Large Strain with Small Hysteresis at High Temperature of Bi0.5Na0.5TiO3-Bi0.5K0.5TiO3-BaZrO3 Lead-Free Piezoelectric Ceramic

This study investigates the effects of temperature on the phase evolution and the electrical properties of the 0.77Bi(0.5)Na(0.5)TiO(3)-0.22Bi(0.5)K(0.5)TiO(3)-0.01BaZrO(3) lead-free piezoelectric ceramic. The ceramic is fabricated using a conventional solid-state reaction method. The crystal structure and microstructure of the sintered sample are analyzed at room temperature. The sample sintered at 1150 degrees C shows a single perovskite structure, dense microstructure, and a relative density of similar to 86%. The temperature-dependent electrical properties of the ceramic are studied in the temperature range of 25-125 degrees C. At room temperature, the 0.77Bi(0.5)Na(0.5)TiO(3)-0.22Bi(0.5)K(0.5)TiO(3)-0.01BaZrO(3) ceramic shows the nonergodic relaxor behavior with a tetragonal structure. A phase transition from a nonergodic relaxor to an ergodic relaxor phase happened in the 0.77Bi(0.5)Na(0.5)TiO(3)-0.22Bi(0.5)K(0.5)TiO(3)-0.01BaZrO(3) ceramic when the temperature increases above 116 degrees C. The electric-field-induced strain property of the 0.77Bi(0.5)Na(0.5)TiO(3)-0.22Bi(0.5)K(0.5)TiO(3)-0.01BaZrO(3) ceramic increases with a temperature coefficient of 0.367 pm/V/K. The thermal energy increases the maximum strain value and decreases the strain hysteresis of the 0.77Bi(0.5)Na(0.5)TiO(3)-0.22Bi(0.5)K(0.5)TiO(3)-0.01BaZrO(3) ceramic. At 125 degrees C, the ceramic shows a maximum electrostrain of similar to 505 pm/V with a minimum hysteresis of similar to 9%, suggesting a potential candidate for lead-free piezo-actuator applications.