Crystallization behaviour of Li2O·Nb2O5·SiO2 glass containing TiO2

This paper deals with the crystallization of glass 30Li2O·15Nb2O5·50SiO2·5TiO2 (mol%). The crystallization behaviour was studied under isothermal and non-isothermal conditions. XRD and SEM methods were employed for determination of phase composition and microstructure of crystallized glass. It was detected that this glass crystallizes by the surface crystallization mechanism. SEM micrographs of the crystallized samples revealed that the crystals grow in the form of dendrites. The glass-ceramics with complex phase composition was obtained. Three crystalline phases were detected where LiNbO3grown as primary phase and a secondary ones Li2Si2O5 and SiO2 appeared. The calculated average crystallite sizes are: 27 nm for LiNbO3, 115 nm for Li2Si2O5 and 45 nm for SiO2. From the experimental data an activation energy of crystals growth, calculated using the Kissinger relation, is Ea = 275 ±10 KJ / mol.