High strain response and improved electrical properties of lead-free (Mn,Sb)-modified (Bi0.5Na0.5)TiO3-BaTiO3 ceramics

Lead-free piezoelectric ceramics (Bi0.5Na0.5)0.94Ba0.06Ti1-x(Mn0.5Sb0.5)xO3 were prepared by a conventional solid-state reaction method and the phase, microstructure, dielectric, ferroelectric, piezoelectric properties, and energy storage efficiency were systematically investigated. The polarization-electric field hysteresis loops indicated a phase transition from ferroelectric to relaxor ferroelectric phase with increasing Mn and Sb content. A maximum unipolar strain of 0.46% and normalized effective d33* of 920 pm/V were obtained under an electric field of 50 KV/cm at room temperature for x=0.020. A highest piezoelectric coefficient d33 of 148 pC/N was observed at 100 Hz for x=0.015. A high energy density of 0.36 J/cm3 and energy efficiency of 49% were attained for x=0.020 and x=0.025, respectively. The improvement of electric properties and high stain response was attributed to the coexistence of ferroelectric and relaxor ferroelectric phase. The enhancements in strain would be suitable for lead-free piezoelectric actuator applications.M.S.Includes bibliographical reference