ceramics materials 03

Ceramic coatings and Ceramic coatings and

surface engineering surface engineering

Suranaree University of Technology October 2007

T. Udomphol

Chapter 1

• Friction and wear

• Chemical corrosion

• Conductivity, insulation

• Reflectivity

• Thermal damage

Problems Protection of material surface

Surface engineering

Ex: Glasses, oxides, carbides,

silicides, borides, nitrides

Ceramic coatings (cermakrome) inside/outside for

exhaust manifold in Aston Martin

www.camcoat.u-net.com

Molybdenum coating on piston head

www.landyonline.co.za




T. Udomphol

Chapter 1

Silicate glass

• On ceramic substrate� glaze.

• On metal surface � porcelain enamel.

• On glass substrate � glass enamel.

Porcelain enamel

Ceramic glaze

• Protect surface ( permeability)

• Spraying, dipping techniques.

Glass enamel

www.tias.com




T. Udomphol

Chapter 1

Oxide coating • Provide oxidation resistance at high temperature.

• Provide corrosion resistance.

Using thermal or flame spraying techniques.

Cr2O3 coating on Hastelloy C for use in

very corrosive envi.

Cr2O3 coating on glass fibre-reinforced

polymer.




T. Udomphol

Chapter 1

Carbide coating • Provide wear resistance due to high hardness

Thermal spraying of tungsten carbide-cobalt

chromium coating (WC/10Co4Cr) on to a roll

for the paper manufacturing industry

Microstructure of WC/10Co4Cr coating




T. Udomphol

Chapter 1

Nitride coating

CrN coating , HV = 1800, Tw = 700oC

TiAlN coating , HV = 3600, Tw = 850oC

TiN coating , HV = 2400, Tw = 500oC

• PVD technique

www.ijs.si/ctp/tin.jpg




T. Udomphol

Chapter 1

Ceramics for energy

P-N junction

Doped with B, Al Doped with P

http://www.leonics.com

Solar cell

http://www.energy.go.th

www.corrosion-doctors.org/.../solarcell.jpg

Ceramics in biomedical Ceramics in biomedical

applications applications


T. Udomphol

Chapter 1

Alumina in orthopedic implants

a) Extensive arthritis damage, b) same hip

after total hip replacement

Various component for total hip prostheses

including the stem with an alumina femoral head,

and alumina AC cup, and a metal base for the AC

cup

• Excellent corrosion resistance

• Wear resistance

• High strength

• Biocompatibility

Co-Cr alloy femoral head with high

strength polyethylene cup (metal on

polymer)

Replaced by alumina (ceramic on

ceramic) to reduce wear particle

formation which causing loosening

of the prostheses.

99.8% Al, 3-6 µµµµm grain size




T. Udomphol

Chapter 1

Applications

• Orthopedic implants

• Eyeglasses

• Laboratory ware

• Dental applications

Bone joint

• Biocompatibility

• Bond well to bone (implant-tissue attachment)

• Corrosion resistance

• High stiffness

• Wear resistance

Ceramic biomaterials

Implant loosening

Burden from healthcare cost

and patient’s life quality




T. Udomphol

Chapter 1

Alumina in dental implants

The dental implant component

• Artificial root which supports tooth

replacement and crown (porcelain).

• Titanium is also a good candidate

due to low modulus of elasticity and

biocompatibility.




T. Udomphol

Chapter 1

Ceramic implants and tissue connectivity

Four types of responses from implant-tissue reaction

• Toxic

Tissue surrounding the implant dies

• Biologically inactive

Thin fibrous tissue forms around the implant

• Bioactive

Interfacial bond between the bone and the prosthesis forms

• Resorption (Dissolving)

The surrounding tissue replaces the implant material or portions of it.

Nanotechnology and Nanotechnology and

ceramics ceramics


T. Udomphol

Chapter 1

Nanotechnology and ceramics

Nanocrystalline ceramic Improving toughness ?

Nanosize powder (<100µm)

Agglomerates

Compaction 20-50% pore

Sintering and densification

Very quick due to nanosize

Ex: TiO2 (< 40 µµµµm)

98% theorectical density after 700oC

sintering for 2 h.

Pore shrinkage through plastic flow (grain

boundary sliding) in nanocrystalline ceramics


T. Udomphol

Chapter 2

www.umms.sav.sk

composite materialscomposite materials


T. Udomphol

Chapter 2

What is composite material?

Structural material made of two or more different materials in a

macroscopic level.

