Effect of Powder Characteristics on Microstructure and Properties in Alkoxide Prepared PZT Ceramics

摘要

Effects of coprecipitation parameters on agglomerate structure in PZT (53:47) powders prepared from butoxide precursors were studied. Results showed that differences in the agglomerate structures developed during coprecipitation persisted throughout the subsequent processing steps and the resulting sintered densities and microstructures to be correlated to the agglomerate structures. Coprecipitation parameters which most significantly affected the powder characteristics included temperature, dilution, pH, and hydrolysis rate (controlled by water concentration). Such processing parameters as powder rinsing, calcination temperature and spray-drying conditions also significantly influenced the developed microstructures. For equivalent processing conditions, most dense and uniform microstructures were developed with the softer (and smaller) agglomerate structures, achieved from an acid (pH 3.7) medium of low (3-5 vol%) solids content with rapid hydrolysis (about 32 ml water/min) and low temperature rise (10 to 15 C). Measured dielectric constants (700-1000) on the sintered PZT samples were found to increase with average grain size which typically were larger for the basic (pH 11) powders.