LIANG Zhihao, HUANG Rongxia, ZHANG Yi
(School of Electromechanical Engineering, Guangdong University of Technology, Guangzhou 510006, Guangdong, China)
Abstract:Mn/Wco-doped Bi4Ti3−x(Mn1/3W2/3)xO12(BITMW-100x,0.01≤x≤0.07) bismuth layered high temperature piezoelectric ceramics were prepared by using direct reaction sintering method. The effects of Mn/W content on structural and electrical properties of the BITMW-100x ceramics were studied. XRD results indicated that all samples exhibited typical bismuth layered structure. With increasing content of Mn/W, grain size of the ceramic grains increased first and then decreased. Dielectric loss of the Bi4Ti3O12 ceramic samples is effectively suppressed after the doping with Mn/W, while the Curie temperature shows a slight reduction. Owing to the decrease in the concentration of oxygen vacancy in the Bi4Ti3O12 ceramics after replacing Ti, the pinning effect of oxygen vacancies on electric domains is weakened, so that the piezoelectric coefficient is increased. When the Mn/W doping content is x=0.05, the ceramic samples have the optimal overall performance, with dielectric loss (tanδ) of 0.7%, Curie temperature of 674 ℃ and piezoelectric constant (d33) of 18.1 pC·N−1. Meanwhile, the piezoelectric constant has promising thermal stability.
Key words: piezoelectric ceramics; Bi4Ti3O12; B-site doping; ferroelectricity; bismuth lamellar structure