| 摘要 |
PURPOSE:To obtain a silicon nitride-based ceramic composite material having improved high-temperature strength and thermal shock resistance and useful as parts for high-temperature use, sliding parts and abrasion resistant parts. CONSTITUTION:This silicon nitride-based ceramic composite material is composed of yttrium oxide, hafnium oxide, silicon carbide and silicon nitride. A dense composite material can be produced by mixing the raw material powders and forming and baking the mixture. The use of yttrium oxide and hafnium oxide is effective for precipitating crystalline phase in the grain boundary phase to improve the high-temperature strength and the oxidation resistance of the material. Since silicon carbide has high thermal conductivity, the thermal shock resistance of material can be improved by forming a composite with the silicon carbide. The toughness is improved by the use of silicon carbide in the form of whisker. A ceramic composite material having excellent high-temperature strength, oxidation resistance and thermal shock resistance can be produced by combining silicon nitride with these above oxide and carbide. |
