A R C H I V E S

o f

F O U N D R Y E N G I N E E R I N G

Published quarterly as the organ of the Foundry Commission of the Polish Academy of Sciences

ISSN (1897-3310) Volume 9

Issue 3/2009

159 – 168

29/3

A R C H I V E S o f F O U N D R Y E N G I N E E R I N G V o l u m e 9 , I s s u e 3 / 2 0 0 9 , 1 5 9 - 1 6 8 159

The thermal analysis and derivative

bronzes cast to plaster moulds

B. Pisareka,*, M. Pawlak

a,*

aDepartment of Materials Engineering and Production Systems, Technical University of Lodz

1/15 Stefanowskiego Str., 90-924 Łódź, Poland

*Corresponding authors. E-mail addresses:boguslaw.pisarek@p.lodz.pl, marek.pawlak@p.lodz.pl

Received 20.04.2009; accepted in revised form 24.04.2009

Abstract

It plaster moulds gets casted the alloys of following metals: Al, Cu, Ag, Au in precise and artistic founding. The investigation of the crys-

tallization of bronzes in hot plaster moulds the method of the thermal analysis and derivative (TDA) was not realized out so far. Probe

TDAg and tripod enabling the execution of measurements on inductive casting machine INDUTHERM-VC 500D were designed for this

technology especially. It was confirmed that one the method TDA can identify the crystallization process of the bronze in hot plaster

moulds.

The investigations of the superficial distribution of the concentration of elements in the microstructure of the studied grades of the bronze

on X-ray microanalizer were conducted. It results that they be subject to in bronze CuSn10-C (B10) and the CuSn5Zn5Pb5-C (B555) of

strong microsegregation from conducted investigations: Pb, Sn and Sb. The single separates of intermetallic phase κ was identified in the

bronze B10 rich first of all in Zn, Sn, Sb and Fe, and two intermetallic phase, one rich were identified in the bronze B555 first of all in Zn,

Sb, (Nor, Fe) and second rich in Sn, Sb, (Nor, Fe). The most homogeneous microstructure from the bronze CuAl10Fe5Ni5-C (BA1055) is

characterizes among the studied grades of the bronze in the cast state.

Keywords: Innovative materials and casting technologies, Method TDA, Casting bronzes, Plaster mould, Microstructure

1. Introduction

The plaster is the main component of plaster masses and their

binder also makes up [1]. Plaster masses are used on very exact

plaster moulds or models [1, 2]. One executes moulds to slip

casting from the plaster of Paris [3, 4]. Plaster moulds are used in

dentistry wide [5], jeweller's craft [6] and in the technology lost

models executed the method rapid prototyping [7]. Developmen-

tal investigations over the optimization of the processes of the

thermal processing of plaster moulds are make [8-10] and them

dylatometry changes [11]. It plaster moulds gets casts alloys: Al,

Cu, Ag, Au in precise and artistic founding [6, 7].

The investigation of the crystallization of bronzes in plaster

moulds the method of the thermal analysis and derivative (TDA)

was not realized out so far.

On precise casts as also artistic bronzes tin CuSn10-C (B10)

and tin-zinc-lead CuSn5Zn5Pb5-C (B555) are applied [12]. These

bronzes are resistant on corrosion, the abrasion and they can work

in the raised temperature: 280°C (B10) and 225°C (B555). They

are characterize good castability and machinability. They belong

to basic problems connected with their casting: the microsegrega-

tion of elements during crystallization (B10, B555) and the wide

range of the temperature of crystallization (B555).

Aluminium bronzes CuAl10Fe5Ni5-C (BA1055) belong to high-

grades materials constructional, applied on strongly the put under

load parts of machines, about good sliding, resistant properties on

corrosion both in the state the cast as and after the thermal proc-

essing. Manganese and nickel are characterize the comparatively

even distribution in all phase of the microstructure of the bronze

aluminum-nickel-iron, Al and Cu they place themselves first of all

A R C H I V E S o f F O U N D R Y E N G I N E E R I N G V o l u m e 9 , I s s u e 3 / 2 0 0 9 , 1 5 9 - 1 6 8 160

in the metal matrix of the bronze ( , 2) however it is the basic

components of the phase of the type Fe and Si [13].

It results from the analysis of the binary alloys systems of the

alloys of the copper, that make additions to the tin bronzes of the

addition Pb, Zn, Ni, Fe rises its temperature liquidus, however he

reduces the addition of Sb and P its [14]. It was showed in Figure

1 the influence of chosen elements on the temperature liquidus of

alloys Cu-X (X={Sn,Zn,Pb,Ni,Fe,Sb,S,P,Mn,Al}).

