SOL-GEL SYNTHESIS OF BARIUM-TITANATE POWDERS OF VARIOUS COMPOSITIONS

The barium titanates BaTiO3, Ba2TiO4, BaTi2O5 and BaTi4O9 can be synthesized by a sol-gel method at low temperatures. The reaction between barium acetate solutions and titanium(IV) isopropoxide leads to the formation of barium titanate gels. The gels can be converted to the barium titanates by drying and calcination. The resulting ultrafine, phase-pure barium titanate powders have a small impurity content. They are very sinter active above 1200-degrees-C. The rate of densification (which considers the green densities, the densities at a given time and the theoretical densities of the titanates for the calculations) during the sintering of compacts increases as BaTi4O9<Ba2TiO4<BaTiO3<BaTi2O5. The barium titanate gels and the titanate powders were characterized by DTA, TG, XRD and chemical analysis.