Grain-controlled barium titanate ceramics prepared from high-gravity reactive precipitation process powder

Abstract

Using powders prepared by a high-gravity reactive precipitation process, grain-controlled barium titanate ceramics were obtained under conventional sintering conditions. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, as well as dielectric measurements were used to characterize the samples. The powder was densified to >95% of theoretical density when sintered at 1200 °C (K1200), and the average grain size of the resulting ceramics was <0.5 μm. Increasing sintering temperature increased the grain size and did not arise the exaggerated grain growth. The grain size significantly affects the permittivity of the resulting ceramics. Room temperature permittivity of the sample K1200 showed relatively low values (2800) compared with those (typically 4143) for ceramics sintered at 1250 °C, consisting of larger grains (≈1 μm). The lower permittivity was attributed to an incomplete development of the tetragonal structure.