In the comparison with tin bronzes, bronzes are characterize the

aluminum-iron-nickel the higher temperature liquidus.

Fig. 1. The influence of chosen elements

on the temperature liquidus of binary alloys Cu-X, X={Sn, Zn,

Pb, Ni, Fe, Sb, S, P, Mn, Al} (1084,5°C the temperature

of melting Cu), the own study on the basis [14]

2. Methodic of research

Two species of tin bronzes were used to the investigations of the crystallization process in plaster moulds: CuSn10-C (B10) and CuSn5Zn5Pb5-C (B555) and bronze the aluminium-iron-nickel CuAl10Fe5Ni5-C (BA1055). Bronzes B10 and B555 contain these same elements in the chemi-cal composition (Cu, Nor, Pb, Sn, Zn, Fe, Si, Sb, Al, P, S). The approximate values of the maximum concentrations of elements occur in them:

Ni - ~1,8-2,0%,

Si - ~0,1-0,2%,

Al - ~0,01%.

They are elements differentiating their compositions:

Pb B555 - ~5%, B10 - ~1%,

Sn B555 - ~5%, B10 - ~10%,

Zn B555 - ~5%, B10 - ~0,5%,

Fe B555 - ~0,28%, B10 - ~0,18%,

Sb B555 - ~0,25%, B10 - ~0,18%,

Mn B555 - ~0,0%, B10 - ~0,1%,

S B555 - ~0,090%, B10 - ~0,045%,

P B555 - ~0,065%, B10 - ~0,125%.

Studied bronzes the largest difference in the composition are

characterize in the reference to concentration Pb, Sn and Zn.

The bronze BA1055 contains maximally to: 10,5% Al, 6% Ni,

5,5% Fe, 3% Mn, 0,5% Zn, 0,1% Sn, 0,1% Si, 0,03% Pb.

The bronze was smelted in the inductive casting machine of

INDUTHERM-VC 500D in the atmosphere of argon. Studied

bronzes were submitted the definite quantities of the batch the

granulation to weigh, being drowned cut up pieces of the pig sow

of the bronze in casting machine, and then pouring out they liquid

the alloy to granulator full the water about the temperature 20°C

±2 °C. The stream of the liquid metal was protected during the

granulation the stream of argon. The granulated product of the

studied grades of the bronze was introduced in Figure 2.

Fig. 2. The granulated product of the bronze

The process of the melting of the bronze B555 and B10 in the

furnace INDUTHERM-VC 500D characterizes oneself large

efficiency (the short time of the melting). The small surface of the

point of contact of the metal with argon limits to the minimum

absorbing O2 or H2 through the bronze. Bronzes after melting

were overheated to the temperature suitably 1200° C, cast the

mould then the probe TDAg.

Plaster moulds were executed from the mixture PRIMA-

CAST about the water-plaster relation 0,4. Special metal mold to

casting probe TDAg were flooded the plaster mass, and then the

probe was removed after binding the plaster from the metal mold.

The probe TDAg (after the extraction from the mold) before the

cast the liquid bronze, the thermal processing was subjected. The

program of the thermal processing of plaster moulds was showed

in Figure 3.

The probe TDAg before the cast was heated up to 500°C

±10°C initially. In the aim of making possible the execution of the

thermal analysis and derivative studied bronzes, cast to plaster

moulds, on the inductive casting machine INDUTHERM-VC

500D, it was designed especially for this technology the probe

TDAg and tripod. Cross - section the probe it was shown in Fig-

ure 4.

0 1 2 3 4 5 6 7 8 9 10

stężenie pierwiastka, %

700

750

800

850

900

950

1000

1050

1100

1150

1200

t, C

Sn

Zn

Ni

Fe

Pb

Sb

S

P

1084,5 C

Al

Mn

A R C H I V E S o f F O U N D R Y E N G I N E E R I N G V o l u m e 9 , I s s u e 3 / 2 0 0 9 , 1 5 9 - 1 6 8 161

The general pattern of the measuring position was shown in Figure 5.

