Composition designing and sintering behavior tailoring in [(Ba1−xCax)0.995Eu0.005](Ti1−yHfy)O3 multifunctional piezoceramics

Abstract

[(Ba1−xCax)0.995Eu0.005](Ti1−yHfy)O3 (B1−xCxT1−yHy-Eu) lead-free ceramics were fabricated by conventional solid-state method, in which the effects of sintering temperature and the ratios of Ba/Ca and Ti/Hf cations around the morphotropic phase boundary (MPB) on the electrical and fluorescent properties were explored. Rather pure perovskite structure B1−xCxT1−yHy-Eu ceramics with densified microstructure and high density are obtained, which locate around the MPB region and show dependency on compositions and sintering conditions. Complex ferroelectric characteristic is confirmed by dielectric performance measurement and dielectric behavior fitting. Enhanced ferroelectric and piezoelectric properties can be attributed to the donor doping characteristic induced by Eu doping, which engenders donor point defects EuBa/Ca•. Extremum piezo-luminescence figure of merit FPC-PLI appears in the sintered B1−xCxT1−yHy-Eu ceramics, in which the 1450 °C sintered [(Ba0.86Ca0.14)0.995Eu0.005](Ti0.9Hf0.1)O3 ceramics exhibit the most outstanding multifunctional performance. The high-temperature conductance mechanism of the B1−xCxT1−yHy-Eu ceramics can be attributed to the oxygen vacancies produced by the evaporation of cations during sintering process.