Advances in Lead-Free Piezoelectric Materials for Sensors and Actuators

Piezoelectrics have widespread use in today's sensor and actuator technologies. However, most commercially available piezoelectric materials, e. g., Pb [ZrxTi1-x] O-3 (PZT), are comprised of more than 60 weight percent lead (Pb). Due to its harmful effects, there is a strong impetus to identify new lead-free replacement materials with comparable properties to those of PZT. This review highlights recent developments in several lead-free piezoelectric materials including BaTiO3, Na0.5Bi0.5TiO3, K0.5Bi0.5TiO3, Na0.5K0.5NbO3, and their solid solutions. The factors that contribute to strong piezoelectric behavior are described and a summary of the properties for the various systems is provided.