Phase transition and domain variation contributions to piezoelectric properties of alkaline niobate based lead-free systems

摘要

The intrinsic correlation and mechanism between electrical properties and phase transitions in alkaline niobate based lead-free piezoelectric ceramics were explored by taking typical (Na_(0.52)K_(0.48-x))(Nb_(0.95-x)Ta_(0.05))O_3-xLiSbO_3 compositions as a case study. The diffuseness of the phase transition leads to two-phase coexistence promoting piezoelectric activity and simultaneously induces remarkable temperature sensitivity, based on the variation of ortho-rhombic and tetragonal domains. The polymorphism, not a morphotropism of the phase boundary was considered as a structural root for these kinds of compositions. The refinement of compositions within two-phase coexistence zone compromises two opposite effects, although the composition range is narrow, suggesting the property sensitivity to the composition and a processing solution to the property optimization as well.