Composition design of PMN-PH-PT piezoelectric ceramics for high-temperature actuator applications

Abstract

Abstract High-Curie temperature (Tm) piezoelectric ceramics 0.15Pb(Mg1/3Nb2/3)O3-xPbHfO3-(0.85-x)PbTiO3 (0.15PMN-xPH-(0.85-x)PT, x = 0.36, 0.38, 0.39, 0.40, 0.42, 0.15PMN-PH-PT) were synthesized by the solid-state reaction method via the columbite precursor route. The synthesized 0.15PMN-PH-PT ceramics exhibit pure perovskite structure with compositions locate near the morphotropic phase boundary (MPB), where the rhombohedral phase and the tetragonal phase coexist. The sintered samples present high densification, in which the 0.15Pb(Mg1/3Nb2/3)O3-0.38PbHfO3-0.47PbTiO3 (0.15PMN-0.38PH-0.47PT) ceramics present the highest relative density, being 97.76%. The dielectric performance-temperature curves measured at different frequencies, the Curie-Weiss law fitting and the quadratic law fitting indicate that the ferroelectric phase transition from ferroelectric phase to paraelectric phase occurred at T0 in the 0.15PMN-PH-PT ceramics is driven by the displacive phase transition, and the 0.15PMN-PH-PT ceramics belong to normal ferroelectrics with diffused phase transition characteristic. Due to the MPB effect and high relative density, the 0.15PMN-0.38PH-0.47PT ceramics exhibit the best integral electrical properties, excellent thermal stability and large electric field induced strain, which present prospect promising for actuator applications under elevated environmental temperatures.