Why is a 'clad' coating sometimes applied to aluminum?

The application of a 'clad' coating to aluminum primarily serves the purpose of protecting the base metal from corrosion. Cladding involves bonding a layer of pure aluminum to an aluminum alloy, which helps to leverage the beneficial qualities of both materials. The pure aluminum layer forms an effective barrier against corrosion, enhancing the longevity and durability of the structure, particularly in environments where exposure to moisture and other corrosive elements is a concern.

Aluminum naturally forms a protective oxide layer, but cladding adds an extra measure of protection. This additional layer not only improves resistance to various environmental factors but also helps maintain the structural integrity of components made from aluminum alloys, which may be more susceptible to corrosion compared to pure aluminum.

While enhancing electrical conductivity, improving aesthetic appearance, or altering thermal expansion properties might be important considerations in other contexts, they are not the primary reasons for applying a clad coating to aluminum. The main focus is always on the corrosion resistance that clad aluminum provides, making it vital for applications in aviation and marine environments where durability is essential.