WANG Hui,  JIANG Xiangping, WANG Xianwen, NIE Xin, CHEN Chao, HUANG Xiaokun, YANG Liqiang
(Jiangxi Key Laboratory of Advanced Ceramic Materials, School of Material Science and Engineering,Jingdezhen Ceramic University, Jingdezhen 333403, Jiangxi, China)

Abstract:  BaBi₈Ti₇−_xMg_xO₂₇₋₆   (x=0,  0.2,  0.4,  0.6,  0.8)  intergrowth bismuth  layered  lead-free piezoelectric  ceramics  were prepared by using the conventional  solid-state reaction method. The effect of Mg²⁺on  structure, electrical properties and temperature stability of the ceramics was studied. All the samples have a single phase structure. With increasing content of Mg²⁺ , both the dielectric constant and dielectric loss showed a decreasing trend, while the impedance and activation energy increase at high temperatures. In addition, a small quantity of Mg²⁺ resulted in a variation in the microstructure from plate-like grains  to  particle-like  grains,  leading  to  an  improvement  in  piezoelectric  properties  of the  ceramics.  The  sample  with x=0.60 exhibited optimum electrical properties, with Curie temperature of about 480 ℃ and piezoelectric constant (d33) of 18.8 pC·N⁻¹ , which is higher than that of the undoped sample by about 250%.
Key words: intergrowth bismuth layered lead-free piezoelectric ceramic; piezoelectric constant; doping