4l i<?l ^ ^ ^ , CMC, HPC, OP-10 ^ ^ r ^ ^ - i ^ - S ^e) Af-g-sln ^
TiOCk -g-°^4l^fe -E ^Sl-1- a.°l^l ^ 4 nefl^41fe 4 4
Ti-nitrate -§-<aHH-& HPCfe
<£•§: f - 1 TiO2 ^-^l-ol iJ^a} o.s. J i j l i | a l $U - TiO2
# A ^ ^cfls. 4^-^
TiO2 ^ V ^ l ^
•S-
, Fig. 3-6-9fe cflS^'?! PMMA/TiO2
S l - SEMJ5.S. ^-#*> 5J°14. Fig. 3-6-9(a)fe £^*l-*!-§-, Fig. 3-6-9(b)
^- i - 4 ^ ^ ^ ° 1 ^ . Fig. 3-6-9(c)sl ^^A>^i^- ^ £ 5 1 1 ^ 3 ^ 6 . 3 .
0.3 /an 3.7121 T1O2 °l^>°d^}7l- ^-a-s|<H polymer network^-S %<^\
- 166 -
r *
2.2 wt.% (0.15 g TiO2, 6.8 g PMMA-^x}-^ 120,000)-!: £ W J L <$ 800
^ a 3 * H <2£ *W4. a, polymer• polymer ^ ^ 7 ] - ^ ^ > # 4 | ^«fl^i
^ Safe SEM# <>1-S-«B ^ ufl^5- ^^r«fl°>^4. Fig. 3-6-9(a)3 5:
TiO2
100 nm «]§>^
^ i - 3.4 ^ s
0.3 /ffll
TiO2 0]^}^7.Vfe * } ^ -^#S]^ ^aL ^ A S S . ^ ^#S\°] PMMA fl
TiO2 ] f^ *
50 nm
PMMA ^r^r S ^ ^ : ^ TiO27l- 0.154 2.16 wt.% ^7>^ PMMA/TiO2
1- 2 ^ ^ - ^J* HlSsH Fig. 3-6-10*11 M-El-^^cl-. TiO2 ^7l-^o11 4e}-
£71- ^I-SW1?]: CR39/TiO2 4^^1 S ^ i ^ ^ l S f i ] ^ ^ - 4 p
TiO2l- ^7>§}^(^7fl 0.15 wt.% TiO2l- ^7>*>5S-i- °fl) 90 %
« ^^:*1 ^ 4 ^r ^^-^r ^ ^ $14. ^ 4 , ^^fl^^l -8-8-^- ^«fl^fe 9598 % ^£S] 31-MHt- Ji<>lfe ^-^o] ^2:Sl<Ho>^: ^ S TiO2 °^^}^
5.
HPPLT5. ^ S ^ ^ 1 ^ TiO2 a^l^-^ll- -§--§-§}• 7) ^sfl £ A f ^ ^ 4 PMMA
/TiO2
- 167 -
(stony)^ 7 >
<£•§: 3.711 ^ ^ 3 ^ ^ i peeUng l ^<H^ ^ ^ 4 f e 3-i- ^ ? 1 ^ ^r Si Si
4 . PMMA/TiO2 4 t ^ l 4 ^ - i ^ TiO2
CR39/TiO2 4^t^l ^ ^ ^ ^ € S ^ ^-fsf ny$7Ma T1O2I- ^ 7 } ^ 90%
clxtfi, HPPLTSL ^ ^ ^ TiO2 ^-^
-8-8-^- ^«fl^fe 95 ~ 98 %
|-s.a TiO2
- 168 -
r3—Residual Stress for Ti & Resin. 'DSF = 0.100E + 01TIME = O.OOOE + 00
CNUMPL
j
•
§ §
Fig.3-6-1. Initial mesh system for the residual stress analysis of the coating
layer
- 169 -
fv= 19% Stress for Ti & Resin.DSF = 0.100E + 01TIME = 0.100E + 00
3.00
CNUMPL
III
Fig.3-6-2. Deformed mesh at 0.1 sec, fsoivent=19%
- 170 -
fv=19% Stress for Ti & Resin.TIME= 0.10000E+00 CONTOURS OF TEMPERATUREDSF = O.1O00OE+O1
CNUMPLMIN(-)=0.503E+02MAX(+)=0.508E+02CONTOUR LEVELS
A=0.503E+02
B=0.504E + 02
= 0.504E+02
= =0.505E+02
0.505E + 02
0.505E+02
0.506E+02
0.506E+02
0.507E+02
0.507E+02
O.507E+02
=0.507E+02
Fig.3-6-3. Contour of the solvent percent at 0.1 sec, fsoivent=19%
- 171 -
fv=19% Stress for Ti & Resin.TIME= 0.10000E+01 FRINGES OF PRESSUREDSF = 0.10000E+01
3.00
2.00
1.00
0.00
-100
-3.00
-4:00
-5M
-6.00
CNUMPL'MINVAL=-.500E+01MAXVAL=0.455E+00
FRINGE LEVELS
A=-.450E+01
B=-.400E+01
C=-.351E+01
-.301E+01
-.252E+01
-.202E+01
-.153E+01
-.103E+01
-.536E+00
-.404E-01
Fig.3-6-4. Fringe of the pressure of the substrate and the coating layer at 1.0
Sec, Isolvent=iy/o
- 172 -
fv=19% Stress for Ti & Resin. ' nXTTTtf TDTTIME= 0 10000E+01 VECTOR PLOTS OF DISPLACEMENT LJSUMrLDSF= 0.10000E+01 B ^
3.00
2.00
100
-2.00
-3.00
-5.00
VECTOR LEVELS
0.106E + 01
0.793E+00
0.529E+00
3.264E+00
D.194E-04
Fig.3-6-5. Displacement vector at t=1.0 sec, fSoivent-19%
- 173 -
4x1 (r
3x10 -
Light Spetrurcd 2x10 J
COQ.O
1x10J
200 300 400 500 600 700 800
Wavelength (nm)
Fig.3-6-6. Optical spectra for the light source, Glass/PMMA, and Glass/(TiO2
+ PMMA) composites
- 174 -
CDOcCD
100
80 -
60
•$= 4 0CO
I20
Glass / (TiO + PMMA) Composite
Glass / PMMA
- As-synthesized
400°Cfor1hr
250 300 350 400 450
Wavelength (nm)
Fig.3-6-7. Optical transmittance for Glass/(TiO2 + PMMA) composite, where
TiO2 powder was annealed at 400 °C and 650 °C for lh in air.
- 175 -
100
90
0>O
CD
CO
co
(DO
"Ecoc2
60
50
(A)
300
100
302a324b
324b-360°C
450 600 750
Wavelength (nm)
900
300 450 600 750
Wavelength (nm)
900
Fig.3-6-8. Optical transmittance (%) for the spin-coated PMMA/rutile T1O2composite thin films (302a: rutile TiO2 from Ti-nitrate solution,324b: rutile TiO2 from TiOCk solution, CMC, HPC and OP-10:additives)
- 176 -
(a)
(b)
. 18fmKAERI 15KM X2,000 21mm
(c)
Fig.3-6-9. SEM photographs for the surface and fractural section of
PMMA/TiO2 thin film by spin coater.
- 177 -
0.15wt.% TiOa(PMMA+TiOi) /Glass
2.16wt.%(PMMA+TiOa)/Glass
Fig.3-6-10. Comparison of a representative (PMMA + TiCWGlass composite
specimen with Glass substrate.
- 178 -
4-1 ^ ^ 7 1 1 ^ 5 .
(1) ^4<q^ * m ^ 3i#^^-8- TiO2
(2) ^7 f5 ] 4j-6>^
*11 rutile TiO2 ^ - ^ ^ ^ (0.4/an °}*})
(1) ^*}$)# *}# ^ a!#3i-§:-g- TiO2
.Rutile TiO2 2:^1^^]^ ^1^7)^
.Rutile TiCVf &$$. S^J-g- sol
- TiO2 S^S-^]7l- ^-A]-^ sol
.Rutile Ti
(2) s | 7 >^ aj-o>^
Rutile TiO2 S^^-^7]- S^sl-Tfl ^ - ^ ^ sol *
.TiO2 «a l-7> 5^ 1-711 ^ - ^ ^ PMMA/TiO2
.TiO2
4.
- 179 -
(1)X}<2]A| *}# £ a L ^ ^ - g - TiO2
.TiO2
.Rutile TiO27>
- T i - ^ 3 ] sol-i- ol-8-$ TiO2
*sol£] ^ l l S S ^ i 4^- S ^ ^ - ^ ^^^^ (T i 4 * ^ H , NaCl ^7>^ f- sol
^12 a?i SHI)
-TiO2 S^l^^}7> ^ A V ^ so l^. ol-g.^ TiO2/CR39
*sol ^ S S ^ ^ l i4€- ^ - ^ ^ ] ^ ^-^
-Spin Coaterl- 6l-§-^: PMMA/TiO2
*PMMA/TiO2 3-^*113 ^^"^ ^-^
(2) 3j7]-^ ^-o>^
.TiO2 2^v)^xW ^ A > ^ 6j.^^. soi
.TiO2
.TiO2
2.
(1)
U o.S ^ - ^ ^ - i - ^fe ^ ^ ^ TiO2
TiO2
3.5L
- 180 -
TiO2
TiOCkl- NH40H4Ti0(N03)25. t h W 4^-, o]
TiO2 ^^^^1 ^S^^- i - 711
^ ^ A O V T i 0 2
TiO2 S^l^-^11- S2}^^^Soll 7>S>7l fl^ 7 l s^^S .^ PMMA
TiO2 S^m^l l - ^ ^ " ^ 4^" -FM7m<>fl 3 ^ § l - ^ # nfl
f l TiO2
(2) 3871-3
TiO2 i^l^-^ll- 0.05 ~ 0.5
TiO2
4 . a , TiO2^ tfl^fli-^ol CeO2 n l^.
o.2 ~ 0.4 im^\ ^^(0 .4 ^n °l§l-)4 150 ~ 200
TiO2»
- 181 -
(1)
.Rutile TiO2
TiO2
- TG, DTA, DSC
- Raman, FTIR
TiO2
.Rutile TiO27f ^ - ^ ^ S ^ ^ - sol
Ti-^^ssfll- o]-8- r sol ^ 2
- Ti ^-g-^l ^°fl ^>^^iSo] tfl.g.o.
i i ^ ^ ^ S ] TiO2 ^- 7OVA>S^O]1^ TiO2
E.S. 71^-S^o) positive charge
-7]- 4
negative charge
Tio2
fe 100°C
fe sol*
- 182 -
TiO2 W- t -
TiO2
. TiOCl2
APS, PSS 3.^A
positive charge* 5M1 =|fe -B-e]7l^-i- nj-^jL <>]!• -7]-
.TiO2 s^^-^7} -^^ sol
TiO2 &^
TiO2
TiO2 °d
V -.
^ ^ ^ . S ^ ^ r TiO2
^s j of 30 nm 3 7 l S TiO2
f".TiOCb
- TiCl4 1 tt 5]-^#^
«>-§-, ^ ^ A i ^ ^ssj-TiM-, ^ a ^ TiO2 ^ ^ - i - -8-
TiO2 &°\ ^A$\ ^ - ^ ^ ^ - 1 : ^ r ^ ^ ^ ^ 25
TiO2
sol ^ S # fl«B Na2SO44 NaPSS^r «a^l-fi^^ S ^ M ^ electrostatic4 stericforce A>oio
- 183 -
Rutile TiO27r £tM-7I S ^ - A.X. "Pi "7l *5L <
~ -^y _ T- r* r 5^ / 1 ^*
b CR39) Hfe ^f-
^?1 PMMA O:fe CR39)
TiO 2 » <?
*.
S. 1 TiO2
PMMA
rutile phased ^n]A|| TiO2l- AC powder EL
dielectric layer(BaTiO3H ^A*}^ ^±.3.7}$) TiO2
TiO24 ^ ^ ^ S ^ l PMMA
- TiOCk«]-fe ' S^ l - r ^ M PMMA 7]x) v j T i027|-
•i-
- AC Powder EL^] dielectric layer (BaTiO3)°ll
TiO2 €-^:# 7>f-6.5.^ -B-^i^-^ ^sl-1- ^ # * H TiO2 S^l^
o] fe TiO2
^ J L # € ^ - 8 - TiO2
.Rutile TiO2 S ^ l l - ^ ^ ^ S 7 l ^
7 l f ^ TiO2
TiOCl2s] i p
.Rutile TiO27> ^AV€ S ^ ^ - sol ( T i - ^ ^ ^ 1 - 6l-§-«- sol *flS)
^-§-^)^°fl #5i°1 3.^ ^ 5 ] € -n-^7)^^ ^-^ 10nm
TiO2 W ] i ^ ^ } ] ^ ^ ]
- 184 -
or °I.Rutile TiO27> £ # € 2^-g- sol ^ (T1O2 S*l£*)l7} £ # ^ sol aflat)
^ TiO2
^ , Sei-^^^l € - ^ 1 ^ ^r 9X5m- TtQQ&^tfl $n <££: TiO2
25 nm °M3.
.Rutile TiO27>
2 *}id£ 91^°!]^ ^"^€ S ^ ^ ^ } TiO2
<L^ n. ^ 4 # TiO2 iM£*l)7l- ^ ^ ^ sol
(2)
.Rutile TiO2 2^1 €-^|7l- 5^«J->fl ^ - ^ € sol
-T1O2 "9 71- 5^t|-7fl ^-a-€ PMMA/ TiO2
-TiO2 £ ^ # 3 fc€-*S ^ f-Ji
- Rutile TiO2 ^ P 1 ^ - ^ 7 > a-^§>7l) ^<+^ sol ^ l S » ^§1) o]n]
%&H £fe T1OCI2 ^r-S- l-i- PMMA°fl 5^^711 ^ T ^ A ] ^ TiO2
PMMA/TiO2 4tl"*ni- £•§: ^r ^ ^ ^ - ^ , TiO2 2 ^ 1 ^250 nm o)*}^^} 10^- ^ 1 ^ - ^ ^^-^-g-^ofl $m ^ 25 nm
. TiO2 l -^ -^S fe^^- SCI ^
o.a sciTiO2
(1)
- 185 -
.TiO2
^*(|fe * " 4 ^ ^Sofl TiO2
^ i ^ 2 -TdS. 11 # - $ € ^ ^ r S - ^ J ^ ^ ^ «.S ^ 1 ^ € ^ - ^ ^ TiO2
°}# ^ H f e # 500 mL4 1 g^ TiO27> 1-^
7]-x] -3-71(0.1 g^ polyethylene glycol, 15 mL2] CH3COOH, 15 mL$\
(CH3)2NH, 15 mL^ ethylene glycol, 15 mL^ ethylenediamine) ^ f e ^-71 3.^
4(1 g^ Na2Si02) 1 g^ NaA102)» 4 4 ^ 1 5 ^ s « J f 4 4
TiO2
CR39/TiO2
.Rutile TiO27>
TiO2
4+ , NaCl $71-3= f- sol
4 ^ " ± 3 . Ti-^^^KTiOCk ^r-
lOnm <>1*> ^ ^ 1 ^ 4 ^ 1 ^ ^ TiO2
Ti4+4
TiOCk ^-8-^1 soM: ^
peeling € ^ ^ : NaCl^ %7}%£ 1
-TiO2
*sol
TiO2 ^r^-l-
- 186 -
90% °
alfe- CR39 40 mL, TiO2:
0.01 g, IPP 2.6 ~ 3.0
-Spin Coaterl- <>l-8- PMMA/TiO2
*PMMA/TiO2 4 f -^ l ]^ ^-^-^ ^-^
CH2CI2 -§-^°fl *1B| €-^:Al?l TiO2» PMMA
^ ] S ^ 4 # spin coating 1J-^AS -B-B]7l :<i||
TiO2/PMMA • •sjfl ij-^-i- ^ ^ § 1 - ^
TiO2 ^ - n ^ ^ 7 ] - ^ ^ 2 g/L
^ 100 nm
90% o]^1"^
(2)
.TiO2 sol TiO2
TiO2
-40 mV
90% TiOa/CR39
TiO2
.TiO2
T1O2 2: 1 x> ^ ^ fe^ ^3L# 4|«l| ^ifl^-Hfe 2000^
$ ^ ^ l ^ ^ ^ - a ^ s l i - 4 ^ 5 ^ 5 3 3 . ^ t l S f e '99 MRS Fall meeting(^l
^, i i € ) , '00 CIMTEC(ol^2l, tflN^), Nano 2000(<a^-) ^cf° l)^ ^-^ »i3.
r A S f e -ifl /i]e}-Hi«}-3*Hl 2?i, ^ - ^ ^ J. Mater. Sci. Lett
l, J. Sol-Gel Sci. and Tech.i TiO2 #?> special issued ^ J l
5>° accept € ^V^O14. °1 special issued-fe
reviewerS.
