Anodized aluminum refers to the coating of dense alumina on the surface of aluminum and aluminum alloys. In order to prevent further oxidation, its chemical properties are the same as alumina. However, unlike ordinary oxide films, anodized aluminum can be colored by electrolytic coloring.
Chemical treatment to remove copper from the surface of some alloys;
Cleaning and degreasing (for parts that have been anodized, if anodizing is needed again, the original anodized surface layer is removed with alkali or special chemicals);
Put it in dilute sulfuric acid as the anode and energize it to form a surface oxide layer (it is porous and is a white translucent film);
Fixation (heat or close the pores of the oxide layer on the surface with chromate solution).
Anodizing can significantly improve the corrosion resistance of aluminum alloys, increase the surface hardness and wear resistance of aluminum alloys, and have good decorative properties after proper coloring treatment. Aluminum and its alloy anodic oxide film coloring technology can be divided into three types: chemical dyeing, electrolytic coloring and electrolytic overall coloring. Chemical dyeing uses the porosity and chemical activity of the oxide film layer to adsorb various pigments to color the oxide film. According to the coloring mechanism and process, it can be divided into organic dye coloring, inorganic dye coloring, color paste printing, register dyeing and decoloring dyeing. Wait. Electrolytic coloring is the alternating electrolysis of anodized aluminum and its alloy in an aqueous solution containing a metal salt. A metal, metal oxide, or metal compound is deposited on the bottom of the porous layer of the oxide film. Presentation of various colors. Electrolytic overall coloring means that aluminum and its alloys are colored at the same time as anodic oxidation. Its characteristics are that oxidation and coloring are completed in one step. The colored film has good light resistance, heat resistance, corrosion resistance and wear resistance. The overall electrolytic coloring is divided into natural hair color, electrolytic hair color and power color method, of which electrolytic hair color is dominant, natural hair color is second, and power color is being developed.