Phase transition and temperature stability of KNN-based lead-free piezoceramics

Abstract

Three step sintering method has been introduced in KNN-based lead free piezoceramics. The phase structure of the ceramics transform from rhombohedral phase to the coexistence of rhombohedral phase and tetragonal phase, and phase transition temperature shifts to −10 °C by three step sintering. Excellent piezoelectric properties have been obtained, d33 = 405pC/N at room temperature, the d33 values are above the 300pC/N from room temperature to around 200 °C.