Influence of TiO2 excess on the sintering behavior and abnormal grain growth of barium titanate ceramics

The sintering behavior and abnormal grain growth of BaTiO₃ with TiO₂ excess were investigated. The BaTiO₃ powders used in this study were prepared by conventional calcination of BaCO₃ and TiO₂. The contents of TiO 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 TiO₂ excess. The rates of densification with increasing amounts of TiO₂ were considerably faster than those of stoichiometric BaTiO₃. Grain growth was inhibited with increasing TiO₂ 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 TiO₂ excess