Effects of BaSiO3 on the strain properties of Bi0.5Na0.5TiO3-based lead-free piezoelectric ceramics

Abstract

To improve the strain properties of lead-free piezoelectric ceramics, the (0,82-x)Bi_0.5Na_0.5TiO₃-0.18Bi_0.5K_0.5TiO₃-xBaSiO₃ piezoelectric ceramics with x=0-5% were investigated. The piezoelectric ceramic samples were fabricated using a conventional solid-state reaction method. The results of X-ray diffraction analysis and density measurements show a single
perovskite structure as a pseudo-cubic phase with a relative density of over 95%. The dielectric properties of the studied samples strongly depend on the frequency, temperature, and BaSiO₃  content. The bipolar electric field-induced strain curves of the analysed samples show a phase transition from a ferroelectric phase to a relaxor phase when the BaSiO₃ content is over 3%. In particular, the maximum uni electric field-induced strain was found at the morphotropic phase
boundary (MPB) composition. The x=0.03 sample shows a maximum strain of 0.167%, corresponding to the strain value under the electric field of 278 pm/V. The results suggest the potential of BaSiO3 doping to enhance the strain properties of the lead-free Bi_0.5Na_0.5TiO₃-based piezoelectric ceramics.