Evaluation of the transformation kinetics of Ga7.5Se92.5 chalcogenide glass using the theoretical method developed and isoconversional analyses

Kissinger Method in Kinetics of Materials: Things to Beware and Be Aware of

“…As already noted, detecting the curvature requires using multiple heating rates spread over a broad range. For example, the effect is detectable ( Figure 5 ) in the data obtained for crystallization of Ga 7.5 Se 92.5 and Si 12.5 Te 87.5 glasses [ 41 , 42 ]. Note that in both cases the range of the heating rates used is unusually broad, 5–90 °C min −1 .…”

“…Expectedly, it is much easier to detect a variation in the activation energy by using an isoconversional method. For these two glasses the isoconversional activation energy decreases 1.5 times (from 85 to 55 kJ mol −1 for Ga 7.5 Se 92.5 and from 200 to 130 kJ mol −1 for Si 12.5 Te 87.5 ) in the temperature range of crystallization [ 41 , 42 ]. It should be emphasized that the curvature of the Kissinger plots for crystallization increases dramatically when using ultrafast scanning calorimetry [ 43 ].…”

An investigation of the kinetic transformation mechanism of Ge12.5Te87.5 chalcogenide glass under non-isothermal regime

“…From Table 2, it is clear that both K iso and T iso increase with increasing β, as well as the value of T iso lies within the experimental temperature range, T r , for each β, which indicates that the reaction models g(α), which assumed to describe the process, were properly chosen. Otherwise, the value of T iso will lie outside the experimental temperature range of a particular rate [2][3][4]10].…”

“…After determining the experimental values of E(α) and A(α) one can reconstruct the reaction model numerically [2][3][4]7,10]. By comparing the obtained experimental values of E(α) and lnA(α) with those obtained from each model, as well as the best value of R C , then the suitable reaction model g(α) will be chosen to describe the transformation process of the Ge 12.5 Te 87.5 chalcogenide glass.…”

“…In order to reveal this variation, the isoconversional methods are widely used to determine the effective activation energy E of the crystallization process. The variation of the effective activation energy with the extent of conversion can be used to investigate different nucleation and growth mechanisms associated with this transformation [2][3][4][5][6][7][8][9][10][11][12]. The kinetics of isothermal transformation involving nucleation and growth is usually analyzed using the Johnson-Mehl-Avrami (JMA) model.…”