Biomedical Engineering. Ceramic Materials. Dr-Ing. Ewald Pfaff. Materials and Processing. Laboratory visit

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Institut für Werkstoffanwendungen im Maschinenbau

Biomedical Engineering

Material Science

ate a Sc e ce

Ceramic Materials

Dr-Ing. Ewald Pfaff

Lesson 1: Fundamentals

Lesson 2:

Materials and Processing

Lesson 3:

Exercise Hip Joint

Laboratory visit

Q estions

Questions

Preparation for Examination: 22. July 2011 (Proposal)

V1-1

Institut für Werkstoffanwendungen im Maschinenbau

Material Groups

Metals

Broeckmann

Ceramics

Pfaff

Polymeres

Michaeli

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Institut für Werkstoffanwendungen im Maschinenbau

Complementary Sciences from Powder to Component

3 Si + 2 N₂₂

Si₃N₄

Atoms

Molecules Powder Microstructure Sample Component

Chemistry Physics 100 nm m mm m Material Science Chemistry, Physics 100 g 100 mg Engineering Science 1 kg V1-3

Institut für Werkstoffanwendungen im Maschinenbau

Materials

Metals (metallic)

Ductile (> 5 slide systems)

A B C

3m m Dense sphere packing (density)

Ductile (> 5 slide systems)

Chemically reactive

Conductive (therm. und electric)

Gl

(i

i /

l

t)

0,3

amorph = near regularity

Glas (ionic / covalent)

Direction independed properties

Optical transparency

Isolator

amorph = near regularity

without distant regularity

Isolator

Ceramics (ionic / covalent)

Breaking elongation 1‰, strain

polycrystalline =

near regularity

and distant regularity

Chemical resistant, temperature resistant, hard

Polymeres (covalent; Dipole-Dipole strengths,

van-der-Waals)

Z

0

Elastic and plastic deformable

Chemical resistant

Isolating (electr. and therm.)

Y

0

Si 0

(3)

Institut für Werkstoffanwendungen im Maschinenbau

Types of Bonding

Metal Bonding

Undirected, not dedicated

Very high coordination numbers

Bonding electron

belongs to …

Very high coordination numbers

Dense sphere packing

i.e. iron, messing

a lot of atoms

Ionic Bonding

Undirected, dedicated

High coordination numbers

… a lot of atoms

High coordination numbers

Sphere packing

i.e. Al

₂

O

₃

, ZrO

₂

Covalent Bonding

Directed and dedicated

- Density



E M d l



… to one atom

- E-Modulus



- Melting point



- Corrosion resistance



- Thermal expansion



to t o atoms

V1-5

p

i.e. SiC, Si

₃

N

₄

… to two atoms

Institut für Werkstoffanwendungen im Maschinenbau

Ionic (heteropolar) Bonding

•

Atom 1 emits one or more electrons and becomes electropositiv

•

Atom 2 absorbs one or more electrons and becomes electronegativ

•

Coulomb attraction bonds Ions

Example

ZrO

Example

ZrO

₂

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Institut für Werkstoffanwendungen im Maschinenbau

Covalent Bonding

Electrons are shared between 2 atoms similar Electronegativity

Source: TU Freiberg, Institut für Werkstoffwissenschaften

Example: SiC

V1-7

Source: library.thinkquest.org/05aug/o1o87/bond.html

Institut für Werkstoffanwendungen im Maschinenbau

Bond Strengths in Comparison

1,2337

1,4

covalent

]

1

1,2

0

15

N/mol

0,622

0,8

ionic

F [1

0,4

0,6

metallic

Van

Van--der

der--Waals

Waals

0

0,1852

0,0608

0,2

0

1

2

3

r/r

0

[-]

0

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Institut für Werkstoffanwendungen im Maschinenbau

Ion Radius

Ion

Radius [Å]

r

_cat

/r

_an

Al

3+

0,51

0,39

Si

4+

0,42

0,32

Zr

4+

0,79

0,59

Ti

4+

0,68

0,52

Mg

2+

0 66

0 50

Mg

0,66

0,50

Ni

2+

0,69

0,52

O

2-(Anion)

1,32

V1-9

Institut für Werkstoffanwendungen im Maschinenbau

Stable and unstable Ion Configuration

unstable

stable

unstable

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Institut für Werkstoffanwendungen im Maschinenbau

