DU Daming, WEI Shengquan, JIANG Xiaodong, BAI Xiaobo

((School of Mechanical and Materials Engineering, Jiujiang University, Jiujiang Jiangxi 332005)

Abstract:Si3N4 -Y2O3 -La2O3 ceramics were fabricated by pressureless sintering, and the mechanical properties, phase composition and microstructure of the ceramics were studied and discussed. The results show that Si3N4 ceramic is made up of rod-like β-Si3N4 grains, its bending strength and fracture toughness are 960MPa and 7.5MPa·m1/2, when 4%Y2O3-4% La2O3 is added.

Key words: rare earth oxides; Si3N4; mechanical property; microstructure