Views:1 Author:Jia Hua Aluminium Co., Ltd Publish Time: 2019-09-30 Origin:Site
Anodizing is one of the important processing in the production of aluminum profiles. It will let the aluminum profiles stay in a suitable electrolyte solution. And then take the aluminum product as the anode for electrolysis. It will make the surface of aluminum products get a anodized film with 10 μm thickness. With this film, the profiles can have strong corrosion resistance and wear resistance to make it have longer life time.
Sometime it will have some trouble during Anodizing production.
Before the anodizing, the aluminum profiles need to be sent to do the pretreatment, which is use the water wash the surface to clear the dust and oil. Or use the mechanical processing to get the mirror surface or matt surface. But it can not have the artificial oxide layer and uniform color if the pre-treatment is not completed done.
Sometime the profiles after anodizing it will comes out the black spot, holes. The reason is below
1. It relate to the aluminum alloy of the aluminum profiles.Aluminum-magnesium alloy or pure aluminum is easy to form a good quality oxide film, aluminum-silicon alloy or aluminum-copper alloy. The formation of oxide film is slightly more difficult, and the color of the produced oxide film is dark and dark, which affects the appearance.Just like 6063. It suitable for doing the powder coating, Anodizing, wooden grain. If you want to know more about 6063 alloy, please read our article:
2. The uniformity of the structure and phase is related: if the metal phase produced on the surface is uneven or the structure is not uniform, the resulting oxide film will be uneven. If the silicon content in the aluminum alloy is uneven, local non-oxidation will occur, and even pores will appear.
3. Metal ions in the electrolyte: If the content of impurity ions such as iron and copper in the electrolyte is too high, dark spots will appear.
4. Suspension impurities in the electrolyte: If the dust and impurities in the electrolyte are too much suspended, it will cause streaks in the oxide film, reduce the corrosion resistance of the aluminum profile, and affect the use effect.
Since the aluminum oxide film is insulated, in order to ensure its electrical conductivity, the conductive bar of copper or copper alloy is used to hang the aluminum profile on the fixture, and the contact area between the clamp and the profile is controlled, and the contact area is too large. The contact between the fixture and the profile is large, and the residual oxide film is likely to form an uneven oxide film; the contact area is too small, the current density is increased, and the oxygen fixture and the oxide film are easily burned, resulting in poor texture. The oxide film affects the anodizing effect of the aluminum profile.
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