Non-isothermal crystallization kinetics of MgO-BaO-B_2O_3-Al_2O_3-SiO_2 glass

摘要

5MgO-9BaO-33B_2O_3-33Al_2O_3-20SiO_2 (mol percent ) glass was prepared by the melt quenching method at 1823 K for 2 h. Dilatometry and differential scanning calorimetry (DSC) curves of the glass have been investigated. Fragility index F was used to estimate glass formability. The crystallization kinetics of the glass was described by the activation energy (E) for crystallization and numerical factors (n, m) depending on the nucleation process and growth morphology. XRD and SEM analysis were also used to describe the crystals' types and morphology precipitated from the MgO-BaO-B_2O_3-Al_2O_3-20SiO_2 glass. The results show that the effective activation energy of the crystallization process E was 45.19 kJ/ mol, and n up to 4.05. Two crystals phases, i.e. Al_4B_2O_9 and Al_(20)B_4O_(36) were observed in the crystallized samples. SEM results were consistent with crystallization kinetics.