Hydroxide coprecipitation route to the piezoelectric oxide Pb(Zr,Ti)O3(PZT)

Abstract

A homogeneous and stoichiometric fine powder of the piezoelectric oxide Pb(Zr_0.52Ti_0.48)O₃(PZT) has been prepared by the hydroxide coprecipitation route. By considering the thermodynamic equilibrium constants, the solubility and ionic equilibria relationships for individual metal hydroxides in aqueous media could be theoretically evaluated as a function of solution pH and metal ion concentration. An optimal pH of 9 for the coprecipitation of the ternary Pb-Zr-Ti system as hydroxides was predicted from the solubility diagrams, and the quantitative coprecipitation of metal hydroxides was confirmed experimentally. Pb(Zr_0.52Ti_0.48)O₃ as a single phase was obtained by thermal decomposition of the coprecipitated hydroxide precursor above 500 °C. The calcined powders at various temperatures were characterized by inductively coupled plasma (ICP) studies, thermogravimetry-differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) surface area measurements.