Which four factors must be present in the electrochemical cell to drive galvanic corrosion?

• A. Anode, Cathode, Electrolyte, Temperature
• B. Anode, Cathode, Metallic path, Electrolyte
• C. Anode, Cathode, Oxygen, Electrolyte
• D. Anode, Cathode, Inert gas, Electrolyte

Answer: (B)

Galvanic corrosion happens when two different metals form a galvanic couple in the presence of an electrolyte, with a complete electrical circuit allowing current to flow. The four essential elements are two metals that serve as an anode and a cathode, a metallic path that conducts electrons between them, and an electrolyte that enables ion movement to balance charges. The anode is the metal that oxidizes and corrodes, while the cathode remains protected as the site of reduction. The metallic path is crucial because, without a conductor linking the metals, electrons can’t move and the corrosion reaction can’t proceed. The electrolyte completes the circuit by allowing ions to move.

Temperature, oxygen, or inert gas aren’t required components of galvanic corrosion; they can influence the rate or environment but the process can occur without them.