Nucleation and Crystallization of Na₂O · 2CaO · 3SiO₂ Glass by Differential Thermal Analysis

Abstract

The nucleation and crystallization of the NazO * 2Ca0 * 3Si02 (NC2S3) glass were studied by differential thermal analysis (DTA), and a (nucleation rate-temperature)-like curve was determined by plotting either the reciprocal of the temperature corresponding to the crystallization peak maximum, l/T,, or the height of the crystallization peak, (ST),, as a function of nucleation temperature, T . . The temperature where nucleation can occur for this glass ranges from 550" to 650°C and the temperature for maximum nucleation is 600" * 5°C. Both temperatures are in excellent agreement with those determined by the classical technique of nucleation followed by isothermal crystallization. The activation energy for crystallization, E,, for this glass is the same for surface and/or bulk crystallization, and is 370 -C 15 kJ/mol. The analysis of the crystallization data with the Kissinger equation yields the correct value for E, only when crystal growth occurs on a fixed number of nuclei. When a majority of the nucleation occurs during the DTA measurements, a modified Kissinger equation must be used to calculate E,. E, is also independent of the heating rate when determined using a single-crystallization-peak analysis technique. The single-peak analysis technique is useful for a rapid determination of E, or when only a small amount of sample is available. [

Kinetic study of surface nucleated MgO-CaO-Al2O3-SiO2 glasses

“…In addition, when surface crystallization predominates, it was suggested in several papers [2,3,10] to use m=n=l so that Eq. (2) Figure 3 reports a set of DTA measurements of A glass at different heating rates, where the shift in the maximum peak temperature, Tp, is clearly visible.…”

Computer modeling of non-isothermal crystallization

“…Given a single nucleation event within a panicle of radius R. a cluster will grow with a cluster-dependent growth velocity given by Eq. (5). If the cluster were to nucleate at the exact center of the particle and if there were no other growing clusters within the particle, the transformation would proceed unimpeded until the particle was completely transformed.…”

Viscous Flow and Crystallization Behaviors of P-bearing Steelmaking Slags with Varying Fluorine Content

“…The wide use of differential scanning calorimeter (DSC) at non-isothermal mode has required reliable methods to deal with non-isothermal kinetics, which has been put forward by many researchers. [22][23][24][25][26][27][28] One of these methods is the Kissinger method, which has been widely used for the description of the crystallization kinetics in non-isothermal process. 27,28) Kissinger equation gives the correct values of E a only when the crystal growth occurs on a constant number of nuclei.…”