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

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 res ult, according to literature, is that the Kissinger equation can be applied to the analysis of heterogeneous solid state transformations. Bearing in m ind the quoted generalization, the isothermal and non-isothermal crystalliz ation kinetics of Sb0.16AszSe0.84-z (z = 0.22, 0.29, 0.36, 0.43) glassy all oys 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 indic ate that the crystallization of these alloys is a thermally activated proce ss 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 ph ases that crystallize with the thermal treatment have been identified by X- ray diffraction. The diffractograms of the transformed materials suggest th e presence of microcrystallites of Sb2Se3 and AsSe, embedded in a residual amorphous matrix. (C) 2001 Elsevier Science B.V. All rights reserved.