A theoretical method for analyzing the glass-crystal transformation observed by DSC in the continuous heating regime. Application to the Sb 0.16As 0.36Se 0.48 semiconducting alloy

Abstract

A theoretical procedure has been developed for deriving the evolution equation with time of the actual volume fraction transformed, for integrating the above mentioned equation under non-isothermal regime, for deducing the kinetic parameters and for analyzing the glass-crystal transformation mechanisms in solid systems involving formation and growth of nuclei. By defining an extended volume of transformed material and assuming spatially random transformed regions, a general expression of the extended volume fraction has been obtained as a function of the temperature. Considering the mutual interference of regions growing from separate nuclei (impingement effect) and from the above mentioned expression the actual volume fraction transformed has been deduced. The kinetic parameters have been obtained, assuming that the reaction rate constant is a time function through its Arrhenian temperature dependence. Besides, it has been shown that the different models, used in the literature for analyzing the glass-crystal transformation, are particular cases of the general expression deduced for the actual volume fraction transformed. The theoretical method described has been applied to the crystallization kinetics of the Sb 0.16As 0.36Se 0.48 glassy alloy, thus obtaining values for the kinetic parameters that agree satisfactorily with the calculated results by the Austin–Rickett kinetic equation, under non-isothermal regime. This fact shows the reliability of the theoretical method developed.