Study of the crystallization kinetics of LAS glass by differential scanning calorimetry, X-ray diffraction, and beam bending viscometry
| Autor: | D. Ovono Ovono, Giovanni Bruno, Philippe Pradeau, S. Berre, Monique Comte |
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| Rok vydání: | 2012 |
| Předmět: |
Arrhenius equation
Ostwald ripening Materials science Analytical chemistry Viscometer Crystal growth Activation energy Condensed Matter Physics law.invention symbols.namesake Crystallography Differential scanning calorimetry law symbols Crystallite Physical and Theoretical Chemistry Crystallization Instrumentation |
| Zdroj: | Thermochimica Acta. 527:158-164 |
| ISSN: | 0040-6031 |
| DOI: | 10.1016/j.tca.2011.10.021 |
| Popis: | The crystallization kinetics of a commercial lithium-aluminum silicate (LAS) glass were characterized by differential scanning calorimetry (DSC) under non-isothermal conditions, by in-situ X-ray diffraction, and by three point beam bending viscosimeter (BBV). Non-isothermal DSC experiments were conducted at different heating rates. Results show that the crystal growth is controlled by a thermally activated process of the Arrhenius type. The activation energies obtained from isoconversional analysis are close to that extracted using the Johnson–Mehl–Avrami equation. While X-ray diffraction volume fraction data confirm the DSC analysis, it also shows that the crystallite size changes only at the end of the heat treatment protocol, during a hold at temperatures as high as 1000 °C. In this latter case, the crystal growth follows the Ostwald ripening mechanism. Finally, the viscosity measured in the crystallization region by BBV provides the activation energy for viscous flow, and it is slightly higher than the values obtained by DSC. |
| Databáze: | OpenAIRE |
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