Influences of rare earth site engineering on piezoelectric and electromechanical response of (Ba 0.85 Ca 0.15 ) (Zr 0.1 Ti 0.9 )O 3 lead-free ceramics

The significant deterioration of temperature and fatigue stability are often observed in (Ba0.85Ca0.15) (Zr0.1Ti0.9)O3 (BCZT) ceramics, which will cause great resistance in practical applications. We have demonstrated that introducing various rare earth elements (e.g., Dy, Er, Eu, Ho, Pr and Sm) into BCZT ceramics can effectively solve above obstacle. The effects of the doped rare earth element types on the crystal phase, microstructure and resulting properties have been comparatively investigated. The rare earth ions (e.g., Dy, Eu, Ho, Pr and Sm) substituting at the A site are beneficial to acquire the enhanced piezoelectric properties (475–521pC/N) and electromechanical response (505–546 pm/V) for BCZT ceramics, while Er doping generates degraded electrical properties. More importantly, significantly improved temperature stability of piezoelectric properties was achieved in Eu-and Ho-doped BCZT ceramics, featured by less than 8% and 2% variation in the temperature range 20–70 °C. Moreover, excellent fatigue endurance and good frequency dependence were also realized in rare earth element-modified BCZT ceramics, which originated from the decreased defect density due to the reduction of oxygen vacancies. This work will provide a promising way to improve the temperature and fatigue stability of BCZT material without affecting the piezoelectric properties through doping various rare earth elements.