Molecular progress of the corrosion of passivated Iron: The effects of structural strain

MM Li and SR Wu and P Wang and JR Zhang and BQ Dong and ML Ma and Z Wang and DS Hou and MH Wang, CONSTRUCTION AND BUILDING MATERIALS, 360, 129537 (2022).

DOI: 10.1016/j.conbuildmat.2022.129537

Structural strain of steel is a general phenomenon in reinforced concrete, which significantly affects the per-formance of the passivation film but is still unclearly due to its nanoscale characteristics. In this work, the process of the chloride attack on gamma-FeOOH is revealed by the molecular dynamics simulation with different structural strains. It is found that the properties of the gamma-FeOOH structure changed significantly with the increase of strain. In the low strain status, the gamma-FeOOH structure exhibit typical ductility. However, it exhibits obvious brittleness in the high strain state. The analyses of molecular interaction indicate that the chloride is easier to penetrate the layer structure of gamma-FeOOH in high strain status, thus resulting in a huge shift in the gamma-FeOOH properties. The generation of iron hydroxyl induces the penetration of chloride ions and is regarded as the origin of the gamma-FeOOH deterioration.

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