Fig. 3. The program of the thermal processing of plaster moulds

Fig. 4. The probe TDAg

They are the basic elements of the position measuring TDAg:

the position of casting the probe TDAg:

o the probe TDAg,

o the tripod,

o thermocouple Pt-PtRh10 the (type S) with the

line compensatory,

o Crystaldigraph – the transducer μV/Hz;

the position of the registration of measurements and

the visualization of analyses:

o computer with installed program TDA to the

registration of temperature and characteristic

curves t=f(τ) and dt/dτ=f’(τ),

o printer to the filing of characteristic curves

t=f(τ) and dt/dτ=f’(τ) and analyses in the form

of printouts (optional),

the line of the transmission of the data - connection

Crystaldigraph with computer for the aid of the line in

single isolation TLYp.

Investigations on the metallographic and electron microscope

were carried out on samples low-cut from the probe TDAg. Met-

allographic microsection on the sample from the probe TDAg it

was made on the height „head” of thermocouple. Microsections

etch the reagent Mi15Cu. The superficial microanalysis of the

concentration of elements was executed on the microanaliser of

the firm Thermo Electro Corporation.

Fig. 5. The general diagram of the measuring position with aid of the probe TDAg

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 , h

0

100

200

300

400

500

600

700

800

t, C

4h 6h min 3h

200 C

720 C

500 C

the plaster mould

the quartz tube

vaulted one-sidedly

OPERATOR

of THE SYSTEM

Position

of the registration

of measurements

and visualization

COMPUTER

PRINTER

LINE

of THE TRANSMISSION DATA

INDUCTIVE

CASTING MACHINE

INDUTHERM

- VC 500D Position

of casting

the TDAg probe

TDAg

PROBE

TRIPOD

CRYSTALDIGRAPH

COMPENSATORY

LINE

SCREEN of THE DISPLAY

A R C H I V E S o f F O U N D R Y E N G I N E E R I N G V o l u m e 9 , I s s u e 3 / 2 0 0 9 , 1 5 9 - 1 6 8 162

3. The results of investigations

The characteristic curves TDA of the bronze B10 were shown

in Figure 6. The identification on the characteristic curve dt/dτ

(the curve kinetics of the processes of crystallization) or d2t/dτ2

(the curve dynamics of the processes of crystallization) of charac-

teristic points makes possible delimitation of following quantity

describing the crystallization process of bronze (fig. 6):

kinetics dt/dτ

(e.g.: for the point K – (dt/dτ)K=KK, °C/s),

dynamics d2t/dτ2

(e.g.: for the point K – (d2t/dτ2)K=DK, °C/s2),

temperature t

(e.g.: for the point K – tK, °C),

time τ from the beginning of the visualization of the

measurement (e.g.: for the point K – τK, s).

The small addition Pb<1% crystallize on boundarys between

phase in the temperature approx. 326° C not creating identifiable

thermal effects on curve dt/dτ.

Individual points mark on curves the following stages of cooling

down, crystallization and phase transformation in the solid state:

from the beginning of the registration to the point Pk -

cooling down the liquid bronze - the giving back to

surroundings heat overheating,

Pk-A-B the crystallization of primary phase α,

B-C-D the peritectic reaction α+L→β,

D-E-F the partial transformation of phase β → α

along the solvus line,

I-J-K the eutectoid transformation β→α+γ and

γ→α+δ.

The maximum thermal effects of the process of the crystallization

of the bronze B10 mark the temperature:

A – tA of the liquidus (L→α),

C – tC of the peritectic transformation (α+L→β),

E – tE of the transformation of phase β→α,

J – tJ the eutectoid transformation β→α+γ and

γ→α+δ.

Remaining characteristic points mark the temperature of proc-

esses setting in the volume of the probe:

Pk – tPk of the beginning of the crystallization of

phase α,

B – tB of the beginning of the peritectic transforma-

tion,

D – tD of the beginning of the transformation of

phase β→α,

F – tF of the end of the transformation of phase β→α,

I – tI of the beginning of the eutectoid transformation

β→α+γ and γ→α+δ,

K – tK of the end of the eutectoid transformation

β→α+γ and γ→α+δ.

Appointed in the method ATD make possible characteristic

points delimitation of the time of duration of the following stages

of the process:

of the crystallization - phase transformation in the

solid state:

o of primary phase α,

from the point Pk to C – time SPkC,

o of the peritectic reaction (α+L→β),

from the point B to E – time SBE,

o of the partial transformation of phase β→α,

from the point D to F – time SDF,

o of the eutectoid transformation β→α+γ and

γ→α+δ, from the point I to K – time SIK;

of cooling down the bronze in the solid state:

o from the point F to I – time SFI.

