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.