Non-isothermal crystallization kinetics of sodium borosilicate-based glass
摘要
To study the crystallization process of Na2O–B2O3–SiO2 based materials, sodium borosilicate-based glass materials used as the ground coating material of steel enamel were prepared by melting and quenching. The powder, fully milled for a certain time, was subjected to differential scanning calorimetry (DSC) at different cooling rates with the starting sample and the non-isothermal crystallization process was observed. The non-isothermal kinetic analysis of the DSC measurements was carried out by the Jeziorny, Ozawa and Mo methods of the modified Avrami equation. The results of the study showed that the Jeziorny and Mo methods well explained the non-isothermal crystallization kinetics of the sodium borosilicate-based glass materials, but the Ozawa method was not suitable. From the Avrami index n obtained, the crystal growth pattern of the corresponding glass material was confirmed by 2D surface growth. As the cooling rate increased, the non-isothermal crystallization kinetics factor Zc increased and F(T) reflecting the effect of cooling rate on crystallization increased with increasing relative crystallinity. The dependence of the effective activation energy on the relative crystallinity during non-isothermal crystallization was evaluated by the iso-conversional method of Friedman analysis. The effective activation energy of glass materials ranges from − 1330 to − 369 kJ/mol.