Influence of PbO stoichiometry on the properties of PZT ceramics and multilayer actuators

Lead-oxide stoichiometry of lead-zirconate-titanate (PZT) ceramics and multilayer actuators is a critical issue for fabrication and performance. During sintering, the high vapor pressure and the corresponding volatility of lead oxide (PbO) require a careful design of sintering setup and parameters, as both may significantly impact on the PbO content in ceramics and devices. In order to investigate the effects of PbO stoichiometry, PZT compositions with different PbO contents have been synthesized and were sintered under varying temperature conditions and sintering setups. Structure and microstructure of the material was characterized using X-ray diffraction and scanning electron microscopy (SEM). Dielectric properties and high field strain behavior were analyzed with respect to their relation to PbO content and grain size. Corresponding experiments with multilayer actuators were carried out, whereby the PbO content was varied by controlling the sintering atmosphere. The results indicate that there is a pronounced correlation between PbO content, structure and high field strain in both, PZT ceramics, and multilayer actuators.