Al₂O₃-Si₃N₄ウイスカー系複合セラミックスのち密化と二, 三の機械的特性

抄録

α-Al₂O₃-β-Si₃N₄ whisker composite ceramics with a whisker content of 20wt% were prepared by hot-pressing at prescribed temperature between 1300°-1800°C for 30min under the pressure of 30MPa. Fairly dense composites were obtained at sintering temperature above 1500°C. The composites obtained below 1700°C are consisted of α-Al₂O₃ and β-Si₃N₄, while β'-sialon was produced in the composite sintered at 1800°C. The composite fired at 1600°C had a bending strength of about 620MPa, whose value was 50% larger than that of hot-pressed Al₂O₃ at the same sintering temperature, but could not exceed the maximum bending strength of monolithic Al₂O₃ (about 830MPa). The fracture toughness (4.3-4.8MPa·m^1/2) was one and half times as large as that of Al₂O₃ sintered at 1400°-1600°C.