Kinetics of non-isothermal crystallization in the chalcogenide glass Cu0.25As0.30Te0.45

A study of the crystallization kinetics of glassy alloy Cu0.25As0.30Te0.45 was made using a method in which the crystallization rate is deduced bearing in mind the dependence of the reaction rate constant on time, through temperature. The method was applied to experimental data obtained by differential scanning calorimetry, using continuous-heating techniques. The studied alloy exhibited overlapping exothermic peaks which were resolved using a numerical method developed by the authors, making it possible to study the crystallization phases separately. The kinetic parameters determined have made it possible to discuss the different types of nucleation and crystal growth exhibited by each stage of crystallization process. The phases at which the alloy crystallizes after the thermal process have been identified by X-ray diffraction. In the first stage of the process, microcrystallites of As2Te3 are crystallized in an amorphous matrix. In the second transformation, Cu7Te5 is crystallized. Finally, in the third stage, the volume fraction of the crystalline phase As2Te3 is increased.