BaZrO 3 ‐modified (K, Na)NbO 3 ‐based lead‐free piezoceramics: High unipolar fatigue resistance

Abstract (K, Na)NbO 3 ‐based lead‐free piezoelectric materials are considered a promising candidate to replace a lead‐containing counterpart in actuator applications, with electrical fatigue being a major concern during this transition. This study elaborates on a promising material with a nominal composition of 0.92(K 0.5 Na 0.5 )NbO 3 ‐0.02(Bi 0.8 Li 0.2 )TiO 3 ‐0.06BaZrO 3 (BZ6) and evaluates its unipolar fatigue resistance. After 10 7 cycles of unipolar fatigue, the strain variation of the BZ6 ceramic is within 8% of its initial value, and both its S ( E ) and ε 33 ( E ) curves exhibit less pronounced asymmetry than that of PIC151. Strain asymmetry and the development of internal bias fields are observed in the composition, which originates from the agglomeration of space charge during unipolar cycling. The post‐annealing treatment allows the full restoration of electrical properties for the fatigued BZ6 ceramic, making it highly suitable for actuator applications.