When people talk about anodizing, they are actually talking about a very specific chemical process which is mainly used in the treatment of aluminum. The process of anodization is an electrochemical method to change a metal surface into a surface which is much more decorative and resistant to corrosion.
The metal which is the most conducive to anodizing is actually aluminum. This is because it is a nonferrous metal. There are other metals which can be put through an anodizing tank such as magnesium or titanium but aluminum is still the best. The oxide structure is made up completely of aluminum oxide. This structure is born in the substrate of the aluminum.
The way in which it is applied is not like paint or staining at all. In fact, it is fully sealed into the metal itself. The anodized surface is so porous in an orderly fashion that it is very suitable to be colored or sealed. The way anodization works are taking the metal and placing it into a bath of acidic electrolytes. Once the metal is fully submerged, an electrical current is passed through the liquid solution.
Inside the anodizing tank, a cathode is placed. The metal, which is usually aluminum, acts as an anode in the solution and so, therefore, the ions of the oxygen nature are combined with the atoms of the oxygenic nature and result in being anodized. As you can see, there are very many steps into properly transforming raw aluminum into anodized aluminum but the effort is well worth it.
The enhancement that the metal undergoes is far more strong than just the metal by itself. This means that it can be used for far more purposes than they would be able to without undergoing the treatment of the metal.