低純度β型窒化ケイ素粉末のガス圧焼結

概要

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Coarse β-silicon nitride powder of low purity, which was used as a refractory material, was tested as a raw powder for the usage of engineering structural materials. Y_2O_3-Nd_2O_3-doped β-Si_3N_4 was sintered at temperature from 1700° to 1900℃ for 4h under 10 MPa N_2, and the effects of impurities and grain size on the strength, fracture toughness and microstructure were investigated. A dense material was obtained by firing at 1900℃ with addition of 2 to 4 mol% Y_2O_3-Nd_2O_3. The material containing 2 mol% oxides fired at 1900℃ had a strength of 600 MPa and a fracture toughness of 5.3 MPa√<m>. Iron impurity decreased the strength and Weibull modulus. Coarse particles in raw powder suppressed the grain growth, so that the microstructure of self-reinforced composite, which contains in-situ developed elongated rod-like grains, were not obtained.
社団法人日本セラミックス協会の論文
1992-11-01