Zhang Youfeng ^1,2 Zhou Yu ² Jia Dechang ² Meng Qingchang ²

(1. Material Engineering College, Shanghai University of Engineering Science, Shanghai 201620; 2. Institute for Advanced Ceramics, Harbin Institute of Technology, Harbin 150001)

Abstract:Domain structures in LiTaO₃ grains in Al₂O₃ /LiTaO₃ composite ceramics were investigated systematically by TEM.Domain structures in LiTaO₃ crystal, LiTaO₃ as matrix and LiTaO₃ as second phase were investigated. The results show that dagger-shaped 180°domain structures mainly occurred in LiTaO₃ single crystal, and only a few non-180°domain structures were present. Wedge - and band -shaped non -180° domain structures significantly increased, and dagger -shaped 180°domain structures were also found in 15ALT composite ceramics. Only a few 180°domain structures were found in 30ALT composite ceramics, and domain quantity, density of non-180° domain structures were the highest. The formation of domain structures in LiTaO₃ grains are related to the stress around LiTaO₃ grains produced by Al₂O₃ grains.

Keywords:LiTaO3, Al₂O_3, domain structure, ceramic composite