Phase transformation and microstructural evolution after heat treatment of a terbium-doped lithium–aluminum phosphate glass
| Autor: | Bogdan Alexandru Sava, Regina da Conceição Corredeira Monteiro, Roque S. Soares, Maria Margarida Rolim Augusto Lima, Mihail Elisa |
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| Rok vydání: | 2014 |
| Předmět: |
Materials science
Mechanical Engineering Metaphosphate Mineralogy Crystal growth Activation energy law.invention Phosphate glass chemistry.chemical_compound chemistry Chemical engineering Mechanics of Materials law Differential thermal analysis Phase (matter) General Materials Science Crystallization Glass transition |
| Zdroj: | Journal of Materials Science. 49:4601-4611 |
| ISSN: | 1573-4803 0022-2461 |
| Popis: | The crystallization kinetics and phase transformation of a transparent Tb3+-doped lithium–aluminum phosphate glass, prepared by melt quenching, were investigated. The energy associated to the glass transition and the crystallization parameters (activation energy for crystallization and Avrami exponent) were evaluated by different methods using the experimental data obtained by differential thermal analysis performed at different heating rates. Using an isoconversional method to determine the change of the activation energy for crystallization with the fraction of crystallization, it was verified that with the increase in the fraction of crystallization from 0.1 to 0.9, the value of the activation energy decreased slightly from ~370 to ~310 kJ mol−1 and that the Avrami exponent varied from 0.8 to 1, suggesting a surface crystal growth mechanism. Observation of the microstructural evolution of heat-treated glass samples confirmed a surface crystallization process revealing spherulitic crystals constituted mainly by aluminum metaphosphate. |
| Databáze: | OpenAIRE |
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