Piezoelectric properties of (K0.5Na0.5)NbO3-BaTiO3 lead-free ceramics prepared by spark plasma sintering

(K,Na)NbO3 (KNN)-based lead-free piezoceramics have been the spotlight in search for practically viable candidates to replace the hazardous but dominating lead-containing counterparts. In this work, BaTiO3 (BT) modified KNN ceramics were fabricated by spark plasma sintering (SPS) and the influence of BT content as well as sintering temperature on the phase structure, microstructure, and electrical properties were investigated. It was found that the 0.96(Na0.5K0.5)NbO3-0.04BaTiO(3) (BT4) ceramics sintered at 1000 degrees C have the optimal performance. Additionally, in-depth analysis of the electrical hysteresis revealed that the internal bias field originating from accumulation of space charges at grain boundaries is responsible for the asymmetry in the hysteresis loops.