Barium titanate derived from mechanochemically activated powders

A high-energy ball milling process was applied to a mixture with equal molar ratio of BaCO₃ and TiO₂. X-ray diffraction data indicated that there was no reaction happening during the milling process although the particle size was greatly reduced. The effect of post-annealing on the phase formation and grain growth of BaTiO₃ was investigated by thermal analysis (DTA/TGA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). No reaction was observed in the sample annealed at 600°C. Ba₂TiO₄ was found as the mixture annealed at 700°C. An 800°C-annealing led to single phase BaTiO₃ with a cubic structure. The temperature at which BaTiO₃ phase was derived is lower than required by the solid-state reaction process, which could be attributed to the refined grains/particles of the mixture as a result of high-energy ball milling. Tetragonal structured BaTiO₃ was formed at 1150°C together with a sharp increase in grain size.