Influence of TiO/sub 2/ excess on the sintering behavior and abnormal grain growth of barium titanate ceramics

The sintering behavior and abnormal grain growth of BaTiO/sub 3/ with TiO/sub 2/ excess were investigated. The BaTiO/sub 3/ powders used in this study were prepared by conventional calcination of BaCO/sub 3/ and TiO/sub 2/. The contents of TiO/sub 2/ excess were varied from 0.5 to 3 mol.%. The onset temperatures of the sintering (initial state sintering-3% shrinkage) were lowered with increasing amounts of TiO/sub 2/ excess. The rates of densification with increasing amounts of TiO/sub 2/ were considerably faster than those of stoichiometric BaTiO/sub 3/. Grain growth was inhibited with increasing TiO/sub 2/ excess. The inhibition of grain growth caused abnormal grain growth due to the inhomogeneous distribution of a Ti-rich second phase. Abnormally grown grain shapes were changed with TiO/sub 2/ excess.<
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