Aplikasi Dan Proses Fabrikasi Keramik

7/26/2019 Aplikasi Dan Proses Fabrikasi Keramik

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Chapter 13 -

Aplikasi dan Proses Fabrikasi

pada Keramik

1


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Chapter 13 - 2

Properties:

-- Tmfor glass is moderate, but large for other ceramics.

-- Small toughness, ductility large moduli ! creep resist.

"pplications: -- #igh T, $ear resistant, no%el uses from charge neutrality.

&abrication -- some glasses can be easily formed

-- other ceramics can not be formed or cast.

Glasses Clayproducts

Refractories Abrasives Cements Advancedceramics

-optical

-composite

reinforce

-containers/household

-whiteware

-bricks

-bricks for

hih T

!furnaces"

-sandpaper

-cuttin

-polishin

-composites

-structural

enine

-rotors

-valves

-bearins

-sensors

"dapted from &ig. 13.1 and discussion inSection 13.2-', Callister 7e.

#a$onomy of Ceramics


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Chapter 13 - 3

(eed a material to use in high temperature furnaces.

Consider the Silica )Si*%+ - "lumina )"l%*&+ system.

Phase diagram sho$s: mullite, alumina, and crystobaliteas candidate refractories.

"dapted from &ig. 12.2,

Callister 7e. )&ig. 12.2

is adapted from &.. lug

and /.#. 0oremus,"lumina Silica Phase

0iagram in the ullite

/egion, J. American

Ceramic Society'()1+,

p. 45, 165.+

Application) Refractories

Composition )$t7 alumina+

8)9C+

1

1'

15

2

22

2 ' 5 1

alumina ;

mullite

mullite; L

mullite


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Chapter 13 -

Sumber: Dedi Supriyadi, Pelatihan Dasar-dasar Refraktori: Teknologi Refraktori, PT. Refratech Mandala Perkasa, 2!!


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Chapter 13 -



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Chapter 13 -



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Chapter 13 -Sumber: Dedi Supriyadi, Pelatihan Dasar-dasar Refraktori: Teknologi Refraktori, PT. Refratech Mandala Perkasa, 2!!


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Chapter 13 -36

tensileforce

Ao

Addie

die

0ie blan>s: -- (eed $ear resistant properties?

0ie surface: -- m polycrystalline diamond

particles that are sintered onto a

cemented tungsten carbide substrate.

-- polycrystalline diamond helps control

fracture and gi%es uniform hardness

in all directions.

Courtesy artin 0ea>ins, @A

Superabrasi%es, Borthington,

*#. sed $ith permission.

"dapted from &ig. 11.5 )d+,

Callister 7e.Courtesy artin 0ea>ins, @A

Superabrasi%es, Borthington,


Application) *ie +lanks
http://blank%20die-working%20animation%20on%20catia%20dmu.mp4/http://blank%20die-working%20animation%20on%20catia%20dmu.mp4/


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Chapter 13 -

8ools: -- for grinding glass, tungsten,

carbide, ceramics

-- for cutting Si $afers

-- for oil drilling

bladesoil drill bits Solutions:

coated single

crystal diamonds

polycrystalline

diamonds in a resin

matriD.

Photos courtesy artin 0ea>ins,

@A Superabrasi%es, Borthington,


Application) Cuttin #ools

-- manufactured single crystal

or polycrystalline diamonds

in a metal or resin matriD.

-- optional coatings )e.g., 8i to help diamonds bond to a Co matriD

%ia alloying+ -- polycrystalline diamonds

resharpen by microfracturing

along crystalline planes.


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Chapter 13 -1

ADample: *Dygen sensor Er*2

Principle: a>e diffusion of ions fast for rapid response.

Application) ,ensors

" Ca2;impurity

remo%es a Er;and a

*2-ion.

Ca2;

"pproach:

"dd Ca impurity to Er*2:

-- increases *2-%acancies -- increases *2-diffusion rate

referencegas at fiDedoDygen content

*2-

diffusion

gas $ith anun>no$n, higheroDygen content

-;%oltage difference produced?

sensor *peration: -- %oltage difference produced $hen

*2-

ions diffuse from the eDternal

surface of the sensor

to the reference gas.


