Influence of sintering conditions on piezoelectric properties of KNbO3 ceramics

Abstract

A homogeneous KNbO3 (KN) phase was formed in specimens that were sintered at 1020 degrees C and 1040 degrees C, without formation of the K2O-deficient secondary phase, indicating that the amount of evaporation of K2O during sintering was very small. However, the KN liquid phase was formed during sintering and assisted the densification of the KN ceramics. A dense microstructure was developed in the specimen sintered at 1020 degrees C for 6 h and abnormal grain growth occurred in this specimen. A similar microstructure was observed in the specimens sintered at 1040 degrees C for 1.0 h. The dielectric and piezoelectric properties of the KN ceramics were considerably influenced by the relative density. The KN ceramics sintered at 1020 degrees C for 6 h, which showed a large relative density that was 95% of the theoretical density, exhibited promising electrical properties: epsilon(T)(33)/epsilon(o) of 540, d(33) of 109 pC/N, k(p) of 0.29, and Q(m) of 197. (C) 2014 Elsevier Ltd. All rights reserved.