Effect of poling on piezoelectric and ferroelectric properties of Bi0.5Na0.5Ti1-xZrxO3 ceramics

Lead-free bismuth sodium titanate zirconate powders with the stoichiometric formula of Bi0.5Na0.5Ti1 − xZrxO3 (where x = 0, 0.20, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80 mol fraction) were prepared by solid state reaction method. Based on XRD pattern from phase analysis of Bi0.5Na0.5Ti1-xZrxO3 powders, the quantitative profile fitting analysis was carried out. Phase characterization of the powders showed that at x = 0–0.65 mol fraction, only rhombohedral phase existed. With x = 0.68–0.75 mol fraction, the coexistence of rhombohedral and orthorhombic phases occurred. Orthorhombic phase completely formed with x = 0.80 mol fraction. Small addition of Zr into BNT caused dielectric constant to increase. High Zr concentration induced more unit cell distortion which caused the degradation of dielectric properties. Poling also had some effects on ferroelectric behavior of BNTZ ceramics particularly in the rhombohedral phase region in terms of improved breakdown strength.