Formation of nano-sodium niobate crystals in ferroelectric glasses and glass-ceramics of the Na2O-Nb2O5-Al 2O3-SiO2 system

Abstract

Ferroelectric glasses and glass-ceramics were prepared from selected composition in the Na2O-Nb2O5-Al2O3-SiO2 glass system. Small amount of TiO2 was also added. Conventional melt-quenching technique was employed for a glass production and the selected bulk parent glass samples were subjected to the heat-treatment process. Clear transparent glass was obtained but with surprise presence of precipitated nano-size NaNO3 crystals as the result of phase separation. For the heat-treated samples, the longer treatment time induced a higher volume fraction of the NaNbO3 crystals, but thier size was not significantly increased. Dielectric response of the glass-ceramics contained NaNbO3 crystals is the combination of all contribution from both crystalline phases and the glass matrix. Copyright © Taylor & Francis Group, LLC.