Aluminum and its alloys are placed in an appropriate electrolyte as an anode for electrification, a process called anodizing. After the anodic oxidation of aluminum alloy anodizing equipment, the aluminum surface can generate an oxide film with a thickness of several to several hundred microns. The surface of this layer of oxide film is porous honeycomb, compared with the natural oxide film of aluminum alloy, its corrosion resistance, wear resistance and decoration have been significantly improved and improved. Anodic oxide films with different properties can be obtained by using different electrolytes and process conditions.
Aluminum anodizing process is widely used in the surface treatment of aluminum products. Applications in industry can be roughly divided into the following categories.
1) Prevent product corrosion: the film obtained by anodizing is properly closed and has good stability in the atmosphere. Moreover, the oxidation film obtained by anodic oxidation has good corrosion resistance. 2) Protection - decoration: On the oxide film with high transparency, the oxide film has the characteristics of adsorbed a variety of organic dyes or inorganic pigments, and a variety of bright colors and patterns can be obtained on the oxide film. This layer of color film is both a decorative layer and an anti-corrosion layer.
3) As a hard wear layer: the thick and hard film obtained by anodizing aluminum is used. The holes and absorption properties of the film layer are used to store the selected oil, which is effectively applied to the working conditions under the friction state, and has the characteristics of lubrication and wear resistance.
4) As an electrical insulation layer: the oxide film of aluminum and its alloy has the characteristics of large resistance, the thickness of the film is proportional to the resistance, which has certain practical significance as an electrical insulation, and can be used as a dielectric for capacitors, and aluminum oxide can also be used as a cable sheath.
5) The bottom layer for painting and electroplating: Because the oxide film has porosity and good adsorption capacity, it has good bonding force with paint film and organic film, and can be used as the bottom layer for painting. The anodized film with phosphoric acid can be used as the base layer for electroplating on aluminum.
6) For modern buildings: due to the introduction of aluminum alloy electrolytic coloring process, in recent years, the application of electrolytic coloring in building aluminum profiles has been increasing, it not only has the appropriate architectural tone of bronze, black, red, etc., its wear resistance and fast light is very good.