A complex material, such as wood or fiberglass, in which two or more

distinct, structurally complementary substances, especially metals,

ceramics, glasses, and polymers, combine to produce structural or

functional properties not present in any individual component.

A structure or an entity made up of distinct components.

Structural materials can be mainly divided into four categories: metals,

ceramics, polymers and composites.



T. Udomphol

Natural forms Artificial forms


Chapter 2



T. Udomphol

Chapter 2

Composites

CMCs

MMCs

PMCs

Other

Al Composites

Ti Composites

Ni based alloy

Composites Steel

Composites

Carbon

CompositesWood

Composites

Resin

Composites

Cement

CompositesPolymer

CompositesGlass

Composites

Mg

Composites


T. Udomphol

Chapter 2

Applications

Boeing 787 Dreamliner

Hockey stick made

from fibre-glass

tsa.imageg.net

www.nrc-cnrc.gc.ca


Matrices and Matrices and reinforingreinforing materialsmaterials


T. Udomphol

Chapter 2

Composites

• Metals

• Ceramics

• Polymers

•Wood

• Fibres

• Filament

• Particulates

• Flakes

• Globular

Matrix + Reinforcing materials

• Platelet

• Needles

•Woven

• Honey comb

Choices of reinforcing materialsChoices of reinforcing materials


T. Udomphol

Chapter 2

• Reinforcing materials normally provide

stiffness, strength and sometimes

improved toughness.

• Mostly in the form of fibres,

• Properties are directly related to their

atomic arrangement and defect

content of the reinforcements

(manufacturing process***).

• Reinforcing materials can be

polymers : Kevlar

ceramics : SiC, glass fibres

metals : steels fibres

Glass fibres

www.millipore.com

Single glass fibres

http://en.wikipedia.org

Steel

Different shapes of Different shapes of

reinforcing materialsreinforcing materials


T. Udomphol

Chapter 2

Different shapes of reinforcing materials

• Fiber/filament

(continuous or non-continuous)

•Woven

• Flake

• Needle

• Aggregate

• Particulate

• Globular

• Platelet


T. Udomphol

Chapter 2

1) Carbon fibres

2) Boron nitride fibres

3) Glass fibres

4) Organic fibres

5) Silicon carbide fibres

6) Alumina and aluminosilicatesMicrofilaments

Multifilaments

Short fibres

CVD monofilaments

PCS multifilaments

Whiskers

Fibres Particulates

1) Carbide particles

2) Boride particles

3) Nitride particles

7) Nylon

Different types of Different types of



T. Udomphol

Chapter 2



Carbon fibres

Schematic structure of carbon fibres

Boron nitride fibres

sierra.univ-lyon1.fr

Tensile strength

Young’s Modulus

Density

2000-7000 MPa

250-530 GPa

1.75 g/cm3

A cloth of woven

carbon filaments

• Boron nitrides are

extremely hard, only

second next to diamond

• Temp ~1000-1400oC


T. Udomphol

Chapter 2



Glass fibres

Glass fibres

www.vscht.cz

• Most are silica (SiO2) with addition

of Ca, Na, B, Al, Fe.

• Can be divided into electrical,

corrosion and strength glass.

Organic fibre :Kevlar

or aramid fibres

• Kevlar fibres are long molecularchain structure of polymer (poly-

paraphenylene terephthalamide).

• Expensive.

Kevlar fibres

www.fiber-tensioners.com

Kevlar


T. Udomphol

Chapter 2



Production of glass fibres

Continuous E-glass fibre production

www.jmeurope.com

• The raw materials are melted in

a reservoir and fed into a series of

platinum bushings, each of which

has several hundred holes in its

base.

• The glass flows under gravity and

fine filaments are drawn

mechanically downward onto a

drum (at speed 2000-3000 m/min).


T. Udomphol

Chapter 2



Silicon carbide fibres

iar-ira.nrc-cnrc.gc.ca

1) CVD monofilaments

2) PCS multifilaments

3) Whiskers

4) Particulates

Carbon fibre

SiC

Whiskers

• Strongest reinforcing materials available

• Defect free, single crystal rods.

• 0.1-1.0 µm in diameter and 5-100 µm.

Tensile strength

Young’s Modulus

7.0 GPa

550GPa

fb6www.uni-paderborn.de


T. Udomphol

Chapter 2



CVD monofilaments

• Carried out in a reaction chamber

by passing gaseous carbon

containing methyl-trichlorosilane

(CH3SiCl3).

Reaction chamber

http://sic.eng.usf.edu/cvd/www/

• The core fibre is heated (by passing

electrical current through it).

