Below is Pumay Aluminum Cindy's explanation for you.
Anodic oxidation
Aluminum or aluminum alloy products as anodes, placed in the electrolyte solution for electrification treatment, the use of electrolysis so that it's the surface formation of the alumina film process, known as aluminum and aluminum alloy anodizing process. After anodic oxidation treatment, the surface of aluminum can be formed into several micrometers —— several hundred micrometers of an oxide film. Compared with the natural oxide film of aluminum alloy, its corrosion resistance, wear-resistance, and decorative properties have been significantly improved and improved.
Oxide film
Anodizing forms a dense oxide film on the surface of the aluminum profile. Because alumina is non-conductive, the aluminum profile coated with alumina becomes an insulator
Some people also ask here, doesn't aluminum form an oxide film naturally? Yes, aluminum does form an oxide film, but the thickness of the natural oxide film is very thin, not even enough, not artificially uniform, so it doesn't act as an insulator, and so does chemically oxidized aluminum, which is 3 to 5 μ thick and can conduct electricity. If the material has conductive requirements, there are to be anti-corrosion, and chemical oxidation can be used.
