LI Longzhu¹ ,JIANG Xiangping ²

(1. Material Engineering Department of Changzhou Institute of Engineering Technology, Changzhou 213164; 2. School of Material Science and Engineering of Jingdezhen Ceramic Institute, Jingdezhen 333001)

Abstract: (Na_1-xK_x)_0.5Bi_0.5TiO_3-xSrTiO₃-0.3%Mn lead-free ceramics were prepared by solid-state reaction. The electric operties were studied. XRD results show that all ceramic samples are perovskite of coexistent rhombohedral and tetragonal phases at room temperature. With the increase of Sr content, the tetragonal phase will increase and the rhombohedral phase will decrease. The ceramic samples have outstanding piezoelectric properties, with maximum piezoelectric constant d₃₃ being171pC·N^-1, planar electromechanical coupling factor k_p being 33.1% and thickness electromechanical coupling factor kt being 30.5% when the content of Sr equal to 0.02. Sr acts as "a soft dopant" in (Na_0.8K_0.2)_0.5Bi_0.5TiO₃ system.

Keywords: (Na_0.8K_0.2)_0.5Bi_0.5TiO₃, SrTiO₃, lead-free piezoelectric ceramics, piezoelectric properties, ferroelectric properties