Anodic films on iron formed in a forced convection system in the transpassive potential region in nitrate electrolytes at current densities up to 40 A/cm2 have been studied by in situ coulometry and ex situ Auger electron spectroscopy (AES) and angle‐resolved x‐ray photoelectron spectroscopy (XPS). Qualitatively similar results on the variation of film thickness with applied current density are obtained by different methods. The transition from transpassive oxygen evolution to transpassive metal dissolution coincides with a marked decrease in film thickness and with the appearance of nitrogen in a reduced state at the metal‐film interface.
Dr. Madhav Datta, Mathieu, H. J., and Landolt, D., “AES/XPS study of transpassive films on iron in nitrate solution”, Journal of The Electrochemical Society, vol. 131, pp. 2484–2489, 1984.