Analysis of Iron Corrosion Products Using Mössbauer Spectroscopy

Abstract

Abstract A brief outline of Mössbauer spectroscopy is presented, and previous work on its application to the field of corrosion is summarized. Practical corrosion products formed under a variety of conditions are identified using the Mössbauer effect, and in some cases the Mössbauer data have been complemented by X-ray diffraction analysis. α-FeOOH, γ-FeOOH, γ-Fe2O3, and Fe3O4 are found in atmospheric corrosion products; Fe3O4, γ-Fe2O3, α-FeOOH, FeCO3, and perhaps γ-FeOOH on buried pipelines; Fe3O4, γ-Fe2O3, α-FeOOH, β-FeOOH, and perhaps γ-FeOOH on buried structures; Fe3O4 in boiler superheaters, and γ-Fe2O3, Fe3O4, α-FeOOH, and possibly γ-FeOOH on heat exchangers, and α-FeOOH, γ-FeOOH, γ-Fe2O3, Fe3O4, and sometimes ZnxFe3-xO4 in galvanized potable water pipe. The ability of the Mössbauer effect to distinguish these oxides and hydrated oxides provides the corrosion engineer with a valuable method for analyzing iron corrosion products.