Representative characteristic curves TDA of the bronze B555

were shown in Figure 7. The crystallization process of the bronze

B555 is similar how for bronze B10 (fig. 6), with this difference,

that:

the thermal effect of the peritectic reaction α+L→β he

is smaller than for the bronze B10 and he overlaps on

the thermal effect of the transformation of phase β

(β→α) creating the common „gibbosity” B-E-F on the

derivative curve,

the thermal effect of the transformation of phase β

(β→α) SEF is characterizes considerably longer time

than for the bronze B10,

the additional thermal effects occur F-G-H of inter-

metallic phase κ crystallizations.

The maximum thermal effect - the point G - it the process of the

crystallization of the bronze B555 marks temperature tG of the

crystallization of intermetallic phase κ (α+β→α+β+κ).

Remaining characteristic points make possible delimitation of the

temperature of characteristic for processes setting in the volume

of the probe:

F – tF of the end of the transformation of phase β→α

and the beginning of the crystallization of phase κ,

H – tH of the end of the crystallization of phase κ.

Appointed in the method ATD for the bronze B555 additional

characteristic points (G, H) make possible the qualification of the

times of duration in the volume of probe TDAg of the stage of the

crystallization of intermetallic phase (α+β→α+β+κ), the time

SFH.

Addition of 5% Pb to the bronze B555 cause the maximally

crystallization intercrystalline Pb in the temperature approx. 326

°C creating on curve dt/dτ, comparatively insignificant thermal

effect, highly elongated in the time.

The primary and secondary crystallization of the bronze

BA1055 causes on the curve derivative (dt/d ) creation of follow-

ing thermal effects (fig. 8):

Pk-C-H the primary crystallization of phase ,

P-Q-R the crystallization of intermetallic phase κ,

A R C H I V E S o f F O U N D R Y E N G I N E E R I N G V o l u m e 9 , I s s u e 3 / 2 0 0 9 , 1 5 9 - 1 6 8 163

J-K-L the partial transformation ,

M-N-O the eutectoid transformation + 2.

Analysing created in the plaster mould macrostructure of the

studied grades of the bronze (fig. 6 ÷ 8) it results that the bronze

B10 characterizes oneself the largest grain. Analysing created in

the plaster mould macrostructure of the studied grades of the

bronze (fig. 6 ÷ 8) it results that the bronze B10 characterizes

oneself the largest grain.

Pk A B C D E F I J K

τ, s 26 58 381 404 411 421 440 750 792 822

t, °C 1031 992 774 758 754 750 735 507 485 470

K, °C/s -2,092 0,006 -0,858 -0,473 -0,538 -0,308 -1,089 -0,552 -0,432 -0,511

D, x10-3

°C/s2 26,8 34,0 0,4 14,1 10,7 -18,1 -9,1 -0,0 0,5 -0,8

Fig. 6. Example characteristic curves TDA for the bronze B10 (t=f(τ), dt/dτ=f ’(τ), d2t/dτ2 = f ”(τ)) and the macrostructure of the cast

0 200 400 600 800 1000

, s

300

400

500

600

700

800

900

1000

1100

t,

C

-4.0

-3.0

-2.0

-1.0

0.0

dt/

d

, C

/s

-0.10

-0.05

0.00

0.05

0.10

d t

/d

,

C/s

t=f( )

d t/d =f ''( )

dt/d =f '( )

2

2 2

22

A CDE J K

Pk I

KK

tK

K

DK

B F

A R C H I V E S o f F O U N D R Y E N G I N E E R I N G V o l u m e 9 , I s s u e 3 / 2 0 0 9 , 1 5 9 - 1 6 8 164

Pk A B E F G H I J K

τ, s 30 56 250 307 422 440 462 674 721 746

t, °C 1024 996 895 854 753 736 714 540 512 498

K, °C/s -1,904 -0,021 -0,871 -0,425 -1,024 -0,868 -1,028 -0,649 -0,497 -0,590

D, x10-3

°C/s2 35,1 42,7 -1,8 -7,5 3,1 -1,5 -0,0 0,1 0,3 0,5

Fig. 7. Example characteristic curves TDA for the bronze B555 (t=f(τ), dt/dτ=f ’(τ), d2t/dτ2 = f ”(τ)) and the macrostructure of the cast

0 200 400 600 800 1000

, s

300

400

500

600

700

800

900

1000

1100

t,

C

-4.0

-3.0

-2.0

-1.0

0.0

dt/

d

, C

/s

-0.10

-0.05

0.00

0.05

0.10

d t

/d

,

C/s

t=f( )

d t/d =f ''( )

dt/d =f '( )

