Processing and Additive Effects of ZrO2 on Microstructure and Dielectric Properties of BaTiO3 Ceramics

摘要

Dielectric properties and structure of BaTiO3 ceramics have been shown to be significantly influenced by small additions of ZrO2. Scanning Electron Microscopy(SEM) and Transmission Electron Microscopy(TEM) observations revealed enhanced microstructural uniformity and retarded grain growth with ZrO2 addition, depending on sintering temperature (T sub S). For T sub S <1320 C, TEM analysis showed ZrO2 at the grain boundaries as discrete particles in a bandwidth of + or - 50 A. Above 1320 C, diffusion of ZrO2 from the grain boundary region was observed, resulting in increased grain size and a tetragonal structure. X-ray diffraction analysis revealed a pseudo-cubic structure below 1320 C with both twinning and domain structure also suppressed. Ceramics with the pseudo-cubic structures showed a flattened dielectric constant response with temperature and significantly lower dielectric loss.