[China Aluminum Network] 1 aluminum alloy anodized parts of the surface, there should be a layer of uniform oxide film, due to aluminum alloy composition, oxidation treatment methods, closed processing methods, oxide film color is not the same. On the entire surface of the oxidized surface, except for the printing of the jig, there are no defects such as scratches, crushes, scratches, electric burns, localized corrosion, and oxide film cracks of the unoxidized portion or the damaged oxide film, or the use of fingers. Friction can remove the loose oxide film. 2 The colorless oxide film anodized by sulfuric acid must not contain: other noises, or defects in the surface due to poor surface preparation, blackening, dark lines, etc., or defects caused by poor sealing. Sulfuric acid anodic oxide film should be orange-yellow after being blocked by potassium dichromate, and it is not allowed to have white and light color due to poor sealing. The colored oxide film should be brightly colored and meet the dyeing template requirements. Not allowed: bright spots, dark spots, uneven colors. 3 Oxalic acid anodic oxidation film Due to the different types of current, the thickness of the film is different, and the surface is yellow-green to dark brown. 4 chromic acid anodized film generally from gray to gray black, does not allow: yellow spots, white spots, local film red, black state.