The metal or alloy parts are used as anodes to form oxide films on their surfaces by electrolysis. The metal oxide film changes the surface state and properties, such as surface coloring, improving corrosion resistance, enhancing wear resistance and hardness, and protecting the metal surface. 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 membrane has strong microporous adsorption capacity and can be colored into various beautiful colors. Nonferrous metals or their alloys (such as magnesium, aluminum and their alloys) can be anodized. This method is widely used in mechanical parts, aircraft and automobile parts, precision instruments and radio equipment, daily necessities and architectural decoration.
Anodic oxidation treatment:
1. Protection
2. Decorative
3. Insulation
4. Improve the adhesion with organic coating
5. Improve the adhesion with organic covering layer, etc
Difference between anodic oxidation and conductive oxidation:
1. Anodizing is carried out under the condition of high voltage, which is an electrochemical reaction process; Conductive oxidation (also called chemical oxidation) does not require electricity, but only needs to be immersed in liquid medicine. It is a pure chemical reaction.
2. Anodic oxidation takes a long time, usually tens of minutes, while conductive oxidation takes only tens of seconds.
3. The film formed by anodic oxidation is several microns to dozens of microns, and it is hard and wear-resistant, while the film formed by conductive oxidation is only 0.01-0.15 microns. The wear resistance is not very good, but it can conduct electricity and resist atmospheric corrosion, which is its advantage.
4. The oxide film is originally non-conductive, but because the film formed by conductive oxidation is very thin, it is conductive.