• The gas dissociates thermally at the

fibre surface to deposit the SiC.

• Deposition of the second layer (graphite

or diamond) is subsequently applied in the

second reaction chamber to improve the

effects of interaction reactions with

matrices such as titanium.

Diamond coated SiC fibre

www.chm.bris.ac.uk


T. Udomphol

Chapter 2



Alumina and

aluminosilicate

Nylon

Aluminium reinforced alumina short fibres

igahpse.epfl.ch

• Refractory

• Alumina and alumiosilicate

fibres can be divided into

multifilaments (FTTM fibre) or

short fibres (SaffilTM fibre).

• Nylon is a thermoplastic polymer

(polyamine) and generally used for

many applications.

• Strong, elastic and has abrasive

resistance.

Nylon

composite

sprocket

www.saffil.com


T. Udomphol

Chapter 2

Properties of different types of fibres


T. Udomphol

Chapter 2



Particulates

Carbides

Borides

Nitrides

•Silicon carbide (SiC)

•Tungsten carbide (WC)

•Titanium carbide (TiC)

• Normally are in the forms of carbides, nitrides or borides.

Titanium nitride-Tinate (TiN)

Titanium boride (TiB2)

SiC particles in Al matrix

• High Tm, high hardness, high wear resistance, low density.

Choices of matricesChoices of matrices


T. Udomphol

Chapter 2

Polymers

• Plastics or resins are

the most widely used.

• Lightweight.

• Easily fabrication.

• Low-moderate

temperatures.

• Low-moderate strength

and stiffness.

• Also used for reinforcing

materials.

Metals

• Moderate to high

temperatures.

• High strength stiffness,

moderate toughness.

• Moderate weight.

• Difficult to fabricate.

• Also used for

reinforcing materials.

Ceramics

• Cements are the most

widely used.

• Light-moderate weight.

• High temperatures.

• High strength and

stiffness but low

toughness.

• Fabrication is not too

difficult.

• Also used for reinforcing

materials.

• Matrix holds reinforcing material together and also determine

the physical properties of the end products.


T. Udomphol

Chapter 2

Maximum service temperatures for

different kinds of materials.

Specific strength of

advanced materials.

Choices of matricesChoices of matrices


T. Udomphol

Chapter 2

Matrices Matrices –– Selected propertiesSelected properties


T. Udomphol

Chapter 2

Matrices Matrices --PolymersPolymers

• The most widely used due to cheap fabrication (low temp ~ 300-400oC).

• Lightweight applications such as aircraft, sporting goods, wheelchairs

• Normally use carbon fibres as reinforcing materials.

• Thermosets: epoxy resin*, phenolic resin or furfuryl resin

Heat+pressure�polymerization with cross-link

Thermoplastics: polyimide (PI), Polyethersulfone (PES),

polyetheretherketone (PEEK), polyetherimide (PEI)

and polyphenyl sulfide (PPS).

Lower temp + better plasticity � injection moulding

•

www.zyex.com

Epoxy resin

with tools


T. Udomphol

Chapter 2

Matrices Matrices --CeramicsCeramics

• Ceramic matrix composites

• Ceramic aggregate composites

• Reinforcing material (fibres) is added to improve its toughness

and strength (tensile and flexural).

• Good oxidation resistance � high temperature applications.

Note:

• Concrete (cement)

• Cermet (ceramic and metal)

• Bone (hydroxyapatite reinforced with collagen fibres)

• Asphalt concrete

• Dental composite

• Synthetic foam (spheres of glass)


T. Udomphol

Chapter 2


Cement matrix composite

Cement

Sand

Gravel

Admixture

• No sand and gravel � cement paste

• Cement and sand � Mortar

• Cement, sand and gravel � concrete

Curing

(Hydration)

• Fine particulate such as silica (SiO2) fume or

polymer such as latex to decrease porosity.

• Short fibres such as glass, steel, carbon

Concrete is the most widely used

civil structural materials.Fracture surface of

carbon fibre

reinforced cement

enpub.fulton.asu.edu

322 ,,, OAlSiOMgOCaO


T. Udomphol

Chapter 2


Dental matrix composite

• Cermet = ceramic (cer) and ~ <20% metallic (met) materials with

Ni, Mo, Co as binders for oxides, boride, carbide or alumina

• High temperature resistance and hardness.

