The interaction of oxygen with clean surfaces of stainless steels has been studied by spectroscopic ellipsometry and AES. The reaction involves chemisorption and dissolution of oxygen into the surface of the metal via a place-exchange mechanism. Oxide thickening occurs via cation and anion migration under the influence of an electric field. The activation energy increases with increasing oxide thickness and the final activation energy equals the energy needed to break the bonds between oxygen and metal ions in the oxide, suggesting diffusion via lattice sites.
Langevoort, J. C., Hanekamp, L. J., & Gellings, P. J. (1987). On the kinetics of oxidation of austenitic stainless steels AISI 304 and incoloy 800H. Applied surface science, 28(3), 189-203. https://doi.org/10.1016/0169-4332(87)90121-8