Incorporation of Cr in the passive film on Fe from chromate solutions

The uptake of Cr species from chromate solutions by Fe has been studied using X-ray absorption near edge structure (XANES). The objective of the investigation was to compare XANES with radioactive tracer techniques used by Brasher et al. Cr(III) was detected on the passive iron surface. The amount of Cr(III) was increased by cathodic polarization and decreased by anodic polarization. This demonstrated that the uptake of Cr(III) was the result of cathodic processes and was not a direct result of the growth of the passive oxide film. Cr(VI) was only found after Fe was exposed to a saturated dichromate solutions for extended periods indicating that Cr(VI) was not strongly absorbed on the passive film. (C) 2002 Published by Elsevier Science Ltd.