In galvanic protection, which metal is anodic to steel?

• A. Zinc is anodic to steel.
• B. Steel is anodic to zinc.
• C. Zinc acts as the coating but not sacrificially.
• D. Zinc corrodes slower than steel.

Answer: (A)

In galvanic protection, the metal that is more electrochemically active becomes the anode and corrodes first, while the more noble metal is protected as the cathode. Zinc is more active than steel, so when they are in electrical contact in an electrolyte, zinc will oxidize and corrode, sacrificing itself to protect the steel beneath. That’s why zinc coatings are used on steel—they provide sacrificial protection, preventing steel from corroding. The idea that zinc is only a coating without sacrificing is incorrect, and the claim that zinc corrodes slower than steel is opposite of how sacrificial protection works.