Effect of High-Current Field on Corrosion Behavior of Copper Wire in Simulated Atmospheric Environment

Copper is the core conductive material of power equipment, which has excellent conductivity and ductility. However, in actual operation, a copper conductor is often subjected to both atmospheric corrosion and a high-current field, and its stability is very important for equipment safety. At present, there are fewer systematic studies on the corrosion behavior of copper conductors under the coupling of high current field and atmospheric environment. In this paper, the corrosion behavior of copper conductor materials in the current field environment was studied through immersion and electrochemical experiments. The immersion tests showed that copper undergoes primarily pitting corrosion in 3.5 wt% NaCl solution, with the corrosion products identified as Cu2O, CuO, and Cu2Cl(OH)3. As the applied current density increases, the pits deepen, and the corrosion rate increases significantly with an increasing applied current, rising from 3.88 mm·y−1 at 0 A to 832.82 mm·y−1 at 40 A. This is because the current causes the electrode potential to deviate from its equilibrium state and accelerates ion migration, promoting corrosion. The electrochemical tests indicated that at the same current, charge transfer resistance (Rct) first increases, and then decreases with the immersion time, while the corrosion current density first decreases, and then increases. This reflects that the corrosion product film provides protective effects in the initial stage, but is gradually damaged over time.