Which statement about galvanisation is accurate?

Which statement about galvanisation is accurate?

• A. It coats steel with copper.
• B. It strengthens steel by alloying with iron.
• C. A zinc coating provides sacrificial protection to steel.
• D. Zinc is anodic to magnesium.

Answer: (C)

Galvanisation works by applying a zinc coating to steel to give sacrificial protection through electrochemical action. Zinc is more electrochemically active than iron, so in a corrosive environment the zinc coating preferentially corrodes (acts as the anode) while the steel remains protected beneath it. This protection holds even if the coating is damaged, because the surrounding zinc continues to act as a galvanic guard and, over time, zinc corrosion products can help seal small defects. That’s why the statement about a zinc coating providing sacrificial protection to steel is the accurate description. Coating steel with copper isn’t galvanising, since galvanising uses zinc, not copper. Galvanising doesn’t strengthen steel by alloying it with iron; it adds a zinc layer rather than forming an iron-zinc alloy. The claim that zinc is anodic to magnesium is incorrect because magnesium is more anodic (more likely to corrode) than zinc, so zinc would be cathodic in that pair, not anodic.

Galvanisation works by applying a zinc coating to steel to give sacrificial protection through electrochemical action. Zinc is more electrochemically active than iron, so in a corrosive environment the zinc coating preferentially corrodes (acts as the anode) while the steel remains protected beneath it. This protection holds even if the coating is damaged, because the surrounding zinc continues to act as a galvanic guard and, over time, zinc corrosion products can help seal small defects.

That’s why the statement about a zinc coating providing sacrificial protection to steel is the accurate description. Coating steel with copper isn’t galvanising, since galvanising uses zinc, not copper. Galvanising doesn’t strengthen steel by alloying it with iron; it adds a zinc layer rather than forming an iron-zinc alloy. The claim that zinc is anodic to magnesium is incorrect because magnesium is more anodic (more likely to corrode) than zinc, so zinc would be cathodic in that pair, not anodic.