Preventing rusting
There are several ways to prevent iron and steel rusting. Some work because they stop oxygen or water reaching the surface of the metal:
- oiling 鈥 for example, bicycle chains
- greasing 鈥 for example, nut and bolts
- painting 鈥 for example, car body panels
- coating with a thin layer of plastic
Iron and steel objects may also be covered with a layer of metal. Food cans are plated with a thin layer of tin.
Galvanising
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 鈥 but the zinc also acts as a A more reactive metal than iron, attached to an iron or steel object to prevent the object rusting. . Zinc is more reactive than iron, so it oxidises rather than the iron object.
Sacrificial protection
A reactivity series lists metals in order of how reactive they are.
Magnesium and zinc are often used as A more reactive metal than iron, attached to an iron or steel object to prevent the object rusting. . They are more reactive than iron and lose their electrons in preference to iron. This prevents iron from losing its electrons and becoming oxidised.