2

2 2

22

A B E FGH J K

Pk I

A R C H I V E S o f F O U N D R Y E N G I N E E R I N G V o l u m e 9 , I s s u e 3 / 2 0 0 9 , 1 5 9 - 1 6 8 165

Pk C H P Q R J K L M N O

τ, s 22 48 262 306 369 413 449 544 631 1127 1159 1196

t, °C 1085 1058 1013 961 903 867 838 775 727 485 473 460

K, °C/s -1,771 0,029 -1,367 -1,079 -0,790 -0,842 -0,786 -0,544 -0,564 -0,403 -0,342 -0,357

D, x10-3

°C/s2 30,1 42,2 -9,0 3,0 -0,5 -1,0 -0,0 -0,8 -1,0 -0,1 1,0 0,1

Fig. 8. Example characteristic curves TDA for the bronze BA1055 (t=f(τ), dt/dτ=f ’(τ), d2t/dτ2 = f ”(τ)) and the macrostructure of the cast

The crystallization of the bronze BA1055 in the hot plaster

mould is characterizes the small growth of the size of primary

phase β. However despite this in the comparison with the bronze

B10, if also B555, its macrostructure is characterizes the smallest

grain.

The pictures of microstructure of the studied grades of the

bronze after the etching the reagent MiCu15 show in Figure

9 (a ÷ c). The microstructure of the bronze B10 (Fig. 9 a) it is

built-up from phase: α+eutectoid (α+δ)+Pb. It characteristic is

arrangement intercrystalline eutectoid α + δ, how also small

quantities Pb. Microstructure of bronze B555 (Fig. 9 b) is built-up

from phase: α+eutectoid(α+δ)+κ+Pb. Eutectoid α+δ, intermetallic

phase κ and Pb nucleation and grow up on the boundary of the

intercrystalline grains of phase α.

0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400

, s

400

500

600

700

800

900

1000

1100

1200

t,

C

-4.0

-3.0

-2.0

-1.0

0.0

dt/

d

, C

/s

-0.10

-0.05

0.00

0.05

0.10

d t

/d

,

C/s

t=f( )

d t/d =f ''( )

dt/d =f '( )

2

2 2

22

C H Q R K L N

Pk P J M

O

A R C H I V E S o f F O U N D R Y E N G I N E E R I N G V o l u m e 9 , I s s u e 3 / 2 0 0 9 , 1 5 9 - 1 6 8 166

a)

b)

c)

Fig. 9. The microstructure of the bronze: a) B10, b) B555 and c) BA1055

Microstructure of bronze BA1055 (Fig. 9 c) is built-up from

phase: α+κ+eutectoid(α+γ2). Intermetallic phase κ they are spread

in the microstructure of the bronze comparatively evenly, both

inside former phase β, how and on her intercrystalline bounda-

ries. The bronze BA1055 the most homogeneous microstructure

of the studied grades of the bronze is characterizes.

In Figures 10 (a, b) and 11 (a, b) shown microstructure ob-

served on the electron microscope suitably (a) and the results of

the investigations of the distribution of elements (b) in the micro-

structure of the bronze suitably B10 (Fig. 10) and B555 (Fig. 11). a)

b)

Fig. 10. Microstructure (BSE) and the maps of the superficial

distribution of the concentration of elements in the bronze B10

50 μm

50 μm

50 μm

α

α+δ

Pb

α

Pb

κ

α+δ

α α+γ2

κ

α

Pb

α+δ

κ

A R C H I V E S o f F O U N D R Y E N G I N E E R I N G V o l u m e 9 , I s s u e 3 / 2 0 0 9 , 1 5 9 - 1 6 8 167

It results that Sn and Sb be subject to, in the bronze B10, of

the strongest microsegregation from the carried out analysis.

These elements are „pushed aside” in front of the front of the

crystallization of phase α, enriching highly they the liquid bronze.

Rich in these elements phase δ crystallizes in the result of phase

alternatively peritectic, and then eutectoid from the liquid staying

in intercrystalline spaces.

a)

b)

Fig. 11. Microstructure (BSE) and the maps of the superficial

distribution of the concentration of elements in the bronze BB555

Small quantities Pb crystallize on intercrystalline boundaries.

