Ultrahigh electrostrain with excellent fatigue resistance in textured Nb5+-doped (Bi0.5Na0.5)TiO3-based piezoceramics

Abstract

(Bi0.5Na0.5)TiO3 (BNT)-based lead-free piezoceramics exhibit excellent electric field-induced strain (electrostrain) properties, but often suffer from large hysteresis and poor fatigue resistance, which strongly limit their applications. Here, <00l> textured Nb5+-doped 0.8(Bi0.5Na0.5)TiO3–0.2(Bi0.5K0.5)TiO3 (0.8BNT–0.2BKT) ceramics with a high degree of texturing (~80%) were prepared by the reactive template grain growth (RTGG) method using Bi4Ti3O12 as a template. By the combination of donor doping in the B-site and the RTGG method, the electrostrain performance achieves a significant enhancement. A high electrostrain of 0.65% and a piezoelectric coefficient (d33*) of 1083 pm/V with reduced hysteresis at an electric field of 6 kV/mm are obtained. No electrostrain performance degradation is observed after unipolar electric field loading of 105 cycles, showing excellent fatigue endurance. These results indicate that the texturing BNT-based lead-free piezoceramics by the RTGG method is a useful approach to developing eco-friendly actuators.

Keywords

• (bi0.5na0.5)tio3 (bnt)-based ceramics
• donor doping
• electrostrain
• textured ceramics