Tailoring electrical properties of (Na_(1/2)K_(1/2)NbO_3-based lead-free piezoelectric ceramics

摘要

Oxide-doped 0.94(Na_(1/2)K_(1/2)NbO_3-0.03LiSbO_3-0.03LiTaO_3 (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 (Na_(1/2)K_(1/2)NbO_3-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.