Effects of stray current on the corrosion behavior of typical grounded materials in northern Shaanxi soil simulation solution

The potential and corrosion current of pure zinc, pure copper and zinc/copper coupling structures with different distances to the stray current source in northern Shaanxi soil simulation solution were studied with a self-made stray current simulating instrument. Electrochemical impedance spectroscopy (EIS) was used to analyze the corrosion behavior of these grounded materials. It is found that there exists an obvious transition from the cathode to anode in the surface of pure zinc as a grounding material, and samples are seriously corroded in the anodic zone. The electrochemical reaction resistance of pure copper is much higher than that of zinc, revealing that copper has a better corrosion resistance in stray current containing media. When zinc is used as a sacrificial anode material and coupled with Cu, the potential of Cu is shifted to the more cathodic part. Previous Cu which located at the exit zone of stray current steps to the cathodic zone and then it is protected.