2, 3
- 187 -
TiO2 ^ ^ - 4 ^ S * l ^ £^*l |2:7l££- D.
TiO2 ] ] ]
4€- ^a< f l ^S . <>1 SL^i-l- 3 H ! ^ ^
f ^ i ^ M q 4€- TiO2
, IMF ^1^1- ^A^^i ^^^S^-Ei^ j i ^ S ] TiO2 Ir^-i-
71 ^ ^ - c ] }
Cf. If-*]
o] 7 ] iM 71 -^#
y\ $\n *\M 1, 2 ^
^ , 3 *>Td£<flfe 1, 2 ^ } \ l £ i 7fl - r TiO2 ^$ ^ sol
*\ 711 # ^ TiO2 ^-^^r PMMA4 ^ ^
^ ^ ^ l " o l 1.7 ol
2000\i 7 ^ ^ * | E M-iJL l
SSI # ^ 1 - ^ - ^*}7}7) ^1*> <a:?7> TiO2
Nb2O5 l: ^ 7 ^ f e
TiO2
- 188 -
T i 0 2
^#€: 33,33, sfails^^aL: 33, ^tfl^^^^^s: 93). H,
^1-^4.(2000^ 3^ lOH KBS, MBC, SBS, YTNo||Ai S.E.,
, a ^ ^ i s , s t i i M , ^Aj^aoii 2000a
^ 2000^ 4 ^ 2 , c||°.^M 2000a 8^S
7\.
TiO2
l."Photocatalytic Effects of Rutile Phase TiCk Ultrafine Powder with High
Specific Surface Area Obtained by Homogeneous Precipitation process at
Low Temperature," S. J. Kim, S. D. Park, C. J. Jeon, Y. H. Cho, C. K. Rhee,
E. G. Lee, and W. W. Kim, J. Sol-Gel Science and Technology, Accepted at
- 189 -
July 17, 2000
2. "Understanding of Homogeneous Spontaneous Precipitation for
Mono-dispersed TiCte Ultrafine Powders with Rutile Phase around Room
Temperature," Soon Dong Park, Young Hyun Cho, Whung Whoe Kim,
Sun-Jae Kim, 1999.8.1, J. Solid State Chemistry, 146(1) (1999) 230-238.
3. "Homogeneous Precipitation of TiCfe Ultrafine Powders from Aqueous TiOCk
Solution," Sun-Jae KIM, Soon-Dong PARK, Yong Hwan JEONG, and Sung
PARK, 1999.4.1, J. Am. Ceram. Soc., 82(4) (1999) 927-932.
4."Preparation of Ultrafine Crystalline T1O2 Powders from Aqueous TiCU
Solution by Precipitation," Hee-Dong Nam, Byung-Ha Lee, Sun-Jae Kim,
Chung-Hwan Jung, Ju-Hyeon Lee, and Sung Park, 1998.8.15, Jpn. J. Appl.
Phys, 57(8) (1998) 4603-4608.
5."Zr/Ti ratio dependence of the deformation in the hysteresis loop of
Pb(Zr,Ti)O3 thin films,"Eun Gu Lee, Jong Kook Lee, Ji-Young Kim, Jae Gab
Lee, Hyun M. Jang, and Sun Jae Kim, 1999. 12, J. Materials Science Letters,
18 (1999) 2025-2028.
6."Numerical Investigation of the Mechanical Behavior of Nanocrystalline
Copper," H.S. Kim, C. Suryanarayana, S.J. Kim, and B.S. Chun, 1998.10.1,
Powder Metallurgy, 44(3) (1998) 217-220
7."Sintering and Electrical Properties of (Ce02)o.9(Gd203)o.i Powders prepared
by Glycine-Nitrate Process for Solid Oxide Fuel Cell Applications," In-Sik
PARK, Sun-Jae KIM, Byung-Ha LEE and Sung PARK, 1997.10.15, Jpn. J.
Appl. Phys, 36(10) (1997) 6427-6431
8."Compaction Behavior of Rapidly Solidified Al-Si-Fe-Cr Alloy Powders,"
Hyoung Seop Kim, Sun-Jae Kim, Hong Ro Lee, Chang Hwan Won, Seong
Seock Cho and Byung Sun Chun, 1997.12.1, Scripta Materialia, 57(11) (1997)
1715-1719
S. TiOCk ^r-g^JHH £ ^ T1O2 ,
$ ^ 1 , 57(5)
- 190 -
(2000) 473-478.
2."TiOCl2 ^r-g-^AS^r-Bl *HH°.5. iHM-fe 3 - ^ ^ H ^ £ 3 # TiO2
], 55(11) (1998) 1212-1221
3."TiCl4 *r-g-«H*1 3 3 1 H W £ 3 ^ TiO2
, 1998. 5, ^ ^ A ^ S ) - ^ ! ^ , 35(4) (1998) 325-332
f - 20mol% Gd-doped CeO2 i
, 1998. 5, tfl##7l*l-3iM, 47(5) (1998) 593-601
20mol% Gd-doped CeO2
(1998) 1898-1904.
5,vfe Pb(Zr,Ti)O3 ^
(1999) 1035-1039
7."Pb(Zr,Ti)O3
, 10(5) (2000) 360-363
!, * # U 1997.6,
2]^], 10(5) (1997) 487-491
9."20mol% Gd-doped 4^*0 CeO2 ^i«ll^^
1998. 2, ^^•-S.^-§)-2i^> 55(1) (1998) 97-105
1."Method for Production of Mono-dispersed and Crystalline TiO2 Ultrafine
Powders from Aqueous TiOCk Solution using Homogeneous Precipitation,"
3^*11, ^ ^ # , 3 ^ S , 3-8-$, ^<&% United States Patent No. 6001326,
1999.12.14
- 191 -
Japanese Patent No.2972752, 1999.8.27.
^224732JL, 1999.7.15.
, ^^(98119338.2, 1998.9.17 ^ # € , CN 1242342A, 2000.1.26
2."Verfahren zur Herstellung ultrafeiner TiO2-Pulver,"
, ^-^(198 41 679.2, 1998.9.11 ^ # 3 1 )
^ - ^ « , P 1 ^ ^ - « 1 # ^ , 2000.
7. 5.
, 1998.7.16.
^ ^ ^ TiO2
^1199-132845:, 1999.4.15.
2000-10242S, 2000.2.29.
- 192 -
1."Effect of Vapor Pressure of H2O on the Formation of Nano-Crystalline
T1O2 Ultrafine Powders," Kang-Ryeol Lee, Sung Park, Jae Song Song,
Sun-Jae Kim, 1999 MRS FallMeeting Abstracts Book F:Nanophase and
Nanocomposite Materials HI, p.125, F8.66
2."Phase transformation of T1O2 ultrafine powders from aqueous TiOCh
solution during homogeneous solution," SJ. Kim, H.G. Lee, S.D. Park, CJ.
Jeon, C.K. Rhee, W.W. Kim, Int'l Conf. Mass and Charge Transport in
Inorganic Materials, B2:PO3, 2000.5.28-6.2, Venice-Jesolo Lido-Italy, p.38
3."Photocatalytic Characteristics of Homogeneously Precipitated TiC"2
Nano-sized Powders," C.J. Jeon, C.K. Rhee, S. Park, W.W. Kim, and S.J.
Kim, Fifth International Conference on Nanostructured Materials(Nano 2000),
2000.8.20-25, Japan, Sendai
20mol% Gd-doped CeO2 ^
'97 ^Tf l^ t f lS j fcS-^ , pp. 30
5-307, 1997.11.29, ^^cflSJ-S, •%•<&
Zr-doped TiO2 ^ ^ S ) ^ ^ % ^ #^<g^;- '99
^ ^ ^ B , 1999.4.21-22.
T1O2 i ^ ^•^•^^°1| *>]*]& <$%" '99
-, 7j^7j), 7j^s, •§-«:, 1999. 4.21-22.
TiO2 ^1 3 1 ^ ^ ^ r ^ s ] ^ A ^ » '99
, 1999.4.30-5.1.
5."TiOCl2 ^r-g-^-i- °l-8-^ l ^ ^v T1O2 #-gr^
-g-g-" S ^ - ^ pp.78-79, ?^tflS)-57, 1999.10.14.
^-2-S. ^11^^ TiO2
- 193 -
, '00p.20, ^ l t f lSJ -SL, 2000. 04.21.
r'GNP^l 3 $ Thermal Battery-g- #^*1)JL CaCrO4 € - ^ t ^ ^ Ca/LiCl-KCl
/CaCrO4 313 ^71 SJ-SJ-3?! ^ H
fl-, ^ ^S ] , ^zJJj!., '00 tt^^l5}^«l-5l ^^ l^ - ' t r f l ^ i l ^ J p.112,
51, 2000. 04.21.
8 . ' * i £ 5 1 ^ ^ ° . 3 . ^ 2 : ^ TiO2 l
^ ^ ^ , ^ ^ ^ , o lW, ^ * ^ , '00
2000.05.12.
, 2000.05.19-20
2000. 3.9
Tel:042-868-8270,2169
Fax: 042-861-1428
f ° l %•§•
- 194 -
UV
waveguide^ 4
^ 3. -§-£.7>
4
(TiCl4)
10~30nm
- 195 -
47],
2-3^
4(042-868-2047/8565)
- 196 -
20-30
3J-iL7}-
1981 Vi ^^r^l^fe S^l^^} *H2:<H| fl]?!: S l ^ l f. i980idifl ^ ^ ^ 1 ^-^51 H. Gleiter^l
S-317} $ 1 ^ 4 . Ol^ol) o] A] 7160
371 W 3 "o1" 0!! 51 *> ^ 2 4 ^ 1 ^ ^BSSl ^02: ^ «1 *3 (quantum dots)2l
Nanodyne Inc. ^ 4 ££r ^ l ^ ^ ^ l r 0 ! SL*f- <>}
. 1991\i °W 4 ^ ^S-^ r€ <a^a.Ji7l- 2775^1 <>]$• %jv
^ . ^ 1996\S
'S: # 3003
- 197 -
711*1,
7} g[o.H
^ ^ TiO2 3171
opacity^ color
o]7l
$\- v
TiO2
TiO2S] 3.
- 198 -
, vinyl sliding^ ^<2]-§- 7Ht«1M 4-8-s|fe- S 4 ^ *l]#£r TiO2^ 7K1" €. o) -8~g-a||^#£ q^-^\ 6>3o] ^A^l-71 nfl^^l &H 5] *}<2}Ai o>
TiO2» ^rS. 4-8-$4.5 ^ *H $171
uv
Waveguide^
fe a^l^-^l TiO2
TiO2
TiO2 ^ - ^ ^
13.
71- &•§• ^ ^>
^7}7> til*}7l
i , - -«H ? 1 t « TiO2 ^
100°C 6is>^ # £ ^Soflxi 2}^ TiO2
- f ^ 7l#S.^, TiCU ^-§-°J]AS^-E-1
TiO2 ^r^^r
- 199 -
Jpn. J. Appl. Phys.H
Am. Ceram. Soc., J. Solid State Chem.,
'98 ^
. 7)
TiO2
TiO2 s ^ m71
fe T1O2
TiO2
-g-§-§1-7l
•8-$ l - XIal
O.5. TiCUl- 1000°C o . s T i o 2
i*-^ HC1 7}i
800°C J2.3. ic3.fl|o] Titan Co.
fe T1O2 ^r^S] tfl^-^-^. D ] ^
TiO2 ^•^•^l cfl*l]A^
nil-8-
- 200 -
, TiO2
<O.S $13} off
1 £ # • $ TiO2
T1O2 ^ - ^ 7fl
fe TiO2 &T&-8: <££$) Teikoku
-S] Micro Titanium Dioxide(MT-series)4 T3!^-^ DOW Chemical Co, Whittaker
^KUnitane C-series), Dupont4^ 4 ^ ^^^-%-SLS,^ ^S. ^'£°] Degussa
4^°} ^r^sjS 91^. 4 ^ $ -f- 1 Z^xW 20 ~ 50 nm^ 3.7]°]3. H]
] 30 ~ 100 m2/g^l4. ^ ^ , € ^ ^ ^ ^ ^ ^ 1 1 ^«fl ^ ^
^ ^ # °l-g-«>^ ^9S€ 2^1€-*fl T1O2 -^^r 10 nm
150 rnVg
. 7] 7fl^-€
60
TiO2 ^ -^#
71 # ^ ^ .
71^01
-5.S 71)
2S
- 201 -
-TiO2
A>-§-ol aLS)£)JL o j ^
^el300nm
fe ^JE-f-g- =21-^
fe 550 nm 2.57, fe 2.743,*\
—7 trJ
M\ n A| § ^ a3} -^ A| § ^ 3.
mm AIS^H(1997) 87,500e|§!
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- 202 -
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- 203 -
6
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- 208 -
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United States PatentKim et al.
US006001326A
[li] Patent Number:
[45] Date of Patent:
6,001,326Dec. 14,1999
[54] METHOD FOR PRODUCTION OF MONO-DISPERSED AND CRYSTALLINETIO2ULTRAFINE POWDERS FOR AQUEOUSTIOCL2SOLUTION USING HOMOGENEOUSPRECIPITATION
[75] Inventors: Sun-Jae Kim; Soon Dong Park;Kyeong Ho Kim; Yong Hwan Jeong;II Hiun Kuk, all of Taejon-ku, Rep. ofKorea
[73] Assignee: Korea Atomic Energy ResearchInstitute, Taejon, Rep. of Korea
[21] Appl. No.: 09/162,009
[22] Filed: Sep. 28, 1998
[30] Foreign Application Priority Data
Jul. 16, 1998 [KR] Rep. of Korea 98-28928
[51] Int. Cl.6 C01G 25/02; C01G 23/047[52] U.S. Cl 423/598; 423/608; 423/611;
423/612[58] Field of Search 423/598, 608,
423/610, 611, 612
[56] References Cited
U.S. PATENT DOCUMENTS
2,832,731 4/1958 Cunningham 204/643,846,527 11/1974 Winter et al 264/633,923,968 12/1975 Basque et al 423/6114,002,574 1/1977 Wade 252/1884,012,338 3/1977 Urwin 252/4614,842,832 6/1989 Inoue et al 423/2114,923,682 5/1990 Roberts et al 423/6114,944,936 7/1990 Lawhorne 423/6125,030,439 7/1991 Brownbridge.
5,068,056 11/1991 Robb 252/313.15,075,206 12/1991 Noda et al 430/5315,173,397 12/1992 Noda et al 430/5315,443,811 8/1995 Karvinen.5,821,186 10/1998 Collins 502/8
OTHER PUBLICATIONS
Kim et al. Preparation of mono-dispersed ultrafine TiO2crystalline powders by homogeneous spontaneous precipi-tation from aqueous TiOC12 solution. Yoop Hakhoechi, 35(11), 1212-1221 (Korean) . Korean ceramic Society, 1998.Nam et al. Preparation of ultrafine crystalline TiO2 powdersfrom aqueous TiC14 solution by precipitation. Jpn. J. Appl.Phs., Part 1, 37 (8), 4603-4608 (English). Japanese Journalof Applied Physics, 1998.Kim et al. Preparation of crystalline TiO2 ultrafine powdersfrom aqueous TiC14 solution by precipitation method. YoopHakhoechi, 35 (4), 325-332 (Korean). Korean CeramicSociety, 1998.
Primary Examiner—Gary P. StraubAssistant Examiner—Cam N. NguyenAttorney, Agent, or Firm—Bachman & LaPointe, P.C.
[57] ABSTRACT
A method for production of mono-dispersed and crystallinetitanium dioxide ultra fine powders comprises preparing anaqueous titanyl chloride solution, diluting the aqueous tita-nyl chloride solution to a concentration of between about 0.2to 1.2 mole and heating the diluted aqueous titanyl chloridesolution and maintaining the solution in a temperature rangeof between 15 to 155° C. to precipitate titanium dioxide. Theaqueous titanyl chloride solution is prepared by adding icepieces of distilled water or icing distilled water to undilutedtitanium tetrachloride.
