The correct option is Galvanising.
Explanation
Corrosion prevention involves treating metal surfaces to inhibit oxidation and rust formation. Different metals require specific coating techniques based on their chemical reactivity and intended application.
- Galvanising Galvanising: This is the process of applying a protective zinc coating to iron or steel. Zinc serves as a physical barrier against moisture and oxygen. Furthermore, because zinc is more reactive than iron, it provides sacrificial protection (cathodic protection), meaning the zinc layer corrodes in preference to the iron, protecting the base metal even if the coating is scratched.
- Anodising Anodising: This process is used primarily for aluminium. It involves an electrolytic process to thicken the natural oxide layer on the metal surface, enhancing corrosion resistance and allowing for coloring.
- Chrome plating Chrome plating: This involves electroplating a thin layer of chromium onto a metal object. It provides a shiny, hard finish and corrosion resistance but does not utilize zinc.
- Tinning Tinning: This is the process of coating sheets of wrought iron or steel with tin. It is commonly used for food cans because tin is non-toxic and resistant to corrosion, though it does not offer the sacrificial protection that zinc does.
Key Takeaway: Galvanisation specifically refers to the protection of iron and steel using a layer of zinc, which offers both barrier and sacrificial protection.