Abstract: In this paper, Sol-gel method was employed to prepare the (1-x) Na0.5Bi0.5TiO3-xK0.5Bi0.5TiO3 system lead-free piezoelectric ceramics. XRD results revealed that pure perovskite- type crystal structure of (1-x) Na0.5Bi0.5TiO3-xK0.5Bi0.5TiO3 powders can be synthesized by Sol-gel method calcined at 650 ℃, and the morphotropic phase boundary (MPB) with rhombohedral and tetragonal crystalline structure co-existed compositions was identified in the range of 0.18 to 0.30 of x concentration. In the MPB composition, the piezoelectric constant d33 reaches maximum 150 pC/N at x =0.30, and when x equals to 0.26, electromechanical coupling factor kp and dielectric constant εT33/ε0 reach the maximum value which are 36.7; and 1107, respectively.

Key words: In this paper, Sol-gel method was employed to prepare the (1-x) Na0.5Bi0.5TiO3-xK0.5Bi0.5TiO3 system lead-free piezoelectric ceramics. XRD results revealed that pure perovskite- type crystal structure of (1-x) Na0.5Bi0.5TiO3-xK0.5Bi0.5TiO3 powders can be synthesized by Sol-gel method calcined at 650 ℃, and the morphotropic phase boundary (MPB) with rhombohedral and tetragonal crystalline structure co-existed compositions was identified in the range of 0.18 to 0.30 of x concentration. In the MPB composition, the piezoelectric constant d33 reaches maximum 150 pC/N at x =0.30, and when x equals to 0.26, electromechanical coupling factor kp and dielectric constant εT33/ε0 reach the maximum value which are 36.7; and 1107, respectively.