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( Ba, Ca)( Ti, Zr) O3 lead-free piezoelectric ceramics have been considered to be one of the most potential lead-free alternatives for PZT in the room-temperature range. The stability of the piezoelectric performance during unipolar cycling is investigated in this study. It is found that the unipolar fatigue behavior is similar to soft PZT. Developments of bias field, offset polarization, asymmetry in strain, and dielectric hysteresis loops are observed during bipolar measurements. The changes are mainly contributed to the migration of charge carriers to the grain boundaries driven by the unscreened depolarization field. Redistribution of the accumulated charge carriers by bipolar electric cycling or thermal annealing can significantly recover the unipolar fatigued state. The unipolar strain response stabilized after 1000 cycles at 0.053% for an electric field of 0.6 kV/mm ( d33*= 883 pm/V), which is a good characteristic for actuator applications. [ABSTRACT FROM AUTHOR]

(Ba, Ca)(Ti, Zr)O3 ceramics have been considered as a potential lead-free alternative to commonly used lead-based piezoelectric ceramics due to their high piezoelectric performance at room temperature. In this study, the bipolar fatigue behavior of this material is investigated at room temperature. Two compositions were cycled with a bipolar electric field signal at 10 Hz with a maximum of three times the coercive field for up to approximately 107 cycles. Both investigated compositions exhibited high bipolar fatigue resistance compared to other ceramics reported in the literatures. The high fatigue resistance originates from the lack of mechanical damage and a weak domain wall pinning effect due to their location in the phase transition region. It was also found that pore morphology affected bipolar fatigue behavior. [ABSTRACT FROM AUTHOR]