Effect of Gd2O3 addition on mechanical, thermal and shielding properties of Al2O3 ceramics

Gd2O3/Al2O3 ceramic composites with different weight percent of Gd2O3 were prepared by adopting a pressureless sintering approach. The effect of Gd2O3 addition on the phase composition, sintering property, microstructure, bending strength, thermal conductivity and shielding property of the composites was investigated. The results show that the properties of ceramic can be improved greatly by introducing a small amount of Gd2O3, owing to the promotion of reaction between MgO, SiO2 and Al2O3 to produce spinel and forsterite. Compared with ordinary Al2O3 ceramic, the bending strength and thermal conductivity coefficient of Gd2O3/Al2O3 composite with 5 wt% Gd2O3 have increased by 38.03 MPa and 8.95 W/(m K), respectively. When the amount of Gd2O3 surpasses 15 wt%, however, the performances of the composite would become worse for excessive new phases formed in the composite hindering its densification. In addition, screening ratio of the composites for Co-60 gamma rays radiation increases with the addition of Gd2O3. And the Gd2O3/Al2O3 composites also exhibit good mechanical stability when exposed to continuous gamma rays irradiation.