Reduction of hexavalent chromium embedded in organic insulation and corrosion inhibition layers during X-ray photoelectron spectroscopy (XPS) measurements

摘要

Chromium compounds are still used in the context of corrosion protection in industrial products, with Cr containing organic coatings on electrical steel as an example. In order to analyse the content of hazardous Cr(VI) components, X-ray photoelectron spectroscopy (XPS) is often promoted as a non-destructive technique which enables the determination of elemental concentrations and chemical states. However, this technique can affect the oxidation state as we show for CaCrO4. The key point is that pure Cr reference materials behave differently as compared to mixed material systems, which has to be considered for a reliable quantification of Cr(VI) by XPS.