The glass of composition 10Na 2O-30Fe 2O 3-5Cr 2O 3-55 P 2O 5 (mol %) is obtained by the melting quench method in 1080˚C. The chemical durability was investigated in distilled water solution. In this paper we present a study of sodium chromium iron phosphate glass 10Na 2O-30Fe 2O 3-5Cr 2O 3-55P 2O 5 which is prepared by the melt quenching technique, and characterized by X-Ray Diffraction, Infra-Red spectroscopy, and Scanning Electronic Microscopy. The P-O-Cr bands seem to play the same role than P-O-Fe bands. The presence of P-O-Fe bands in higher concentrations, makes the glass more hydration resistant. Therefore it has been suggested that the chemical durability of sodiumchromium-iron phosphate glasses is attributed to the replacement of P-O-P bonds by P-O-Cr and P-O-Fe bonds. The combination of chromium phosphate glass with various types of simulated nuclear waste showed that it is possible to have a waste form with a corrosion rate more slowly than that one of a comparable borosilicate glass.
Chromium phosphate glasses for the immobilisation and disposal of nuclear waste were reported in 1984.
The iron phosphate glasses have generally both excellent chemical durability and low melting temperature typical between 9˚C. It was reported that the introduction of oxides such as SnO, PbO, ZnO, Cr 2O 3 and Fe 2O 3, results in the formation of Sn-O-P, Pb-O-P, Zn-O-P, P-O-Cr and P-O-Fe bonds, and leads to improvement in the chemical durability of the modified phosphate glasses. However, their relatively poor chemical durability makes them unsuitable for practical applications. These properties makes them a good candidates in many applications such as glass to metal seals, thick film paste, the molding of optical elements, low temperature enamels for metals. Phosphate glasses are of particular interest in both technological and scientifical fields because they generally have lower processing temperatures less than 1000˚C, lower glass transition temperatures (Tg), and higher thermal expansion coefficients (α) than silicate glasses in the range of 90 to 250 × 10 −7/˚C. The chemical durability of the glass was investigated by measuring the weight loss in distilled water at 90˚C for 22 days. There is also a band at 603 cm −1 attributed to isolated tetrahedral units (PO 4) 3−. The IR of the glass studied, contains two dominant bands, which were characteristic of pyrophosphate groups, (P-O) stretching mode of P-O non bridging oxygen at 1055 cm −1 and sym stretching mode of bridging oxygen at 444 cm −1 respectively.
We have performed the measurement of X-Ray Diffraction (XRD), Scanning Electronic Microscopy (SEM), Infra-Red spectroscopy (IR), and the chemical durability. The sample was annealed at 680˚C for 48 h. The sodium-chromium-iron phosphate glass of composition 10Na 2O-30Fe 2O 3-5Cr 2O 3-55P 2O 5 (mol%) was produced by melting batches of (99, 98% pure) Cr 2O 3, Fe 2O 3, Na 2CO 3, and (NH 4) 2HPO 4 at 1080˚C for one hour and pouring the liquid into steel mold. The introduction of chromium in sodium-iron-phosphate glass is used to compare its effect with iron in inhibition of corrosion. Keywords: Chemical Durability IR Spectroscopy Scanning Electron Microscopy Phosphate Glasses XRDĬhromium iron phosphate glass was investigated for use as waste form because of its improved chemical durability. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. 1Hassan II University of Casablanca, Faculty of Science, High Energy and Condensed Matter Lab, Casablanca, MoroccoĢHassan II University of Casablanca, Faculty of Science, Mineral chemistry Lab, Casablanca, MoroccoĮmail: © 2013 Youssef Makhkhas et al.
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