Aluminum workpiece → hanger → degreasing → water washing → alkali corrosion → water washing → luminescence → water washing → anodic oxidation → water washing → deionized water → dyeing or electrolytic coloring → water washing → deionized water → sealing → water washing → hanger.
2. Technological process of high-brightness aluminum products;
Aluminum workpiece → mechanical polishing → degreasing → water washing → neutralization → water washing → chemical or electrochemical polishing → water washing → anodic oxidation → water washing → deionized water washing → dyeing or electrolytic coloring → deionized water washing → sealing → water washing → mechanical brightness.
Extended data:
Anodic oxidation and electrochemical oxidation of metals or alloys. The process that aluminum and its alloys form oxide films on aluminum products (anodes) under the corresponding electrolyte and specific technological conditions due to the action of external current. Unless otherwise specified, anodizing usually refers to sulfuric acid anodizing.
In order to overcome the defects of surface hardness and wear resistance of aluminum alloy, expand the application scope and prolong the service life, surface treatment technology has become an indispensable part of aluminum alloy, and anodic oxidation technology is the most widely used and successful at present.
Anodic oxidation of aluminum is the process of electrolytic oxidation. In this process, the surface of aluminum and aluminum alloy is usually transformed into an oxide film, which has protective, decorative and other functional characteristics. According to this definition, anodic oxidation of aluminum only includes the process of forming anodic oxide film.
Using metal or alloy as anode, an oxide film is formed on its surface by electrolysis. Metal oxide film changes the surface state and properties, such as surface coloring, improving corrosion resistance, enhancing wear resistance and hardness, and protecting metal surface. Such as anodic oxidation of aluminum, aluminum and its alloys are put into corresponding electrolyte (such as sulfuric acid, chromic acid, oxalic acid, etc.). ) as an anode, electrolysis is carried out under specific conditions and applied current.
Anode aluminum or its alloy is oxidized, and a thin layer of alumina is formed on the surface, with a thickness of 5 ~ 30 microns, and the hard anodic oxidation film can reach 25 ~ 150 microns. After anodic oxidation, the hardness and wear resistance of aluminum or its alloy are improved, reaching 250 ~ 500 kg/mm2, with good heat resistance. The melting point of hard anodic oxide film is as high as 2320K, the insulation is excellent, the breakdown voltage is as high as 2000V, and the corrosion resistance is enhanced. It will not corrode for thousands of hours in ω=0.03NaCl salt spray.
There are a lot of micropores in the thin oxide film, which can absorb various lubricants and is suitable for manufacturing engine cylinders or other wear-resistant parts. The microporous membrane has strong adsorption capacity and can be dyed into various beautiful and gorgeous colors. Non-ferrous metals or their alloys (such as aluminum, magnesium and their alloys) can be anodized and widely used in mechanical parts, aircraft and automobile parts, precision instruments and radio equipment, daily necessities and architectural decoration. ?
Generally, aluminum or aluminum alloy is used as anode and lead plate is used as cathode. Aluminum and lead plate are put together in an aqueous solution, which contains sulfuric acid, oxalic acid, chromic acid, etc. Electrolysis, forming oxide film on the surface of aluminum and lead plate. Among these acids, sulfuric acid anodizing is the most widely used.
References:
Baidu encyclopedia-anodic oxidation