PZT prepared by Spray Drying: from powder synthesis to electromechanical properties

A PZT niobium-doped material (PZTN) was developed from precursor powders obtained by spray drying of water solution of Zr and Pb nitrates, Ti isopropoxide and Nb–ammonium complex. The thermo-oxidative process as well as the phase evolution were analysed. The morphology of powders was investigated as a function of the spray-drying conditions. The stoichiometry of the systems was checked at each stage of the process and no fluctuation was detected. The obtained powders had a spherical, hollow and porous structure and were transformed into a pure perovskite phase at 550 æC. The samples, sintered at 1100 æC for 2 h in air showed 98% relative density at densification temperature of 100 æC lower than following the conventional mixed oxide route. The green and final densities were improved by introducing a grinding step and high pressure cold isostatic consolidation. Some sintered samples were fully densified by hot isostatic pressing (1100 æC, 300 bars) post-treatment, obtaining pore free structures. The electrical characterisation showed comparable or better properties than those obtained with the mixed oxide method.