Phase structure and electrical properties of (0.8 - x) BaTiO sub(3-0.2)Bi sub(0.5)Na sub(0.5)TiO sub(3-x)BaZrO sub(3) lead-free piezoceramics

Lead-free piezoelectric ceramics (0.8 - x)BaTiO sub(3-0.2)Bi sub(0.5)Na sub(0.5)TiO sub(3-x)BaZrO sub(3) (BT-BNT-xBZ, 0 less than or equal to x less than or equal to 0.08) doped with 0.3 wt% Li sub(2)CO sub(3) were prepared by conventional solid-state reaction method. With the Li sub(2)CO sub(3) doping, all the ceramics can be well sintered at 1170-1210 degree 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 sub(33) = 72 pC/N, k sub(p) = 15.4%, E> sub(r) = 661, P sub(r) = 18.5 mu C/cm super(2), E sub(c) = 34.1 kV/cm, T sub(c) = 150 degree C.