TABLE 1 COMPOSITION OF ALUMINA-ZIRCONIA SAMPLES Sample Virgin Alumina Powder (vol%) Polycrystalline Alumina Powder (vol%) Virgin Zirconia Powder (vol%) AZ0 80 0 20 AZ1 70 10 20 AZ2 60 20 20 AZ3 50 30 20 TABLE 2 COMPOSITION OF ALUMINA-GLASS SAMPLES Sample Virgin Alumina Powder (vol%) Polycrystalline Alumina Powder (vol%) Pylex Glass Powder (vol%) Sintering Temperature (K) GV1 50 0 50 1273-1573 GP1 0 50 50 1173-1573 RESULTS AND DISCUSSION Alumina Particulate Zirconia Matrix Composites (Alumina-zirconia) Figure 1 shows the microstructure of alumina-zirconia samples. The samples using only virgin powder shows that fine grains of alumina and zirconia were homogeneously distributed. The samples with the addition of polycrystalline powder show that polycrystalline alumina clusters were dispersed in fine alumina-zirconia matrix and dual scale microstructure was obtained. The coarsening of alumina grains, however, was observed in polycrystalline alumina clusters. Polycrystalline alumina powder was obtained by pre-sintering and thus polycrystalline alumina clusters were suffered double sintering. Such a repeat of sintering caused the coarsening of alumina grains and the further consideration of sintering condition should be needed to obtain fine sintered body. Figure 2 shows the bending strength of alumina-zirconia specimens. The bending strength was slightly increased with the addition up to 20 vol% of polycrystalline alumina powder and dropped with the addition of 30 vol% of that. The decrease in bending strength with the addition of 30 vol% of (a) (b) Figure 1: Microstructure of the thermal etched surface of 20 vol% of zirconia particulate alumina. (a) the sample using only virgin alumina powder (b) the sample adding 20 vol% of polycrystalline alumina powder.
RkJQdWJsaXNoZXIy MjM0NDE=