Zhongshan Shanfeng CNC Welding Aluminum Products Co., Ltd.
Zhongshan Shanfeng CNC Welding Aluminum Products Co., Ltd
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Aluminum parts Anodizing process Application of anodizing aluminum alloy parts anodizing surface treatment technologies Auto parts anodizing
With the development of aluminum alloy material application, its surface treatment technology has also developed rapidly. The use of surface treatment technology can improve the properties of aluminum and aluminum alloys. The main surface treatment technologies include anodizing, chemical oxidation, coating and electroplating. Among them, the use of anodizing technology can improve the corrosion resistance of aluminum alloy parts and increase the adhesion of aluminum alloy parts, which is conducive to the wider application of aluminum alloy in the field of automotive accessories.
Automobile body aluminum alloy parts are usually anodized by direct current. The workpiece is connected to the positive electrode and the other electrode (which can be a metal that is not easy to react with acid, such as a lead plate) is connected to the negative electrode. The electrolyte in the electrolytic cell is usually mainly sulfuric acid.
Application of anodizing
After the aluminum alloy parts are anodized, the thickness of the oxide film on the surface increases by a geometric order of magnitude compared with the thickness of the oxide film spontaneously formed in the air. It has high hardness, greatly increased corrosion resistance, and also makes the aluminum surface less susceptible to damage.
When the anodizing process is applied to automotive parts, another function is to provide a good bonding surface for adhesives. Due to the great difference in mechanical and thermodynamic properties between steel and aluminum, aluminum alloy cannot be welded like traditional steel. Also, due to the different electrical potentials of steel and aluminum, aluminum as the anode of steel will be corroded quickly when mechanically connected; therefore, a glued structure should be used to connect materials with large performance differences. The aluminum alloy parts after anodizing process increase the bonding force during the bonding process.
In order to improve the corrosion resistance, electrical insulation and wear resistance of the anodized film, the aluminum alloy should be sealed after anodizing. After sealing, the surface becomes uniform and non-porous, forming a dense oxide film. The oxide film after sealing is no longer adsorbent, which can avoid pollution or early corrosion due to the adsorption of harmful substances, thereby improving the anti-pollution and anti-corrosion properties of the anodized film.
Non-ferrous metals or their alloys (such as aluminum, magnesium 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.