Structure and electrical properties of (Na0.5Bi0.5)1?x Ba x TiO3 ceramics made by a citrate method

摘要

(Na0.5Bi0.5)1?x Ba x TiO3 (x = 0–0.12) powders were synthesized by a citrate method, and the structure and electrical properties of the resulting ceramics were investigated. A gradual change of crystal structure with the increase of BaTiO3 concentration was detected together with a significant evolution in grain size and shape. A rhombohedral-tetragonal morphotropic phase boundary (MPB) near x = 0.06 at room temperature was ascertained for the ceramics. The dielectric constant (? r) and dissipation factor (tanδ) attain maximum values at x = 0.08 and x = 0.06, respectively. The specimen of x = 0.06 provides the maximum piezoelectric constant (d 33 = 180 pC/N) and electromechanical coupling factor (k p = 0.28), accompanied by a large remanent polarization of P r = 37.1 μC/cm2 and a low coercive field of E c = 42.7 kV/cm.