Properties and structural features of iron doped BABAL glasses
| Autor: | Dalva Lúcia Araújo de Faria, Jinbo B. Yang, Signo Tadeu Dos Reis, W. M. Pontuschka |
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| Rok vydání: | 2003 |
| Předmět: |
Materials science
Mechanical Engineering Analytical chemistry chemistry.chemical_element Mineralogy Condensed Matter Physics law.invention symbols.namesake Octahedron chemistry Mechanics of Materials law Differential thermal analysis Mössbauer spectroscopy symbols General Materials Science Iron phosphate Boron Electron paramagnetic resonance Raman spectroscopy Dissolution |
| Zdroj: | Materials Research. 6:389-394 |
| ISSN: | 1516-1439 |
| DOI: | 10.1590/s1516-14392003000300013 |
| Popis: | The chemical durability, density and structure of the BABAL glasses with batch compositions (100-x)(0.30BaO·0.50B2O3·0.20Al2O3)·xFe 2O3 (1 < x < 10 mol%), were investigated using Mossbauer spectroscopy, electron paramagnetic resonance (EPR), X-ray diffraction, Raman and differential thermal analysis (DTA). The chemical durability for the glass of composition 27BaO·45B2O3·18Al 2O3·10Fe2O3 (mol%) at 90 °C in distilled water was 700 times lower than that of iron phosphate glass 40Fe2O3·60P2O 5 (mol%). The Mossbauer spectra indicate the presence of iron (II) and iron (III) in tetrahedral or octahedral coordination. The results obtained from the gef = 4.3 EPR line are typical of the occurrence of iron (III) occupying substitutional sites and the line gef = 2.0 is related to the association of two or more Fe ions found in the interstices (or holes occupied by the glass modifier cations) of the glass network. The paths of X-ray diffraction are typical for glasses based in borate glasses. The Raman spectra showed that the boroxol ring disappears with the increase of iron content, concomitant with the appearance of BO4 and tetraborate structural units. At these conditions, an increase of dissolution rate and clustering of iron ions is observed. |
| Databáze: | OpenAIRE |
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