After anodic oxidation of aluminum products, the finished product is oxidized after assembly

Aluminum anodizing process: mechanical polishing -- oil removal -- water washing -- chemical polishing -- water washing -- anodizing -- water washing -- sealing -- mechanical bright chemical polishing product: Aluminum alkaline polishing solution anodizing product: aluminum anodizing solution sealing product: Anodic oxidation and dyeing of aluminum products after dyeing method, beautiful color, bright color, corrosion resistance, wear resistance and insulation higher than ordinary aluminum products. The aluminum workpiece is suspended in an appropriate electrolyte solution as an anode for electrolysis. In the process of electrolysis, the hydroxide ions in the water in the anode release electrons into water and new ecological oxygen, it makes aluminum oxide into a thicker alumina film, because this process is metal products as the anode is oxidized, so called anodic oxidation. After anodic oxidation, aluminum products are dyed, sealed and treated. 1. Pretreatment: Aluminum parts are stained with more grease, a small amount of abrasive, dust and defective oxide film in many mechanical processing processes. These materials have poor electrical conductivity and can not be anodized, so they need to be treated in advance. The method is to use carbon tetrachloride, trichloroethylene, gasoline or toluene as cleaning agent, immerse the aluminum parts, brush with a hair brush to wash, and then air dry, and then immersed in water, cleaning for many times. Flush with hot water as soon as the oil runs out. If a black film develops on the surface, soak in 32% nitric acid solution for 20 seconds to remove the black film, and rinse with cold water. Immerse in distilled water for preparation of oxide film. 2. Anodic oxidation: (1) Preparation of sulfuric acid electrolyte: by sulfuric acid 18-20 kg and deionized water 80-82 kg mixed, at this time the specific gravity of the solution is about 1.125-1.140. Sometimes a small amount of oxalic acid is added to the sulfuric acid electrolyte in order to obtain a protective oxide film. The oxidation process: the line instrument is installed, will be dyed aluminum anode and all immersed in the electrolyte, and then switch on the power supply, according to the following process conditions control. The electrolyte temperature is controlled at 12-25℃, the anode current density is 1-2 ampere/decimeter 2, and the voltage in the tank is between 13-23 VOLTS. It takes about 30-40 minutes. According to the above process operation is completed, the aluminum parts are removed from the electrolyte at any time, and the acid stained with water is washed clean. The concave part should be paid more attention to, otherwise there will be white spots. After cleaning the acid, immerse it in clean water for later use. 3. Dyeing: aluminum after anodic oxidation, the surface of the formation of adsorption, covalent bond or hydrogen bond bonding and other types of colored complexes, color. ⑴ Dye selection: dyes are divided into inorganic dyes and organic dyes. Inorganic dyes are mostly composed of inorganic salts. During dyeing, aluminum parts are soaked in a and B compound solutions to generate colored compounds to achieve the purpose of dyeing. Inorganic dyeing solution Dye Color Solution A Solution B Dyeing Compound Name Concentration Name Concentration Blue or light blue Potassium ferrocyanide 10-50 ferric chloride 10-100 Prussian blue brown potassium ferrocyanide 10-50 copper sulfate 10-100 copper ferrocyanide black cobalt acetate 50-100 potassium permanganate 15-25 Cobalt oxide yellow potassium dichromate 50-100 lead acetate 100-200 Lead dichromate golden yellow soda 10-50 Lead permanganate 10-50 manganese trioxide white lead acetate 10-50 sodium sulfate 10-50 lead sulfate orange yellow aluminum lead sulfate 5-10 Silver nitrate 50-100 There are many kinds of silver chromate organic dyes. The commonly used dyes, dye concentration and color list are introduced as follows for reference. Dye Color Dye Name Dye Concentration Remarks Yellow acidic medium RH direct yellow brown D3G alcohol-soluble yellow GR Direct frozen yellow G 0.7-11-50.5-11-2 All acidic dyes should be added glacial acetic acid 1-2 ml adjust pH use alcohol as solvent yellow alizarin yellow indiditin orange acid orange H 1-211-2 The dye should be dyed with 10 grams of sodium