Modeling of thermal studies on melt quenched Ge18Bi4Se78 chalcogenide

Abstract

Abstract The crystallization characteristics for Ge18Bi4Se78 glass are studied in this work by means of differential thermal analysis (DTA) under non-isothermal conditions. One stage endothermic glass transition and one exothermic crystallization are observed in the DTA curves. The results of topological constraints for Ge18Bi4Se78 glass show that the calculated value of glass transition temperature (Tg) is very close to that of the experimental results. The as-prepared, as well as the annealed samples, are examined using x-ray diffraction (XRD), energy dispersive x-ray spectroscopy (EDX), scan electron microscope (SEM) techniques. Avrami’s exponent (n) found to have an average value of 1.61 ± 0.2 reveals a mixture of one dimensional and surface nucleation stages of growth. Many models are used to estimate the activation energies for glass transition (Eg) and crystallization (Ec). The crystallization process was found to be described by the Sestak- Berggren SB(M, N) model.