HYDROTHERMAL SYNTHESIS OF BARIUM-TITANATE FINE PARTICLES FROM AMORPHOUS AND CRYSTALLINE TITANIA

Barium titanate fine particles of cubic system were synthesized hydrot hermally from aqueous barium hydroxide, solutions with fine particles of either amorphous or crystalline (rutile) titania in suspension. The mean size of barium titanate particles prepared from amorphous titani a ranged from 0.03 mu m to 0.11 mu m, depending on hydrothermal condit ions. The particle size approximately agreed with the crystallite size (0.04-0.09 mu m). On the other hand, the mean size of barium titanate particles prepared from rutile titania ranged from 0.2 to 0.7 mu m, w hich was about six times as large as the crystallite size. The differe nce of sizes of barium titanate particles prepared might be ascribed t o the difference in dissolution rates of amorphous or crystalline tita nia particles.