Aluminium is a versatile metal which is used in all sorts of applications. Principally, this is because it possesses a low density. Essentially, this quality means that it is lightweight considering the amount of material that will be used in a particular application.
In addition, aluminium has an extremely thin layer of oxides on its surface. This means that the problem of oxidisation, or rusting as it tends to be called, throughout the material is lessened. The surface-based oxides prevent water and airborne moisture from getting to the metal beneath the outer layer. In other words, this property makes aluminium resistant to corrosion.
How is this very light and virtually corrosion-free metal used in modern applications?
One of the things that the civil aviation industry requires of its materials is that they are light. Any extra weight that an aeroplane or helicopter has in its construction will translate into many thousands of litres of additional fuel consumption over the course of the lifespan of the vehicle. Therefore, the selection of lightweight materials like aluminium is essential for the industry. Since aluminium is also corrosion resistant, it is the ideal choice for aircraft parts, like fuselage, that will be exposed to the elements often at high altitude.
Another important area where aluminium is chosen as the metal of choice is when a marine environment will be faced. Aluminium fabrications of all kinds are constructed for quaysides and marinas. A typical installation might be an extruded aluminium handrail, for example, which might get splashed by seawater when the tide is high. Unlike other metals, aluminium can stand up to repeated exposure to seawater and spray. It is even used for offshore installations, too, such as within the parts that make up an oil rig.
High-quality circuits and components tend to be made from expensive metals like gold, but in outdoor situations, aluminium really comes into its own. The material is frequently chosen to make the type of electrical distribution lines that are found in overhead cables. This is because it can stand up to the rigours of rainwater whilst providing an efficient level of electrical conductance.
When it has not oxidised at all, aluminium offers an extremely reflective surface. Acting like a super efficient mirror, polished aluminium is sometimes set inside a vacuum where it won't dull over time. As such, it is used in the construction of things like astronomy telescopes as a material of choice.