What is the anodizing process?

Aluminum anodizing process:

Mechanical polishing -- degreasing -- washing -- chemical polishing -- washing -- anodizing -- washing -- sealing -- mechanical brightness

Chemical polishing products: aluminum alkaline polishing liquid

Anodizing product: aluminum anodizing liquid

Sealing product: aluminum coloring sealing liquid

Anodizing and dyeing process of aluminum

Aluminum products treated by dyeing method have beautiful color, bright color, corrosion resistance, wear resistance and insulation than ordinary aluminum products. The aluminum workpiece is suspended in an appropriate electrolyte solution to act as an anode for electrolysis. In the process of electrolysis, hydroxide ions in water give electrons to the anode to become water and the new ecological oxygen, which oxidizes aluminum into a thicker alumina film, because this process is metal products as the anode is oxidized, so it is called anodizing. After anodizing, aluminum products are dyed, sealed and treated.

First dyeing process

1.     Pretreatment:

Aluminum parts are stained with more grease, a small amount of abrasive, dust and defective oxide film in the process of mechanical processing. These substances have poor 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, wash them with a brush, then air dry, then immerse in water, and clean them many times. Once the oil is gone, rinse immediately with hot water. If a black film is formed on the surface, soak it in 32% nitric acid solution for 20 seconds to remove the black film, and rinse it off with cold water. Immersed in distilled water for preparation of oxide film.

2. Anodizing:

Preparation of sulfuric acid electrolyte: It is composed of 18-20 kg sulfuric acid and 80-82 kg deionized water. At this time, the specific gravity of the solution is about 1.125-1.140. A small amount of oxalic acid is usually added to sulfuric acid electrolyte in order to obtain a good protective oxygen electrode oxide film.

Oxidation process: the line meter is installed, the dyed aluminum parts are used as the anode and all immersed in the electrolyte, and then the power supply is switched on, according to the following process conditions control.

The electrolyte temperature is controlled at 12-25℃, the anode current density is 1-2 A/decimeter 2, and the voltage in the tank is between 13-23 volts. The time is about 30-40 minutes.

According to the above process, at any time to remove the aluminum from the electrolyte, the acid stained with clean water, the concave part should pay more attention to, otherwise there will be white spots. After cleaning the acid solution, immerse it in clean water and set aside.

Matters needing attention

1. After washing oil treatment, aluminum parts should be oxidized immediately and should not be placed for too long. When aluminum parts are made of oxide film, they should all be immersed in the electrolyte, and the tank voltage is from

Head to tail should be smooth and consistent, the same batch of products, must be completely consistent, even when dyeing should be followed.

2, in the process of anodic oxidation, the electrolyte solution of aluminum, copper, iron, etc., is increasing, affecting the luster of aluminum. Electrolyte replacement should be considered when aluminum content is greater than 24g/l, copper content is greater than 0.02g/l, and iron content is greater than 2.5g/l.

3, the purchase of raw materials and dyes to choose products with high purity, because of the general impurities slightly more or mixed with tin powder, dextrin, dyeing effect is not good.

4, a large number of dyeing, dyeing solution after the initial strong light, the color will appear different shades, so should pay attention to timely mixing slightly strong dye solution, as far as possible to maintain the consistency of the concentration of dye solution.