12 Claims, 4 Drawing Sheets
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U.S. Patent Dec. 14,1999 Sheet 1 of 4 6,001,326
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U.S. Patent Dec. 14,1999 Sheet 2 of 4 6,001,326
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U.S. Patent Dec. 14,1999 Sheet 3 of 4 6,001,326
FIG. 3
FIG. 4
U.S. Patent Dec. 14,1999 Sheet 4 of 4
FIG. 5
6,001,326
FIG. 6
6,001,3261 2
METHOD FOR PRODUCTION OF MONO- conventionally hydrolyzed at temperatures higher than 95°DISPERSED AND CRYSTALLINE C., calcined at 800-1,000° C. and then pulverized to produce
TIO2ULTRAFINE POWDERS FOR AQUEOUS titanium dioxide powders. During these calcination andTIOCL2SOLUTION USING HOMOGENEOUS pulverization processes, impurities are introduced causing
PRECIPITATION 5 the quality of the final titanium dioxide powder to be low.However, compared with gas phase process, the liquid
FIELD OF THE INVENTION p b a s e p r o c e s s represented by the sulfate process needs aThe present invention relates to a method for production milder temperature condition and makes it possible to pro-
of mono-dispersed and crystalline titanium dioxide (TiO2) duce titanium dioxide in a large amount, thus there haveultrafine powders. In particular, the present invention relates 10 been some other reports about an improved liquid phaseto a method for production of mono-dispersed and crystal- process or new liquid phase process to fabricate crystallineline titanium dioxide ultrafine powders, which comprises (a) titanium dioxide powder using titanium tetrachloride, thestep of preparing aqueous titanyl chloride (TiOCy solution starting material in the chloride process,in a concentration of greater than or equal to 1.5M, by Russia patent SU-1,398321 shows a new liquid phaseadding ice pieces of distilled water or icy distilled water to : 5 process, in which an adequate amount of anatase phasethe undiluted titanium tetrachloride (TiCl4); (b) step of titamferous seed was added into titanium tetrachloridediluting the above aqueous titanyl chloride solution to a solution, hydrolyzed to precipitate titanium dioxide powdersspecific concentration by adding an adequate amount of by heating and the precipitated titanium dioxide was fabri-distilled water; (c) step of obtaining titanium dioxide pre- cated by an additional process such as a high temperaturecipitates by heating the above diluted aqueous titanyl chlo- 20 treatment. This process is simple but requires additive highride solution and maintaining the temperature within a range temperature treatment of 600-650° C. to obtain anataseof 15-155° C; and (d) step of fabricating the mono- phase titanium dioxide, and a much higher temperaturedispersed and crystalline titanium dioxide ultrafine powders treatment to obtain rutile phase titanium dioxide,by filtrating, washing and drying the above titanium dioxide ^ in addition, in JP 9-124,320, gel was formed by addingprecipitates. water to titanium tetrachloride dissolved in alcohol such as
BACKGROUND OF THE INVENTION butanoL together with one of various kinds of acetate,BACKGROUND Vb IHb INVbNilOlN carbonate, oxalate and citrate containing alkali metals or
Titanium dioxide, which is usually used as photocatalyst alkali earth metals. Then, the obtained gel was treated withremoving environmental pollutants, pigment materials, high temperature and titanium dioxide was fabricated. Theadditives for plastic product or optical multi-coating reagent, physical properties of titanium dioxide powders produced byhas two phases of crystalline structure, that is anatase and this method are good, but the process requires expensiverutile. Titanium dioxide with anatase phase has been used as additives such as organic acids and needs a high temperaturea photocatalyst for photodecomposition of acetone, phenol treatment to remove added organic acids after gel formation,or trichloro ethylene, oxidation system of nitric oxide such 3J Another process like sol-gel method and hydrothermalas nitrogen mono-oxide and nitrogen dioxide and conversion synthesis has been developed to control the titanium dioxidesystem of solar energy because of its high photo-activity. powder characteristics such as particle shape, particle sizeTitanium dioxide with rutile phase has been widely used for ancj distribution of the particle size. Metal alkoxide iswhite pigment materials because of its good scattering effect usually used to fabricate spherically shaped titanium dioxidethat protects the ultraviolet light. It has also been used for 4Q powders with a uniform size on a laboratory scale and thisoptical coating, beam splitter and anti-reflection coating sol-gel method using alkoxide produces fine sphericallysince it has a high dielectric constant and refractive index, a shaped powders with a uniform, size smaller than 1.0 fim.good oil adsorption ability and tinting power, and chemical However, tight control of the reaction conditions is requiredstability, even under strongly acidic or basic conditions. s i n c e alkoxide is intensely hydrolyzed in air. Furthermore,Titanium dioxide shows different electrical characteristics 45 the high price of the alkoxide limits its commercialization,according to oxygen partial pressure since it has wide The hydrothermal synthesis using an autoclave under highchemical stability and non-stoichiometric phase region. temperature and pressure conditions produces high qualityBecause of this, it can also be used for a humidity sensor and powders but a continuous process has been impossible, up toa high-temperature oxygen sensor, and the field of its use has n o w .become wide. 50 The p r e s e n t inventors have successfully developed a new
Generally, titanium dioxide powders are fabricated by a titanium dioxide powder fabrication method. In the method,chloride process, which is a gas phase process, or by a it is possible to prepare titanium dioxide powder with goodsulfate process, which is a liquid phase process. characteristics such as particle shape, particle size and
In the chloride process, which was industrialized by Du distribution of the particle size, reproducibly and continu-Pont in USA in 1956, titanium tetrachloride, vigorously 55 ously. In addition, it is easy to control the mixture ratio ofreacting with moisture in the air and undergoing hydrolysis, rutile and anatase phase of the titanium dioxide crystalline,is used as a starting material and the reaction temperatureneeds to be higher than 1,000° C. Also, this method requires SUMMARY OF THE INVENTIONextra protection devices because of the corrosive HC1 or Cl2 The object of the present invention is to provide a methodgas by-produced in the process, leading to higher production go for production of mono-dispersed and crystalline titaniumcosts. Because titanium dioxide powders produced by the dioxide ultrafine powders, in which it is possible to preparechloride process are fine but rough, additive equipment for titanium dioxide powder with good characteristics such asgiving external electric fields or controlling reactant mixing particle shape, particle size and distribution of the particleratios are required to control the particle shape and the size, reproducibly and continuously not requiring an addi-particle size of titanium dioxide powders. 55 tional treatment, and in which it is also easy to control the
In the sulfate process, which was industrialized by Titan mixture ratio of rutile and anatase phase of the titaniumcompany in Norway in 1916, titanium sulfate (TiS04) is dioxide crystalline.
6,001,3263 4
BRIEF DESCRIPTION OF THE DRAWINGS The present invention also provides a method for theFIG. 1 is a graph showing the volume ratio of ruffle phase Production of mono-dispersed and crystalline titanium diox-
for mono-dispersed and crystalline titanium dioxide ide ultrafine powders compnsmg the steps of: (a) preparingultrafine powders with the precipitation reaction a £ 5 u e o u s M"* 1 c h l o n d e ^ ^ ^ m a concentration oftemperature, which is calculated from the ratio of peak 5 8 r e a t e r t h a n o r e c i u a l t 0 1 5 M > bV a d d i n g i c e P i e c e s o f
intensity of X-ray diffraction of rutile phase and anatase d l s t l l ^ d water,?[ »<* bu l led water to the undiluted titaniumphase of the precipitates prepared from titanyl chloride te^achlonde; (b) dilutmg the above aqueous titanyl chloridesolution with a titanium ion concentration of 0.47M at solution to a specific concentration with an adequate amountvarious reaction temperatures. of distilled water; (c) obtaining titanium dioxide precipitates
__„ . . . , . .. . .. . , 10 by heatmg the above diluted aqueous titanyl chloride solu-FIG. 2 is a graph showing the primary particle size at ^ a n d m a i n t a i n i n ^ temperature within the range of
various precipitation reaction temperatures, which resulted 15_?()O Q fof 2 {o fi* ^ f a b r i c a t i ^ msQno_
from the X-ray diffraction patterns for mono-dispersed and e d a n d ^ t i t a n i u m d i o x i d e u l t r a | n e d e r scrystalhne titanium choxide ultrafine powders. by filtrating, washing and drying the above titanium dioxide
FIG. 3 is a SEM micrograph of mono-dispersed and l 5 precip;tatescrystalline titanium dioxide ultrafine powder with a mixture . . . ,.of rutile and anatase phases which are precipitated at 130° C. I n W s t eP of the above methods, the concentration of thefxlOOOOl prepared titanyl chlonde is preferable at 0.2 to 1.2M.
HG. 4 is a SEM micrograph of mono-dispersed and T ^ precipitation reaction of (c) step of the above meth-crystalline titanium dioxide ultrafine powders with rutile 20 ods can be carried out by adding ethanol higher than or equalphase which is transformed from the precipitates with the t 0 x volume % after (b) step. And the added ethanol can bemixture of rutile and anatase phases formed at 100" C. by a evaporated completely during (c) step,pressure of 5 bar (xl0,000). In addition, between (c) step and (d) step, a pressure of
FIG. 5 is a SEM micrograph of mono-dispersed and higher than 4 bar can be applied to the precipitates for 48crystalline titanium dioxide ultrafine powders with rutile 25 hours or more,phase which is precipitated at 60° C. (xl0,000). The present invention is characterized by the mono-
FIG. 6 is a SEM micrograph of mono-dispersed and dispersed and crystalhne titanium dioxide ultrafine powderscrystalline titanium dioxide ultrafine powders with rutile that can be obtained by spontaneous hydrolysis and crys-phase which is precipitated at 17° C. (xlO,000). tallization occurring simultaneously at 80 to 95% of yield.
DETAILED DESCRIPTION OF THE 30 Titanium tetrachloride used in the present invention isINVENTION really difficult to quantify since it has high vapor pressure at
In the present invention, mono-dispersed and crystalline r o o m temperature and tends to vigorously react with mois-titanium dioxide ultrafine powders are prepared by sponta- |» r e "? t h e air> a n d " ? a l s o d l f f i c u l t t 0 toow «*?«*>« theneous precipitation using a stable transparent titanyl chloride 35 form m aqueous solution state is titanium tetrachlonde orsolution that is prepared from titanium tetrachloride as a btu^1 c h l o n d e - Therefore, a stable aqueous solution with
- . j constant titanium ion concentration which is prepared by_, ' . . , ,. , „ . . . diluting unstable titanium tetrachloride-undiluted solution isThe present invention provides a method for production fi precipitation reactions quantita-
of mono-dispersed and crystalline titanium dioxide ultrafine ^ a n d tQ ^ J ^ J ^ o ? t i t a m - u m c h i o r i d e with thepowders comprising the steps of: (a) preparing aqueous 40 m o i / t u r e i n t h e a i rtitanyl chloride (TiOClj) solution in a concentration ofgreater than or equal to 1.5M, by adding ice pieces of F°r the reason, in (a) step of the present invention,distilled water or icy distilled water to the undiluted titanium transparent and stable titanyl chloride solution with a tita-tetrachloride; (b) diluting the above aqueous titanyl chloride "him ion concentration higher than 1.5M is prepared bysolution to a specific concentration by adding an adequate 45 adding ice pieces of distilled water or icy distilled water toamount of distilled water; (c) obtaining titanium dioxide the undiluted titanium tetrachloride of high purity via aprecipitates by heating the above diluted aqueous titanyl yellow and unstable intermediate solid, and the preparedchloride solution and maintaining the temperature within the titanyl chloride solution is kept at room temperature to userange of 15-155° C; and (d) fabricating the mono-dispersed a s a starting material of the precipitation reaction. If titaniumand crystalline titanium dioxide ultrafine powders by 50 tetrachloride is used with a volume ratio to prepare thefiltrating, washing and drying the above titanium dioxide starting stock solution, the vapor pressure increases duringprecipitates. the preparation of the titanyl chloride solution, with titanium
In detail, the present invention provides a method for i o n concentration higher than 1.5M. Thus, the loss of aproduction of mono-dispersed and crystalline titanium diox- titanium tetrachloride increases and the reproducibility ofide ultrafine powders comprising the steps of: (a) preparing 55 t h e reaction falls off. This result makes it difficult to controlaqueous titanyl chloride solution in a concentration of the amount of reactant and predict the productive efficiencygreater than or equal to 1.5M, by adding ice pieces of o f t h e final product. Therefore, in the present invention, adistilled water or icy distilled water to the undiluted titanium s t a b l e t l t a ny ! chlonde solution is firstly prepared by addingtetrachloride; (b) diluting the above aqueous titanyl chloride a l e s s e r amount of water than the quantitative amount to thesolution to a specific concentration with an adequate amount 60 titanium tetrachlonde and an accurate concentration of theof distilled water; (c) obtaining titanium dioxide precipitates s t a r t i nS matenal can be given by determining the titaniumby heating the above diluted aqueous titanyl chloride solu- 10n concentration of the prepared solution. This makes ittion and maintaining the temperature within the range of e a sy t o Predict the productive efficiency of the final product75-155° C. for 20 minutes to 3 hours; and (d) fabricating the a n d k e eP t h e reproducibility of this invention,mono-dispersed and crystalline titanium dioxide ultrafine 65 If titanium tetrachloride is added to the water instead ofpowders by filtrating, washing and drying the above tita- adding water to titanium tetrachloride to prepare titanylnium dioxide precipitates. chloride solution, vigorous hydrolysis occurs as follows.
6,001,3265 6
Scheme I to provide the hydroxide ion and the reaction system isheated so as to jump over the activation energy barrier, thencrystallization, as shown in Scheme IV, occurred at the same
TIC14+4H2O-TI(OH)4+4HC1 t j m e ^ m e hydrolysis shown in Scheme III, leading to the, , „ , T T,v/~.ir. . , , , 5 formation of titanium dioxide precipitates with increasing
As shown in the above Scheme I, Ti(OH)4, insoluble . . . v * s
hydroxide is formed and the resultant is a suspension of ^Scrf me IIIstrong hydrochloric acid containing both aqueous titanicacid solution and hydroxide. Although titanium dioxideprecipitates are formed in this suspension by continuous 1Q
hydrolysis, the formed titanium dioxide precipitates areamorphous or have weak crystallinity leading to low pro- Scheme IVductivity even if using a starting material with a very lowtitanium ion concentration.
