Because of its high strength and weight ratio, easily molding as well as excellent physical and chemical properties, aluminum and its alloys become the second largest category of metal in industry currently compared with the first iron and steel. However, low-alloy hardness, poor wear resistance, abrasion damage often occurs, therefore, the surface of aluminum alloy is often required to be treated before used to meet its environmental adaptability and security and reduce abrasion, extending its life. In industry the method of anodizing aluminum surface to formulate thick dense oxide film is more and more widely adopted, to significantly change the corrosion resistance of aluminum alloys and improve hardness, wear resistance and decorative properties.

　　Anodizing is the country's modern basic and most common method of aluminum surface treatment. Oxidation can be divided into ordinary anodizing and hard anodizing. The color film obtained by electrolytic coloring of aluminum and its alloy has good abrasion resistance, light fastness, heat and corrosion resistance, widely used in modern building decoration corrosion. However, with high porosity and adsorption capacity, vulnerable to pollution and erosion corrosion medium, anodized aluminum  needs sealing treatment to improve corrosion resistance, contamination resistance and fixed chloroplasts.