Effect of iron ion diffusion on the corrosion behavior of carbon steels in soil environment

The corrosion behavior of metal materials in soil environments has been intensively studied recently. Even so, the detailed corrosion mechanisms remain elusive, especially regarding the role of metal ions. In this study, we investigated the effect of ion diffusion on the corrosion processes of carbon steel via scanning electron microscopy (SEM), in situ laser Raman spectroscopy and scanning Kelvin probe (SKP). It was found that the Fe³⁺ diffusion was a key factor to the corrosion rate, as well as the formation of corrosion products. Typically, the corrosion products suppressed the diffusion of ions to the surface of carbon steels, and thus the cation diffusion coefficient played a significant role in formation processes of corrosion products, which furthermore affected the corrosion processes of the carbon steels.