Research on the Corrosion Mechanism of Galvanized Steel in AC and DC Electric Fields

With the construction of ultra-high voltage direct current (UHV DC) transmission lines, power transmission equipment in the power industry is exposed to complex environmental conditions, leading to issues such as electrochemical corrosion and oxidative corrosion, particularly in the humid and high-temperature regions of southern China. To study the corrosion issues of metal equipment in power systems, this Research investigated the corrosion mechanisms of galvanized steel under the influence of alternating current (AC) and direct current (DC) electric fields. Galvanized steel, as a common metallic material, extends the service life of carbon steel components through its zinc coating, ensuring safe operation.The research employs a variety of experimental methods, including weight loss measurement, electrochemical impedance spectroscopy (EIS), polarization curve testing, X-ray diffraction (XRD), and scanning electron microscopy (SEM), to systematically characterize the corrosion behavior of galvanized steel under different electric field conditions. The results indicate that the corrosion damage to galvanized steel is significantly higher under the influence of electric fields compared to natural corrosion, with the DC electric field exhibiting the most pronounced effect. Although the impact of the electric field on the zinc protective layer is not apparent in the early stages of corrosion, over time, the electric field promotes the migration of chloride ions (\(\text{Cl}^-\)) to the metal surface, accelerating the corrosion process.