Ferroelectric fatigue mechanism under bipolar electrical loading in KNN lead free piezoelectric ceramic

The effect of bipolar cyclic electrical loading on the ferroelectric and piezoelectric properties of KNN ceramics is investigated. The results showed that the bipolar fatigue leads to a decrease in domain switchability and piezoelectric responses of the ceramic. In the early period of cyclic loading, the fatigue mechanism is dominated by the domain wall pinning effect. When the number of fatigue cycles increases, the microstructural damage has a large impact on the fatigue process. From this, a qualitative model based on the relationship between domain pinning mechanism and internal stress is proposed.