LIU Leiren ¹, NIE Guanglin ¹, HUANG Danwu ¹, ZHAO Zhenhua ¹, BAO Yiwang ², WU Shanghua ¹

(1. School of Electromechanical Engineering, Guangdong University of Technology, Guangzhou 510006, Guangdong, China;2. State Key Laboratory of Green Building Materials, China Building Materials Academy, Beijing 100024, China)

Abstract: Al₂O₃ is the most widely used ceramic substrate, due to its excellent mechanical strength, toughness and thermal conductivity, for safe and reliable service. Doping with rare earth metal oxides (La₂O₃, Y₂O₃) is an effective method to improve the mechanical properties of Al₂O₃ ceramics. However, the strengthening effect of single doping is limited. Therefore,La₂O₃-Y₂O₃ codoping was used to further improve the bending strength and fracture toughness of Al₂O₃ ceramic substrates. Also,the influence of La₂O₃-Y₂O₃ codoping on the thermal conductivity of Al₂O₃ ceramics was discussed. The Al₂O₃ ceramics were prepared by using tape casting process and sintered at 1550 ℃ and 1600 ℃ for 2 h. The effects of sintering temperature and La₂O₃/Y₂O₃ ratio on phase composition, microstructure and  mechanical/thermal properties of the Al₂O₃ ceramics were studied.

Key words: Al₂O₃ ceramics; bending strength; thermal conductivity; fracture toughness; tape casting