In addition, in the present invention, only the titanyl TIO(OH)2+2HC1-TIO2XH2O+2HCIchloride solution prepared by adding the water to titanium ^ s ^ d u r f ^ { n ^ ^tetrachlonde is used for the precipitation reaction. When * ^ J £ soicwhitadding the water to the titanium tetrachlonde, it is important . , , . , , , , . , , . " '. ,B , . . , , t , , , ' , r , irregular, and is not suitable for obtaining mono-dispersednot to cause the reaction slowly but to add a lesser amount . . ,. . , . . . . . . . , 6 ., , v . .7 . . . . , ' . . . , . . . , . titanium dioxide particles, stirring is done until the precipi-
of water to the titanium tetrachlonde than the stoichiometnc 2Q r e a c t - o n ^ . a n d ' J ^ Jamount Even if hydrolysis takes place dunng the reaction ^ {s ^ ^ r e a c t i o n v J e l with
P?alid fe J d i n fhe
it is not hydrolysis in apparent reaction, therefore the Many { ^ ^ n Q t (Q c o n ( r o l i n n e r r<;
chlondesoluuon prepared m the present invention does not ^ . ^ ^ r a t i o n o f m a t e r i a l s S 1 K / a n d
contain insoluble hydroxide and has transparent character- . . , . , , . , ,„<> _•• , ,. . " . . • • T i ui • J ,1 u .u ethanol which begins to evaporate at 60 C. and to completeistics from the beginning. Titanyl chloride, prepared by the , . . ,. & . / „ . , „ . . . *c ,, • t. TT • ,-n . t.1 • .u . ,u 2 5 t n e precipitation reaction at 90 C. or more within 1 hour. Infollowing scheme II, is still more stable ,n the water han ^ ^ m o n o . d i s e d t i t a n i u m d i o x i d e w d e r s i stitanium tetrachlonde and can be kept as in stable stock t h a n 1 5 5 O ^solution state at room temperature through stabilizing after m p c r a t n r e . I t k d e s i r a b l e t h a t t h e p r e c i p i t a t i o n r e a c t i o n i s
the preparation reaction and adjusting concentration of this ^ ^ a J t a t u r e s l o w e r t h a ^ 155P<, c s i n C 6 a d d ; t i v e
solmion to higher than 1.5M. 3Q e q u i p m e n t p a r t i c u i a r i y d e s i g n e d for safety, is required toe m e increase the water vapor pressure over 5 bar during the
reaction.TiCl4+H O-Tioci2+2HC1 *n particular, the physical properties of titanium dioxide
powders are controlled by changing the reactionThe solution also remains stable and transparent even 35 temperature, the reaction time, the amount of added ethanol
though a large amount of water is added within a short time or the state of the reaction vessel, in the present invention,as long as the concentration of the solution is adjusted to Firstly, the reaction temperature of the present invention ishigher than 1.5M. That is, the hydrolysis producing Ti(0H)4 controlled within 15 to 155° C. The complete rutile phase ofdoes not occur even if hydrolysis does occur by adding titanium dioxide ultrafine precipitates are obtained when thewater. 40 precipitation reaction is carried out at temperatures within
In (b) step of the present invention, the above titanyl 15 to 70° C , preferably 15 to 65° C. and the anatase phasechloride solution in a concentration of higher than 1.5M is is increased when the precipitation reaction is carried out asdiluted in a titanyl chloride solution with a concentration of the temperature increases within the range of 70 to 155° C ,0.2 to 1.2M by adding water, which is used as a starting thus the anatase phase is increased to about 45 volume % atmaterial. This diluted solution is sensitive to form precipi- 45 155° C. Secondly, with a precipitation reaction time longertates and gives high productive efficiency of the final prod- than 1 hour at over 100° C. or the addition of ethanol beforeuct. Additionally, the diluted solution prevent the loss of the precipitation reaction becomes over 1 volume %, thetitanium ion, which is resulted from the increase of vapor results are improved crystalline properties of rutile phase orpressure during the reaction, so the productive efficiency of an increased volume ratio of rutile phase to over 80 volumefinal product can be determined by theoretic volume ratio. 50 % or more. In addition, pressure over 4 bar for over 48 hours
However, if the concentration of the titanyl chloride transforms the anatase phase, which is contained in thesolution is higher than 1.2M, even during the diluting resultant precipitates, to a rutile phase completely., or itprocess of the present invention, crystalline precipitates do improves the crystalline properties of rutile phase which isnot form homogeneously even after 10 days at temperatures originally contained in the resultant precipitation reaction,lower than 100° C. Moreover, if the concentration of the 55 Thirdly, manipulating the opening of the equipment totitanyl chloride solution is lower than 0.2M, the nucleus of control the evaporation amount of water or ethanol canthe titanium dioxide precipitates are formed in a large result in a completely pure anatase phase of titanium dioxideamount but the growth of the nucleus does not occur at the crystalline of 100 volume %.same time, thus the size of the formed titanium dioxide In addition, the size of mono-dispersed titanium dioxideparticles is lower than 0.05 /un and the yield of the final 60 particles can be controlled by changing the reaction tem-product is lower than 30 volume % by usual filtration using perature in the present invention. Mono-dispersed titaniumfilter paper and centrifugation. dioxide ultrafine powders, which consists rutile and anatase
In (c) step of the present invention, the titanyl chloride phases having secondary particles with a size of 0.2 to 0.4solution is heated and maintained at a certain temperature /im formed by uniform cohesion of primary particles with afor precipitation reaction. It takes some degree of time to 65 size of about 10 nm, can be obtained regardless of theprecipitate, which means that activation energy is required reaction temperature and reaction time, as long as thefor the precipitation reaction. In the reaction, water is added reaction is carried out within 70 to 155° C. On the other hand
6,001,3267 8
mono-dispersed titanium dioxide powders, which consist of The present invention is further illustrated with referenceonly rutile phase having secondary particles with a size of to the following examples that are not intended to be in any0.05 to 0.5 fan relative to the increase of the reaction way limiting to the scope of the invention as claimed,temperature formed by uniform agglomeration of primaryparticles with a size of smaller than 10 nm, can be obtained 5 EXAMPLE 1if the precipitation reaction is carried out within the tem-perature range of 15 to 70° C, preferably 15 to 65° C. For Fabrication of the Mono-Dispersed Titaniummono-dispersed titanium dioxide ultrafine powders with a Dioxide Powders (1)size of smaller than 0.1 urn, it is preferable that the precipi- . - , , , .tation reaction is carried out using a titanyl chloride solution n
T o V™?^ a stable aqueous titanyl chloride solution withproperly-diluted at lower than 20° C. or using titanyl chlo- 10 a concentration of greater than or equal to 1.5M, an adequateride solution with a low dilution concentration at higher than amount of ice pieces of distilled water or icy distilled watermid-range temperature for about 48 hours. Although a long w a s slowly added to the undiluted titanium tetrachloride,time is required for the reaction, a continuous process makes which had been cooled below 0" C, to cool the reaction heatit possible to produce titanium dioxide particles economi- generated by the reaction of titanium tetrachloride withcally with relatively low energy consumption. 15 water, and the solution was then stirred.
Titanium dioxide powders, which are fabricated by apply- The above titanyl chloride solution was diluted with aning pressure higher than 4 bar to the precipitates obtained adequate amount of distilled water to a concentration offrom the above (c) step, consists of only rutile phase having 0 7 M a n d s t i r r e d s l o w l y T h e i l ; t h e d i h l t e d s o l u t i o n w a s p u t
secondary particles with a size of 0.05 to 0.5 /m, relative to i n t 0 a t e f l o n c o n t a i n e r ^ a lid> m o v e d ,0 , o v e n w i ( hthe increase of the reaction temperature formed by uniform 20 c o n s t a n t t e m p e r a t u r e o f 1 3 0 ° C . and was kept untouched foragglomeration of primary particles with a size of about 10 Q5 h o u f for d i r e c t j i t a t i o n reaction
F T h e o b t a i n e d
nm, sirmhr to the above titanium dioxide powders of rutile I i t a n i u m d i o x i d e p r e c ; i t a t e s w e r e filtered u s i a ^ m t e rphase. Therefore, crystalline titanium dioxide ultrafine pow- ^ a { o f a l tQ lcJ r e m o v e ( h eders with only note phase can be obtained with the follow- s t r o n g a d d i c ^ ^ from ( h e ; . ( h e n w a s h e ding process, which can be developed to be a useful indus- 25 w i t h , d i s t i l l e d w a t e r o f h i h e r t h a n 4 0 ° c t 0 b e n e u t r a l s t a t etnahzed fabncation method; titanium dioxide precipitates of a n d finaU w a s h e d ^ ethmolnitile phase, which are mixed with anatase phase, are firstly „ . . . , . . ,formed by the precipitation reaction at a temperature of ™ e c r y s t a £" o
e ' U a ° l u n ! d l ° x i d e P r ecJP l t a t e s w « e dned inhigher than 70° C. in a short time and the formed titanium • d n e r *l ^° C" ,,for X? hours and resulted in mono-dioxide precipitates are changed to titanium dioxide par- 30 d.spersed and crystalline titanium dioxide ultrafine powderstides witfi only rutile phase by applying pressure. w f h c o n s i s t ,o f " ^ P h a s e a n d a n a t a s e P h a s e bV t h e
In (d) step of the present invention, titanium dioxide v o I u m e r a t l ° o f a b o u t 5 0 : 5 ° -precipitates obtained in (c) step became final products The examination of the shapes of the above mono-through the post-treatment such as filtering, washing and dispersed titanium dioxide ultrafine powders by SEMdrying. In the post-treatment, the precipitates are filtered 35 showed that the size of the mono-dispersed titanium dioxideusing a usual filter paper of 0.1 jum pore size or a centrifuge powders were in the range of 0.2 to 0.4 /im (mean particleto completely remove the strong acidic solution from the size 0.3 /rai) formed by homogeneous agglomeration and theprecipitates and washed with distilled water which is heated powders consisted of primary particles with a size of aboutto over 40° C. In the conventional process, a pH-controlled 1 0 n m (FIG- 3 ) - I n addition, the specific surface area of thebuffer solution was used for complete washing of precipi- 40 mono-dispersed titanium dioxide powders was 150-200tates and preventing peptization during filtering, but in the m% and the y i e l d was 95% or more,present invention, distilled water which is heated to over 40°C. is used for washing acidic precipitates quickly to neutral hXAMPLh, 2stale without peptization. If the washed precipitates are Fabrication of the Mono-Dispersed Titaniumpulverized by ultrasonic waves, the fabricated titanium 45 Dioxide Powders (2)dioxide are composed of fine primary particles since theformed cohesive particles are dissolved to pass through the Firstly, the diluted titanyl chloride solution with a con-filter paper with 0.1 /an pore size. On the other hand, centration of 1.0M was prepared using the same procedurelong-term washing with water causes the precipitates to as in example 1. Mono-dispersed titanium dioxide powdersbond with water and causes agglomeration, thus it is desir- so with a mixture of 65 volume % rutile phase and 35 volumeable to treat the washed precipitates by ethanol before drying % anatase phase were obtained using the same procedure asto prevent agglomeration of the precipitates. in example 1 except that the reaction container was kept in
The ethanol-treated precipitates can be dried at tempera- a bath with a constant temperature of 100° C. and wastures higher than 50° C. for longer than 12 hours to obtain untouched for 1 hour for direct precipitation reaction. Inthe final mono-dispersed titanium dioxide powders, but for 55 addition, mono-dispersed titanium dioxide powders withcomplete removal of water and obtaining highly-pure crys- pure (100 volume %) rutile phase were obtained throughtalline titanium dioxide ultrafine powders, the precipitates filtering, washing and drying when the reaction time was 90should be dried at 150° C. for longer than 12 hours. minutes or ethanol of greater than 10 volume 90 was addedParticularly, when the size of titanium dioxide powders to the prepared titanyl chloride solution before the precipi-needs to be controlled, according to the various uses of the 60 tation reaction. On the other hand, mono-dispersed titaniumproduct, such as the need for large size titanium dioxide dioxide powders with pure (100 volume %) anatase phasepowders. The size of titanium dioxide powders can be were obtained when ethanol greater than 30 volume % wascontrolled by the following course; the dried titanium diox- added and completely evaporated during the precipitationide powders are calcined at temperatures higher than the reaction.drying temperature to reinforce the crystallinity of the 65 The size of the mono-dispersed titanium dioxide powdersparticles and pulverized to a suitable size by ultrasonic were in the range of 0.2 to 0.4 jura (mean particle size 0.3waves. /«n) and the powders consist of primary particles with a size
6,001,3269 10
of about 10 nm. In addition, the specific surface areas of the ders was in the range of 0.1 to 0.4 fan (mean particle sizemono-dispersed titanium dioxide powders were 150-200 0.25 /an) (FIG. 5). In addition, the specific surface area ofm2/g and the yield was 95% or more. the mono-dispersed titanium dioxide powders was 1£:0-200
m2/g and the yield was 90% or more.EXAMPLE 3 5
EXAMPLE 6Fabrication of the Mono-Dispersed Titanium
Dioxide Powders (3) Fabrication of the Mono-Dispersed TitaniumDioxide Powders (6)
Firstly, the diluted titanyl chloride solution with a con-centration of 0.47M was prepared using the same procedure 10 Firstly, the diluted titanyl chloride solution with a con-as in example 1. Mono-dispersed titanium dioxide powders centration of 0.4M was prepared using the same procedurewith a mixture of 70 volume % rutile phase and 30 volume as in example 1. Mono-dispersed titanium dioxide powders% anatase phase were obtained using the same procedure as with rutile phase were obtained using the same procedure asin example 1 except that the reaction container was kept in in example 1 except that the titanium dioxide precipitates,a bath with a constant temperature of 80° C. and was 15 which were resulted from the precipitation reaction carrieduntouched for 3 hours for direct precipitation reaction. In out at 17° C. for 48 hours, were washed by centrifugation.addition, mono-dispersed titanium dioxide powders with The obtained mono-dispersed titanium dioxide powderspure rutile phase were obtained through filtering, washing consist of primary particles with a size of 3.5 nm. Theand drying when ethanol of greater than 10 volume % was examination by SEM showed that the size of the mono-added to the prepared titanyl chloride solution before the 20 dispersed titanium dioxide powders was in the range of 0.05precipitation reaction. On the other hand, mono-dispersed to 0.08 fim (mean particle size 0.25 fim) (FIG. 6). Intitanium dioxide powders with pure (100 volume %) anatase addition, the specific surface area of the mono-dispersedphase were obtained when ethanol of greater than 30 volume titanium dioxide powders was about 200 m2/g and the: yield% was added and completely evaporated during the precipi- was 95% or more.tation reaction. 2S
^, . - , .. , . . , . . , , EXAMPLE 7The size of the mono-dispersed titanium dioxide powders
was in the range of 0.2 to 0.4 fim (mean particle size 0.3 fim) Fabrication of the Mono-Dispersed Titaniumand the powders consist of primary particles with a size of Dioxide Powders (7)10 nm. In addition, the specific surface area of the mono-dispersed titanium dioxide powders was 150-200 m2/g and Firstly, the diluted titany! chloride solution with a con-the yield was 95% or more. centration of 0.2M was prepared using the same procedure
as in example 1. Mono-dispersed titanium dioxide powdersEXAMPLE 4 with rutile phase were obtained using the same procedure as
in example 1 except that the titanium dioxide precipitates,Fabrication of the Mono-Dispersed Titanium 35 which was resulted from the precipitation reaction carried
Dioxide Powders (4) out at 65° C. for 48 hours, were washed by centrifugation.
