Effects of Poling Process on KNN‐Modified Piezoceramic Properties

Abstract

The influence of the orthorhombic to tetragonal phase transition near room temperature in the poling process of KNN‐modified piezoceramics was studied. Poling temperatures of 25° and 120°C were used. The percentage of 90° domains reorientation induced by poling was evaluated trough X‐ray diffraction analysis. The improvement of the piezoelectric properties when the poling temperature was 25°C could not be explained by the reorientation of 90° domains alone. Raman spectroscopy evidenced that the polarization process was assisted by the stabilization of orthorhombic phase, which promotes a stress reduction in the material.