XU Mingzhu, JIANG Xiangping, GU Xunjiu, ZHENG Kaiping, CHEN Chao, TU Na

(Jiangxi Key Laboratory of Advanced Ceramic Materials, Department of Material Science and Engineering, Jingdezhen Ceramic Institute, Jingdezhen 333001, Jiangxi, China)

Abstract: Lead-free piezoelectric ceramics (1-x) (0.828(Na, Bi)_0.5 TiO₃-0.06(K, Bi)_0.5TiO₃ - 0.021BaTiO₃ - 0.091SrTiO₃) - xCo₂O₃ (x ~ mol%) were prepared by the solid state route. Effects of the amount of Co₂O₃ on the electrical properties and phase transition were studied. The results of X - ray diffraction revealed that all the ceramic samples were pure perovskite phase; SEM indicated that the suitable Co₂O₃ addition was benefi cial to the growing of grain size. The temperature dependence of dielectric constant showed that the frequency dispersion was more obvious at the temperature near the Tm. The test results of electrical properties indicated that the addition of Co enhanced the mechanical quality factor Q_m , reduced the dissipation factor tanδ, and meanwhile increased the piezoelectric property. The best comprehensive properties of such system can be obtained at x = 0.50%: d33, Q_m, tanδ, and k_p were 226, 126, 4.68% and 33.4% respectively.

Key words: lead - free piezoceramics; Co₂O₃; doping modifi cation