Firstly, the diluted titanyl chloride solution with a con- The obtained mono-dispersed titanium dioxide powderscentration of 0.85M was prepared using the same procedure consist of primary particles with a size of 7.5 nm. Theas in example 1. Mono-dispersed titanium dioxide powders 40 examination by SEM showed that the shape of the mono-were obtained using the same procedure as in example 1 dispersed titanium dioxide powders was the same as FIG. 6except that the pressure of 5 bar for 48 hours was applied to a n d , t h e size was in the range of 0.05 to 0.08 /an (meanthe titanium dioxide precipitates which were resulted from particle size 0.25 fim). In addition, the specific surface areathe precipitation reaction carried out at 100° C. for 1 hour. o f t n e mono-dispersed titanium dioxide powders was aboutThe obtained mono-dispersed titanium dioxide powders 4S
1 8 5 m fe a n d t h e y i e l d was 8 7 % or more,were pure (100 volume %) rutile phase and consisted of As a result of the precipitation reactions in variousprimary particles with a size of 10 nm. The examination by conditions including the condition of the above examples, itSEM showed that the size of the mono-dispersed titanium was confirmed that the temperature of the precipitationdioxide powders was in the range of 0.3 to 0.5 fim (mean reaction should be lower than 30° C. or the concentration ofparticle size 0.4 fan) (FIG. 4). In addition, the specific 50 the titanyl chloride solution should be less than 0.4M tosurface area of the mono-dispersed titanium dioxide pow- obtain mono-dispersed and crystalline titanium dioxideders was 150-200 m2/g and the yield was 95% or more. ultrafine powders with a size smaller than 0.1 fim. On the
other hand, it was also confirmed that the temperatures of theEXAMPLE 5 precipitation reaction should be higher than 30° C. or the
55 concentration of the titanyl chloride solution should beFabrication of the Mono-Dispersed Titanium greater than 0.4M to obtain mono-dispersed and crystalline
Dioxide Powders (5) titanium dioxide ultrafine powders with a size of 0.1 to 0.5Firstly, the diluted titanyl chloride solution with a con- /*m-
centration of 0.67M was prepared using the same procedure TH£ E F F E C T Q F TRE INVENTIONas in example 1. Mono-dispersed titanium dioxide powders 60with rutile phase were obtained using the same procedure as As described distinctly in the above, mono-dispersed andin example 1 except that the reaction container was kept in crystalline titanium dioxide ultrafine powders can be pre-a bath with a constant temperature of 60° C. and was pared by the method of the present invention using stableuntouched for 4 hours for a direct precipitation reaction. The and transparent titanyl chloride solution, which is preparedobtained mono-dispersed titanium dioxide powders consist 65 from titanium tetrachloride, as a starting material withoutof 6 nm primary particles. The examination by SEM showed precipitating of white amorphous titanium hydroxide, whichthat the size of the mono-dispersed titanium dioxide pow- is liable to be formed thermodynamically. Further, long-term
6,001,32611 12
growing-up or additive post-heating treatment is not titanyl chloride solution and maintaining the tempera-required because titanium dioxide is crystallized directly hire within a range of 75-155° C. for 20 minutes to 3from the spontaneous precipitation reaction, which makes it hours; andpossible to simplify the preparing process and to put it to ( d ) f a b r i c a t i n g t n e mono-dispersed and crystalline tita-practical use with lower production costs In addition, the 5 n i u m d i o x k J e u h r a f i n e d e n ; fe fiUratin wmixture ratio of rutile and anatase phase and the particle S1Ze ^ d { ^ a b o y e t i t a n i u m ^ . ^ p r e c i p i t a t e s . &
of the titanium dioxide crystalline are reproducibly con- ^ ^ for ^ ^ o f m ^ J . ^trolled by changing the amount of added ethanol, the pre- „. . . *\ , y
cipitation temperature, the precipitation time or the pressure crystalhne "amum dioxide ultranne powders according toapplied to the precipitates, in the preparation process of the 10 c l a m \ 5 ' ^ « e i n the precipitation reaction of (c) step ispresent invention earned out with the addition of ethanol of higher than or
What is claimed is: e 9 u a l t 0 1 v°h»nie % after (b) step.1. A method for production of mono-dispersed and crys- 7- T h e method for production of mono-dispersed and
talline titanium dioxide (TiO^ ultrafine powders comprising crystalline titanium dioxide ultrafine powders according tothe steps of: 15 claim 6, wherein the added ethanol is evaporated completely
(a) preparing an aqueous titanyl chloride (TiOCl2) solu- d u r i n 8 (c) Op-tion in a concentration of greater than or equal to 1.5M, 8- The method for production of mono-dispersed andby adding ice pieces of distilled water or icy distilled crystalline titanium dioxide ultrafine powders according towater to the undiluted titanium tetrachloride (TiCl4); claim 5, wherein pressure of higher than 4 bar is applied to
(b) diluting the above aqueous titanyl chloride solution to 20 t h e titanium dioxide precipitates for 48 hours or morea specific concentration within the range of 0.2 to 1.2M between (c) step and (d) step.by adding an adequate amount of distilled water; 9 - A method for production of mono-dispersed and crys-
(c) obtaining crystalline titanium dioxide, which t a l l i n e t i t a n i u m dioxide ultrafine powders comprising theprecipitates, by heating the above diluted aqueous 25
s t e P s °fititanyl chloride solution and maintaining the tempera- (a) preparing an aqueous titanyl chloride solution in atare within a range of 15-155° C; and concentration of greater than or equal to 1.5M, by
(d) fabricating the mono-dispersed and crystalline tita- adding ice pieces of distilled water or icy distilled waternium dioxide ultrafine powders by filtrating, washing to the undiluted titanium tetrachloride;and drying the above titanium dioxide precipitates. 30 (b) diluting the above aqueous titanyl chloride solution to
2. The method for production of mono-dispersed and a specific concentration within the range of 0.2 to 1.2Mcrystalline titanium dioxide ultrafine powders according to w i t h a n adequate amount of distilled water;claim 1, wherein the precipitation reaction of (c) step is , ,. , . . ... . .carried out with the addition of ethanol of higher than or <c> °bta.ning crystalline titanium dioxide, whichequal to 1 volume % after (b) step. 35 P^apHates, by heating the above diluted aqueous
3. The method for production of mono-dispersed and titanyl chlonde solution and maintaining the tempera-crystalline titanium dioxide ultrafine powders according to t u r e W l t t u n a r a n 8 e o f 1 5 - 7 0 C- f o r 2 t 0 6 0 h°urs; andclaim 2, wherein the added ethanol is evaporated completely (d) fabricating the mono-dispersed and crystalline tita-during (c) step. nium dioxide ultrafine powders by filtrating, washing
4. The method for production of mono-dispersed and 40 and drying the above titanium dioxide precipitates,crystalline titanium dioxide ultrafine powders according to 10. The method for production of mono-dispersed andclaim 1, wherein pressure of higher than 4 bar is applied to crystalline titanium dioxide ultrafine powders according tothe titanium dioxide precipitates for 48 hours or more c i a i m 9> wherein the precipitation reaction of (c) step isbetween (c) step and (d) step. carried out with the addition of ethanol of higher than or
5. A method for production of mono-dispersed and crys- 45 e q u a i t 0 \ volume % after (b) step.talline titanium dioxide ultrafine powders comprising the u j ^ m e t h o d for p r o d u c t i o n o f mono-dispersed andsteps of: crystalline titanium dioxide ultrafine powders according to
(a) preparing an aqueous titanyl chloride solution in a c i a i m io, wherein the added ethanol is evaporated com-concentration of greater than or equal to 1.5M, by pletely during (c) step.adding ice pieces of distilled water or icy distilled water 50 1 2 . The method for production of mono-dispersed andto the undiluted titanium tetrachloride; crystalline titanium dioxide ultrafine powders according to
(b) diluting the above aqueous titanyl chloride solution to c l a ; m 9> wherein pressure of higher than 4 bar is applied toa specific concentration within the range of 0.2 to 1.2M the titanium dioxide precipitates for 48 hours or morewith an adequate amount of distilled water; between (c) step and (d) step.
(c) obtaining crystalline titanium dioxide, whichprecipitates, by heating the above diluted aqueous * * * * *
journal J. Am dram. Soc, 82 [4] 927-32 (1999J
Homogeneous Precipitation of TiO2 Ultrafine Powders fromAqueous TiOCl2 Solution
Sun-Jae Kim, Soon-Dong Park, and Yong Hwan JeongAdvanced Nuclear Materials Development Team, Korea Atomic Energy Research Institute,
Yusong, Taejon 305-600, Korea
Sung ParkDepartment of Inorganic Materials Engineering, Myongji University, Youngin, Kyunggi-Do 449-728, Korea
Crystalline TiO2 powders were prepared by the homoge-neous precipitation method simply by heating and stirringan aqueous TiOCU solution with a Ti4+ concentration of0.5Af at room temperature to 100° C under a pressure of 1atm. TiO2 precipitates with pure rutile phase havingspherical shapes 200-400 nm in diameter formed betweenroom temperature and 65°C, whereas TiO2 precipitateswith anatase phase started to form at temperatures >65°C.Precipitates with pure anatase phase having irregularshapes 2-5 um in size formed at 100°C. Possibly because ofthe crystallization of an unstable intermediate product,TiO(OH)2, to TiO2-xH2O during precipitation, crystallineand ultrafine TiO2 precipitates were formed in aqueousTiOCl2 solution without hydrolyzing directly to Ti(OH)4.Also, formation of a stable TiO2 rutile phase between roomtemperature and 65°C was likely to occur slowly underthese conditions, although TiO2 with rutile phase formedthermodynamically at higher temperatures.
I. Introduction'"TITANIUM DIOXIDE (TiO2) with a rutile phase has been widelyJL used for white pigment materials because of its good scat-
tering effect that protects materials from ultraviolet light. It hasalso been used for optical coatings, beam splitters, and antire-flection coatings because it has a high dielectric constant andrefractive index, as well as good oil adsorption ability, tintingpower, and chemical stability, even under strongly acidic orbasic conditions.1"4 TiO2 with an anatase structure has beenused as a photocatalyst for photodecomposition and solar en-ergy conversion because of its high photoactivity.5"7 TiO2shows different electrical characteristics with oxygen partialpressure, because it has wide chemical stability and a nonstoi-chiometric phase region. Because of this, it can also be used asa humidity sensor and high-temperature oxygen sensor.8-9
Generally, TiO2 powders are fabricated by the sulfate orchloride processes. In the sulfate process, ilmenite dissolved insulfuric acid is conventionally hydrolyzed at >95°C, calcined at800°-1000°C, then pulverized to produce TiO2 powders (al-though precipitation of crystalline TiO2 from titanium sulfateusing thermal hydrolysis was recently reported by E. Santa-eesaria et al.10). During these calcination and pulverizationprocesses, impurities are introduced, causing the quality of thefinal TiO2 powder to be low. In the chloride process,11"13 re-acting natural rutile ore with HCl gas at a high temperature atfirst produces TiCl4. A TiO2 powder with a high-purity rutilestructure (>99.9%) is then obtained by reacting TiCl4 withoxygen gas at temperatures >1000°C. Because TiO2 powdersproduced by this method are fine but rough, the use of externalelectric fields or reactant mixing techniques is necessary to
C. F. Zukoski—contributing editor
Manuscript No. 190476. Received January 7. 1998; approved August 21, 1998.
control the particle size and crystallinity of the TiO2 pow-ders.14-15 This method also requires extra protection devicesbecause of the corrosive HCl or chlorine gas, leading to higherproduction costs.
Additionally, other researchers have fabricated crystallineTiO2 powder using TiCl4, the starting material in the chlorideprocess. Ocana et al.16 obtained rutile TiO2 powder at 98°C,using 3A/ TiCl4, for measuring its infrared and Raman spectra,but did not comment on the fabrication method. Matijevic etal.11 reported that precipitation of crystalline TiO2 occurred indilute TiCl4 solution after aging at 98°C for 37 d in the pres-ence of SO4
2~ ions. This is not an economical method becauseof the long aging time and low productivity.
On the other hand, because the characteristics of the finalceramic products are determined by the starting ceramic pow-ders, many other studies are actively being performed to con-trol the characteristics of TiO2 powder using the sol-gelmethod,18-19 hydrothermal synthesis,1-20 etc. Metal alkoxideis usually used to fabricate spherically shaped TiO2 powderswith a uniform size on a laboratory scale. This sol-gel methodusing alkoxides produces fine, spherically shaped powderswith uniform size <1.0 urn. However, tight control of the re-action conditions is required because the alkoxide is intenselyhydrolyzed in air. Furthermore, the high price of the alkoxidelimits its commercialization. Hydrothermal synthesis using anautoclave under high-temperature and high-pressure condi-tions produces high-quality powders, but a continuous processhas been impossible up to now. Therefore, it is necessary todevelop a powder fabrication method in which it is easy tocontrol the characteristics of TiO2 powder and to fabricate iteconomically.
In this study, a stable aqueous TiOCl2 solution made fromTiCl4 that vigorously reacts with atmospheric moisture is usedas the starting material to obtain an ultrafine TiO2 powder withuniform size. Because crystalline TiO2 precipitates are formedhomogeneously at room temperature to 100°C with a produc-tivity >90% by just heating and stirring the TiCl4 solution,which is diluted with an appropriate amount of water, neitherhigh temperature nor oxygen gas is needed for oxidation andcalcination to take place during this process. Thus, processsimplification leads to lower production costs and makes acontinuous process possible. In this paper, crystallinity, particleshape, and particle size of the crystalline TiO2 precipitate ob-tained by the homogeneous precipitation method are examinedin detail based on various precipitation conditions.
II. Experimental ProcedureTransparent titanium tetrachloride (3/V; TiCl4, Aldrich
Chemical Co., Inc., Milwaukee, WI) was used as a startingmaterial to fabricate TiO2 powder using the homogeneous pre-cipitation method. In order to prepare aqueous TiOCl2 solutionto use as a stock solution, TiCl4 that had been cooled below0°C was placed in a constant-temperature (0°C) reaction con-
927
928 Journal of the American Ceramic Society—Kim et al. Vol. 82, No. 4
tainer, then distilled water ice pieces were added to the con-tainer for the hydrolysis reaction. During the reaction, yellowcakes, such as an unstable TiO(OH)2 intermediate product,were formed at first with the slow melting of ice pieces andthen dissolved with the continuous addition of ice pieces toform a yellow, aqueous TiOCl2 solution. The ice pieces cooledthe reaction heat of the TiCl4 solution, which occurred from thereaction with water and moisture from the air, and also helpedthe following reaction via the formation of yellow TiO(OH)2
cake
TiCl4 + H2O -> TiOCl, + 2HC1
under conditions for maintaining the pH values of the solutionat < 1.0 by adding the ice pieces. Here the concentration of theaqueous TiOCl2 stock solution was 2M, which was controlledby adding ice pieces. This aqueous TiOCl2 solution was kept ina stable state without precipitation, even after one year at roomtemperature. Finally, distilled water was added to this stocksolution to obtain a transparent aqueous TiOCl, solution with aTi4+ concentration of 0.5M for homogeneous precipitation. Onthe other hand, direct addition of a large amount of water toTiCl4 easily made it white and turbid with formation ofTi(OH)4 by the hydrolysis of the TiCl4 solution,21-22 and with-out formation of a yellow aqueous TiOCl3 solution. CrystallineTiO2 powder was not precipitated during the process.
Homogeneous precipitation was performed by changing theheating rates and reaction time of an aqueous TiOCl2 solutionat room temperature to 100°C under a pressure of 1 atm. Theprecipitates were then filtered using distilled water and ethanoland a polytetrafluoroethylene (PTFE) membrane filter (Micro-Filtration System Co., Lapeer, MI) with a porosity of 0.2 \x,mto completely remove the Cl" ions from the precipitates aftercompleting the precipitation and keeping it untouched for 24 h.During the initial filtering stage, the precipitates were filteredby distilled water whose pH was controlled by HC1 solution toprevent peptization during filtering. When the pH value of theprecipitate was >4, the precipitates were continuously filteredusing ethanol until the pH value of the precipitates becameneutral. Here, use of ethanol served to prevent agglomerationbetween precipitates as well as to wash them. The filteredprecipitates were dried at 50°C for 12 h to obtain the finalpowder. All of the chemical agents used in this study hadanalytical reagent grades. The pH values of aqueous TiOCl2solution during precipitation were measured using a 355-ionanalyzer (Model 355, Mettler Toledo Co., Greifensee, Switzer-land). The crystallinities of the dried and heat-treated precipi-tates were analyzed using XRD (3 kW/40 kV, 45 mA; ModelD/Max-IHc, Rigaku, Tokyo, Japan) with CuKa radiation andTEM diffraction, and the shape of the precipitates was exam-ined by SEM (3 kV; Model ABT DX-130S, JEOL, Tokyo,Japan). Also, the specific surface area of the precipitate wasmeasured with BET method after drying at 200°C for 24 h.
III. Results and Discussion
In general, to obtain crystalline TiO2 powder using TiCl4having high reactivity with atmospheric moisture, two types ofprocesses were used. One of them was the chloride process inwhich a final powder was directly obtained by reacting it withoxygen gas. The other was a process in which a titanium hy-droxide, such as Ti(OH)4, was precipitated by reacting it withNH4OH and then continuously heat-treated at a high tempera-ture to form crystalline TiO2. Figure 1 shows the XRD patternof the powders at each temperature when the titanium hydrox-ides obtained by the second process were heat-treated at in-creasing temperatures in the air for 1 h. The as-precipitatedhydroxide was amorphous at first and became crystalline as theheat-treatment temperature increased. Up to 650°C, only meta-stable anatase-phase TiO2 formed. The anatase phase wastransformed into stable rutile-phase TiO2 at >650°C, and itscrj'£'a"iriit> Iin-n-uatu. Compicie rutne-pnase liO2 formed at1000°C. Therefore, in order to obtain crystalline TiO2 powder
1O0O°C
as-precipitated and dried
atSO°Cfor 12h
20 30 40 50 60 70 80
Cu ka (2*theta)
Fig. 1. XRD pattern of titanium hydroxide calcined at various tem-peratures for 1 h in air (A is anatase phase and R is rutile phase).
with the general precipitation method using TiCl4, heat treat-ment at >400cC was required. Heat treatment at 1000°C wasrequired to obtain the thermodynamically stable rutile phase ofTiO2.
When aqueous TiOCl2 solution was heated with stirring at100°C for 6 h without using NH4OH, precipitates were ob-tained easily. These precipitates, after filtering, were heat-treated at 400°C for 1 h. (Their XRD patterns before and afterthe heat treatment are shown in Fig. 2.) The powder obtainedsimply by heating aqueous TiOCl2 solution at 100°C with stir-
Heat treatment for anatase phase TiO2 obtained
by heating and stirring at 100"C for 6h
calcined at 400"C for 1h
20 30 40 50 60 70 80
Cu ka (2*theta)
Fig. 2. XRD pattern of TiO2 anatase particles prepared from aqueousTiOCl2 solution heated at 100cC for 6 h under 1 atm.
April 1999 Homogeneous Precipitation ofTiO2 Ultrafine Powders from Aqueous TiOCI, Solution 929
ring under 1 atm pressure showed the anatase phase of TiO2from the stage of precipitation without extra heat treatment at40O°C. When titanium hydroxide directly precipitated usingNH4OH was heated at 100°C for 6 h in the aqueous solutionwith the same concentration of Ti4*, the obtained precipitateswere still amorphous. In the general precipitation method usingNH,OH, extra heat treatment at >400°C was required to obtaincrystalline TiO2.
In this study, however, by just heating aqueous TiOCl2 so-lution at 100°C, we can obtain crystalline anatase phase ofTiO2. Also, the X-ray peak of the precipitates becomes strongerwhen the precipitate is heated at 400°C for 1 h. The precipitatesobtained by heating at 100°C for 6 h show an increase incrystallinity without decomposition, even with heat treatmentat higher temperatures. This means that the stable anatasephase has already been formed at the precipitation stage. Also,when this precipitate is heat-treated at >400°C, the same crys-tallinity and phase transformation phenomena as in the hydrox-ide result (Fig. 1).
