Structural features of iron-phosphate glass

This paper reports a study and discusses the role of Fe ions in the inhibition of corrosion of iron phosphate glasses. The structure of the 40Fe(2)O(3)-60P(2)O(5) (mol%) glass, having a confirmed dissolution rate in aqueous solution at 90 degrees C superior to borosilicate glasses, was investigated. Samples were crystallized at characteristic temperatures defined by differential thermal analysis and analyzed by X-ray diffraction. Crystalline phases of Fe2Fe[P2O7](2) and Fe-4[P2O7](3) were detected. The hyperfine parameters from the Mossbauer spectrum indicate that both Fe2+ and Fe3+ ions are in octahedral coordination, and 18% of the Fe3+ ions in the starting batch are reduced to Fe2+ ions after melting. The broad and symmetric spectra centered in g approximate to 2.0 from the EPR measurements indicate the presence of two or more Fe interacting ions occupying sites of relatively high local symmetry.