Synthesis of Nano-sized BaTiO3 Powders by the Rotary-Hydrothermal Process

Nano-sized BaTiO3 powders with narrow size distribution and high tetragonality were attempted to be synthesized by the rotary-hydrothermal process in a water system as a novel technique, using a mixture of anatase-type TiO2 and Ba(OH)(2) as starting material. The rotary-hydrothermal syntheses were performed under conditions with a rotary-speed of 20 revolutions per minute at 423-523 K for 3-96 h. Highly- and mono-dispersed BaTiO3 powders mainly composed of coarse-faceted particles with the tetragonal phase were successfully synthesized by controlling the conditions for rotary-hydrothermal treatments. TEM and TG results revealed that these coarse-faceted BaTiO3 particles contained very few structural defects such as hydroxyl content. Thus, the rotary-hydrothermal process was a useful method to synthesize very high-quality BaTiO3 particles, and the further control of various conditions of the rotary-hydrothermal treatment is expected to control the crystalline phase and microstructures of final BaTiO3 powders.