Structural and piezoelectric properties of MnO2-added 0.95(Na0.5K0.5)NbO3-0.05SrTiO(3) ceramics

Abstract

The structural and piezoelectric properties of the x mol% MnO2-added 0.95(Na0.5-x/200K0.5-x/200)NbO3-0.05SrTiO(3) [(NK)xMN-ST] ceramics were investigated. A dense microstructure with enlarged grains was formed for the specimens sintered at 1040 degrees C through liquid-phase sintering. However, the grain size decreased for the specimen sintered at 1060 degrees C because of the formation of a large amount of the liquid phase. Therefore, the microstructural variations in the (NK)xMN-ST ceramics can be explained by liquid-phase-assisted abnormal grain growth. The specimens sintered at 1020 and 1060 degrees C showed low piezoelectric properties because of their low relative density and small grain size, respectively. On the other hand, the (NK)xMN-ST ceramic with x=0.1 sintered at 1040 degrees C showed promising piezoelectric properties: d(33) = 260 pC/N, k(p) =0.42, Q(m) = 202 and epsilon(T)(33)/epsilon(0) = 1291. (C) 2012 Elsevier B.V. All rights reserved.