The size effect of precursor particles in W6+-doped CaBi2Nb2O9 high-temperature piezoelectric ceramics

Abstract

High-temperature piezoelectric ceramics face a persistent challenge in simultaneously raising the piezoelectric coefficient (d₃₃) and resistivity (ρ) to a practical level. Furthermore, conventional doping strategies exhibit limited effectiveness in further enhancing these properties. Here, we propose a novel approach of reducing precursor particle size in CaBi₂Nb_1.98W_0.02O₉ ceramics where WO₃ and Nb₂O₅ were involved as a dopant and a host matrix, respectively. As compared with microscale precursors, nanoscale counterparts can facilitate the diffusion of W⁶⁺-dopant ions into Nb⁵⁺-sites, leading to homogeneous elemental distribution, intrinsic structure distortion and suppression of vacancy defects. CaBi₂Nb_1.98W_0.02O₉ prepared from nanoscale precursors achieves a d₃₃ value of 15.6 pC N⁻¹ and a record high ρ value of 4.5 × 10⁶ Ω cm at 600 °C, outperforming other single-dopant modified CBN-based ceramics. This study paves a practicable approach to obtain high-temperature piezoelectric ceramics for developing vibration-sensors applicable in aircraft engines and nuclear reactors.