Fabrication of Spherical and Irregularly Shaped Powders of Li and Ba Titanates from Titanium Tetrachloride by Inorganic Sol-Gel Process

摘要

We report preparation procedures for some lithium and barium titanate compounds. The procedures utilize inexpensive, commercial superconductors in an aqueous HC1 solution. The main preparation steps consist of chloride elimination by distillation with nitric acid, addition of hydroxides of Li (or Ba), evaporation of sols to dry powders, and thermal treatment to titanates. Thermal and X-ray analyses indicate that the formation temperatures are lower than the corresponding temperatures necessary for conventional solid-state reactions. These temperatures can be further decreased by addition of ascorbic acid during formation of Ti nitrate sols. Spherical powders are obtained by solvent extraction of water from sol drops emulsified in 2-ethylheksanol-1. Final correction of the composition of the spherical powders is carried out by an impregnation process.