Passivation of steel surface: An atomistic modeling approach aided with X-ray analyses

Using a quantum mechanics-based atomistic modeling approach and X-ray analyses, we explored the oxidation process of steel surface in a typical ambient condition. The growth of iron oxides on steel surface was found to be highly dependent on the thermodynamics and availability of reactants. Three oxidation stages were identified before the formation of a high-density triplex structure on steel surface, after which the oxidation of iron atoms progressed at a significantly reduced speed. Results from this atomistic study can be expected to improve the understanding of the passivation and depassivation of steel surface toward an effective control of iron corrosion.

► Oxidation of iron surface involves three stages with distinct oxidation speeds.
► Early iron oxidation is highly thermodynamic and involves many unstable species.
► A triplex structure formed on iron surface notably reduces the oxidation speed.