The precipitate was obtained simply by heating aqueousTiOCl2 solution at 100°C for 6 h, and, furthermore, it was notamorphous but crystalline. Precipitation was performed bychanging the heating rate to see the changes in crystalline struc-ture as the heating rate increased. Figure 3 shows the XRDresults for precipitates with increased heating rate when thesolution was heated from room temperature to 100°C and forprecipitation performed at 100°C for 6 h. The X-ray peak in-dicates that all of the precipitates obtained from the solutionhad an anatase phase, regardless of the various heating rates.However, a solution was heated up to 50°C with a rate of1.3.6°C/min and precipitated at that temperature for 6 h, andthen again heated at 100°C for 6 h. In this case, the precipitates
HR=75'C/mm
(101)precipitate at 50°C for 6h
and then boiled at 10O°C for 6h
(111)
20 25 30 35 40
Cu ka (2*theta)
45
had rutile-phase TiO2 that was thermodynamicalty more diffi-cult to form. As shown in Fig. 4, the intensity of the X-ray peakfrom the ratile-phase TiO2 increased as heating temperatureincreased. On the other hand, as the transparent aqueousTiOCl2 solution became opaque, the precipitates started to beproduced at temperatures >80°C for >30 min when the heatingrate was changed. When the solution was kept at 50°C, pre-cipitation started to occur after -100 min. From these results,we can assume that precipitation is not determined by the heat-ing rate but by heating temperature and time. To confirm this,precipitates were prepared by heating at <100°C for >6 h. Fortemperatures <40°C, the solution was heated for 72-168 hbecause of the slow precipitation. Figure 5 shows the XRDresults for these precipitates.
Figure 5 shows the X-ray peak intensity ratios of the (110)reflection of the rutile phase to the (101) reflection of theanatase phase for TiO2 prepared from solution at each reactiontemperature. The rutile-phase TiO2 formed between room tem-perature and 65°C, and there was a mixture of rutile and ana-tase phase at >65°C. Only anatase phase TiO2 formed at 100°C.Figure 6 shows the TEM selected area diffraction pattern foras-precipitated rutile-phase TiO2 powders prepared by keepingthe solution at room temperature for 7 d under 1 atm pressure.It shows the diffraction cycle very clearly, indicating that thehomogeneous precipitation method using simple heating pro-duced nanosized crystalline powders. As shown in Fig. 1, heattreatment of Ti(OH)4 precipitates at temperatures >650°C wasrequired to obtain rutile-phase TiO2. However, in the presentstudy, the complete rutile-phase TiO2 formed just by heating atroom temperature to 65°C under 1 atm pressure. This is a veryinteresting result.
Figure 7 shows the pH value change with reaction time whenprecipitation was performed by heating an aqueous TiOCl2solution together with stirring. Precipitation was performed byadding a 300 mL mixed solution of water and ethanol to a 100mL aqueous TiOCl2 stock solution. The pH values of aqueousTiOCl2 solution decreased and became constant as reactiontime increased. The pH value of aqueous TiOCl2 solution de-creased rapidly with decreased amounts of added water, but thefinal pH value of the solution showed a lower value when morewater was added. All of the crystalline TiO2 precipitated bythese conditions showed a rutile phase, regardless of the pH
30 40 50 60
Cu ka (2*theta)
70
Fig. 3. Effect of heating rates on crystalline TiO-> phase during theprecipitation from room temperature to 100°C under 1 atm.
Fig. 4. XRD pattern of TiO2 rutile particles prepared from aqueousTiOCl2 solution heated at 50°C for 6 h under 1 atm and then calcinedfor 1 h at various temperatures in air.
930 Journal of the American Ceramic Society—Kim et al.
0.6
Vol. 82, No. 4
20 40 60 80 100
Reaction Temperature (°C)
Fig. 5. X-ray intensity ratios of the (110) reflection of the rutilephase to the (101) reflection of the anatase phase for crystalline TiO2
prepared from aqueous solutions with the reaction temperature.
values. It was also observed that the amount of precipitatedTiO2 was small when a very small amount of water was added,even though the amount of TiOCl2 involved in the reaction wasconstant. However, when the concentration of Ti4* was verydilute, <0.45, the aqueous TiOCl2 solution became white andturbid, even showing a small amount of TiO2 precipitate withvery low crystallinity or amorphous TiO2 precipitate. This in-dicated that an appropriate condition obtained by the increaseof OH~ ions in the aqueous TiOCl2 solution with added watermight have accelerated the transformation from TiOCl2 toTiO2, because the added alcohol did not change the pH valueof the solution, and the large amounts of added water hydro-lyzed TiOCl2 to Ti(OH)4 directly.
This precipitation process is likely to be conducted with thegrowth of TiO(OH)2 embryo in the state of the dissolution of
o 300ml H2Oa 200ml H2O-M00ml Ethanol
100ml H,O+200ml Ethanol
Fig. 6. TEM selected area diffraction pattern for as-precipitated TiO~.mill, puwuci;, piepaieu at room temperature tor 7 d under 1 atm.
100 200 300 400 500
Reaction Time (min.)
Fig. 7. Effect of added H2O amounts on the pH change of aqueousTiOCl2 solution heated at 50°C with reaction time under 1 atm.
the yellow cake, TiO(OH)2, in strongly acidic HC1 solution.When the stock solution has been prepared, the increase in theTiOCl2 concentration leads to a decrease in the pH value in thepresence of a sufficient amount of water. This is due to theincrease in the concentration of HC1, indicating that Cl~ andH+, which come from the transformation from TiOCl2 to TiO2via the formation of an unstable TiO(OH)2 phase, decrease thepH value of the solution under the process, as follows:
TiOCl2 + 2H2O -> TiO(OH)2 + 2HCI -» TiO 2 xH 2 0 + 2HC1
Solution acidity and the amount of TiO2 precipitate increasesimultaneously as the transformation of TiOCl2 to TiO2 is ac-celerated by the increasing amount of OH~ ions, which comefrom the added water. Experimentally, when the concentrationof Ti4* is 1.2M-0A5M, formation of crystalline precipitateswith a specific surface area of -148 m2/g is observed withproductive efficiencies >90%, even for longer reaction times at15°C, where the productive efficiency is calculated from theratio of the actually obtained amount to the theoretically avail-able amount of TiO2 from TiCl4.
It is also observed that the pH value decreases after a reac-tion that results in anatase-phase formation (80°-100°C).Variation in the pH value of the solution with reaction time cannot be measured at 100°C, because the temperature is out ofrange for the pH meter. Using ligand field theory, Cheng et al.1
insisted that the difference in the pH value of the reactionsolution determined the final crystalline phase when the ex-periment was performed using an autoclave. According to theirtheory, titanium(IV) complexes [Ti(OH)nClm]2-, which are de-pendent on the acidity and ligand of the TiOCl2 solution, forman anatase phase when the pH value of the solution is high,because of the high probability of edge-shared bonding and theincrease in OH" concentration. If the pH value of the solutionis low, edge-shared bonding is suppressed by the decrease inOH~ concentration, and the high possibility of corner-sharedbonding leads to the formation of a rutile phase. However,when we use aqueous TiOCl2 solution with a Ti4+ concentra-tion of 1.2M-0.45M under the same conditions as those in thepresent study without using an autoclave (such circumstancesProduce hish-presinrp rnnrKtJo^c t W r ; l n result in Ciii iiWiv.u:>tUreaction rate), the precipitates always show the same crys-
April 1999 Homogeneous Precipitation ofTiO2 Ultrafine Powders from Aqueous TiOCl2 Solution 931
talhne structure as that ot TiOCl2 that was involved in thereaction. Then, the pH value in the solutions after the reactionis almost the same, regardless of the reaction temperatures.This suggests that the determining factor for crystallinity of thefinal precipitate is only the reaction temperature.
Figure 8 shows the crystallite size calculated from XRDresults for the samples of Fig. 5. The crystallite size of rutile-phase TiO2 increases as the reaction temperature increases, butthat of anatase-phase TiO2 is almost constant, regardless of thereaction temperature. As Cheng et al. reported, however, thecrystallite size of anatase-phase TiO2 increases when the reac-tion temperature is >100°C. Increase in the rutile-phase TiO2crystallite size with an increase in the reaction temperaturemight be explained by the increased agglomeration or growthof TiO2 primary particles with the increase in thermal energyfor the reaction. Figure 9 shows SEM photographs of crystal-line TiO, powders prepared by heating aqueous TiOCl2 solu-tions for~6 h at 50° and 100°C. Rutile-phase TiO2 precipitatesformed at 50°C have 200-400 nm secondary particles consist-ing of 6.5 nm sized primary particles. On the other hand, ana-tase-phase TiO2 precipitates formed at 100°C have 2-5 u.msized secondary particles with very irregular shapes consistingof 10 nm primary particles. Therefore, at higher reaction tem-peratures, active agglomeration and rapid precipitation result inanatase-phase TiO2 that is energetically more favored to form.Rutile-phase TiO2, which is a high-temperature stable phase, isthought to form even at low temperatures, because the reactionrate is low enough to form stable crystalline structure at lowreaction temperatures. In summary, the formation of crystallineTiO2 during precipitation occurs just by heating and stirring anaqueous TiOCl2 solution under a pressure of 1 arm. This directformation of TiO2 from aqueous TiOCl2 solution is probablydue to the crystallization of the TiO(OH)2 intermediate phaseto TiO2-;tH2O, not to hydrolyzing it to Ti(OH)4 in highly acidicHC1 solution.
In the present work, it was observed that the phase formationsequence of crystalline TiO2 was reversed; the low-temperatureanatase phase formed at high temperatures (>65°C); and thehigh-temperature rutile phase formed at low temperatures. Thisphenomenon is probably due to the reaction rate in the nucle-ation state of the TiO2 embryo.
(a)
16
ICO
O
2 -
IT£,CDN05
0
alii
14
12
10
8
6
- • - Ruble- A — Anatase
-
-
-
20 40 60 80 100
Reaction Temperature (°C)
Fig. 8. Effect of reaction temperatures on crystallite size for ultrafineTiO2 powders prepared from aqueous 0.5A/ TiOCl, solution.
Fig. 9. SEM photographs for the crystalline TiO2 powders preparedsimply by heating aqueous TiOCl2 solutions at (a) 50° and (b) 100°Cfor 6 h under 1 atm.
IV. Conclusions
Crystalline TiO2 powders, which consisted of primary par-ticles <10 nm in size, were prepared by the homogeneous pre-cipitation method simply by heating and stirring aqueousTiOCl, solution with a Ti4+ concentration of 0.5M at roomtemperature to 100°C under 1 atm pressure. The results follow.
Crystalline TiO2 precipitates with pure rutile phase havingspherical shapes 200-400 nm in diameter were formed betweenroom temperature and 65°C, whereas TiO2 crystalline precipi-tates with anatase phase started to form at temperatures >65°C.Precipitates with pure anatase phase having irregular shapes2-5 |i.m in size formed at 100cC. Possibly because of thecrystallization of an unstable intermediate product, TiO(OH),,to TiO,-xH2O in highly acidic HC1 solution, crystalline TiO2precipitates were formed directly by the transformation ofTiOCl, to TiO2 without hydrolysis to Ti(OH)4. Also, the for-mation of stable TiO2 rutile phase at room temperature to 65 °Cwas likely to occur slowly under these conditions, althoughTiO, with rutile phase formed thermodynamically at highertemperatures.
References'H. Cheng. J. Ma, Z. Zhao, and L. Qi, "Hydrothermal Preparation of Uniform
Nanosize Rutile and Analase Particles," Chem. Mater., 7. 663-71 C1995).
932 Journal of the American Ceramic Society—Kim et al. Vol. 82. No. 4
2T. Fuyuki and H. Matsunami, "Electronic Properties of the Interface be-tween Si and TiO2 Deposited at Very Low Temperatures," Jpn. J. Appl. Phys.,25 [9] 1288-91 (1986).
3A. Bally, K. Prasad, R. Sanjines, P.E. Schmid, F. Levy, J. Benoit, C.Barthou, and P. Benalloul, "TiO2:Ce/CeO2 High Performance Insulators forThin Film Electro-luminescent Devices," Mater. Res. Soc. Symp. Proc., 424,471-75 (1997).
4R. U. Flood and D. FiUmaurice, "Preparation, Characterization, and Poten-tial-Dependent Optical Absorption Spectroscopy of Unsupported Large-AreaTransparent Nanocrystalline TiO2 Membranes," J. Phys. Chem., 99, 8954-58(1995).
5S. A. Larson and J. L. Falconer, "Characterization of TiO2 PhotocatalystsUsed in Trichloroethene Oxidation," Appl. Catal. B: Env., 4, 325-42 (1994).
6P. V. Kamat and N. M. Dimitrijevic, "Colloidal Semiconductors as Pho-tocatalysts for Solar Engery Conversion," Solar Energy, 44 [2] 83-98(1990).
7A. L. Micheli, "Fabrication and Performance Evaluation of a Titania Auto-motive Exhaust Gas Sensor," Am. Ceram. Soc. Bull., 54, 694-98 (1984).
SK. L. Siefering and G. L. Griffin, "Kinetics of Low-Pressure Chemical Va-por Deposition of TiO2 from Titanium Tetraisopropoxide," J. Electrochem.Soc, 137 [3] 814-18 (1990).
9H. Tang, K. Prasad, R. Sanjines, and F. Levy, "TiO2 Anatase Thin Films asGas Sensors," Sensors Actuators B, 26-27, 71-75 (1995).
10E. Santacesaria, M. Tonello, G. Storti, R. C. Pace, and S. Carra, "Kineticsof Titanium Dioxide Precipitation by Thermal Hydrolysis," / . Colloid InterfaceSci., 111 [1] 44-53 (1986).
"Y . Suyama and A. Kato, "Effect of Additives on the Formation of TiO2
Particles by Vapor Phase Reaction," J. Am. Ceram. Soc, 68 [5] C-154-C156(1985).
l 2S. E. Pratsinis, H. Bai, and P. Biswas, "Kinetics of Titanium(IV) ChlorideOxidation," J. Am. Ceram. Soc., 73 [7] 2158-62 (1990).
I3M. K. Akhtar, Y. Xiong, and S. E. Pratsinis, "Vapor Synthesis of TitaniaPowder by Titanium Tetrachloride Oxidation," AlChE J., 37 [10] 1561-70(1991).
14S. E. Pratsinis, W. Zhu, and S. Vemury, "The Role of Gas Mixing in FlameSynthesis of Titania Powders," Powder Technoi, 86. 87—93 (1996).
I5S. Vemury and S. E. Pratsinis, "Corona-Assisted Flame Synthesis of Ul-trafine Titania Particles," Appl. Phys. Lett., 66, 3275-77 (1995).
""M. Ocana, V. Fomes, J. V. Garcia Ramos, and C. J . Sema, "Factors Af-fecting the Infrared and Raman Spectra of Rutile Powders," J. Solid StateChem., 75, 364-72 (1988).
n E . Matijevic, M. Budnik, and L. Meites';"'Preparation and Mechanism ofFormation of Titanium Dioxide Hydrosols of Narrow Size Distribution " JColloid Interface Sci., 61 [2] 302-11 (1977).
ISX.-Z. Ding, Z.-Z. Qi, and Y.-Z. He, "Effect of Hydrolysis Water on thePreparation on Nano-Crystalline Titania Powders via a Sol-Gel Process " /Mater. Sci. Lett., 14, 21-22 (1995).
"E. A. Barringer and H. K. Bowen, "High-Purity. Monodisperse TiO2 Pow-ders by Hydrolysis of Titanium Tetraethoxide. 1. Synthesis and Physical Prop-erties," Langmuir, 1 [4] 414-20 (1985).
20Q. Chen, Y. Qian, Z. Chen, G. Zhou, and Y. Zhang, "Preparation of TiO2
Powders with Different Morphologies by an Oxidation-Hydro-thermal Combi-nation Method," Mater. Lett., 22, 77-80 (1995).
2IK. Kudaka, K. Iizumi, and K. Sasaki, "Preparation of StoichiometricBarium Titanyl Oxalate Tetrahydrate," Am. Ceram. Soc. Bull, 61, 1236 (1982).
