Which of the following lists the three methods of non-ferrous metal protection?

• A. Aluminium cladding; Anodising; Alodising.
• B. Galvanising; Electroplating; Painting.
• C. Cathodic protection; Anodising; Rust-proofing.
• D. Shot peening; Nitriding; Cladding.

Answer: (A)

Non-ferrous metal protection relies on surface techniques that enhance corrosion resistance without relying on ferrous substrates. The trio of methods in question fits this approach because each creates a durable, protective surface on non-ferrous metals.

Aluminium cladding works by bonding a thin layer of aluminum to another metal, giving the underlying component the corrosion-resisting properties of aluminum while retaining its core material. This barrier reduces exposure to corrosive environments and helps prevent galvanic attack where different metals meet.

Anodising is an electrochemical process that thickens the natural oxide layer on aluminum (and some other non-ferrous alloys). The thicker oxide is harder, more wear-resistant, and far more resistant to corrosion than the native film, providing a robust protective layer without changing the metal’s base characteristics.

Alodising is a conversion coating applied to aluminum alloys (and some non-ferrous materials) that creates a protective oxide-chromate layer. This coating substantially improves corrosion resistance and also enhances paint adhesion, making subsequent coatings more durable.

The other options don’t fit as neatly. Galvanising protects ferrous metals by applying a zinc coating, not a non-ferrous-specific protection method. Painting and rust-proofing are general strategies that can apply to multiple metals but aren’t distinct non-ferrous surface treatments. Cathodic protection, while used in some contexts, is not a primary non-ferrous protection method like these three, and shot peening or nitriding are not primarily chosen for corrosion protection of non-ferrous metals.