Si_3N_4/SiC複合セラミックスのクリープ特性に及ぼす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 creep properties was investigated. Creep tests were performed by 4-point bending for 100h at 1250-1350℃ under 250-450 MPa in air. Grain growth in the Si_3N_4 matrix was prevented by the dispersed SiC particles. The Si_3N_4 matrix grain size decreased with decreasing SiC particle size. Steady state creep strain rate ε increased with decreasing Si_3N_4 matrix grain size. Accordingly, the creep properties were not improved by the dispersed SiC particles. Stress exponents, n were 1.5-2.7. It was assumed that the creep deformation was controlled by grain boundary sliding accompanied by cavitation. Moreover, weight gains of Si_3N_4/SiC composite ceramics were larger than that of monolithic Si_3N_4 after creep tests. However, the bending strength of Si_3N_4/SiC slightly increased.
社団法人日本セラミックス協会の論文
1996-11-01