STUDIES ON THE FORMATION OF LEAD TITANATE BY SOLID-STATE REACTION FROM PBO AND TIO2

Reaction between PbO and TiO2 mixed in the stoichiometric ratio for th e preparation of PbTiO3 has been followed using DTA and XRD techniques . Studies reveal that the reaction is initiated at approximately 800 K . Samples heat-treated at 875 K showed the characteristic X-ray patter n for crystalline PbTiO3 and, on the basis of dielectric constant meas urements, a Curie transition temperature of 765 K. SEM micrographs als o showed a single phase sample with well defined grains, The samples w ere also characterized by ac resistivity measurements. The DTA curve s howed an exothermic heat effect in the temperature range 835-1020 K co rresponding to the formation of lead titanate. The Curie transition in the compound so formed could be observed as another exothermic peak a t 783 K in the cooling cycle. Simultaneous TG measurements confirmed t hat both heat effects were unattended by changes in sample weight.