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Chapter 13 -2

Pressing:

@


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Chapter 13 -3

,heet Glass Formin

Sheet formingH continuous dra$

H originally sheet glass $as made by IfloatingJ glass

on a pool of mercury

"dapted from &ig. 13.6, Callister 7e.


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Chapter 13 -

KuartL is crystalline

Si*%:

Gasic nit: @lass is amorphous

"morphous structure occurs by adding impurities

)(a;,g2;,Ca2;, "l3;+

Fmpurities: interfere $ith formation of

crystalline structure.

)soda glass+

"dapted from &ig. 12.11,

Callister, 7e.

Glass ,tructure

Sitetrahedron-

Si;

*2-

Si;

(a;

*2-


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Chapter 13 -4

Specific %olume)1/+ %s 8emperature )T+:

@lasses:-- do not crystalliLe

-- change in slope in spec. %ol. cur%e at

glass transition temperature, Tg -- transparent

- no crystals to scatter light

Crystalline materials:-- crystalliLe at melting temp, Tm

-- ha%e abrupt change in spec.

%ol. at Tm

"dapted from &ig. 13.', Callister, 7e.

Glass Properties

T

Specific %olume

Supercooled


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Chapter 13 -'

Glass Properties) iscosity

Miscosity, :-- relates shear stress and %elocity gradient:

has units of )Pa-s+

yv

dd=

%elocity gradient

dv

dy

glass dvdy


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Chapter 13 -

Miscosity decreases $ith T

Fmpurities lo$er Tdeform

"dapted from &ig. 13., Callister, 7e.

)&ig. 13. is from A.G. Shand, Engineering

Glass, odern aterials, Mol. ', "cademic

Press, (e$ Nor>, 16'5, p. 2'2.+

Glass iscosity vs0 # and .mpurities

fusedsilica

123sili

ca

soda-lime

lass

Misco

sityOPa

s

1

12

1'

11

11

2 ' 1 1 15 T)9C+

Tdeform

: soft enough

to deform or I$or>J

annealing range

Pyre

$

Tmelt

strain point

fused silica: Q 66.4 $t7 Si*2

soda-lime glass: 7 Si*2

balance (a2

* )soda+ ! Ca* )lime+

Mycor: 6'7 Si*2, 7 G2*3

borosilicate )PyreD+:

137 G2*3, 3.47 (a2*, 2.47 "l2*3


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Chapter 13 -5

"nnealing:

--remo%es internal stress caused by une%en cooling. 8empering: --puts surface of glass part into compression

--suppresses gro$th of crac>s from surface scratches.

--se=uence:

4eat #reatin Glass

further cooled

tension

compression

compression

before cooling

hot

surface cooling

hot

cooler

cooler

--/esult: surface crac> gro$th is suppressed.


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Chapter 13 -6

illing and screening: desired particle siLe

iDing particles ! $ater: produces a slip

&orm a green component

0ryand firethe component

ram billet

container

containerforce

die holder

die

Ao

AdeDtrusion--#ydroplastic forming: eDtrude the slip )e.g., into a pipe+

"dapted from

&ig. 11.5 )c+,

Callister 7e.

Ceramic Fabrication ethods-..A

solid component

--Slip casting:

"dapted from &ig.

13.12, Callister 7e.

)&ig. 13.12 is fromB.0. ingery,

ntrod!ction to

Ceramics, ohn

Biley and Sons,

Fnc., 16'.+

hollo$ component

pour slipinto mold

drain

moldIgreenceramicJ

pour slipinto mold

absorb $aterinto mold

Igreen

ceramicJ

@


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Chapter 13 -4

Clay Composition

" miDture of components used

)47+ 1. Clay

)247+ 2. &illerH e.g. =uartL )finely ground+

)247+ 3. &luDing agent)&eldspar+ binds it together

aluminosilicates ; ;, (a;, Ca;


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Chapter 13 -41

Clay is ineDpensi%e

"dding $ater to clay -- allo$s material to shear easily

along $ea> %an der Baals bonds

-- enables eDtrusion

-- enables slip casting

Structure of

aolinite Clay:"dapted from &ig. 12.1, Callister 7e.

