Crystallisation kinetics, glass forming ability and thermal stability in glassy Se100 − xInx chalcogenide alloys
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Differential scanning calorimetry (DSC) studies have been done under non-isothermal conditions at different heating rates for glassy Se100 − xInx (5 ≤ x ≤ 20) alloys. DSC traces with well-defined endothermic and exothermic troughs and peaks at glass transition (Tg), crystallisation (Tc) and melting (Tm) temperatures were observed. The crystallisation kinetics parameters, Avrami index (n), activation energy for crystallisation (Ec) and frequency factor (Ko), have been calculated on the basis of the classical Johnson–Mehl–Avrami (JMA) model and related methods derived by Kissinger, Augis–Bennett and Mahedevan. Activation energy for glass transformation (Et) has been evaluated on the usual two different non-isothermal methods developed by Moynihan and Kissinger. An extension of the Augis–Bennett method well known for evaluating Ec to calculate Et has been explored with satisfactory results. Results obtained from these methods are in close agreement with each other. Close correlation between Et, Ec and heating rate (β) was observed. The glass forming ability (GFA) and thermal stability parameters have been calculated for each glass system. It was found that the proportion of indium additive changed significantly the values of glass/crystal transformation, GFA and thermal stability of the studied system.
ElsevierDepartment of Physics, University of Nairobi