Highly enhanced thermal stability in quenched Na0.5Bi0.5TiO3-based lead-free piezoceramics

Abstract Unquenched and quenched ceramics of 0.85Na 0.5 Bi 0.5 TiO 3 -0.11K 0.5 Bi 0.5 TiO 3 -0.04BaTiO 3 have been prepared, and their crystal structure, temperature-dependent ferro-/piezoelectric properties and domain structure have been comparatively investigated. It is shown that quenching process can significantly improve the ferroelectric-relaxor transition temperature ( T F-R ), which is 130 °C for unquenched ceramics and 198 °C for quenched one. As the result, the thermal stability of ferro-/piezoelectric properties is highly enhanced. These observations are mainly attributed to the quenching induced stable rhombohedral ferroelectric phase and the defect altered domain evolution. This work may deepen the understanding of the effect of quenching on crystal structure, domain structure and their contributions to thermal stability of NBT-based ceramics.