Model-free method for analysis of non-isothermal kinetics of a bulk sample of selenium

In this work, the activation energies of crystallization of amorphous Se were studied under non-isothermal conditions using a differential scanning calorimetric (DSC) technique. The Johnson–Mehl–Avrami and isoconversional models were used to describe the DSC crystallization data. The isoconversional methods of Friedman, Kissinger–Akahira–Sunose (KAS) and Vyazovkin were used to determine the variation of the activation energy for crystallization with temperature, Eα (T). The KAS and Vyazovkin methods gave identical values, and the range of Eα (T) was found to vary in the range 110.4–44.2 kJ mol−1, while the Friedman method gave lower values with Eα (T) in the range 100.5–28.3 kJ mol−1. The effects of annealing were revealed by studying the morphology of the samples with a scanning electron microscope.