POLYMORPHIC PHASE-TRANSFORMATION OF LEAD MONOXIDE AND ITS INFLUENCE ON LEAD ZIRCONATE TITANATE FORMATION

The polymorphic phase transformation of PbO from massicot to litharge phase is easily produced by mechanical force. The transformation is relatively quick by wet ball‐milling. The additions of TiO2 and ZrO2 tend to retard it. A second‐order exponential relation is observed between the fractional conversion and the milling time for pure PbO, PbO‐TiO2, and PbO‐ZrO2‐TiO2 systems with a rutile constituent. This exponential relation is changed into a first‐order logarithmic relation when anatase instead of rutile is used. Although the PbOss phase is observed irrespective of the phase of the PbO in the raw materials, this PbOss peak is more obvious when massicot PbO or anatase TiO2 is used. The formation of PbOss phase is also dependent on the reactivity of the ZrO2, and its presence can affect the formation and piezoelectric properties of PZT ceramics. Copyright © 1990, Wiley Blackwell. All rights reserved