Structure and electrical properties of Ce-modified Ca1-Ce Bi2Nb1.75(Cu0.25W0.75)0.25O9 high Curie point piezoelectric ceramics

Abstract Ca1-xCexBi2Nb1.975(Cu0.25W0.75)0.025O9 (CBNCW-xCe: x = 0.00, 0.02, 0.04, 0.06, and 0.09) lead-free piezoelectric ceramics with improved piezoelectric properties were prepared by the traditional solid-state reaction method. The effects of CeO2 doping on the microstructure and electrical properties were investigated in detail. XRD patterns and Rietveld refinement show that the crystal structures of the samples transform from the orthorhombic phase into the pseudotetragonal phase and that the lattice distortion is weakened. Raman and XPS spectra indicate that Ce ions exist with +3 and + 4 valences in the air sintered ceramics, in which Ce4+ replaces Nb5+, causing the weakened NbO6 octahedral vibration of torsional and tensile and an increase in oxygen vacancies in the doped ceramics. When x = 0.04, it shows excellent comprehensive properties with a high d33 value of 18.1 pC/N, a Tc value of 900 °C, and a ρdc value of 2.8 × 105 Ω cm at 500 °C. Our results suggest that the CBNCW-0.04Ce ceramic is a promising candidate in high-temperature piezoelectric applications.