Preparation and stoichiometry effects on microstructure and properties of high purity BaTio3

Effects of stoichiometry, precursor origin and powder synthesis method on sintered microstructure and dielectric properties of commercial high purity BaTiO3 were examined, with a view to potential interchangeability. Powders used were prepared by conventional calcination, by precipitation from oxalate precursors and by hydrothermal synthesis. Stoichiometric (Ba:Ti) ratios were in the range 0.987 to 1.002. Characterization by SEM, x-ray diffraction, BET surface area and particle size analysis revealed significant differences, particularly in agglomerate structure, resulting in different microstructural development. Stoichiometric effects on microstructure were also significant, if predictable. However, the combined effects of agglomerate structure and stoichiometry on measured dielectric properties could not be predicted, hence interchangeability of powders could not be achieved.