NONISOTHERMAL CRYSTALLIZATION KINETICS OF THE AMORPHOUS Cu 18 As 30 Te 52 ALLOY: MODEL-FREE AND MODEL-FITTING ANALYSIS

摘要

The kinetics of the crystallization process of glassy Cu 18 As 30 Te 52 alloy was studied under nonisothermal conditions using differential scanning calorimetry (DSC). Three exothermic peaks were observed, indicating the presence of three distinct stages of crystallization. The kinetic parameters (the effective activatio n energy (E), the preexponential factor (A) and the Avrami exponent (n) ) for the three stages were evaluated using model-free and model- fitting analysis. The insignificant variation of n, E, and A with extent of conversio n during the progress o f first peak crystallizat io n sho ws that this stage of transformation can be described by single-step mechanism of crystallization. For the subseq uent stages of crystallization, the behavior of the kinetic parameters indicates that multi -step mechanisms are involved in the transformation. Based on the model-fitting analysis of the present data, the reaction models, g( . ), describing the crystallization stages is the Avrami-Erofeev model.