Preparation of fine-grained BaTiO3 ceramics by spark plasma sintering

Dense BaTiO3 ceramics consisting of fine grains were prepared using fine powder (average grain size of 0.06 mum; BT006) as a starting material and the spark plasma sintering (SPS) method. The powder was densified to >95% of theoretical x-ray density by the SPS process, and the average grain size of the resulting ceramics was <0.5 mum; the particle size of the initial powder significantly affects the grain size of the resulting SPS pellets. Fixed-frequency (100 kHz), room-temperature permittivity measurements of the BT006-SPS ceramics showed relatively low values (3000-3500) compared with those (typically 5000) for SPS ceramics consisting of larger grains (approximately 1 mum). Lower permittivity was attributed to poor development of ferroelectric domains in the ceramics, which originated from incomplete development of the tetragonal structure as well as the presence of a local orthorhombic structure.