Nowadays, the use of metal technology is quite popular, and many machines in the market have large metal parts. One of the surface treatment processes for metal is anodizing, which is very commonly used and can be used for both corrosion prevention and protective decoration purposes.
The anodizing treatment of aluminum and aluminum alloys is a process in which aluminum or aluminum alloy products are placed as the anode in an electrolyte solution to form an aluminum oxide film on the surface by electrolytic action. The thickness of the anodized film of aluminum and its alloys can reach tens to hundreds of microns, and it not only has good mechanical and corrosion resistance properties, wear resistance, and weather resistance, but also has strong adsorption properties. Aluminum products can be electrolytically colored after anodizing, and with the increasing coloring time, the color can go from light to dark. A variety of colors can be produced, and a beautiful decorative appearance can be achieved by using various coloring methods.
Porosity——the oxide film has a porous honeycomb structure, and the porosity of the film layer depends on the type of electrolyte and the anodizing process conditions. The porous structure of the oxide film allows the film layer to exhibit good adhesion ability to various organic substances, resins, waxes, inorganic substances, dyes, and paints, and can be used as the bottom layer of the coating. The oxide film can also be dyed in various colors to enhance the decorative effect of the metal.
Wear resistance——The aluminum oxide film has a high hardness and can improve the wear resistance of the metal surface. When the film layer absorbs lubricant, its wear resistance can be further improved.
Corrosion resistance——The aluminum oxide film is very stable in the atmosphere, and therefore has good corrosion resistance. Its corrosion resistance depends on the film layer thickness, composition, porosity, substrate material composition, and structural integrity. In order to improve the corrosion resistance of the film, the anodized film layer is usually sealed or painted.
Electrical insulation——Anodized films have high insulation resistance and breakdown voltage, and can be used as dielectric layers for electrolytic capacitors or insulation layers for electrical products.
Insulation——The aluminum oxide film is a good insulating layer, and its stability can reach1500℃, so for parts working under instantaneous high temperature, the oxide film can prevent the aluminum from melting due to its existence.
Bonding strength——The anodising film has strong bonding strength with the base metal, making it difficult to mechanically separate them. Even if the film layer bends with the substrate to the point of rupture, the film layer and the base metal still maintain a good bond.