Preparation of fine powders with perovskite structure from metal alkoxides

The preparation of perovskite powders was investigated by the metal alkoxide methods. The complex alkoxide as a precursor was hydrolysed under specific conditions, and submicrometre powders of perovskite compounds differing in composition, BaTiO3, Ba(Mg1/3Nb2/3)O3, PbTiO3, and Pb(Mg1/3Nb2/3)O3, could be obtained. The simultaneous use of a dipolar aprotic solvent, such as acetone, etc., with ethanol was found to be effective for the preparation of the spherical or nearly spherical powders with submicrometre diameter. The submicrometre powders were formed through nucleation–aggregation, but not by the usual nucleation–grain growth. Such powder formation, and the affinity of the solvent for the diffusion layer surrounding the colloidal particle, are important. The powders obtained here could be crystallized to the desired crystalline phase at lower temperatures.