Si_3N_4/SiC複合セラミックスの微細組織と機械的特性に及ぼすSiC粒径の影響

概要

論文の詳細を見る
Si_3N_4/SiC composite ceramics containing 20 mass% dispersed SiC particles were fabricated by hot-pressing at 1800℃ under 35 MPa for 2h. SiC powders with average particle sizes of 0.03, 0.27, 0.60 and 1.20 μm were used, and the influence of the SiC particle size on the microstructure and mechanical properties (3-point bending strength and fracture toughness values) was investigated. As a result, grain growth and α-β transformation in Si_3N_4 matrix were prevented by the dispersed SiC particles. The Si_3N_4 matrix grain size decreased with decreasing SiC particle size, and in Si_3N_4/SiC(0.03 μm) and Si_3N_4/SiC(0.27 μm), α-phase remained. The fracture toughness decreased with decreasing Si_3N_4 matrix grain size. Accordingly, the fracture toughness was not improved by the dispersed SiC particles. In Si_3N_4/SiC(0.03 μm), the bending strength showed a maximum value of 1161 MPa at room temperature and 950 MPa at 1400℃. It is considered that the remarkable improvement in the strength of Si_3N_4/SiC(0.03 μm) is attributed to fine grains of Si_3N_4 matrix. On the other hand, other composites showed almost the same strengths as monolithic Si_3N_4.
社団法人日本セラミックス協会の論文
1995-07-01