Localized corrosion of carbon steel in marine media: Galvanic coupling and heterogeneity of the corrosion product layer

Corrosion at the carbon steel-clay borehole water interface under anoxic alkaline and fluctuating temperature conditions

“…Interestingly, a similar heterogeneity in surface corrosion was observed for steel in contact with clay materials [14,70] or in seawater [71]. The surface dichotomy was linked to the formation of a differential aeration cell, with minerals such as Fe oxide and sulfide phases associated to cathodic reactions [71]. Here a similar process is observed, with thin Fe silicate and (Fe,Cu) sulfide layers acting as surface electron-conducing phases on large cathodic areas.…”

“…In contrast, the heterogeneity in the corrosion damage for Series 3-Rods 3-4 samples reveals that the whole surface is not protected, suggesting that anodic and cathodic sites are spatially separated. Interestingly, a similar heterogeneity in surface corrosion was observed for steel in contact with clay materials [14,70] or in seawater [71]. The surface dichotomy was linked to the formation of a differential aeration cell, with minerals such as Fe oxide and sulfide phases associated to cathodic reactions [71].…”

Predicting long-term corrosion of metal alloys in physical infrastructure

“…It also can be expected to relate to the micro-environment, such as under and the corrosion products, noting the variability with depth of corrosion product layers that has been observed for longer term exposures. 98 An immediate challenge is the better understanding and definition of the relationships between the micro-scale corrosion phenomena to macro-scales and to include the environmental effects. Provocatively, it could be considered that only then will what is largely empirical corrosion engineering have the chance to morph into corrosion engineering science.…”

A Novel Approach for the Evaluation of Under Deposit Corrosion in Marine Environments Using Combined Analysis by Electrochemical Impedance Spectroscopy and Electrochemical Noise

“…There would always exist some microscopic pathways (mainly the inner porosity of formed deposits or tiny gaps between deposits) for the accessibility of corrosive electrolytes to the substrate [9]. In the present case, the mechanism of UDC is believed to be analogous to regular crevice corrosion because of the oxygen differential aeration cell formed [32,58] i.e. beneath the areas covered with deposits, the anodic dissolution currents will be intense, whereas the cathodic currents (controlled mainly by the oxygen reduction reaction) will be concentrated typically around the deposited layer at microscopic uncovered areas [59].…”