ZrB2, YAG and Al2O3 are widely applied because of some excellent properties, but ZrB2 is easily oxidized in high-temperature air. To achieve better properties in ZrB2 ceramics, high-density ZrB2-YAG-Al2O3 ceramics were prepared. Below 1000 oC, the shrinkage of ZrB2-YAG-Al2O3 ceramics is less than that of ZrB2-YAG ceramics. From 1000 oC to 1600 oC, the second largest shrinkage occurs. Above 1600 oC, the shrinkage of ZrB2-YAG-Al2O3 ceramics is more than that of ZrB2-YAG ceramics. The fracture toughness of sintered ceramics from coated raw materials is higher than that of sintered ceramics with mixed raw materials with the same phases and phase content, the fracture toughness of ZrB2-YAG-Al2O3 ceramics is higher than that of ZrB2-YAG ceramics with the same raw materials. The weight gain of all types of ceramics is increased with all increase in the oxidation temperature, the weight gain of ceramics is reduced with all increase in the YAG-Al2O3 content and Al2O3 proportion, especially above 1500 oC.

Keywords: ZrB2 ceramics, Sintering shrinkage, Fracture toughness, Oxidation.