Ex: Spark plugs for internal combustion engine, composed of a shell,

insulator (aluminium oxide) and conductor (Cu, Ni-Fe, Cr).Spark plug http://en.wiki

pedia.org

Cermet

Polymerizable dental

composite

polymers.nist.gov

Dental composite blocks

www.cereconline.com• Consist of resin based matrix such as

methacrylate resin and an inorganic

filler such as SiO2 (silica) with a wide

range of compositions.

• wear resistance and translucency.


T. Udomphol

Chapter 2

Matrices Matrices --CarbonCarbon

C-C composite

http://www.composites-by-

design.com

• Highly-ordered graphite fibres

embedded in carbon matrix..

• Strength and toughness superior to

conventional graphite.

• Stiffer, stronger and lighter than steels

or other metals.

• C-C composites consist of two brittle

phases but are very tough.

Carbon-carbon composites

• Oxidation problem at T > 320oC.

� required SiC coating or glassy

sealant

↑→+ 22 COOC

honeycomb panels for

aircraft and helicopter

firewalls

Fracture of 2D C-C composite: two brittle

phases but high toughness.

Surface

energy

Fracture

surface area

BUT

Toughness


T. Udomphol

Chapter 2

Matrices Matrices --MetalsMetals

Note: Al, Mg and Ti are active with oxygen � chemical reactions at the interface.

• Aluminium alloys

• Magnesium alloys

• Titanium alloys

• Nickel base alloys

• Steels

• Copper alloys

ewkmmc.tuwien.ac.at

SiC fibre reinforced in

titanium matrix composite.


T. Udomphol

Chapter 2

Metal matrix composites (PMC)Metal matrix composites (PMC)

Nylon steel composites

www.duragear.com

Copper clad steel trolley wires

in bullet train

www.fujikura.co.jp

www.afrlhorizons.com Ti/SiC reinforced bling in

aeroengine Rolls-Royce Plc.

www.isis.rl.ac.uk

Fibre-reinforced plastic

with Al laminates

www.compositesiq.com

Applications


T. Udomphol

Chapter 2

Mechanics of compositesMechanics of composites

How many fibres we can put in to improve strength?

• Volume fraction of fibres

• Fibre arrangement

• Interfacial bonding between fibres and matrix

- Square array

- Hexagonal array

r

S

2RSquare array

r

S

2R

Hexagonal array

785.0max =fV

907.0max =fV


T. Udomphol

Chapter 2

σσσσ1σσσσ1

2

1

3mmffc VV σσσ +=

mmffc VEVEE +=

Note: let c – composite

f – fibre

m - matrix

Longitudinal stress and stiffness

1=+ mf VV

Transverse stiffness

m

m

f

f

c E

V

E

V

E+=

1

σσσσ2

σσσσ2

2

1

3



T. Udomphol

Chapter 2


Example: By assuming the law of mixture, and a square array of continuous

fibres, calculate the maximum and minimum moduli that can be achieved in

an unidirectional reinforced composite if seven fibre mm-1 is required for the

design specification, the fibres are of 100 µm in diameter. Given the modulus of the fibre and the matrix are 450 and 120 GPa.

The volume fraction of fibres

( )( )

385.010

49105023

26

=××

==−

−π

c

f

c

f

A

A

V

V

The maximum modulus

GPaE

E

VEVEE

c

c

mmffc

05.247

)385.01(120385.0450

=

−×+×=

+=

The minimum modulus

( )

GPaE

E

E

E

V

E

V

E

c

c

c

m

m

f

f

c

2.167

1098.51

120

385.01

450

385.01

1

3

=

×=

−+=

+=

−


T. Udomphol

Chapter 2

Fabrication of compositesFabrication of composites

Composite

manufacturing

Nature of fibre and matrix

Fibre architecture

Fibre arrangement

Fibre volume fraction

Processing route

Manufacturing cost

The development in fabrication

process strongly affects

commercial exploitation.


T. Udomphol

Chapter 2

Open mould

(spray-up)

Hot-melt prepregging process

Prepreg tapes

www.imhotepcomposites.co.uk



T. Udomphol

Chapter 2


Machine for producing sheet-moulding compound

• Continuous fibres are

chopped and fed in the

middle of resin filler

pastes (from top and

bottom) to produce a

form of sheet.

• The sheet is then rolled

for further compaction.

Sheet moulding compound


T. Udomphol

Chapter 2


Premixed injection

moulding

Injection of thermoset premixed

Automated filament winding process

Filament winding


T. Udomphol

Chapter 2


Resin transfer moulding

High speed resin transfer

moulding process


T. Udomphol

Chapter 2


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