Which surface treatment is commonly used to improve corrosion resistance of aluminum components?

• A. Painting for steel.
• B. Galvanizing for steel.
• C. Anodising for aluminium.
• D. Mechanical plating.

Answer: (C)

Anodising increases the corrosion resistance of aluminum by transforming the surface into a thick, hard layer of aluminum oxide that's bonded to the metal. This protective oxide barrier slows or stops the ingress of corrosive ions, and when the porous layer is sealed, moisture and salts are less able to reach the aluminum beneath. Because the oxide is integral to the surface, the protection is durable and wear-resistant, and it can also be colored if desired. Other methods mentioned either rely on coatings that can chip or wear away, or are not standard for aluminum (like zinc-based coatings for steel or surface coatings applied by mechanical plating), so they don’t provide the same reliable, long-lasting protection in aluminum components.