Study on barium titanate ceramics prepared by various methods

Barium titanate (BaTiO3) ceramics have been fabricated using powders prepared by sol-gel, coprecipitation and mixed oxide methods. The powders prepared by sol-gel and coprecipitation have average crystallite diameters of 100 nm and 300 nm, respectively while the diameter of the mixed oxide powder is similar to1-3 mum. When sintered at the same temperature of 1320 degreesC, the three BaTiO3 ceramics have very different grain size, with the one prepared by the mixed oxide method having the largest grain size of 20 mum. The dielectric permitivity increases as the grain size of the ceramic becomes smaller. The room temperature (25 degreesC) dielectric permittivity, pyroelectric and piezoelectric properties of these ceramics have been measured as functions of the poling field. The BaTiO3 ceramic fabricated from nanosized powder derived from the coprecipitation method is found to have the smallest grain size and better properties than prepared from the sol-gel route, and is thus a good candidate for use in devices that required thick (10 to 20 mum) ferroelectric films. (C) 2001 Kluwer Academic Publishers.