Study of Crystallization Kinetics in Glasses along the Diopside-Ca-Tschermak Join

Abstract

We report on the thermal stability and crystallization kinetics of the glasses in the diopside (CaMgSi2O6)–Ca-Tschermak (CaAl2SiO6) system. Four glasses with compositions corresponding to different diopside/Ca-Tschermak ratio were studied. Structural investigations on the glasses have been made by employing Infrared spectroscopy (FTIR). Activation energies for structural relaxation and viscous flow have been calculated using the data obtained from differential thermal analysis. The existence of glass-in-glass phase separation was observed in all the glasses. Kinetic fragility of the glasses along with other thermal parameters have also been calculated. Nonisothermal crystallization kinetic studies have been employed to study the mechanism of crystallization in all the four glasses. The Avrami parameter for the glass powders is ∼2, indicating the existence of intermediate mechanism of crystallization. Crystallization sequence in the glasses has been followed by X-ray diffraction analysis, scanning electron microscopy, and FTIR.