BINGHAM, Paul, FORDER, S. D., HAND, R. J. and LAVAYSIERRE, A. (2005). Mössbauer studies of phosphate glasses for the immobilisation of toxic and nuclear wastes. Hyperfine Interactions, 165 (1-4), 135-140.Full text not available from this repository.
Various iron-containing phosphate glasses were investigated by Mössbauer spectroscopy. Iron was found to occur predominantly as Fe3+ in all glasses, and largely occupied sites with distorted octahedral coordination for both redox states. Using a base glass of nominal composition 60 P2O5–40 Fe2O3 (mol%), stepwise molar replacement of Fe2O3 by (0.67 Na2O × 0.33 Al2O3) increased the redox ratio, Fe2+/ΣFe, from 0.13 at 40% Fe2O3 to 0.25 at 10% Fe2O3. The centre shift increased and quadrupole splitting decreased by up to ∼20% over this range, interpreted as a decrease in the average distortion of Fe sites from cubic symmetry, and an increase in average iron coordination. Literature revealed that recoil-free fraction ratio f (Fe3+) / f (Fe2+) ≈ 1.3 in iron phosphate glasses, and this was considered when assessing redox. Mössbauer parameters of these and other glasses demonstrated a combination of structural stability and compositional flexibility which makes them so suitable for waste immobilisation.
|Research Institute, Centre or Group:||Materials and Engineering Research Institute > Structural Materials and Integrity Research Centre > Centre for Corrosion Technology|
|Depositing User:||Hilary Ridgway|
|Date Deposited:||06 Sep 2012 14:48|
|Last Modified:||06 Sep 2012 14:48|
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