Liquid Phase Sintering and Microstructure of Y-TZP/Al_2O_3 Composite

The influence of additive on the sintering and microstructure of Y-TZP/Al2O3 composite wasstudied through adding some additives in Y-TZP/Al2O3. The composite with 99% theorecitaldensity can be obtained at 1350C. The liquid phase formed at sintering process existed aroundthe ZrO2 and A12O3 crystal grains. The small ZrO2 ajnd large Al2O3 crystal grains can be foundin the microstructure of the composite. This was related to the solubility of ZrO2 and Al2O3 insilicate liquid phase. The ZrO2 had a low solubility in silicate liquid phase ajnd the growth ofZrO2 crystal grain was limited by liquid phase around it. A12O3 had a high solubility in the liquidphase, it formed a large and whisker-like crystal grain by solution-precipitation mechanism. Thecomposite also showed high mechanical properties. The fie-cure strength and fracture toughnesswere 640MPa and 7.2MPa.m1/2 respectively.