Thermal Shock Resistance of Al2O3/ZrO2 (Y2O3) Composites

ZrO(2) containing 2% ( mol fraction) Y(2)O(3) and 3% ( mol fraction) Y(2)O(3) were added into Al(2)O(3) matrix, compositing composites with 15% volume fraction of addictives mentioned above. The testing of property and analysis of SEM presented that, after vacuum sintering at 1550 degrees C, thermal shock resistance of two composites was superior to Al(2)O(3) ceramic. The experiment showed that the properties of Al(2)O(3) composites was higher than Al(2)O(3) ceramic, and Al(2)O(3)/ZrO(2)(3Y) was higher than Al(2)O(3)/ZrO(2)(2Y) in thermal shock resistance. Improvement of thermal shock resistance of composites was attributed to many toughness machanisms of ZrO(2)(Y(2)O(3)). By calculation, the fracture energy of Al(2)O(3), Al(2)O(3)/ZrO(2) (2Y) and Al(2)O(3)/ZrO(2)(3Y) was 38100.8 and 126.2 J . m(-2), respectively. Cracks initiation resistance (R') of Al(2)O(3)/ZrO(2)(3Y) and Al(2)O(3)/ZrO(2)(2Y) was higher than Al(2)O(3) ceramic by 1.57 and 1.41 time, respectively, and cracks propagation resistance (R"") was higher than Al(2)O(3) ceramic by 1.46 and 1.38 time, respectively, which was corresponding to the results of residual strength.