Stability Areas of Coordination Polyeder in

Ion Crystals

0,414

coordination number

Octa-

TiO

6

AlO

Al

3+

Fe

3+

r

cat

/r

an

6

hedron

Octa

AlO

6

MgO

6

Fe

Mn

3+

Li

3+

0,732

Zr

4+

8

Cubes

CaO

8

ZrO

8

Na

1+

1,00

V1-11

Institut für Werkstoffanwendungen im Maschinenbau

C

i

ll

l

i

i l

Definition Ceramic

Ceramic are all non metal anorganic materials

or:

Ceramic Materials are compositions of metal or semi metal elements with

t l l

t

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Institut für Werkstoffanwendungen im Maschinenbau

C

i

Definition Ceramic

Cearamis are:

Wear resistant

Bio compatible

Pump components

HIP joint balls

hard

p

Corosion resistant

j

Cutting tools

Membranes

V1-13

Institut für Werkstoffanwendungen im Maschinenbau

Definition Ceramic

C

i

Ceramics are:

dense

or

porous

p

•SiC

•TiATi

•200µm

•SiC

•50µm

•TiATi

•200µm •20µm

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Institut für Werkstoffanwendungen im Maschinenbau

Functional Cavities

Ceramic Membranes

Filters

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Institut für Werkstoffanwendungen im Maschinenbau

Ceramic Bearings in MRT

Non magnetic properties

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Institut für Werkstoffanwendungen im Maschinenbau

Composites, schematic

Fibre compound

Particle compound

Penetration

compound

Layer compound

compound

C-fibres in SiC for car breaks



ZrO₂in Al₂O₃



Si in SiC Ceramic-Metal in multilayer capacitors

Glass with polymer p y films in bullet-proof glass

V1-17

Institut für Werkstoffanwendungen im Maschinenbau

Material data in comparison (1)

Density Bending Strength Tensile Strength Critical stress intensity f t Impact toughness Ultimate strain Young-modulus Hardness factor Material ρ [g/cm3_] σh [MPa] σz [MPa] KIc [MPa m1/2_] -[J/m2_]  [%] GPa -[HV] St l 7 8 360 140 105 ₁₀6 _{10 20} ₂₀₀ _{200 400} Steel 7.8 -σ_t 360 – 700 140 105_{– 10}6 _{10 – 20} ₂₀₀ _{200 – 400} High-temp. steel 7.8 -σ_t 500 – 1000 50 – 154 – – 200 < 900 Cast iron 7.3 300 – 600 150 – 400 15 – 25 104 _{< 2} _{70 - 130} _{150 – 250} Aluminum 2.8 150 - 300 350 45 105 _{5 – 20} ₇₀ _{30 – 140} alloys Plastics 0.9 – 2.2 10 – 150 10 – 705 0,3 – 4 104 _{2 – 1200} ₁₀ _– Str ct ral 2 25 30 2 8 10 5 106 ₁₀8 _{< 0 1} _{30 450} ₁₂₀₀ Structural ceramics 2.25 – 5.98 30 – 1200 – 2.8 – 10.5 106_{– 10}8 _{< 0.1} _{30 – 450} _{1200 –} 3200 Porcelain 2.4 50 – 70 50 – 100 1 – – 2.5 – Glass 2.2 – 2.5 70 70 – 100 < 1 10 – 2.5 200 – 800

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Institut für Werkstoffanwendungen im Maschinenbau

Material data in comparison (2)

thermal electric

Material Max. working cte Heat Spec. Electr. Relative temperature conductivity Resistivity Permittivity

Tmax [°C] α(RT-1000°C) [10-6_K-1_] λ [W/mK] ξ [Ωcm] εr [ - ] St l 400 > 10 > 30 > 105 Steel 400 > 10 > 30 > 10-5 High-temperature steel 800 > 6 > 30 > 10-5 steel Cast iron 400 5 - 18 13 - 60 (0,5 – 1,7) 10-4 Aluminum alloys 250 20 - 26 70 - 130 (0,03 – 0,1) 10-4 Plastics 200 20 - 180 0,14 - 025 1015_{- 10}18 _{2,2 – 4,6} Structural ceramic 1000 - 2000 1 – 10,9 1,4 - 155 10-2_{- 10}14 _{8 - 10} ceramic Porcelain 1000 2 – 6 1 - 6 > 1013 _{5 – 6,5} Glass 200 - 1200 3 - 10 1 - 2 > 1013 _{3 - 19} V1-19 Glass 200 - 1200 3 - 10 1 - 2 > 10 3 - 19

