Biomedical Engineering Reference
In-Depth Information
Table 7.2 Material properties (at room temperature) of dense ceramics, currently used or in process of approval for total joint replacement,
compared with those for CoCr alloy and cortical bone
Property
Al
2
O
3
Mg-PSZ
Y-TZP
ZTA
Si
3
N
4
CoCr
Cortical bone
Density (g/cm
3
)
>3.97
5.75
6.05
4.40
3.15±3.20
8±9
1.7±2.0
Elongated
a
Grain size (m)
1±5
50
0.1±1.0
1±2
±
Strength (MPa)
Tensile
250±300
300±400
±
±
±
600±1800
±
Compressive
2000±3000
2000±3000
3000±4000
±
±
130±180
Flexural
300±400
600±700
1000±1500
700±1000
800±1200
60±160
Fracture toughness,
4±5
6±10
6±12
6±10
8±12
50±100
2±12
K
IC
(MPam
1/2
)
Elastic modulus (GPa)
400±450
200±250
200±250
300±350
300±320
210±250
10±20
Hardness (Vickers) (GPa)
14±16
10±12
12±14
12±15
14±16
3±4
Thermal expansion coefficient
8
7±10
11
8.5
3.0±3.5
14.0
(10
±6
K
±1
)
Thermal conductivity
30
2
2
17
20±30
100
(Wm
±1
K
±1
)
Al
2
O
3
alumina (>99.9%purity);Mg-PSZmagnesiapartially stabilized zirconia (8mol%MgO);Y-TZPyttria-stabilized tetragonal zirconiapolycrystals (3mol%
Y
2
O
3
); ZTAzirconia toughened alumina (20 vol% ZrO
2
); Si
3
N
4
in situ toughened silicon nitride.
a
Typically1±3m in diameter 5±20m long.
