Crystallization of KNbO3 in a B2O3 glass network

The ferroelectric material potassium niobate (KNbO3) has a large number of exceptional electronic and optical properties with important technological applications. Due to the high preparation difficulties and costs of the single crystals, a considerable interest in the preparation of glass-ceramics with the KNbO3 crystal phase exists. In this work we present the preparation of a glass, with the composition 40B(2)O(3)-40K(2)O-20Nb(2)O(5) (% mole), through the melt-quenching method and glass-ceramics obtained by controlled heat-treatments. The samples structure was analyzed using X-ray power diffraction (XRD), scanning electron microscopy (SEM) and Raman spectroscopy. KNbO3 crystals were detected in the glass sample treated at 500 degrees C. For treatments at temperatures above 500 degrees C, other niobium-based crystal phases are present. The behavior of the heat-treatment temperature parameter, in the glass and glass ceramic structure, is discussed. (C) 2008 Elsevier B.V. All rights reserved.