In situ synthesis of nanosized PZT powders in the precursor material and the influence of particle size on the dielectric property

Nanosized PZT powders, with Zr/Ti ratio of 60/40, have been prepared starring from a solution of Diethanolamine (DEA) and hydrated metaloxides of Ti(iv), Zr(iv) and Pb(ii) ions. The metal ions were in solution through complexformation. The soluble metal-DEA complex on complete dehydration, followed by decomposition formed the precursor material. The precursor material was found to be x-ray single phasic PZT with average particle size 25 nm. The precursor and heat-treated powders were characterized by DTA, XRD and TEM analysis. For comparative studies PZT powders have also been prepared by heating directly and hydrothermally from the coprecipitate hydrated metal oxides and resulted in single phase PZT at 500 degrees C/5h, and 220 degrees C/5h having average particle sizes 190 and 480 nm respectively. The dielectric constant increased exponentially with decreasing size of particles of agglomerated crystallites due to efficient sintering and densification. The dielectric constant of the sintered product from DEA complex gives superior value, i.e., 11518. (C)1999 Acta Metallurgica Inc.