Phase transition behavior and electrical properties of (1-x)Bi0.5Na0.5TiO3-x(Na0.53K0.44Li0.04)(Nb0.88Sb0.08Ta0.04)O3 lead-free ceramics

(1 - x)Bi0.5Na0.5TiO3-x(Na0.53K0.44Li0.04)(Nb0.88Sb0.08Ta0.04)O-3 (BNT-xNKLNST) with x = 0-0.10 lead-free piezoelectric ceramics were prepared by a solid state method, and the structure and electrical properties were investigated in this study. It is found that a morphotropic phase boundary (MPB) of rhombohedral (R) and tetragonal (T) phase exists in the range of 0.03 <= x <= 0.05 and the structure changes to paraelectric phase when x > 0.07. The samples with x = 0.05 exhibit improved electrical properties owing to the formation of MPB, which are as follows: piezoelectric constant d(33) = 120 pC/N, remnant polarization P-r = 39.4 mu C/cm(2) and coercive field E-c = 3.6 kV/mm. These results indicate that the enhanced piezoelectric properties for BNT can be achieved by forming the coexistence of R and T phase. Crown Copyright (C) 2012 Published by Elsevier Ltd. All rights reserved.