Preparation and characterizations of tetragonal barium titanate powders by hydrothermal method

Tetragonal barium titanate powder with an average particle size of 80 mn has been successfully prepared by a hydrothermal process at 240 C for only 12 h. The influence of processing parameters on the phase and the particle size of hydrothermally derived BaTiO3 powders was investigated. Increasing NaOH excess concentration and decreasing the initial titanium tetrachloride concentration promote to increase the particle size and are benefit for preparation of tetragonal BaTiO3 powder, while increasing the reaction temperature and time also obtain same result. There is a relationship between the particle size and the phase of BaTiO3 powder and a critical size of transformation of cubic-BaTiO3 to tetragonal-BaTiO3, In the present work the critical size was 80 nm and finer than other previous works. (C) 2002 Elsevier Science Ltd. All rights reserved.