Study on alternating current corrosion of carbon steel grounding electrode

Grounding electrode corrosion occurs in soil, corrosion products deposit on the electrode surface prone to form the sedimentary layer. As the electric current flow out the grounding electrode will accelerate the corrosion rate, and greatly affect the corrosion products depositing process. The formation of the sedimentary layer of the corrosion products changed the surface structure of the grounding electrode and the physical and chemical properties between the grounding electrode interface and soil, which seriously affect the current spillage characteristics of the grounding electrode. In order to study the mechanism of the influence of grounding electric current spilling on the depositing process of corrosion products, a dynamic model of corrosion products depositing process is established. By analyzing the model, with the progress of the corrosion process, the corrosion products deposit on the electrode surface, the corrosion rate first increased and then decreased; After a period of time, the local corrosion rate increased, the local corrosion pits and bumps appear on the grounding electrode surface, the deposition of the corrosion products change the structure of the contact surface between grounding electrode and soil. The injection of DC into the grounding electrode will obviously accelerate the corrosion process, and corrosion deformation is unevenly distributed during the injection of AC.