EFFECT OF Se ADDITIVE ON THE STRUCTURE, PRE-CRYSTALLIZATION CRITERIA AND CRYSTALLIZATION KINETIC PARAMETERS IN GLASSY MELT-QUENCHED As-S ALLOY

The present framework is consecrated to studying structural parameters, pre-crystallization criteria and crystallization kinetics by non-isothermal and iso-conversional methods for melt-quenched As40S60-xSex glassy alloys, with (x=0, 15, 30, 45 and 60 at. %). Energy dispersive x-ray analysis of the As40S60-xSex glassy system appears that the constituent element ratio of the studied samples have been agreed with the nominal compositions. Likewise, Differential Scanning Calorimetry (DSC) and x-ray diffraction (XRD) has been utilized to depict the thermal and structural properties, respectively. Four characteristic temperatures linked to several phenomena are obviously noticed in the studied DSC traces. The first one is Tg that harmonizes with the glass transition temperature. The second one is Tc that harmonizes with the onset of the crystallization temperature. The third one, T p corresponds to the peak crystallization temperature. The last characteristic temperature, T p is the melting point. The XRD analysis signalizes to the amorphous structure of the as-prepared glassy alloys. The crystallization kinetics of the powdered of As40S60-xSex, have been investigated under non-isothermal and iso-conversional conditions. Besides, the values of diverse kinetic parameters such as the activation energy of glass transition, the weight stability criterion, and Avrami exponent, have been computed. The activation energies of the crystallization process of the As40S60-xSex glassy alloys were determined by means of classical and also by the iso-conversional methods. The results referred that the rate of crystallization is linked to the thermal stability and glass-forming ability. The kinetic parameters that computed via some classical and isoconversional methods, were found to be dependent on the change of Se content.