Perovskite lead-free piezoelectric ceramics

Lead zirconate titanate (PZT)-based piezoelectric materials are the most widely used piezoelectric materials for electromechanical devices. However, due to the toxicity of lead, there is a strong interest in the development of environmental friendly lead-free piezoelectrics. Several classes of lead-free materials, such as barium titanate, bismuth and sodium titanate, potassium niobate (KNbO₃) and their solid solutions, have been reported as alternatives to PZT, and they exhibit relatively high piezoelectricity through the compositional modifications, and, in some cases, comparable to those of PZT. However, solid solutions of these lead-free perovskite families are not yet suited to replace PZT because of their limited operational temperature range. This chapter reviews recent developments in lead-free piezoelectric materials. Origin of enhanced properties and thermal stability of these families are discussed.