[14] [14] LIU N, ZHANG J X, DUAN Y S, et al. Effect of rare earth oxides addition on the mechanical properties and coloration of silicon nitride ceramics［J］. Journal of the European Ceramic Society, 2020, 40(4): 1132-1138.

[20] [20] BECHER P F, PAINTER G S, SHIBATA N, et al. Effects of rare-earth (RE) intergranular adsorption on the phase transformation, microstructure evolution, and mechanical properties in silicon nitride with RE2O3+MgO additives: Re=La, Gd, and Lu［J］. Journal of the American Ceramic Society, 2008, 91(7): 2328-2336.

[21] [21] YANG H T, GAO L, YUAN R Z, et al. Effect of MgO/CeO2 on pressureless sintering of silicon nitride［J］. Materials Chemistry and Physics, 2001, 69(1/2/3): 281-283.

[24] [24] KRSTIC Z, YU Z B, KRSTIC V D. Effect of grain width and aspect ratio on mechanical properties of Si3N4 ceramics［J］. Journal of Materials Science, 2007, 42(14): 5431-5436.