Influence of NiO on the crystallization kinetics of near stoichiometric cordierite glasses nucleated with TiO2

This work presents the effect of NiO on the thermal behavior and the crystallization kinetics of glasses lying near the stoichiometric cordierite composition nucleated with TiO2. Three glasses with NiO content varying between 1 and 5 mol% have been synthesized in Pt crucibles. Activation energies for structural relaxation and viscous flow have been calculated using the data obtained from differential thermal analysis ( DTA). Kinetic fragility of the glasses along with other thermal parameters has been calculated. Non-isothermal crystallization kinetic studies have been employed to study the mechanism of crystallization in all three glasses. The crystallization sequence in the glasses has been followed by x-ray diffraction analysis of the heat treated glass samples in the temperature range of 800-1200 degrees C. mu-cordierite has been observed to be the first crystalline phase in all the glass samples after heat treatment at 850 degrees C, while NiO plays an important role in determining the crystallization sequence at higher temperatures, leading to the formation of alpha-cordierite.