Question

What is done to prevent rusting of iron door of your house?

Hint:

Galvanization is particularly effective for outdoor objects like gates and fences, while oiling and painting work well for indoor objects where exposure to moisture is minimal.

Answer 1

Rusting of iron occurs due to the reaction of iron with oxygen and moisture from the atmosphere, forming hydrated ironoxide (rust). To prevent the rusting of an iron door, a protective barrier must be created to stop the iron from coming into contact with air and water. Common methods include:
Painting: Applying a layer of paint is the most common method for household doors. The paint acts as an impermeable barrier, preventing moisture and oxygen from reaching the iron surface.
Oiling or Greasing: Applying a layer of oil or grease can also provide a protective barrier against moisture. This is more common for moving parts rather than a whole door.
Galvanization (Coating with Zinc): For greater durability, especially for outdoor gates, the iron can be galvanized. This involves coating the iron with a thin layer of zinc. Zinc is more reactive than iron and corrodes preferentially (sacrificial protection), protecting the iron even if the coating is scratched.
Electroplating with Another Metal: Another method is to electroplate the iron surface with a less reactive, corrosion-resistant metal such as chromium or nickel. This adds a durable and often decorative protective layer.