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 [Zr(x)Ti(1-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 BaTiO(3), Na(0.5)Bi(0.5)TiO(3), K(0.5)Bi(0.5)TiO(3), Na(0.5)K(0.5)NbO(3), 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.