An alternative method for analyzing the non-isothermal glass-crystal transformation kinetics

Analysis of solid state phase transformation kinetics: models and recipes

“…) Because the interpretation of values determined for the activation energy of a phase transformation often led and leads to confusion in the literature, [46][47][48][49][50] the following remarks are made.…”

A Kinetic Study on Crystallization in TiO2-SiO2-CaO-Al2O3 Glass under Nucleation Saturation Conditions for the High Value-Added Utilization of CaO-SiO2-Based Solid Wastes

“…Many authors have published various methods to explain the non-isothermal crystallization kinetics of glass [25,26,28,29,[39][40][41]. Among these, Matusita et al underlined that taking the crystallization mechanism into account is necessary to obtain the valid activation energy [28,39,40].…”

“…For instance, in a well-nucleated bulk glass, the amount of existing nuclei in the sample is so large that it does not grow anymore throughout the DTA test, so in such situations, m = n; however, in an as-quenched bulk glass, nucleation is an ongoing process through the heat treatment, and in this situation, m = n − 1 [28,33,41]. However, some important caveats are particularly noteworthy: for fine-particle glass, because of the precedence of nucleation at the particle edge, surface, corners, or junction of particle boundaries, the tremendous number of grain boundaries and the large surface area provide sufficient nucleation sites such that this glass shows the characteristic of heterogeneous nucleation, i.e., "nucleation saturation" [26,32,33,35]. Thus, for fine-particle glass, the nucleation sites on the grain surface are basically saturated, to the extent that the newly formed nuclei inside the particle, through the DTA test, can be safely neglected.…”

“…There has been widespread application of non-isothermal techniques to study the crystallization kinetics of glass via differential scanning calorimetry (DSC) or differential thermal analysis (DTA) in different fields [25][26][27][28]. The techniques have contributed a lot to investigations on the nucleation and crystal growth processes occurring throughout the glass transition process as it is heated, by providing important crystallization parameters such as glass transition temperature, crystallization temperature, transformation enthalpy, the crystal growth mechanism, and activation energy.…”

“…When the crystallization mechanism and activation energy are estimated based on some of these equations, the effects of particle size must be fully considered to obtain the correct relationship between n and m, thereby ensuring the correctness of calculating activation energy. However, in some studies, either the influences of particle size are ignored, or the state of "nucleation saturation" (i.e., the nucleus number is invariable during DTA process) for the fine-particle as-quenched glass samples [26,32,37] is poorly comprehended in the determination of the values of n and m; thus, some of the various rules of activation energy values proposed by these studies may be obscure, and the proposed conclusions may lead to misunderstandings. Another work published by our team on the crystallization kinetics of CaO-SiO 2 -B 2 O 3 -TiO 2 glass takes into account the occurrence of "nucleation saturation", and confirms that it is necessary to keep the effects of glass particle size in focus to correctly calculate the kinetic parameters [38].…”