Which statement best describes galvanic corrosion regarding anodic and cathodic metals?

• A. The anodic metal experiences decreased corrosion rate while the cathodic increases
• B. The anodic metal experiences increased corrosion rate while the cathodic is reduced
• C. Both metals experience equal corrosion
• D. Neither metal corrodes in galvanic setups

Answer: (B)

Galvanic corrosion happens when two dissimilar metals are connected in an electrolyte. The metal that is more anodic (more easily oxidized) becomes the anode and dissolves faster, while the more cathodic metal acts as the cathode and its corrosion rate is reduced because electrons flow from the anodic metal to the cathodic metal. This means the anodic metal experiences an increased corrosion rate, and the cathodic metal is protected to some extent, which is exactly what the statement describes. The other ideas conflict with the basic mechanism, which always drives dissolution of the anodic metal in the pair.