Phase transition and piezoelectric property of (Bi0.5Na0.5)0.94Ba0.06ZryTi1-yO3(y=0-0.04) ceramics

The ceramics with the composition of (Bi0.5Na0.5)(0.94)Ba0.06ZryTi1-yO3 (BNBZ100yT, in which y=0,0.01,0.02,0.04) were prepared successfully by the solid state reaction method. X-ray diffraction studies revealed the perovskite structure in BNBZ100yT ceramics sintered at 1170 degrees C for 2 h in air. The relative densities of the sintered ceramics were around 97%-99%. The temperature dependent dielectric properties of BNB6T and BNB6Z4T ceramics showed their relaxor-like behaviors. Decreases in remnant polarization, coercive field, and disappearance of piezoelectric properties were found by the substitution of 2 and 4 mol % Zr4+ for Ti-4+ in these ceramics. Electron diffraction patterns taken in a transmission electron microscope demonstrated the existence of cubic crystalline phase in the BNB6Z4T ceramics leading to the disappearance of piezoelectric property. Decrease in grain size was also observed with the substitution of Zr4+ for Ti4+ in BNB6T ceramics. (c) 2007 American Institute of Physics.