科研之友
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摘要
The Al2O3-ZrO2(Y2O2) composite powder was synthesized through a sol-gel process using aluminum sec-butoxide and zirconium butoxide as precursors. The as-received powders in an amorphous phase were crystallized with c-ZrO2 at around 980 degreesC. As the calcination temperature increased, the c-ZrO2 crystalline phase was transformed to t-ZrO2 at about 1200 degreesC. However, the Al2O3 phase in the Al2O3ZrO2 composite powders still existed in an amorphous phase up to 1050 degreesC. In the sintered body using the calcined powders at 400 degreesC, the Al2O3 phase was crystallized in an alpha-phase at 1200 degreesC during the sintering for 2 h. Using the sol-gel Al2O2-ZrO2(Y2O2) powder, a typical nano-composite having a nano-crystalline phase (less than 20 nm) can be successfully obtained by a pressureless-sintering process even at 1200 degreesC for 2 h. Using the sol-gel Al2O3-ZrO2(Y2O2) powder, a typical nano-composite having a nano-ctystalline phase (less than 20 nm) can be successfully obtained by a pressureless-sintering process even at 1200 degreesC for 2 h. The values of relative density and Vickers hardness were comparatively high value with about 96.2% and 1100 Hv, respectively, even though it was made at low temperature. In the composite sintered at 1400 degreesC, the hardness value was saturated with 1570 Hv and the values of fracture toughness were almost same with about 6MPam(1/2) .
- 出版日期2005-1
