Anodic oxide film is an electrochemical oxide film of a metal or alloy. Under the corresponding electrolyte and specific process conditions, a layer of oxide film is formed on the anode due to the action of external current. The anodic oxide film has a two-layer structure, with an inner layer of high-purity aluminum oxide, a dense and thin glassy film, with a thickness of approximately 0.01-0.05mm and high hardness; The outer layer is a hydrated aluminum oxide (Al2O3. H2O) film.

Anodic oxide films have properties such as wear resistance, corrosion resistance, insulation, insulation, and decoration, and are widely used in fields such as aviation, aerospace, automotive, electronics, and architecture.