Material data of ceramics

* *  cp

* * * E  _b4 m _0V K_IC log A n

Properties (short- and longtime reliability )

g/cm3_GPa _- _{MPa -} _{MPa MPa} _{[ ]*} _{- 10}-6_K-1_{W/mK J/gK} _Open

p

orosity Shrin- kage Electr

. con-d uctive Material m

g/cm GPa MPa MPa MPa [ ] 10 K W/mK J/gK _p S E _d at high m 0,90 0,40 0,40 Al₂O₃(99%) ZrO₂(MgO) ZrO₂(Y₂0₃) 3,99 5,65 5,90 410 210 210 0,30 0,25 0,30 330 520 950 10 25 20 4,9 8,1 10,5 1082 456 572 -40 60 30 2,5 2,5 10,7 10,9 8 g temp. , 0,70 0,73 0,70 no ZrO₂(Y₂0₃) Al₂TiO₅ CORDIERIT SiSiC 5,90 3,10 2,10 3,06 210 30 80 360 0,30 0,22 0,19 950 30 105 330 20 20 10 13 , 4,0 1082 34 145 416 -95 160 yes yes ,5 1,4 3 140 0,9 1,5 2,0 4,5 yes , 0,60 0,95 HPSiC HlPSiC SSiC B₄C 3,10 3,18 3,20 2,51 440 440 400 450 0,16 0,16 , 0,17 0,18 610 610 430 400 12 12 10 5,5 5,5 4,8 3,5 789 789 595 110 110 100 50 5,0 5,0 , 4,7 5,0 0,70 0 78 SSN HPSN HIPSN BN RBSN 3,25 3,30 3,30 2 10 2,40 290 300 300 75 150 0,26 0,26 0,26 0,20 600 660 800 80 220 15 20 20 15 6,0 7,0 7,0 2,8 727 752 911 267 -95 -43,5 -43 130 73 80 yes 30 35 35 50 10 no 3,2 3,2 3,2 4 0 3,0 0,78 0,80 AIN BN 2,10 3,25 75 350 80 335 3,25 50 155 4,0 5,7 *: A in units for v [m/s] und K [M Pa _m]; v = A× Kn

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Basic Equations (1)









_t _B



_c_B _B

to

(

10

20

)

1

40

20

1

,



(1)

σt,B tensil stress at breakage σ_c,B compressive stress at b k breakage



_B shear stress

(2)

E

t









E

Stress-Strain-Curve

σ_t tensile stress



strain E E-modulus

(2)

E

t



t



E

E E-modulus IC

K

Fracture Mechanics



A



J



R

sharp

σ

t,c critical tensil stress

K

IC critical stress intensity

factor



A R J IC c t Y a

K

_ _ _   ,

(3)

2 a

factor a length of crack Y dimansional factor σ_A application stress V1-21 σ_R residual stress σ_J joining stress

Basic Equations (2)

ln



Size Effect

(5)

m const V

V

F

Z Z B t t 1 1 2 2 1 ) ( _        



Size Effect

σt1,σt2 peak stresses of two distributions

lnV

_V two distributions Z1,VZ2 volumes

S b iti l C

k G

th

ln v a length of crack

(6)

n

da

Subcritical Crack Growth

n n1 A t time K_I stress intensity factor K_IC critical stress n I

K

A

dt

da

v





ln K_I K_IC A1 KI K_IC critical stress intensity factor

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Institut für Werkstoffanwendungen im Maschinenbau

Stress-Strain-Curves

MNm

-2

600

Fibre reinforced Ceramic

(Fest Load Capacity)

ootnote 2)

otnote 1) 400

500

(Fest Load Capacity)

2

Stress (f

o

S

tress (fo

o

300

400

Monolithic Ceramic

2

Bending

Tensile

S

200

Steel

1

100

Polypropylene

1

Strain

0,1

% 0,2

5 10 15 20

200 400 600

yp py

1 V1-23

Strain

Institut für Werkstoffanwendungen im Maschinenbau

l

f

i bl d

f

Development of new Ceramic blades for

cataract surgery (Eyes)

Movie of an operation at a Berlin hospital

AVT GmbH

Bleichstraße 12

45468 Mülheim an der Ruhr