Identify single, in the microstructure of the bronze B10, the sepa-

rates of intermetallic phase κ in the composition which the ele-

ments: Zn, Sn, Sb and Fe come in. The lead undergoes, in the

bronze B555, of the strongest microsegregation and similarly

how in the case of the bronze B10, Sn and Sb. These elements are

„pushed aside” in front of the front of the crystallization of phase

α enriching highly they the liquid bronze. Rich in these elements

phase δ crystallizes, in the result of phase alternatively peritectic,

and then eutectoid, from the liquid staying in intercrystalline

spaces. The lead, being characterizing the lack of dissolubility in

Cu and the lowest temperature of crystallization, it crystallizes as

last phase from the liquid bronze in intercrystalline spaces. Two

kinds of intermetallic phase κ were also identified in these spaces.

One of them rich is first of all in Zn, Sb, Ni and Fe second

meanwhile in Sn, Sb, Ni and Fe.

4. Conclusions

From carried out investigations, in the reference to the bronze solidifying in hot plaster mould, following conclusions result:

one the method of the thermal and derivative analysis

(TDA) can identify the crystallization process of the

bronze,

they be subject to, in bronze B10 and the B555, of

strong microsegregation: Pb, Sn and Sb,

single was identified, in the bronze B10, the separates

of intermetallic phase κ rich first of all in: Zn, Sn, Sb

and Fe,

two intermetallic phase κ were identified in the

bronze B555, one rich first of all in Zn, Sb, (Ni, Fe)

and second including Sn, Sb, (Ni, Fe),

the bronze BA1055 the most homogeneous micro-

structure in the cast state is characterizes.

References [1] L. Lewandowski: Moulding materials, Akapit , Warsaw 1997

(in Polish). [2] R. Hayverova, N. Kasabova: Gypsum composition for pre-

paring moulds and models based on local raw materials,

Journal of the University of Chemical Technology and Metal-

lurgy, 42, 4, Sofia (2007), 381-386. [3] K. Konopka, M. Szafran, E. Bobryk: Fabrication of Al2O3-Fe

gradient composites by slip casting method, Composite 6 (2006) 1, 57-61 (in Polish).

[4] T. Banno, Y. Hotta, S. Sano, A. Tsuzuki, K. Oda Cake growth control in slip casting, Journal of the European Ce-

ramic Society, Volume 21, Issue 7, July 2001, Pages 879-

882. [5] T. Mori: Thermal Behavior of the Gypsum Binder in Dental

Casting Investments, Journal of Dental Research, Vol. 65, No. 6, (1986) 877-884.

[6] http://www.utilisegold.com/assets/file/discover/sci_indu/GTech/1998_23/Innov.pdf

κ(Sn,Sb,Fe,Ni)

κ(Zn,Sb,Fe,Ni)

α

Pb

A R C H I V E S o f F O U N D R Y E N G I N E E R I N G V o l u m e 9 , I s s u e 3 / 2 0 0 9 , 1 5 9 - 1 6 8 168

[7] H. Kaneshige: Molding of Cylinder Head Materials by the Lost-Wax Casting Process Using a Gypsum Mold, Mitsubishi

Motors Technical Review, No. 14 (2002) 56-59. [8] M. Wiktorski, M. Pawlak, Z. Niedźwiedzki: Effect of plaster

moulds compositions on thermal dilatation plaster moulds used in precision casting, Archives of Foundry, Polish Acad-

emy of Science 2005, Vol. 5, N° 17, 225-232 (in Polish). [9] M. Pawlak: Influence of temperature and time of firing on

the properties of gypsum. Research in Polish Metallurgy AT the Beginning of XXI Century. Committe of Metallurgy

of the Polish Academy of Science, AKAPIT, Cracow, (2006),

287-293.

[10] M. Wiktorski, M. Pawlak, Z. Niedźwiedzki: Derivatograph investigation of plaster moulds composition for plaster

moulds used in precision casting Archives of Foundry, Pol-ish Academy of Science, 2004, Vol. 4, N° 13, 225-232.

[11] M. Pawlak, Z. Niedźwiedzki: Dilatometric studies of plas-ter sandmix in raw and heat treated state, Archives of

Foundry, Polish Academy of Science, 2008, Vol. 3, N° 8, 145-148.

[12] Z. Górny, J. Sobczak: Modern casting materials on the base of non-ferrous metals, ZA-PIS, Cracow (2005) (in Polish).

[13] B.P. Pisarek, Influence Cr on crystallization and the phase

transformation of the Bronze BA1044, Archives of Foundry Engineering, Vol. 7, Issue 3, July-September 2007, 129-

136.

[14] T.B. Massalski :Binary alloy phase diagrams, American

Society of Metals, 1990.