Tailoring electrical properties of (Na_1/2K_1/2)NbO₃‐based lead‐free piezoelectric ceramics

Abstract

Oxide‐doped 0.94(Na1/2K1/2)NbO3‐0.03LiSbO3‐0.03LiTaO3 (NKN‐0.03LS‐0.03LT) lead‐free piezoelectric ceramics were prepared by the conventional solid‐state reaction method sintered under ambient pressure. The kind of oxide dopant and sintering temperature exert great influences on crystal structure, density, and electrical properties of the synthesized (Na1/2K1/2)NbO3‐based (NKN) ceramics. The addition of appropriate sintering additives can produce a liquid‐phase sintering mechanism in the NKN‐based ceramics, which will promote the development of grains and improve densification of the ceramics. Pure tetragonal perovskite structure oxide‐doped NKN‐0.03LS‐0.03LT ceramics can be prepared sintered in a narrow sintering temperature range. As compared to the undoped NKN‐0.03LS‐0.03LT ceramics, the oxide‐doped NKN‐0.03LS‐0.03LT ceramics sintered at the optimized sintering temperature exhibit rather large relative density, comparable dielectric and piezoelectric properties, and improved ferroelectric and electromechanical properties.