Glass transition and crystallization kinetics of a new chalcogenide-alkali metal Se$_{80}$Te$_8$(NaCl)$_{12}$ alloy

[摘要] A new chalcogenide-alkali metal alloy of Se$_{80}$Te$_8$(NaCl)$_{12}$ has been prepared by a melt-quench technique. The crystallized phases due to the thermal annealing are observed by X-ray diffraction of the powdered sample. The glass transition and kinetics of crystallization in the Se$_{80}$Te$_8$(NaCl)$_{12}$ alloy are studied using the differential scanning calorimetric technique under non-isothermal conditions. The activation energy of the glass transition is evaluated by Kissinger and Mahadevan methods. The crystallization activation energy ($E_{\rm c}$) is calculated by isoconversion Friedman methods. The decrease of $E_{\rm c}$ with increasing crystallization conversion is attributed to the complex mechanism of the crystallization process. Based on the shape of the characteristic kinetic function, the crystallization growth is found to be a three-dimensional growth from the bulk nuclei. The results show that the conditions of the Sestak–Berggren model are satisfied for describing the crystallization process of the studied Se$_{\rm 80}$Te$_8$(NaCl)$_{12}$ alloy. The parameters $M$ and $N$ involved in this model are calculated and related to the crystallization process.

[学科分类] 材料工程

[关键词] Chalcogenide;alkali metal;glass transition;crystallization kinetics.