Galvanic Corrosion Behavior Between Copper (T2) and Carbon Steel (Q235) in Simulated Deep Geological Environment

In this study, the galvanic corrosion behavior of Cu and CS (carbon steel) in simulated Beishan groundwater was investigated. The influence of Cu:CS area ratio (up to 8000), temperature (20–70 °C), O 2 content (groundwater sparged with air, N 2 , and in a N 2 -filled glove box), on galvanic current density ( i g ) was investigated. In the presence of sufficient O 2 , the slope of steady-state galvanic current density ( i g ∞ ) to Cu:CS area ratio indicates the segmented control process of galvanic corrosion, which are O 2 reduction kinetic control, O 2 diffusion control, and anodic reaction control. As Cu:CS area ratio increases, i g ∞ plateaus show up, revealing the most intense galvanic corrosion situation. As the O₂ content decreases, the Cu:CS area ratio at which the i g ∞ plateau appears decreases. In addition, it was found that in the presence of O 2 , Cu, as the cathode of the galvanic couple, undergoes anodic dissolution. The dissolution of Cu + was confirmed by complexing it with bathocuproine disulfonate disodium (BCS). The oxidation of Cu + to Cu 2+ in solution was confirmed by ICP-MS analysis.