Piezoelectric and ferroelectric properties of Na0.5Bi0.5TiO3-K0.5Bi0.5TiO3-BaTiO3 piezoelectric ceramics

Piezoelectric and ferroelectric properties of (1−5x)NBT-4xKBT-xBT lead-free ceramics were investigated. XRD results show that the crystalline structure of the investigated materials were perovskite. The morphotropic phase boundary (MPB) of the system between rhombohedral and tetragonal locates in the range of x=0.024-0.030. The best piezoelectric constant d33=149 pC/N at x=0.030 and planar electromechanical coupling factor kp=0.282 at x=0.028 are observed. Accordingly, the composition shows larger remanent polarization and low coercive field than pure NBT ceramic.