Phase structure and electrical properties of (0.8-x)BaTiO3-0.2Bi0.5Na0.5TiO3-xBaZrO3 lead-free piezoceramics

Lead-free piezoelectric ceramics (0.8 - x)BaTiO3-0.2Bi(0.5)Na(0.5)TiO(3)-xBaZrO(3) (BT-BNT-xBZ, 0 <= x <= 0.08) doped with 0.3 wt% Li2CO3 were prepared by conventional solid-state reaction method. With the Li2CO3 doping, all the ceramics can be well sintered at 1170-1210 degrees C. The phase structure, dielectric, ferroelectric and piezoelectric properties of the ceramics were investigated. Results show that a morphotropic phase boundary (MPB) between tetragonal and pseudocubic phases exists at x = 0.03-0.04. The addition of Zr can improve the piezoelectric properties of BT-BNT ceramics. Furthermore, a relaxor behavior is induced and the tetragonal-cubic phase transition shifts towards lower temperatures after the addition of Zr. The ceramics with x = 0.03 possess the optimum electrical properties: d(33) = 72 pC/N, k(p) = 15.4%, epsilon(r) = 661, P-r = 18.5 mu C/cm(2), E-c = 34.1 kV/cm, T-c = 150 degrees C. (C) 2011 Elsevier B. V. All rights reserved.