Phase structure and electrical properties of barium-modified potassium-sodium niobate-based lead-free ceramics

In this work, effects of barium content on phase structure, microstructure, and electrical properties of 0.96K(0.45)Na(0.55)Nb(0.96)Sb(0.04)O(3)-0.04Ba(x)(Bi0.5Na0.5)(1-x)ZrO3 ceramics have been investigated. Their grain sizes climb up and then decline with increasing Ba2+ content, and Ba2+ is homogenously distributed in the matrix. With adding Ba2+ to replace both Bi3+ and Na+, it slightly influences the T-C. A rhombohedral-tetragonal (R-T) phase boundary appears in the ceramics with the compositional range of x=0-0.20, drastically enhancing both dielectric and piezoelectric properties of the ceramics. In addition, the ceramic with x=0.15 has the largest d(33) similar to 360 pC/N, together with a good temperature stability of ferroelectricity and an enhanced thermal stability of piezoelectricity. Therefore, it is proved that such a ceramic system is a promising candidate for piezoelectric devices. (C) 2015 Elsevier B.V. All rights reserved.