Modification of both d33 and TC in a potassium–sodium niobate ternary system
Abstract
In this work, we simultaneously achieved a giant d33 and a high TC in a lead-free piezoelectric ternary system of (1 − x − y)K0.48Na0.52NbO3–xBiFeO3–yBi0.5Na0.5ZrO3 {(1 − x − y)KNN–xBF–yBNZ}. Owing to the rhombohedral–orthorhombic–tetragonal (R–O–T) phase coexistence and the enhanced dielectric and ferroelectric properties, the ceramics with a composition of (x = 0.006, y = 0.04) show a giant d33 of ∼428 pC N−1 together with a TC of ∼318 °C, thereby proving that the design of ternary systems is an effective way to achieve both high d33 and high TC in KNN-based materials. In addition, a good thermal stability for piezoelectricity was also observed in these ceramics (e.g., d33 > 390 pC N−1, T ≤ 300 °C). This is the first time such a good comprehensive performance in potassium–sodium niobate materials has been obtained. As a result, we believe that this type of material system with both giant d33 and high TC is a promising candidate for high-temperature piezoelectric devices.