Kinetic analysis of crystallization in Li2O-Al2O3-SiO2-B2O3-BaO glass-ceramics

The crystallization mechanisms for Li2O-Al2O3-SiO2-B2O3-BaO glass-ceramics were studied by differential scanning calorimetry (DSC) under non-isothermal conduction. The activation energy and Avrami exponent of the glass-ceramics had been calculated by Kissinger method and Kissinger-Akahira-Sunose (KAS) method. Comparison of the measured DSC data with calculated curves at different heating rates using Sestak-Berggren (SB) model and Johnson-Mehl-Avrami-Kolmogorov (JMAK) model revealed the commonly used JMAK was not a suitable kinetic model for this glass-ceramic. However, the empirical SB model was found to be acceptable for analyzing the kinetics of crystallization for the studied glass composition. This model matched well with the DSC curves, with slight deviations at the tails of the peaks. Furthermore, the crystalline phases and microstructure of samples sintered at 730 degrees C for 2 h were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Energy dispersive spectrometer (EDS). The LiAlSi2O8 and LiAlSi3O8 constituted as the predominant phases in the studied glass-ceramic.