PZT crystalline powders with different grain sizes and morphologies were synthesized by hydrothermal reactions below 200°C using KOH as a reaction-accelerator. The grain size of the PZT powders decreased with increasing reaction temperature. PZT powders with a cubic shape were obtained when the KOH concentration was low. Addition of about 22% excess Pb to the starting solution was necessary to obtain stoichiometric PZT powders. The ceramics prepared from cubic powders with the large grain sizes had low coercive fields, and showed relatively high electromechanical coupling factors even with the low electric field for poling. The ceramics prepared from powders of small grains did not have a high coupling factor, but the mechanical quality factor (Qm) was high.
