CHEMICAL SYNTHESIS OF PZT POWDER BY AUTO-COMBUSTION OF CITRATE-NITRATE GEL

A simple and convenient method for the synthesis of PZT powder with di fferent compositions near the morphotropic phase boundary is reported. The technique involves auto-combustion of a citrate-nitrate gel resul ting from a thermally induced oxidation-reduction reaction forming an ash, which on calcination produces the desired powder. It is possible to use solid titanium dioxide as one of the starting materials instead of strongly hydrolyzable titanyl nitrate without any compromise with the quality of the final product. The method produces fine, homogeneou s powders without any compositional fluctuation after calcination of t he burnt ash at an appropriate temperature. Powders formed have an ave rage particle size of around 1.1 mu m as determined by Sedigraph and a round 0.16 mu m based on surface area measurements. Fully tetragonal p hase is observed up to 52 mol% ZrO2 whereas fully rhombohedral phase i s obtained with a ZrO2 content of 54 mol% and greater.