Phase transition and dielectric characteristics of nano-grained BaTiO3 ceramics synthesized from surface-coated nano-powders

Nano-grained BaTiO3 (BTO) ceramics were synthesized by pressureless sintering BTO nano-powders coated with Mn materials. The BTO ceramics, which were prepared at 800 °C from nano-powders of 40 nm size, are of a cubic structure with a small fraction of tetragonal phase, similar to that of the starting BTO nano-powders of the same size. On the other hand, the BTO ceramics with about grains of 1300 nm size, which were prepared at sintering temperature ranging from 1100 to 1200 °C, have a mainly tetragonal phase. By increasing the sintering temperature and/or the amount of the coating materials, the crystallinity of the tetragonal phase was increased. The relation of the dielectric features of the nano-grained BTO ceramics with the structural variation is discussed in terms of process parameters.