XU Jingdong, JIANG Xiangping, CHEN Chao, HUANG Xiaokun, NIE Xin, WANG Xianwen

(Jiangxi Key Laboratory of Advanced Ceramic Materials, School of Material Science and Engineering, Jingdezhen Ceramic Institute, Jingdezhen 333403, Jiangxi, China)

Abstract: Lead-free piezoelectric ceramics, Na_0.5Bi_2.5Ta_2-xW_xO₉ (NBTO–x, 0≤x≤0.05), were prepared by using the solid state reaction method. The effect of W⁶⁺ on structure and electrical properties of the NBTO ceramics was studied. The XRD results showed that all the ceramic samples had a bismuth layered structure with m=2, the orthogonal distortion was decreased first and then increased, as the doping centration was increased. Both piezoelectric and ferroelectric properties of the ceramics were improved due to the doping with W⁶⁺. Specifically, the sample with x=0.03 exhibited optimal properties, with TC=755 ℃, tanδ=0.393% (600 ℃), d₃₃=13.9 pC/N and P_r=7.51 μC/cm². After annealing at 600 ℃ for 1 h, piezoelectric constant (d₃₃) of the NBTO (x=0.03) ceramics was still as high as 12.8 pC/N, about 92.1% of the original value (d₃₃=13.9 pC/N), demonstrating high temperature stability.

Key words: bismuth layer-structured; high temperature piezoelectric ceramics; electrical property