Aluminium components and assembled structures resist corrosion when properly designed and manufactured with appropriate alloys.  This makes it a material of choice when it comes to transport application. Aluminium is a highly reactive metal and oxidizes readily and quickly in air, forming a thin, transparent, protective, layer of aluminium oxide. This very thin layer will hinder deeper intrusion of oxygen and other gases or liquids.  This layer clings strongly to the surface of aluminium: it does not flake off thereby exposing more fresh surfaces to further oxidation. And if the layer is damaged, it will “regenerate” itself, thus providing continuous protection. There are forms of corrosion that can occur on transport aluminium components if general guidelines are not followed.  For example, corrosion can occur whenever two dissimilar metals are in contact in the presence of an electrolyte, such as water.  A common corrosive incidence is caused by steel fasteners on an aluminium component.  The primary prevention method involves the use of barrier materials to isolate the steel from the aluminium, thereby eliminating contact. Another example of corrosion is shown in the picture, where a carpet had covered aluminium steps on a vehicle.  Moisture and salts had penetrated the carpet, which then effectively trapped the salt solution in contact with the aluminium.  In order to rectify this situation, the aluminium was replaced and a sealant was applied over the entire area between the carpet and step, forming a barrier to penetration of moisture and salts.  No further corrosion was observed.  In essence, components should be constructed in such a manner that entrapment areas for moisture, salts and dirt are avoided as much as possible.