Investigation on the composition design and properties study of perovskite lead-free piezoelectric ceramics

Lead-free piezoelectric ceramics can be divided into perovskite, tungsten bronze, and bismuth layered structure ceramics. In recent years, the authors' group concentrates the researches on the composition design and the properties study of perovskite lead-free piezoelectric ceramics, especially on the (Bi1/2Na1/2)TiO3 (BNT)- and K1/2Na1/2NbO3 (KNN)-based ceramics. All the ceramics were prepared by the conventional ceramic technique. In this paper, the main results obtained are reviewed with emphasis on KNN-based ceramics, including (1) the design on new BNT-based ceramics based on the multiple complex in the A-site of ABO(3) compounds; (2) the design of KNN-based ceramics focused on the effects of Ag ion substitution, K/Na ratio, and LiSbO3 on KNN-based ceramics; (3) the effects of doping on the properties of BNT- and KNN-based ceramics; and (4) the temperature stability of BNT- and KNN-based ceramics. And some prospects to be resolved in coming years from the viewpoint of the applications of the perovskite lead-free piezoelectric ceramics are also pointed out.