nitrite, a liter of warm water to prepare the dyeing solution, the dyeing time is 30 minutes, and then in sulfuric acid 25 ml of warm water in a liter of color for one minute. Red direct fast peach G Acid bright red GR Alizarin red S 2-55-105-10 Red Basic Rose essence acid orange ⅱ 0.753 The two dyes were dissolved separately and combined into A liter of grass green direct fast emerald green direct green B 3-52-5 blue direct fast emerald blue GL active brilliant blue acid lake blue V Acid lake blue A Dyeing operation: (1) Dyeing monochrome method: the anodized aluminum products with clean water are immediately immersed in coloring solution of 40-60℃. Soaking time: light 30 seconds to 3 minutes; Dark, black 3-10 minutes. Remove after dyeing and rinse with clean water. (2) Dyeing multi-color method: if two or more different colors are dyed on the same aluminum parts, or when the landscape, flowers and birds, characters and characters are printed, the procedures are very complicated, including coating masking method, direct printing and dyeing method, foam plastic dyeing method, etc.. The above methods operate differently, but the principle is the same. Present coating masking method is introduced as follows: this method basically is the varnish that dries quickly and cleans easily is thin and even ground besmear brushings go up in the yellow that needs truly, it masking rises. After the paint film is dry, all the aluminum parts are immersed in the dilute chromic acid solution to recede the yellow part of the unpainted varnish. Take it out, remove the acid with clean water, dry it at low temperature, and then dye it red. If you want to dye the third and fourth colors, you can operate according to the above method. 4. Seal: After washing the stained aluminum parts with water, cook them in distilled water at 90-100℃ for 30 minutes immediately. After this treatment, the surface becomes uniform and porous, forming a dense oxide film. The dye coated with dye is precipitated in the oxide film, can not be wiped off, the oxide film is closed no longer has adsorption, and wear resistance, temperature resistance, insulation has been strengthened. The surface of the aluminum parts will be dried after closed treatment, and then polished with a soft cloth, you can get beautiful and bright aluminum products, such as dyed multicolor, after closed treatment, the protective agent coated on the aluminum parts should be removed, small area with cotton with acetone wipe, large area can be dyed aluminum parts immersed in acetone to wash the paint. 1. Aluminum parts should be oxidized immediately after oil washing, and should not be placed for too long. Aluminum oxide film production, to all immersed in the electrolyte, the tank voltage from beginning to end to be stable and consistent, the same batch of products, must be completely consistent, this point should be followed even when dyeing. 2. In the process of anodic oxidation, aluminum, copper, iron and other solutions in the electrolyte are increasing, affecting the luster of aluminum, etc. Electrolyte replacement should be considered when aluminum content is greater than 24 g/l, copper content is greater than 0.02 g/l, and iron content is greater than 2.5 g/l. 3. Buy raw materials and dyes to choose products with high purity, because the general impurities are slightly more or mixed with sodium sulfate, dextrin, dyeing effect is not good. 4. When dyeing in large quantities, the color will be weak after initial concentration, and the color will appear in different shades. Therefore, attention should be paid to mixing slightly stronger dye at the right time to keep the consistency of the concentration of the dye as far as possible. 5. When dyeing multi-color, it should be dyed light color first and then dark color, and dyed in order of yellow, red, blue, brown and black. Before dyeing the second color, the spray paint should be dry, so that the paint is close to the aluminum surface, otherwise the dye will be immersed, the burr boundary is unknown. 6. Impurities in aluminum affect dyeing: silicon content is more than 2.5%, the bottom film is gray, it is advisable to dye dark. Contains more than 2% magnesium and has a dull staining zone. Contains manganese tone tender, but not bright. Copper tone with blunt, iron, nickel, chromium too much color dull

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