High performance of La, Nd multi-rare earth doped Na 0.46 Li 0.04 Bi 2.5 Nb 2 O 9 high temperature piezoceramics at a new pseudo-MPB

Abstract Aurivillius type Na0.46-xLi0.04Bi0.5-x(LaNd)x/2Bi2Nb2O9 ceramics were prepared by a conventional solid state sintering method. The evolution of crystal structure, microstructure and corresponding electrical properties were studied. A new pseudo morphotropic phase boundary between orthorhombic to pseudo-tetragonal phases was identified near x ∼ 0.06, giving rise to the enhancement of piezoelectric properties. The resonance and antiresonance impedance modulus at rising temperatures demonstrated that the ceramics with 6 mol% La3+/Nd3+ doping (NLN-6) was indeed piezoelectric in nature at 700 °C. The electrochemical impedance spectra indicated that thermally excited intrinsic oxygen vacancies were responsible for both electrical conduction and dielectric relaxation processes. The NLN-6 ceramics exhibited superior electrical properties (d33 ∼ 20.1 pC/N, kp ∼ 6%, TC ∼ 737 °C, ρ ∼1 MΩ·cm@600 °C) and also possessed excellent stability of piezoelectric properties with rising temperature. These results suggest that La3+/Nd3+ multi- rare-earth ions modified Na0.46Li0.04Bi2.5Nb2O9 ceramics are promising candidates for ultra-high temperature piezoelectric applications.