(K0.5Na0.5)NbO3 (KNN) is a potential lead-free replacement for Pb(Zr, Ti)O3 (PZT) piezoceramics, but its piezoelectric properties are inferior to those of PZT. By growing single crystals of KNN, it may be possible to improve the piezoelectric properties. Recently, single crystals of KNN were grown by the solid-state crystal growth (SSCG) method, but the crystals were very porous. In this paper, a method of growing dense single crystals by SSCG in a hot press will be described. (110)-oriented single seed crystals of KTaO3 were buried in KNN powder, with 0.5 mol% of K4CuNb8O23 added as a sintering aid. After consolidation by uniaxial and isostatic pressing, the tablets were hot pressed in a two-stage treatment. During hot pressing, dense single crystals of KNN grew using the KTaO3 seed crystal as a template. The effect of hot pressing on single crystal growth will be discussed.
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Document Type: Research Article
Department of Electronic Ceramics, Jožef Stefan Institute, Ljubljana 1000, Slovenia
Forschungsinstitut für mineralische und metallische Werkstoffe Edelsteine/Edelmetalle GmbH, D-55743 Idar-Oberstein, Germany
May 1, 2008