Which material is commonly used as a sacrificial anode to protect iron components from corrosion?

Which material is commonly used as a sacrificial anode to protect iron components from corrosion?

• A. Brass
• B. Magnesium
• C. Tin
• D. Copper

Answer: (B)

A sacrificial anode works by using a metal that is more electrochemically active than the metal it protects. Magnesium fits this role for iron because it has a more negative electrochemical potential, so it preferentially corrodes in a galvanic couple with iron. As magnesium sacrifices itself, the iron remains protected from rust and pitting in the surrounding environment. This is why magnesium is widely used as a sacrificial anode for iron and steel in various water and surface applications. Copper, tin, and brass are much less reactive and tend to resist corrosion rather than sacrifice themselves first, so they don’t provide the same protective effect for iron.

A sacrificial anode works by using a metal that is more electrochemically active than the metal it protects. Magnesium fits this role for iron because it has a more negative electrochemical potential, so it preferentially corrodes in a galvanic couple with iron. As magnesium sacrifices itself, the iron remains protected from rust and pitting in the surrounding environment. This is why magnesium is widely used as a sacrificial anode for iron and steel in various water and surface applications. Copper, tin, and brass are much less reactive and tend to resist corrosion rather than sacrifice themselves first, so they don’t provide the same protective effect for iron.