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Journal of Solid State Chemistry 146, 230-238 (1999)Article ID jssc.1999.8342, available online at http://www.idealibrary.com on IDE J^L
Understanding of Homogeneous Spontaneous Precipitationfor Monodispersed TiO2 Uitrafine Powders with Rutile Phase
around Room TemperatureSoon Dong Park, Young Hyun Cho, Whung Whoe Kim, and Sun-Jae Kim1
Advanced Nuclear Materials Development Team, Korea Atomic Energy Research Institute, P.O. Box 105, Yusong, Taejon 305-600, Korea
Received January 26, 1999; in revised form April 9, 1999; accepted April 21, 1999
Monodispersed TiO2 ultrafine particles were obtained fromaqueous TiOClj solution with a 0.67 M Ti4+ concentration pre-pared by diluting TiCl4 with the homogeneous precipitation pro-cess in the range 17-230°C. With the spontaneous hydrolysis ofTiiOCl2, which means the natural decrease of the pH value in theaqueous solution, all monodispersed precipitates were crystal-lized with the anatase or rutile TiO2 phase during the reactions.Tlie TiO2 precipitate with the pure rutile phase was fully formedat temperatures below 65°C, which did not involve the evapor-ation of H2O, and above 155°C, which were available by sup-pressing it. The TiO2 precipitate with the rutile-phase, includinga small amount of the anatase phase, started to be formed atintermediate temperatures above 70°C, showing the full forma-tion of the anatase phase above 95°C under the free evaporationof H2O. However, in the case of completely suppressing H2Oevaporation at temperatures above 70°C, the TiO2 precipitatewith the anatase phase that had already been formed by rapidreaction was fully transformed vrith the reaction time into theprecipitate with the rutile phase by the vapor pressure of H2O.Therefore, the formation of TiO2 precipitates with the rutilephase around room temperature would be caused by the exist-ence of capillary pressure between the agglomerated needle-shaped particles or the ultrafine clusters, together with the slow
react ion r a t e . © 1999 Academic Press
1. INTRODUCTION
TiO2 with rutile phase has been widely used as a whitepigment material because of an excellent light-scatteringeffect along with a coating material for optical or electronicdevices because of its high dielectric constant, high refrac-tive index, and chemical stability, even in strongly acidic orbasic environments (1-4). TiO2 with rutile phase for ap-plications in optical or electronic devices has generally beenadopted in the form of a thin film using various fabrication
' To whom correspondence should be addressed. E-mail: [email protected]. Fax: + 82-42-868-8346.
methods such as rf sputtering, e-gun evaporation, chemicalvapor deposition, and sol-gel. However, these methods re-sulted in a thin film of TiO2 with the substoichiometry oramorphous phase. Thus, it is necessary to doj>e other ele-ments during the deposition of the film for the stability ofthe anatase phase or to anneal it for the conversion ofanatase to rutile phase at temperatures above 400°C forlong times. On the other hand, the screen-printing or castingmethod with the nanosized rutile TiO2 powders has recentlyreceived the attention of the direct application for the dielec-tric layer of an ac powder electroluminescent device in placeof the heat treatment of the thin film prepared using variousvacuum techniques (5). In this method, the nanosized rutileTiO2 ultrafine powders mixed with binder are casted orscreen-printed on the substrate and are then cured at tem-peratures below 200°C for the removal of the binder. After-ward, a special encapsulation process of the casted orscreen-printed layer is carried out for direct application,which will be a very economical process for optical orelectronic devices. For this process, first of all, the ultrafineTiO2 homogeneous powder with rutile phase should bemore massively produced than that with anatase phase.
Up to now, the various processes such as the: sulfate, thechloride, the hydrothermal, and the sol-gel processes for thefabrication of TiO2 powder with the rutile phase have beendeveloped (6-10). To prepare the rutile TiO2 ultrafine pow-der using one of the above processes, however, many faults,such as high costs for high temperatures of synthesis andheat treatment, difficulties in continuous process, low ef-ficiencies in production, and contamination of impuritiesduring the crushing or pulverizing, should be overcome.Kim et al. recently developed a very economical process forultrafine TiO2 homogeneous powder with rutile phase justby heating an aqueous TiOCl2 solution from TiCl4, whichenhances the spontaneous precipitation of TiO2 (11,12).With simple dilution and heating of a highly viscous TiOCl2
solution obtained from the reaction between water andTiCl4 at temperatures below 100°C, the monodispersed
2300022-4596/99 $30.00Copyright © 1999 by Academic PressAll lights of reproduction in any form reserved.
PRECIPITATION FOR TiO2 ULTRAFINE POWDERS 231
crystalline TiO2 powder with specific surface areas of about150 m2/g was easily obtained with efficiencies above 85% inproduction. Moreover, it was highly evaluated for the ap-plications because the ultrafine TiO2 powder with rutilephase, formed thermodynamically at temperatures higherthan 600°C, was obtained even around room temperature.In their process the reverse phase transition of rutile toanatase phase with an increase in the reaction temperaturewas also found to occur because of the difference in thereaction rate of the precipitation of the ultrafine TiO2 pow-der. However, it could not yet be appropriately explainedbecause of the absence of many experimental data, exceptfor the reaction rate in their paper.
Therefore, there is ample interest in closely examining thehomogeneous precipitation mechanism of crystalline TiO2
ultrafine powder in aqueous TiOCl2 solution. The object ofthis paper, for the extension of the development for a newsynthesis method of the ultrafine TiO2 powder, is to investi-gate in detail the reaction of TiOCl2 with H2O for thehomogeneous precipitation. Thus, the shapes and the cha-nges in the crystalline state of the TiO2 precipitates undervarious precipitation conditions were observed to find theprecipitation mechanism of ultrafine TiO2 powder fromaqueous TiOCl2 solution.
2. EXPERIMENTAL PROCEDURE
Transparent titanium tetrachloride (TiCl4, 3 N, AldrichCo.) was used as a starting material to fabricate the ultrafineTiO2 powder using the homogeneous precipitation method.First, to prepare aqueous TiOCl2 solution with a highviscosity to use as a stock solution, TiCl4, which had beencooled below 0°C, was put into a constant temperature(0°C) reaction container, and then distilled water ice pieceswere slowly added to the container for a hydrolysis reaction.During the reaction, yellow cakes, such as an unstableTiO(OH)2 intermediate product, were formed at first to-gether with the slow melting of ice pieces and then theydissolved with the continuously added ice pieces to forma yellow aqueous TiOCl2 solution with a Ti4+ ion concen-tration of 4.7 M. Finally, distilled water was added to thisstock solution to obtain a transparent aqueous TiOCl2
solution with a Ti4 + concentration of 0.67 M for the homo-geneous precipitation. For the precipitation of TiO2 fromaqueous TiOCl2 solution, a cylindrical reservoir (inner dia-meter 80 mm x length 100 mm x thickness 6 mm) obtainedby machining the Teflon rod was utilized to completely sealitself using a cover with a Viton O-ring in the water bath oroven during the reaction at 17-23O°C. Also, for the safety ofexperiments, the mini autoclave of the SS316 with Teflonlining was used because the precipitation reactions above160°C were performed under the pressures above 5 bar ofwater vapor.
After the precipitation was complete and it was left un-touched for 24 h, the precipitates were filtered using distilledwater or ethyl alcohol and a PTFE membrane filter(Micro-Filtration System Co.) with a porosity of 0.1 um tocompletely remove Cl" ions from the precipitates. Thefiltered precipitates were dried at 150°C for 12 h to obtainthe final powder. All of the chemical agents used in thisstudy have analytical reagent grades. The pH values ofaqueous TiOCl2 solution during the precipitation weremeasured using a 355 ion analyzer (Mettler Toledo Co.).The crystallinities of the dried precipitates were analyzedusing XRD (Rigaku D/Max-IIIc: 3 kW/40 kV, 45 mA) withCuXa radiation and TEM diffraction, and the shape of theprecipitates was examined by SEM (JEOL ABT DX-130S:3 kV). Also, the specific surface area of the precipitate wasmeasured by the BET method after drying at 200°C for 24 h.The efficiencies of the precipitates in production were cal-culated by weighing the precipitates after the heat treatmentat 1000°C for 60 min or by analyzing the concentration ofTi4 + ions remaining in the aqueous TiOCl2 solution usingICP-AES after the filtration.
3. RESULTS AND DISCUSSION
Originally transparent TiCl4 solution is a material whichhas a large vapor pressure at room temperature and hy-drolyzes readily by reacting with water from the air. Whena substoichiometric amount of H2O is added to transparentTiCl4, it was found that the hard, yellow hydroxide materialfirst formed was easily dissolved in strongly acidic HC1solution and then finally in situ converted to an aqueousTiOCl2 solution of yellow color. Moreover, homogeneousprecipitation occurred in that solution by a simple heatingmethod (11,12). In the preparation process of the aqueousTiOCl2 solution, the solution was simultaneously preparedwith a self-generating HC1 solution by the dissociation ofTiCl4 into yellow hydroxide and HC1 under the conditionsof the addition of a substoichiometric amount of H2O toTiCl4.
First of all, to compare the precipitation behavior inaqueous TiOCl2 solutions with various concentrations ofTi4 + , the precipitates were prepared using a simple heatingmethod in the closed reaction reservoir made of Teflon.Figure 1 shows SEM photographs for the powders obtainedfrom the precipitation in aqueous TiOCl2 solutions with 4.7and 0.67 M Ti4+ concentrations by a simple heatingmethod at 140°C for 60 min. All the precipitates were withthe rutile phase of TiO2. Largely elongated particles withsizes ranging from 60 to 100 um due to the severe agglomer-ations of the small precipitates are formed in the case ofa higher concentration of Ti4 + . However, in the case ofa lower concentration of Ti4+ by the large addition of H2Oto aqueous TiOCl2 solution with a Ti4 + concentrationof 4.7 M, the obtained precipitates are very fine and
232 PARK ET AL.
TABLE 1Productive Efficiency for the Precipitation of TiO2 from
Aqueous TiOCl2 Solution with the Increase iin the Amount ofWater Added at 50°C
Volume fraction of H2O (%) Productive efficiency (%)
FIG. 1. SEM photographs for the crystalline TiO2 powders preparedfrom (A) 4.7 M and (B) 0.67 M Ti4+ aqueous solutions at 140°C for 60 min.
monodispersed with sizes of 0.2-0.4 nm (specific surfaceareas of about 179 m2/g). On the other hand, no precipitateswere observed when the original TiCl4 solution was heatedwithout the addition of H2O under the same conditions.The productive efficiency for TiO2 powders from aqueousTiOCl2 solution with the increases in the amount of H2Oadded at the reaction temperature of 50°C increases up tomore than 85% at 90 vol% H2O and then became about90% at more than those amounts, as shown in Table 1.Therefore, these indicate that the addition of H2O alone tomake TiCU or TiOCl2 dilute for the reaction can control theshapes and amounts of the precipitates even if none of thespecial additives containing important elements such asO2~ or OH" are furnished to form the crystalline precipi-tates of TiO2.
Figure 2 shows the productive efficiencies for the powdersthat were precipitated for 4 h with extra additions of various
00.265.4
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amounts of ethyl alcohol to the TiOCl2 solution, includingthe same amount of H2O during the same reaction time.After the precipitation, the precipitates ware filtered usingthe paper with a porosity of 0.1 urn and then were dried at150°C for 12 h in open air. As the amount of the added ethylalcohol increases, the productive efficiency of the precipi-tated powders decreases dramatically. It was, however, con-firmed that, with showing almost the same efficiencies at thereaction times more than 24 h in this figure, the concentra-tion of Ti4+ remaining in the aqueous TiOCl2 solution afternitration was almost the same, as low as 10 wt%, regardlessof the amount of added ethyl alcohol according to the resultof ICP-AES analysis. It was also confirmed that because the
too
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80
60
40 -
20 •
0 •
0 20 40 60 80 100
Additional Amount of Ethanol (vol.%)
FIG. 2. The productive efficiency for the crystalline TiO2 powdersprepared from 0.67 M Ti4 + aqueous solution with the various additionalamounts of ethanol.
PRECIPITATION FOR TiO2 ULTRAFINE POWDERS 233
FIG. 3. SEM photographs for the crystalline TiO2 powders prepared from 0.67 M Ti4 + aqueous solution under the reaction conditions of (A) 17°C for7 days, (B) 60°C for 4 h, (C) 100°C for 2 h, and (D) 150°C for 1 h.
precipitates formed together with the addition of ethyl alco-hol were very ultrafine or not formed, compared to the caseof no addition of ethyl alcohol, they mostly passed throughthe filtering paper in the case of the short time reactioncondition. On the other hand, it was found from manypreliminary experiments that the ethyl alcohol did not takepart in the reaction and did not provide OH~ ions for thehydrolysis of TiOCl2. Thus, it can be assumed that the sitenumber for the nucleation of TiO2 in the solution is thesame as the amount of H2O supplied, regardless of thevarious amounts of ethyl alcohol. Therefore, it can be saidthat the decrease of the efficiency in production would bedue to the slow growth rate of the precipitates by thescreening effect of ethyl alcohol based on the real decrease inthe volume fraction of the amount of H2O surrounding theTiOCl2 molecules. Conclusively, it is suggested that theprecipitation of TiO2 ultrafine particles in aqueous TiOCl2
solution occurs easily and rapidly when the sufficientamounts of H2O are supplied.
The precipitation of TiO2 was carried out in aqueousTiOCl2 solution with a 0.67 M Ti4+ concentration underthe reaction conditions with the same efficiency in produc-tion and then the shape of the precipitate was observed, asshown in the SEM photographs of Fig. 3. It was confirmed
that longer times were necessary to obtain the same produc-tive efficiency at lower temperatures due to the smallerreaction rate in the solution. Monodispersed precipitatesare formed, having increasing spherical sizes in the range of40-400 nm with the reaction temperatures. As shown inFig. 4, with respect to the XRD results, the precipitatesconsist of the completely rutile phase of TiO2 at 17, 60, and150°C and consist of the rutile phase including a smallamount of the anatase phase of TiO2 at 100°C alone. On theother hand, it was observed that the crystalline structure ofthe dried precipitates was not changed with the annealingtemperatures below 400°C, regardless of long annealingtime in air. Generally, the anatase phase of TiO2, formedthermodynamically at low temperatures, is obtained around400°C by the transformation from the amorphous phaseformed at lower temperatures. Therefore, it can be knownthat all our precipitates were crystallized with the stablestructures at temperatures lower than 150°C, even at roomtemperature. It was reported that TiO2, in the generalsynthesis of TiO2 using the alkoxide, existed with theamorphous phase at temperatures lower than 400°C and theanatase phase at lower temperatures than 650cC and thentransformed to the rutile phase at higher temperatures (10).However, it was reported by Kim et al. that using aqueous
234 PARK ET AL.(a
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(C)
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20 30 40 50 60 70
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FIG. 4. XRD patterns for the TiO2 powders shown in Fig. 1. (R, rutile;A, anatase).
TiOCl2 solution under the condition of free evaporation ofH2O during the reaction formed the rutile phase of TiO2
because of the slow reaction rate for the precipitation below65°C, and a small amount of the anatase phase started toform at higher temperatures. Then, the complete anatasephase formed due to the rapid reaction rate at 100°C(11,12). On the other hand, it can be seen that most of theprecipitates consist of the rutile phase alone if the freeevaporation of H2O was suppressed at temperatures evenhigher than 70°C, as shown in Figs. 3C and 3D.
In the dilute TiOCl2 solution obtained from TiCl4, cry-stalline TiO2 particles were directly precipitated and at thattime their structure was also purely rutile at the lower aswell as the higher reaction temperatures, except for theintermediate temperatures at around 100°C. Various experi-ments were made to investigate these reasons. At first, toconfirm how the direct precipitation of TiO2 from aqueousTiOCl2 solution occurred, pH value changes of aqueousTiOCl2 solution with the reaction time were measured be-low 80°C, as shown in Fig. 5. Here, the pH value was notmeasured above 80°C due to boiling of the solution. At thesame concentration of Ti4 + , as the reaction temperatureincreases, despite the pH value becoming relatively higherby the temperature effect, the pH values are almost constantor show little decrease at the early stage and then greatdecrease after some time. This abrupt decrease in the pH
Iff1 10° 101 102 103 104
Reaction Time (min.)
0.75 •
Reaction Time (min.)
