Synthesis of BaTi4O9 ceramics by reaction-sintering process

Synthesis of BaTi₄O₉ ceramics by a reaction-sintering process was investigated. The mixture of raw materials for stoichiometric BaTi₄O₉ were pressed and sintered into ceramics without any calcination stage involved. Pure BaTi₄O₉ phases were obtained at 1150-1280 °C. High-sintered density, 98.2-99.5% of theoretical value (4.533 g/cm³), can be obtained for pellets sintered at 1200-1280 °C for 2-6 h. Some rod-shaped grains 3-7 μm in the longitudinal axis appear in pellets sintered at 1230 °C. Both the size and the amount of these rod-shaped grains increase at higher sintering temperature.