Fabrication of fine-grain piezoelectric ceramics using reactive calcination

Fine-grain piezoelectric ceramics with the formula Pb(Zr_0.53Ti_0.47)O₃(PZT) were prepared by a reactive calcination process. Using conventional materials and processing techniques, highly reactive powders of PZT were achieved by calcining to or near the point of maximum volume expansion, whereby associated morphological changes resulted in highly reactive powder. Upon milling, powders <0.3 μm were readily obtained allowing densification at temperatures <1000°C. The B-site precursor method, whereby the ZrO₂ and TiO₂ oxides were pre-reacted prior to reaction with PbO, further enhanced reactivity by eliminating intermediate reactions and subsequent phase(s) which can hinder densification and overall homogeneity. Highly dense piezoceramics with grain sizes ∼1 to 2 μm exhibiting dielectric and piezoelectric characteristics comparable to conventionally prepared large grain size materials were obtained.