PREPARATION OF WELL-DEFINED COLLOIDAL BARIUM-TITANATE CRYSTALS BY THE CONTROLLED DOUBLE-JET PRECIPITATION

A new method for the preparation of well-defined colloidal barium titanate (BaTiO3) crystals by the controlled double-jet precipitation (CDJP) technique is described. The process is extremely fast and requires a low temperature (<100 degrees C). The reactants, barium and titanium salts, can be used in high concentrations and the yield is quantitative. The stoichiometry of the BaTiO3 particles can be controlled precisely and reproducibly. The effects of the composition of the reactant solutions, flow rates, reaction time, and the addition of polymers on the precipitation process were investigated. The BaTiO3 powders, produced by the CDJP technique, sinter to high density at a temperature as low as 1200 degrees C and exhibit a relative dielectric constant of 5000 at 20 degrees C, which is the highest value reported in the literature. The grain sizes of the sintered samples are small and uniform, ranging between 1 and 2 mu m.