)&ig. 12.1 is adapted from B.A. #auth,

Crystal Chemistry of Ceramics,American

Ceramic Society "!lletin, Mol. 3 )+, 1641,

p. 1.+

Features of a ,lip

$ea> %ander Baalsbonding

chargeneutral

chargeneutral

Si ;

"l3;

-*#

*2-

Shear

Shear

*ryin and Firin


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Chapter 13 -42

0rying: layer siLe and spacing decrease."dapted from &ig.

13.13, Callister 7e.

)&ig. 13.13 is from

B.0. ingery,ntrod!ction to

Ceramics, ohn

Biley and Sons,

Fnc., 16'.+

*ryin and Firin

0rying too fast causes sample to $arp or crac> due to non-uniform shrin>age

$et slip partially dry IgreenJceramic

&iring: --Traised to )6-19C+

--%itrification: li=uid glass forms from clay and flo$s bet$een

Si*2particles. &luD melts at lo$er T."dapted from &ig. 13.1,

Callister 7e.)&ig. 13.1 is courtesy #.@.

Grin>ies, S$inburne

ni%ersity of 8echnology,

#a$thorn Campus,

#a$thorn, Mictoria,

"ustralia.+

Si2particle

)=uartL+

glass formedaroundthe particle

micrograph ofporcelain

m


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Chapter 13 -43

Sintering: useful for both clay and non-clay compositions.

Procedure:

-- produce ceramic andRor glass particles by grinding -- place particles in mold

-- press at ele%ated Tto reduce pore siLe.

"luminum oDide po$der: -- sintered at 19C

for ' minutes.


)&ig. 13.1 is from B.0. ingery, #..

Go$en, and 0./. hlmann, ntrod!ction

to Ceramics, 2nd ed., ohn Biley and

Sons, Fnc., 16', p. 53.+

Ceramic Fabrication ethods-..+

56 m

@


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Chapter 13 -4

Powder Pressin

Sintering- po$der touches - forms nec> ! gradually nec> thic>ens

H add processing aids to help form nec>

H little or no plastic deformation

"dapted from &ig. 13.1', Callister 7e.

niaDial compression - compacted in single direction

Fsostatic)hydrostatic+ compression- pressure applied byfluid - po$der in rubber en%elope

#ot pressing- pressure ; heat


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Chapter 13 -44

#ape Castin

thin sheets of green ceramic cast as fleDible tape

used for integrated circuits and capacitors

cast from li=uid slip )ceramic ; organic sol%ent+



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Chapter 13 -4'

Produced in eDtremely large =uantities.

Portland cement: -- miD clay and lime bearing materials

-- calcinate )heat to 19C+

-- primary constituents:

tri-calcium silicate

di-calcium silicate

"dding $ater -- produces a paste $hich hardens -- hardening occurs due to hydration )chemical reactions

$ith the $ater+.

&orming: done usually minutes after hydration begins.

Ceramic Fabrication ethods-...

@


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Chapter 13 -4

Applications) Advanced Ceramics

#eat Angines

"d%antages:

H /un at higher

temperature

H ADcellent $ear !

corrosion resistanceH


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Chapter 13 -45


Ceramic "rmor

H"l2*3, G:C, SiC ! 8iG2

H ADtremely hard materials

shatter the incoming proectile

energy absorbent material underneath


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Chapter 13 -46


Alectronic Pac>aging

Chosen to securely hold microelectronics ! pro%ideheat transfer

ust match the thermal eDpansion coefficient of themicroelectronic chip ! the electronic pac>aging

material. "dditional re=uirements include:H good heat transfer coefficient

H poor electrical conducti%ity

aterials currently used include:

Goron nitride )G(+ Silicon Carbide )SiC+

"luminum nitride )"l(+H thermal conducti%ity 1D that for "lumina

H good eDpansion match $ith Si


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Gasic categories of ceramics:-- glasses

-- clay products

-- refractories

-- cements

-- ad%anced ceramics &abrication 8echni=ues: -- glass forming)impurities affect forming temp+.

-- particulate forming)needed if ductility is limited+

-- cementation )large %olume, room Tprocess+

#eat treating: sed to -- alle%iate residual stress from cooling,

-- produce fracture resistant components by putting

surface into compression.

,ummary

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Aplikasi Dan Proses Fabrikasi Keramik