Soil Corrosion of Grounding Grid Materials Studied by Same Material Three-electrodes

Corrosion behavior of Q235 steel, red copper and hot dip galvanized (HDG) steel in soil was studied by EIS, using a new kind of same material three-electrode. Morphology of corrosion product was observed by metallographic microscope, and corrosion resistance of red copper and HDG steel was compared. The results showed that Q235 steel was corroded heavily with loose corrosion product layer formed, the steel suffered pitting at later stage due to the concentration of corrosive ions in the product layer. Dust-color compact passive film was formed on the red copper surface, film resistance increased with corrosion time and was stable after a max value at the 9th day. Yellow loose covering layer formed on the urface of red copper. Coating resistance of HDG ateel increased first and decreased later with a max value at the 5th day, self-repairing function was found in the coating. Corrosion resistance of red copper is stranger than that of HDG steel.