Model fitted and model free approaches for crystallization kinetics in Se85Te15-xBix glasses

Abstract

In this research work, we have described the model-fitted and model free approaches for the study of crystallization kinetics in Se85Te15-xBix chalcogenide glasses. Se85Te15-xBix bulk alloys were synthesized by melt quenching technique. High Resolution X- Ray diffraction (HRXRD) was used to confirm the amorphous nature of prepared alloys. Non-isothermal Differential Scanning Calorimetry (DSC) measurements were done at heating rates of 5, 10, 15, 20 and 25 K/min for crystallization kinetics studies in Se85Te15-xBix glasses. The various characteristic temperatures, such as glass transition (Tg), on-set crystallization (Tc) temperature, peak crystallization temperature (Tp) and melting temperatures (Tm) have been obtained from various DSC thermograms. The activation energies of glass transition (ΔEt) were calculated by using Kissinger and Moynihan approaches and found to be minimum for Se85Te12Bi3 chalcogenide glass which indicates that this alloy has maximum probability to jump into a less configurational energy state and has larger stability. The model-free approaches; Kissinger–Akahira–Sunose (KAS), Flynn-Wall-Ozawa (FWO), Tang and Straink (TS) reveal that the activation energy of crystallization varies with crystallization degree and temperature both. This variation shows that amorphous to crystalline phase transformation in Se85Te15-xBix chalcogenide glasses is a complex process with various nucleation and growth mechanisms.