Fabrication and performance evaluation of nickel- rich conductive coating for carbon steel grounding grids in saline-alkali soil solution

A nickel-rich conductive anti-corrosive coating (CACC) was fabricated to improve the corrosion resistance of the carbon steel grounding materials. The coating was tested using surface contact resistance measurement, electrochemical impedance spectroscopy (EIS) and surface characterization. The results indicate that the increase of the nickel powder content in the coating induces its electrical conductivity enhancement; the surface contact resistance is as low as 0.05 Omega/cm(2) when the nickel powder content is 20%. The EIS data show that the anti-corrosive performance of the coating with 20% nickel powder content in three soil saline-alkali solutions (mild, moderate and severe) is higher than that with 40% nickel powder content, and the impedance of the coating decreases with the increase of the salt concentration. It is detected that 20% nickel powder content can achieve a good balance between low surface contact resistance and high corrosion resistance of the coating.