Effect of Y₂O₃ and Sm₂O₃ on sintering and mechanical behaviors of alumina ceramics

The effects of Y₂O₃ and Sm₂O₃ doping on the sintering temperature, microstructure and mechanical behaviors of Al₂O₃ ceramics were investigated. The experimental results show that the sintering temperature can be decreased and the mechanical behavior can be improved by adding rare earth in alumina ceramics. The relative density of rare-earth-doped alumina ceramics reaches 98.8% after sintering at 1600°C for 2 h, and its bending strength and fracture toughness reach 439 MPa and 5.28 MPa·m^1/2, respectively. Introduction of Y₂O₃ and Sm₂O₃ in Al₂O₃ can restrain the growth of grains, refine the size of grains, and thus form a fine-grained structure. The fracture characteristic is the mixed modes of intergranular and transgranular fracture.