RUST

1. HOW IS RUST FORMED

1.1. The iron reacts with water and oxygen to form hydrated iron (III) oxide.

1.2. Rust occurs according to this equation : 4Fe + 3O2 = 2FE2O3.

2. WHAT IS RUST

2.1. Rust is an iron oxide, usually red oxide formed by the redox reaction of iron and oxygen in the presence of water or air mosture

3. HOW TO PREVENT RUST

3.1. Galvanising is a method of rust prevention. The iron or steel object is coated in a thin layer of zinc. This stops oxygen and water reaching the metal underneath but the zinc also acts as a sacrificial metal. Zinc is more reactive than iron, so it oxidises in preferences to the iron object.

3.2. There are also other methods of preventing rust which work by stopping oxygen or water from reaching the surface of the metal such as:

3.2.1. Oiling - for example bicycle chains

3.2.2. painting - for example car body panels

3.2.3. Greasing - for example nuts and bolts