| People | Locations | Statistics |
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| Naji, M. |
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| Motta, Antonella |
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| Aletan, Dirar |
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| Mohamed, Tarek |
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| Ertürk, Emre |
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| Taccardi, Nicola |
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| Kononenko, Denys |
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| Petrov, R. H. | Madrid |
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| Alshaaer, Mazen | Brussels |
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| Bih, L. |
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| Casati, R. |
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| Muller, Hermance |
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| Kočí, Jan | Prague |
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| Šuljagić, Marija |
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| Kalteremidou, Kalliopi-Artemi | Brussels |
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| Azam, Siraj |
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| Ospanova, Alyiya |
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| Blanpain, Bart |
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| Ali, M. A. |
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| Popa, V. |
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| Rančić, M. |
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| Ollier, Nadège |
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| Azevedo, Nuno Monteiro |
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| Landes, Michael |
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| Rignanese, Gian-Marco |
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Riley, Brian J.
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (14/14 displayed)
- 2024Insights on the structure and properties of sodium iron phosphate glasses from molecular dynamics simulationscitations
- 2018Final report: Understanding influence of thermal history and glass chemistry on kinetics of phase separation and crystallization in borosilicate glass-ceramic waste forms for aqueous reprocessed high level waste
- 2017Glass Transition Temperature- and Specific Volume- Composition Models for Tellurite Glasses
- 2017Apatite and sodalite based glass-bonded waste forms for immobilization of 129I and mixed halide radioactive wastes
- 2013Sublimation-Condensation of Multiscale Tellurium Structurescitations
- 2009DC Ionization Conductivity of Amorphous Semiconductors for Radiation Detection Applicationscitations
- 2008ASGRAD FY07 Annual Report
- 2007FY06 Annual Report: Amorphous Semiconductors for Gamma Radiation Detection (ASGRAD)
- 2007Differential etching of chalcogenides for infrared photonic waveguide structurescitations
- 2006Summary of Chalcogenide Glass Processing: Wet-Etching and Photolithography
- 2006Pressure-temperature dependence of nanowire formation in the arsenic-sulfur system
- 2005FY 2005 Miniature Spherical Retroreflectors Final Report
- 2004FY 2004 Infrared Photonics Final Report
- 2004Chalcogenide glasses and structures for quantum sensing
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article
Insights on the structure and properties of sodium iron phosphate glasses from molecular dynamics simulations
Abstract
Iron phosphate glasses are promising nuclear waste forms while more detailed understanding of their structures and structure-property relations are still needed to better design waste glass compositions. In this work we report studies of three series of sodium iron phosphate (NFP) glasses: 60P<sub>2</sub>O<sub>5</sub>-(40-x)Fe<sub>2</sub>O<sub>3</sub>-xNa<sub>2</sub>O (x = 0→40), (100–2x)P<sub>2</sub>O<sub>5</sub>-xFe<sub>2</sub>O<sub>3</sub>-xNa<sub>2</sub>O (x = 5→17.5) and one with different iron redox ratio, to understand the composition as well as the iron redox effects on the structure and properties of these glasses using molecular dynamics simulations with effective two-body and three-body potentials. Structural analyses, including pair distribution function, bond angle distribution, Q<sub>n</sub> distribution, and polyhedral connectivity, were performed to obtain in-depth information on short-range and medium-range structural features. The P-O pair distributions showed a first peak splitting with phosphorus-bridging and non-bridging oxygen contributions. This and the average P-O and other cation-oxygen bond distances are in excellent agreement with experiments. The coordination number of P<sup>5+</sup> remained four while that of Fe<sup>3+</sup> increased from 4.30 to 4.72 with decreasing Fe/Na ratio. Polyhedral linkage analysis showed [PO<sub>4</sub>] units linked with [PO<sub>4</sub>] and [FeO<sub>x</sub>] through corner-sharing while the [PO<sub>4</sub>]-[FeO<sub>x</sub>] linkages become dominant for compositions with Fe<sub>2</sub>O<sub>3</sub> larger than 15 mol%. The effect of iron redox ratio on the structure of NFP glasses was also studied and it was found that bond lengths and coordination numbers were not strongly affected, while the reduction of iron introduced higher network distortions, as evident by O-P-O bond angle and Q<sub>n</sub> distribution. The glass transition temperature (T<sub>g</sub>) showed a monotonic increase with Fe<sub>2</sub>O<sub>3</sub> in the first series, in good agreement with experiments, while those of the second series showed a maximum at P<sub>2</sub>O<sub>5</sub> = 82 mol%. Here, calculated elastic moduli were found to increase with Fe<sub>2</sub>O<sub>3</sub> in the first glass series, which was be explained by the increase of network connectivity, while those of the second series decrease with Fe<sub>2</sub>O<sub>3</sub> due to decrease of P<sub>2</sub>O<sub>5</sub>.