New potassium–sodium niobate ternary system with large piezoelectric coefficient and high Curie temperature

Abstract

In this paper, a new potassium–sodium niobate ternary system (0.96 − x)Ka0.48Na0.52NbO3–0.04Bi0.5Na0.5ZrO3–xBiAlO3 [(0.96 − x)KNN–0.04BNZ–xBA] with large piezoelectric coefficient (d 33) and high Curie temperature (T C) simultaneously was attained due to the movement of orthorhombic–tetragonal phase transition temperature (T O–T) to room temperature and the enhanced dielectric properties. Especially, the ceramics with a composition of x = 0.005 show a large d 33 of ~355 pC/N together with a high T C of ~335 °C. And moreover, a good thermal stability of d 33 (e.g., d 33 ≥ 316 pC/N, T ≤ 300 °C) was also observed in the ternary ceramics. Such a good comprehensive performance of d 33 and T C attained in this work is superior to many reported results in the KNN-based materials. As a result, it was believed that this potassium–sodium niobate system with both large d 33 and high T C will become one of the promising materials in the practical application.