COMPOSITION AND GROWTH OF ANODIC OXIDE-FILMS ON IRON

This paper will emphasize the use of surface-analytical techniques to study the nature of passive oxide films on Fe. 18O/SIMS has been used to determine the air stability, cathodic removal, growth and breakdown of anodic films formed in borate buffer solution. SIMS has also shown that these passive films contain no incorporated hydroxyl ions, and electron back-scattering Mössbauer spectroscopy (complemented by XPS) has confirmed that the films resemble small particle size crystalline γ-Fe2O3. Results will also be presented on the anodic passivation of Fe in sulfate and perchlorate solutions and on the influence of halide ions on passivation in borate buffer. © 1990.