Dye can be absorbed in the pores of transparent aluminum anodic oxide film, and the aluminum anodic oxide film can be colored with dye. So what should we pay attention to in anodizing and coloring treatment?

Important factors in Changshu anode coloring treatment: (1) anodizing conditions (bath temperature, sulfuric acid concentration, aluminum ion concentration, anodizing conditions) because the dye is absorbed by the anodizing film, the anodizing conditions have a great impact on the dyeing.

If the porosity of anodic oxide film is reduced, the dyeability will be reduced (low bath temperature, low sulfuric acid concentration, high voltage, polar current density, high current density); If the anodizing conditions are changed, the dyeing results will also change.

(2) The thickness of anodic film in Changshu has an effect on the absorption of dyes. The film has almost no effect in the light color series, but it is difficult to obtain dark color. In particular, if black is to be obtained, the thickness of anodic oxide film must be more than 20um.

(3) The acidic solution in the water washing anodizing tank solution after Changshu anode is left on the membrane, and the membrane surface can not be dyed except for the parts with suitable dyeing conditions. In addition, if the water washing process is not thoroughly cleaned and aluminum ions are brought into the dyeing solution, the dyeing solution will age early. However, excessive water washing will make the anodic oxide film inactive and can not ensure sufficient dyeing effect. Using more than two water tanks with different acidity for a short time is much better than using one water tank for a long time.

The acid is brought into the dyeing bath solution from the anodizing bath, so the pH of the dyeing bath is easy to change. This should be constantly controlled. The dye concentration will change due to the absorption of the dyeing tank solution by the dyeing treatment object, the introduction of water from the previous process, the removal of the dyeing tank solution, and the evaporation of the tank solution water. Colorimeter shall be used for quantitative control and management.

Metal salt sealing is easy to fix the dye, and generally the dye will not dissolve from the metal salt hole. Nickel acetate and cobalt acetate are often used as metal salts. Some dyes are not suitable for sealing holes with metal salts, which must be confirmed in advance.