Piezoelectric and Dielectric Properties of (Bi<sub>0.5</sub>Na<sub>0.5</sub>)TiO3- (Bi<sub>0.5</sub>K<sub>0.5</sub>)TiO<sub>3</sub>-BaTiO<sub>3</sub> Lead-Free Piezoelectric Ceramics

Abstract

A lead-free piezoelectric ceramic ternary system based on (Bi0.5Na0.5)TiO3 (BNT)-(Bi0.5 K0.5)TiO3(BKT)-BaTiO3(BT) near the morphotropic phase boundary (MPB) between the tetragonal and rhombohedral phases has been investigated. The samples were prepared by a conventional sintering technique. Piezoelectric properties, dielectric properties and microstructures of BNT-BKT-BT lead-free piezoelectric ceramic were studied. The X-ray diffraction (XRD) patterns show that the ceramics possess a single-phase perovskite structure. The measurements of piezoelectric properties reveal that this system has a relatively high piezoelectric performance: the piezoelectric constant d33 reached to 178pC/N and planar electromechanical coupling factor kp enhanced to 0.325. The BNT-BKT-BT ternary system ceramics could be well sintered at 11500C with a high-density ratio of more than 95% of the theoretical density.