Effect of Excess PbO on Phase Formation, Microstructure and Dielectric Properties of (Pb0.975Ba 0.025)ZrO3 Ceramics

Abstract

Polycrystalline samples of (Pb0.975Ba0.025)ZrO3 (PBZ2.5). were prepared by a mixed
oxide, solid-state reaction method. Excess PbO (1,3, 5 or 10 wt.%) was introduced prior to
powder calcination to compensate for any PbO that may have been lost from the samples due
to volatilsation during heat treatments. The phase structure was analyzed by XRD.A pure
PBZ2.5 phase was observed in all of the ceramic samples. Microstructurally, excess PbO
produced an increase in average grain size, from ~ 0.5 ??m for no excess to ~0.8 ??m for
excess PbO. Dielectric constant-temperature plots showed a maximum peak value of 8070,
for the 1 wt.% sample which was also the densest sample.

Keywords: lead barium zirconate, dielectric properties, excess lead oxide, phase transition