Ultrahigh electrostrain with excellent fatigue resistance in textured Nb <sup>5+</sup>-doped (Bi <sub>0.5</sub>Na <sub>0.5</sub>)TiO <sub>3</sub>-based piezoceramics
Lixiang Lai, Zhihao Zhao, Shuo Tian, Bao Ou, Gaoyuan Liang, Bin Li, Yejing Dai
Abstract
(Bi<sub>0.5</sub>Na<sub>0.5</sub>)TiO<sub>3</sub> (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, <00<i>l</i>> textured Nb<sup>5+</sup>-doped 0.8(Bi<sub>0.5</sub>Na<sub>0.5</sub>)TiO<sub>3</sub>–0.2(Bi<sub>0.5</sub>K<sub>0.5</sub>)TiO<sub>3</sub> (0.8BNT–0.2BKT) ceramics with a high degree of texturing (~80%) were prepared by the reactive template grain growth (RTGG) method using Bi<sub>4</sub>Ti<sub>3</sub>O<sub>12</sub> 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 (<inline-formula> <math display="inline" id="MA1"><mrow><msubsup><mi>d</mi><mrow><mn>33</mn></mrow><mo>*</mo></msubsup></mrow></math></inline-formula>) 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<sup>5</sup> 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.