Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7901863 | Journal of Non-Crystalline Solids | 2014 | 9 Pages |
Abstract
A transparent Eu3 +-doped lithium aluminophosphate glass was prepared by melt-quenching technique. The thermal behavior of the glass was investigated by differential thermal analysis (DTA), the structure was studied by X-ray diffraction (XRD) and the morphology was observed by optical polarization microscopy and scanning electron microscopy (SEM). The activation energy of glass transition and the activation energy of crystallization and Avrami exponent have been evaluated under non-isothermal conditions from the data obtained by DTA at different heating rates. DTA curves exhibited an endothermic peak associated with the glass transition and two exothermic peaks. The mean value calculated for the activation energy of glass transition was 545 kJ molâ 1. The activation energy of crystallization was ~ 400 kJ molâ 1 for the first exothermic peak and ~ 170 kJ molâ 1 for the second peak. The Avrami exponent was ~ 1 for both peaks indicating surface crystallization. XRD results showed that the main crystalline phase, aluminum metaphosphate, Al(PO3)3, and aluminum phosphate, AlPO4, were formed together with lithium barium phosphate, Li3Ba(PO3)7, during the first exothermic peak and together with barium pyrophosphate, Ba2P2O7, during the second peak. Morphological study of heat-treated glass samples revealed microstructural features that confirmed a surface crystallization process.
Keywords
Related Topics
Physical Sciences and Engineering
Materials Science
Ceramics and Composites
Authors
Roque S. Soares, Regina C.C. Monteiro, Andreia A.S. Lopes, Maria M.R.A. Lima, Bogdan A. Sava, Mihail Elisa,