What Does Metal Ion Concentration Cell Corrosion Mean?
Concentration cell corrosion occurs when two or more areas of the same metal surface are in contact with electrolytic solutions of different concentrations. One type of concentration cell corrosion is metal ion concentration cell corrosion, which typically occurs in underground pipes and tanks.
In metal ion concentration cells, the electromotive force (EMF) is the difference in the concentration of metal ions in the water in contact with the metal's surface. In the presence of water, a higher concentration of metal ions usually occurs under the surface of a buried pipe's joints. Relatively lower concentrations of metal ions exist near the surfaces of crevices in the metal structure. A small electric potential develops due to the difference in metal ion concentration. The area of the metal surface in contact with the lower concentration of metal ions will become a cathode and remain protected. The area of metal surface in contact with the higher concentration of metal ions will become anodic and eventually corrode.