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

(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 (similar to 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 (*d(33)) 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 10(5) 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.

Automated summary

By using the reactive template grain growth method, highly textured Nb5+-doped 0.8(Bi0.5Na0.5)TiO3-0.2(Bi0.5K0.5)TiO3 ceramics were prepared, resulting in a significant enhancement of electrostrain performance and reduced hysteresis. These ceramics also exhibited excellent fatigue endurance.