GAS-CONDENSATION SYNTHESIS OF NANOCRYSTALLINE BATIO3

Nanocrystalline BaTiO3 has been prepared by a gas-condensation process . BaTiO3 and Ti sources are vaporized simultaneously in either a heliu m or an oxygen environment using an electron beam evaporation system. The stoichiometry of nanocrystalline BaTiO3 powders can be controlled precisely and reproducibly. Nanocrystalline BaTiO3 powders, with an av erage particle size of less than 20 nm, can be obtained by postanneali ng the as-evaporated powders at a temperature of 700 degrees C. These powders show good sintering behavior with a high density at a sinterin g temperature as low as 1250 degrees C. Differential thermal analysis indicated that nanocrystalline BaTiO3 was formed through the reaction of Ba/Ti oxidized clusters. Dielectric properties of ceramics from nan ocrystalline BaTiO3 are also reported. (C) 1997 American Institute of Physics.