Glass transition and crystallization kinetics of a new chalcogenide-alkali metal $\hbox {Se}_{80}\hbox {Te}_{8}(\hbox {NaCl})_{12}$ alloy

Abstract

A new chalcogenide-alkali metal alloy of $\hbox {Se}_{80}\hbox {Te}_{8}(\hbox {NaCl})_{12}$ 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 $\hbox {Se}_{80}\hbox {Te}_{8}(\hbox {NaCl})_{12}$ 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 ($E_{\mathrm{c}}$) is calculated by isoconversion Friedman methods. The decrease of $E_{\mathrm{c}}$ 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 $\hbox {Se}_{80}\hbox {Te}_{8}(\hbox {NaCl})_{12}$ alloy. The parameters M and N involved in this model are calculated and related to the crystallization process.