Study on the Corrosion Behavior of Grounding Materials in Acidic Soils With Different Cl − Contents

The grounding system is a key infrastructure that ensures the stable and safe operation of the power system. The corrosion behavior of earthing materials within soil environments significantly impacts their long‐term reliability. This article studies the corrosion behavior of three typical grounding materials systematically: Cu, carbon steel, and galvanized steel, in acidic soil simulated solutions with varying Cl − concentrations (0.05%, 0.5%, 1%, 2%). The corrosion rate and corrosion resistance of the material were evaluated through electrochemical testing and weight loss method, combined with corrosion morphology observation and product analysis. The results indicate that the impedance arcs and the impedance modulus of the three materials both decrease as the concentration of Cl − increases. The impedance modulus of Cu decreased from 10 5 to 10 3 Ω·cm 2 . The corrosion current density increased significantly from 0.157 to 8.190 μA·cm −2 for Cu and from 9.130 to 19.300 μA·cm −2 for carbon steel, and the corrosion rate rises significantly. Cu exhibits optimal corrosion resistance due to its ability to form a dense corrosion product film. The corrosion rate remained low below 0.008 mm/a across all Cl − concentrations. Galvanized steel has certain protective capabilities when the coating is intact, but its failure accelerates with the increase in the Cl − concentration showing a maximum corrosion rate of 0.0273 mm/a at 1% Cl − and a maximum pitting depth of 6.804 μm at 2% Cl − . The corrosion products of carbon steel are loose and porous, with the worst corrosion resistance. The carbon steel exhibits a maximum pitting depth of 109.56 μm at 2% Cl − . This research can provide a basis for selecting materials for grounding electrodes in acidic environments with high Cl − content.