Biomedical Engineering Reference
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(a)
(b)
Figure 10.19.
Microstructures of pure Al
2
O
3
(a) and an Al
2
O
3
/ZrO
2
(80 vol. % Al
2
O
3
) composite
sintered for one hour at 1500 °C. [Anné, 2005a].
investigation. On the resulting micrographs, image processing was performed to
determine the grain size by the linear intercept method.
The grain size versus time and temperature for the sintered Al
2
O
3
samples is
given in Figure 10.21. At a sinter temperature of 1450 and 1550 °C, the average
grain size hardly changes as a function of time and is 1.5
m for 60
minutes soaking time, respectively. A sinter temperature of 1650 °C gives much
larger grains (
μ
m and 2.35
μ
m, Figure 10.22) and severe coarsening was observed after one
hour at 1650 °C (Figure 10.21). From the Al
2
O
3
grain size point of view, a sinter
cycle of one hour at 1550 °C was found to be the best, resulting in near full density
of the ZrO
2
- Al
2
O
3
(50/50) composite (Figure 10.23 ).
>
5
μ
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