What are the benefits after aluminum oxidation processing?

Aluminum itself is a substance with relatively strong corrosion resistance, but after encountering oxygen, aluminum oxide will form on the surface of aluminum, so that after a long time, it will slowly release his corrosion resistance and resistance. In addition, aluminum is very sensitive to acidic substances. If it encounters acid, it will destroy the surface composition layer of aluminum, so we need to undergo oxidation treatment again.

Add a protective film on the surface to enhance the corrosion resistance of the surface layer. After the anodizing treatment of the aluminum pipe material or product, its corrosion resistance, hardness, wear resistance, insulation and heat resistance have been greatly improved . The metal material that is most anodized is aluminum. The anodization of aluminum tubes is generally carried out in an acidic electrolyte, with aluminum as the anode.

In the electrolysis process, oxygen anions react with aluminum to produce an oxide film. This kind of film is not fine enough when it is initially formed. Although it has a certain resistance, the negative oxygen ions in the electrolyte can still reach the aluminum surface to continue to form an oxide film. After the aluminum oxide is processed, as the film thickness increases, the resistance also becomes larger, so that the electrolytic current becomes smaller. At this time, the outer oxide film in contact with the electrolyte is chemically dissolved.

When the rate of oxide formation on the aluminum surface is gradually balanced with the rate of chemical dissolution, this oxide film can reach the maximum thickness under this electrolytic parameter. The outer layer of aluminum's anodized film is porous and easily absorbs dyes and colored substances, so it can be dyed and improve its decorativeness.

After the oxide film is sealed with hot water, high temperature steam or nickel salt, it can further improve its corrosion resistance and wear resistance. In addition to aluminum, industrially anodized metals include magnesium alloys, copper and copper alloys, zinc and zinc alloys, steel, cadmium, tantalum, zirconium, etc.

1. The higher the purity, the better the corrosion resistance. As we all know, pure aluminum reacts with oxygen in the air, and a thin and dense natural oxide film will be produced on the surface of aluminum, which is faster and faster than other metal oxide films. It is much thicker, which prevents the corrosion of harmful gases and moisture in the air and plays a protective role;

2. Although pure aluminum has good corrosion resistance, it has poor mechanical strength, which restricts the application of aluminum to a certain extent. Therefore, people add appropriate amounts of magnesium, copper, zinc and other metals to aluminum to make various types. The high mechanical strength of aluminum alloys and aluminum alloys greatly improves the mechanical strength of aluminum and greatly expands the scope of application. Although aluminum alloys have high mechanical strength, their corrosion resistance is worse than that of pure aluminum, so they may be corroded by oxidation. This requires powder coating to protect the aluminum alloy profiles. Aluminum alloys have been widely used in building doors, windows, curtain walls and other products for many years due to their small specific gravity, easy processing, and high mechanical strength.

After surface treatment, aluminum profiles have many advantages such as high corrosion resistance, diversified colors, good surface texture, etc., echoing with different architectural exterior paints to build colorful buildings.

Note: ①Formulation 1, 2 is suitable for chemical oxidation of pure aluminum, aluminum-magnesium alloy, aluminum-manganese alloy and aluminum-silicon alloy. The color of the film layer is golden yellow, the aluminum oxide is processed after oxidation, but the color of the oxide film obtained on the latter two alloys is darker. The film obtained in the alkaline oxidizing solution is soft, has poor corrosion resistance, high porosity, and good adsorption, and is suitable as a primer for coating.

②Sodium silicate is added to formula 3, the obtained oxide film is colorless, the hardness and corrosion resistance are slightly higher, the porosity and adsorption of aluminum oxidation processing are slightly lower, in the solution of sodium silicate with a mass fraction of 2% After sealing, it can be used as a protective layer alone, which is suitable for the oxidation of aluminum alloys containing heavy metals.

③In order to improve the corrosion resistance of the workpiece after oxidation treatment, it can be passivated in a 20g / L CrO3 solution at room temperature for 5-15s, and then dried at a temperature below 50 ℃.

Aluminum is a relatively active metal with a standard potential of -1.66v. It can naturally form an oxide film with a thickness of about 0.01 to 0.1 microns in air. This layer of oxide film is amorphous. The aluminum oxidation treatment is thin and porous. Poor corrosion. However, if aluminum and its alloys are placed in an appropriate electrolyte and the aluminum product is used as the anode, an oxide film is formed on the surface under the action of an applied current. This method is called anodization.