What is the anodizing of aluminum
The so-called anodic oxidation of aluminum is an electrolytic oxidation process in which the surfaces of aluminum and aluminum alloys are usually converted into an oxide film which has protective, decorative and some other functional properties. The anodization of aluminum from this definition includes only the part of the process of forming an anodized film.
In order to overcome the defects of surface hardness and wear resistance of aluminum alloy, expand the application range and prolong the service life, surface treatment technology has become an indispensable part of the use of aluminum alloy, and anodizing technology is the most widely used and most successful. of.
Anodic oxidation: Electrochemical oxidation of a metal or alloy. Aluminum and its alloys under the corresponding electrolyte and specific process conditions, due to the application of current, the formation of an oxide film on the aluminum product (anode). Anodizing, if not specified, usually refers to the sulfuric acid anode Oxidation.
A metal or alloy article is used as an anode, and an oxide film is formed on the surface by electrolysis. Metal oxide films alter surface conditions and properties such as surface coloration, improved corrosion resistance, enhanced wear resistance and hardness, and protection of metal surfaces. For example, aluminum anodization, aluminum and its alloys are placed in the corresponding electrolyte (such as sulfuric acid, chromic acid, oxalic acid, etc.) as an anode, and electrolysis is carried out under specific conditions and an applied current. The aluminum of the anode or its alloy is oxidized, and a thin layer of aluminum oxide is formed on the surface. The indoor decorative film layer generally requires a thickness of 3 to 10 μm, the outdoor film layer requires 15 to 25 μm, and the hard anodized film can reach 40 to 200 μm. The anodized aluminum or its alloy improves its hardness and wear resistance up to 220-500 kg/mm 2 , good heat resistance, and the hardness of the hard anodized film is as high as 2300K, excellent insulation and resistance. The wearing voltage is up to 2000V, which enhances the corrosion resistance and does not corrode in the salt fog of ω=0.03NaCl for several thousand hours. The oxide film has a large number of micropores in the thin layer, which can adsorb various lubricants, and is suitable for manufacturing engine cylinders or other wear-resistant parts; the membrane microporous adsorption ability can be colored into various beautiful and beautiful colors. Non-ferrous metals or alloys thereof (such as aluminum, magnesium and their alloys) can be anodized. This method is widely used in mechanical parts, aircraft parts, precision instruments and radio equipment, daily necessities and architectural decoration.
Improve adhesion to organic coatings.
Improve adhesion to inorganic coatings
Other features in development
The anodized surface is an AL2O3 oxide layer suitable for flat veneers and slightly curved products.
The anodic oxidation surface is AL2O3 oxidized layer , which is applicable for the products of plane veneering and light bending