FIG. 5. The pH value changes of 0.67 M Ti4 + aqueous solution withthe reaction time at various temperatures, where Fig. 5B is an enlarged partof Fig. 5A.
value with time agreed with the starting of the large precipi-tation in the aqueous TiOCl2 solution. This also occurs ata faster rate with a greater increase in the reaction temper-ature. In other words, a higher reaction temperature enhan-ces the large precipitation in a shorter time. Thus, it can beknown that the precipitation of TiO2 with the reaction timeresulted in the decrease of the OH~ ion concentration or theincrease of the H+ ion concentration in aqueous TiOCl2
solution from the measurement of the decrease in the pH
PRECIPITATION FOR TiO, ULTRAFINE POWDERS 235
value. Therefore, irrespective of the reaction temperatures,the entire precipitation reaction occurred accompanied bythe hydrolysis of TiOCl2 like the reaction in Eq. [1] via theformation of an intermediate hydroxide:
TiOCl2 + 2H2O 2HC1. [1]
Also, as shown in Fig. 5B as an enlarged part of Fig. 5 A, itis observed that a repeatedly small increase and decrease inthe pH value of a shape such as sawtooth is displayedcontinuously during the decrease in the pH value over theentire reaction time. Because this was repeatedly measuredin all the conditions, the local variations in the pH value ofthe solution like this phenomenon may indicate the releaseof H2O from TiO(OH)2 during the crystallization or pre-cipitation, as shown in the reaction in Eq. [2]:
TiO(OH)2 2H2O. [2]
Therefore, it can be suggested that the synthesis of crystal-line TiO2 by the reaction of H2O with TiOCl2 occurred bythe precipitation with hydrolysis, together with the crystalli-zation. On the other hand, the driving force for this spon-taneous formation of crystalline TiO2 from the aqueousTiOCl2 solution even at room temperature may be ascribedto the instability of TiOCl2 in the aqueous solution. Name-ly, when a TiOCl2 molecule is dispersed to be encircled withmany H2O molecules in the solution, the hydrolysis ofTiOCl2 is more enhanced compared to the TiOCl2 moleculeexposed to the air or to substituted ethyl alcohol solutionpartially in place of H2O. On the other hand, in the case ofthe partial addition of ethyl alcohol instead of H2O or theextra addition of ethyl alcohol to the same voluminousTiOCl2 solution, there was a smaller decrease of the pHvalue, a larger decrease of the productive efficiency, anda slower reaction rate than in a normal aqueous TiOCl2
solution. Thus, it can be thought from both the previousreports (11, 12) and Fig. 2 that this was because the ethylalcohol, on behalf of the H2O molecules surrounding theTiOCl2 molecules, actually reduced the number of OH"ions supplied for TiOCl2 by the H2O molecules.
In Fig. 3, all the TiO2 precipitates from the reaction ofH2O with TiOCl2 were crystalline, not amorphous. Theywere pure rutile phase at all the reaction temperaturesexcept for the mixture of the rutile and anatase phases at100cC alone. During the precipitation reaction, to investi-gate how the crystalline status of TiO2 was determined, allthe TiO2 powders formed at the ranges of 17-230°C werecharacterized using XRD and SEM. Because the formedprecipitates always consisted of rutile and/or anatase phasesof TiO2 in this experiment, the volume fraction of the rutilephase of TiO 2 prepared under various conditions was cal-culated using K.-N. P. Kumar's equation [13] after themeasurement of XRD and the results are shown in Fig. 6.
100 •
80
S 60
a: 40
20S
~o 0 - { :40 80 120 160 200
Reaction Temperature (°C)240
FIG. 6. The volume fraction of rutile TiO2 phase formed with thevarious reaction times, (closed data, - • - 300 min under free evaporation ofH2O; open data, 300 min at the temperatures below 65°C; - A - 20 min,- O - 30 min, - V - 40 min, - O - 60 min, and - D - 120 min at the temper-atures above 70°C under no evaporation of H2O).
Here, the rutile phase of TiO2 alone is always formedregardless of the various reaction times in the temperaturesbelow 65°C as well as above 155°C. However, in temper-atures of 70-150°C, the anatase phase of TiO2 is mainlyformed under the free evaporation of H2O in the reactionreservoir, whereas under the conditions to prevent H2Oevaporation completely, the rutile phase of TiO2, includinga small amount of the anatase phase, is formed. In thisrange, the amount of the anatase phase increases with theincrease in the reaction temperature for increasingly shorterreaction times and the amount of the rutile phase increasesfor increasingly longer reaction times. As reported pre-viously (11,12), the increase in the amount of the anatasephase above 70°C may have occurred by the easy formationof the anatase phase due to the rapid rate of the precipita-tion reaction. However, it is not explained by the reactionrate that, at the same temperature, the anatase phase ofTiO2 was transformed into the rutile phase with an increas-ing reaction time. Figure 7 shows the SEM photographs forthe powders prepared with the reaction time. As the reac-tion time increases, the size of the monodispersed particlesincreases somewhat, not showing the changes of the shape.Here, because the precipitates at 85°C for 120 min consistedof a rutile phase including an anatase phase and those at115°C for 60 min consisted of a pure rutile phase, the obser-vation of microstructures like these cannot explain themechanism for the precipitation reaction appropriately.
On the other hand, the formation of the rutile phase ofabout 65 vol% was observed in the reaction at 115°C for
236 PARK ET AL.
FIG. 7. The SEM photographs for the crystalline TiO2 powders prepared from 0.67 M Ti4 + aqueous solution under the reaction conditions of (A)85°C for 120 min, (B) 115°C for 20 min, (C) 115"C for 60 min, and (D) 115°C for 180 min.
40 min under the condition to prevent the evaporation ofH2O completely. However, the formation of the rutile phaseof 100 vol% is observed under the same conditions by theextra addition of ethyl alcohol to the reaction reservoir, asshown in the XRD results of Fig. 8. However, when the ethylalcohol was added to the reaction solution, the anatasephase still existed in times shorter than 40 min. It was alsoconfirmed that the anatase phase was almost transformedinto the rutile phase if the precipitates were filtered afterapplying a pressure of more than 4 bar for 24 h. These meanthat the crystalline structure of the TiO2 precipitate duringthe reaction could be affected by applying a large internalpressure by the vapor pressures of H2O and ethyl alcohol inthe reservoir. Therefore, it is possible to make out that therutile phase of TiO2 precipitates above 70°C was trans-formed from the anatase phase, which had been formed firstbecause the internal pressure in the reaction reservoir ap-plied or increased at higher temperatures. In other words, itcan be thought that the higher internal pressure by thevapor pressure of H2O at the higher reaction temperaturecauses the already formed anatase phase to transform intothe rutile phase.
However, as shown in Fig. 6, all the TiO2 precipitatesconsisted of the rutile phase alone, regardless of the variousreaction temperatures below 65°C, and the precipitates ob-tained in a short time were also the rutile phase showinga weak crystalline state, not the anatase or amorphousphase. Therefore, the fact that although below 65°C notonly was the reaction rate very low but also the internalpressure by the reaction reservoir was almost not applied,the pure rutile phase was more easily formed compared tothe conditions at the high reaction temperature is notunderstood. In accordance with Zhang and Banfield'ssimulated results (14), they showed that the anatase phase ofTiO2 is more stable thermodynamically with the decrease insize of a TiO2 particle. They also insisted that to form therutile phase of TiO2, the size of the particle should be morethan about 8 nm, not considering the surface stress, whereasmore than about 14 nm considering the surface stress. How-ever, with respect to our XRD and TEM measurements, thesize of the primary particles for the rutile phase of TiO2 wasin the range of 3-10 nm by the homogeneous spontaneousprecipitation method. Thus, their results are not applied toour conditions because our values were smaller than those
PRECIPITATION FOR TiO, ULTRAFINE POWDERS 237
3CO
20 30 40 50
2 * theta (degree)60
that the precipitation of a crystalline TiO2 particle fromaqueous TiOCl2 solution was carried out together with theagglomeration of fine clusters or fine acicular-shaped par-ticles. Also, the rutile phase of TiO2 is more symmetriccrystallographically than the anatase phase. It can bethought from these results, therefore, that at lower reactiontemperatures the capillary pressure (negative pressure) for-med between the clusters or the fine particles would easilyenhance the formation of the rutile phase more symmetric-ally than the anatase phase.
FIG. 8. The XRD patterns for the crystalline TiO2 powders preparedfor 0.67 M Ti* + aqueous solution with and without the addition of ethanolunder the reaction conditions of 115°C for 40 min.
of the anatase phase for the primary particle. On the otherhand, Hwang et al. explained that the capillary pressurebetween chaiged clusters played an important role in thesynthesis of a diamond, which theoretically requires hightemperature and pressure conditions, using the CVDmethod (15-18). They suggested that diamond thin film inplace of graphite thin film from a carbon source during theCVD process was easily formed because of the capillarypressure that existed between the ultrafine charged clustersin the gas phase. Also, Multani's group in India (19-21)reported that as the primary particles of PbTiO3, BaTiO3,CeO2, CuO, and A12O3 powders decreased with smallersizes, their crystalline structure transformed with a sym-metry of nearly c/a = 1 by the increase in the capillarypressure in the agglomerated powders. Here, a and c meanthe lattice parameters in the x and z axis, respectively.Figure 9 shows the SEM and TEM photographs for theparticles (~ 1 and ~0.3 mm) of the rutile phase precipitatedat 50°C using ultrasonic stirring and magnetic stirringmethods, respectively. That a particle consists of many fineparticles, not a primary particle (Fig. 9A), on the surface ofthe particle, and the particle also consists of many fineacicular or needle-shaped particles, as shown at the edge ofthe particle is observed (Fig. 9B). Thus, it can be thought
FIG. 9. The SEM and TEM photographs for the representative rutileTiO2 powders from 0.67 M Ti*+ aqueous solution: (A) by ultrasonicallystirring at 50°C and (B) by normally stirring at 50°C.
238 PARK ET AL.
4. CONCLUSIONS
The monodispersed TiO2 ultrafine particles wi' . uia-meters of 40-400 nm were obtained from aqueous TiOCl2solution with a 0.67 M Ti4+ concentration prepared bydiluting TiCl4 with the homogeneous spontaneous precipi-tation process. The process was carried out under condi-tions to prevent H2O evaporation completely in the rangeof 100-230°C and to make it freely or to prevent it thor-oughly in the range of 17-100°C. The results are as follows.
The precipitation of TiO2 ultrafine particles by the reac-tion of TiOCl2 with H2O occurred easily and rapidly whensufficient amounts of H2O were supplied. With the spontan-eous hydrolysis of TiOCl2, which means the natural de-crease in the pH value of the aqueous TiOCl2 solutions, allthe monodispersed precipitates were crystallized with theanatase or rutile TiO2 phase during the reaction regardlessof various conditions. The TiO2 precipitate with a purerutile phase was fully formed at temperatures below 65°C,which did not involve the evaporation of H2O, and above155°C, which were available by suppressing it. The TiO2precipitate with the rutile phase, including a small amountof the anatase phase, started to be formed in the intermedi-ate temperatures above 70°C and showed the full formationof anatase above 95°C under the free evaporation of H2O.However, in the case of completely suppressing H2O evap-oration at temperatures above 70°C, the TiO2 precipitatewith the anatase phase that had already been formed byrapid reaction was fully transformed with the reaction timeinto the precipitate with the rutile phase by the vaporpressure of H2O. Therefore, it can be thought that thesecrystallization behaviors of TiO2 precipitates such as theformation of the rutile phase around room temperaturewould be caused by the existence of capillary pressure be-tween the agglomerated needle-shaped particles or theultrafine clusters, together with the slow reaction rate.
ACKNOWLEDGMENTS
We are particularly grateful to Dr. H. G. Lee and Mr. C. J. Jeon forcomments and helpful discussions. This project has been carried out underthe R & D Program by MOST.
REFERENCES
1. K. L! Siefering and G. L. Griffin, / . Electrochem. Soc. 137(21), 814 (1990).2. T. Fuyuki and H. Matsunami, Jpn. J. Appl. Phys. 25(9) 1288
(1986)'.3. A. Bally, K. Prasad, R. Sanjines, P.E. Schmid, F. Levy, J. Benoit,
C. Barthou, and P. Benalloul, Mater. Res. Soc. Symp. 424, 471 (1997).4. K. Prasad, A. R. Bally, P. E. Schmid, F. Levy, J. Benoit, C. Barthou,
and P. Benalloul, Jpn. J. Appl. Phys. 36, 5696 (1997).5. Y. A. Ono, In "Series on Information Display" (Hiap L. Ong, Editor-
in-Chief) Vol. l,p. 10. World Scientific Pub. Co. Ltd., Singapore, 1995.6. E. Santacesaria, M. Tonello, G. Storti, R. C. Pace, arid S. Carra,
J. Colloid Interface Sci. 111(1), 44 (1986).7. E. Matijevic, M. Budnik, and L. Meites, J. Colloid Interface Sci
61(2), 302 (1977).8. X.-Z. Ding, Z.-Z. Qi, and Y.-Z. He, J. Mater. Sci. Lett. M, 21 (1995).9. M. K. Akhtar, Y. Xiong, and S. E. Pratsinis, AIChE J. 37(10) 1561
(1991).10. E. A. Barringer and H.K. Bowen, Langmuir 1(4), 414 (1985).11. S. J. Kim, S. D. Park, Y. H. Jeong, and S. Park, J. Am. Ceram. Soc. 82(4)
927 (1999).12. S. J. Kim, C. H. Jung, S. D. Park, S. C. Kwon, and S. Part:, J. Korean
Ceram. Soc. 35(4), 325 (1998).13. K.-N. P. Kumar, Scripta Metall. Mater. 32(6), 873 (1995).14. H. Zhang and J. F. Banfield, J. Mater. Chem. 8(9), 2073 (1998).15. N. M. Hwang and J. H. Hahn, J. Crystal Growth 160, 87 (1996).16. K. Choi, S.-J. L. Kang, H. M. Jang, and N. M. Hwang. J. Crystal
Growth 172, 416 (1997).17. N. M. Hwang and D. Y. Yoon, J. Crystal Growth 160, 98 (1996).18. N. M. Hwang and D. Y. Yoon, J. Crystal Growth 143, 103 (1994).19. V. R. Palkar, P. Ayyub, S. Chattopadhyay,and M. Multani. Phys. Rev
B 53(5), 2167 (1996).20. S. Chattopadhyay, P. Ayyub, V.R. Palkar, and M. Multani, Phys. Rev
B 52(18), 13177 (1995).21. P. Ayyub, V.R. Palkar, S. Chattopadhyay, and M. Multani, Phys. Rev
B 51(9), 6135 (1995).
AH I I Ot Al
INIS
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(1O0CHLH21)TiO2/CR39
BIBLIOGRAPHIC INFORMATION SHEET
Performing Org.Report No.
Sponsoring Org.Report No.
Stamdard Report No. INIS Subject Code
KAERI/RR-2052/99
Title / Subtitle Research of Developing and Processing Technology ofNew Visual and Optical Materials
Project Managerand Department
Sun-Jae Kim, Nuclear Materials Development Team
Researcher andDepartment
K. H. Kim, C. K. Rhee, H. G. Lee, W. W. Kim. C. J.Jeon (Nuclear Materials Development Team)S. Park (MyoungJi Univ.), H. S. Kim (ChungNam Univ.)
PublicationPlace
Taejon ! Publisher MOST PublicationDate
2,000
Page 249p. I. & Tab. Yes( O ), No ( ) Size 21x29.7Cm
Note International Joint Research
Classified Open( O ), Restricted! ),Class Document
Report Type Research Report
Sponsoring Org. Contract No.
Abstract( 15-20 Lines)) Crystalline TiO2 powder with rutile phase for the plastic lensmaterial was prepared by the homogeneous precipitation process at ambient orlow temperatures (HPPLT) using simply heating aqueous T1OCI2 solution. Thetransparent TiO2 thin films and CR39/TiO2 composite lens were fabricated usingdispersed TiO2 particle in the aqueous or organic solution. The monodisperse TiO2ultrafine particles with the diameters of 40 ~ 400 nm were obtained from aqueousTiOCi2 solution with an appropriate Ti4+ concentration by the HPPLT. The processwas carried out under the conditions in the ranges of 17 ~ 230°C to prevent H2Oevaporation completely and to make it freely or to prevent it thoroughly. Theexistence of SO42" ion in aqueous TiOCb solution make the preferential growth ofthe acicular primary particles suppressed, resulting in the spherical or roundprimary particles with the anatase phase. The ultrafine TiO2 powder by the HPPLTwas well dispersed with sizes of 20 ~ 50 nm in n-butyl alcohol solution. Themixture of TiO2 particles with silica sol, corresponding to 1.0 wt.% SiO2 in 99 wt.%(TiO2 + H2O) aqueous solution was coated with 40 ~ 50 nm thickness on thesubstrate. The optical transmittance of CR39/TiO2 composite lens with increase inthe addition of the ultrafine TiO2 powder decreases gradually although T1O2particles were well dispersed in n-butyl alcohol solution. Thus, it can be thoughtthat it is appropriate to add 0.3 mL of 1.0 g TiO2/1000 mL n-butyl alcoholsolution to the CR39 solution for the CR39/TiO2 composite lens with opticaltransmittances more than 90 %. It was also confirmed that PMMA/TiO2 compositethin films showed a similar transmittance like the CR39/TJO2 composite lens.
Subject Keywords(About 10 words)
T1O2, rutile phase, monodisperse, HPPLT, plastic lens,TiO2/CR39 composite, crystalline phase, nano-structure,chestnut bur, optical transmittance
