Why is anodization is the most favored in the surface treatment of aluminum ?

Aluminum is widely applied in more than 700,000 kinds of products from construction decoration to transportation and aerospace industries,etc.

What is anodizing ?  Anodizing refers to the process in which formed an oxide film on the aluminum products due to the action of an external current under the corresponding electrolyte and specific process conditions.

Why is anodization is the most favored in the surface treatment of aluminum ?  It can be used to prevent corrosion and achieve the dual purpose of protection and decoration, such as wear-resistant layer, electrical insulation layer, paint and electroplating bottom layer.

1.Since the film layer obtained by anodic oxidation has sufficient stability in the atmosphere, the oxide film on the aluminum surface can be used as a protective layer. The film obtained by anodic oxidation in sulfuric acid has a thick layer and strong adsorption capcity.

2. After chemical or electrochemical polish, anodized oxidation film with sulfuric acid solution can be obtained an oxide film with higher transparency. This kind of film can absorb many types of organic dyes and inorganic dyes.and has a variety of bright colors. The film is both an anti-corrosion layer and a decorative layer,even similar in appearance to porcelain.

3. A thick and hard Al2O3 fim can be obtained on the surface by hard anodizing,which has low roughness. The porous film can store lubricating oil, so it can be effectively applied to the work under friction, such as the engine cylinders and pistons of automobiles and tractors, which can extremely improve the wear resistance.

4.With a large resistance, the film has a certain effect on improving the electrical insulation. Anodization can be used to prepare the dielectric layer of the capacitor.

5.Due to the porosity and great adsorption capacity, the film can be used as the bottom layer of spray paint, which can be firmly combined with the products increasing its corrosion resistance.

5. Before electroplating aluminum, a base layer must be applied. There are many methods for applying the bottom layer, anodizing is also one of the important methods in addition to electro-galvanizing,dipping zinc and electroless nickel plating.