Kinetic analysis on the crystallization of some alloys from the Sb–As–Se glassy system

Abstract

An alternative method is proposed for generalizing the Johnson–Mehl–Avrami equation, under restrictive assumptions for non-isothermal transformations on the basis of nucleation and crystal growth processes. An interesting result, according to literature, is that the Kissinger equation can be applied to the analysis of heterogeneous solid state transformations. Bearing in mind the quoted generalization, the isothermal and non-isothermal crystallization kinetics of Sb 0.16As z Se 0.84− z ( z=0.22, 0.29, 0.36, 0.43) glassy alloys have been analyzed using differential scanning calorimetric (DSC) data. The kinetic parameters calculated from both sets of calorimetric data are in agreement, within experimental error, with the use of adequate equations and assumptions clearly stated for each regime. The obtained results indicate that the crystallization of these alloys is a thermally activated process and it is mainly controlled by a volume nucleation mechanism. The z=0.43 alloy shows the strongest stability against crystallization, while the z=0.36 alloy is the least stable composition among analyzed alloys. The phases that crystallize with the thermal treatment have been identified by X-ray diffraction. The diffractograms of the transformed materials suggest the presence of microcrystallites of Sb 2Se 3 and AsSe, embedded in a residual amorphous matrix.