What is anodizing? The basics of anodizing

What is anodizing? The basics of anodizing

Ⅰ Introduction to anodizing

Anodizing is a surface treatment process that uses electrochemistry to form an Al2O3 (alumina) film on the surface of aluminum and aluminum alloys. Through anodizing, the surface state and performance of the material can be changed, thereby improving corrosion resistance, enhancing wear resistance and hardness, and protecting the metal surface.

Non-ferrous metals or their alloys (such as aluminum, magnesium and their alloys) can be anodized. The method is  widely used in mechanical parts, aircraft and automotive parts, precision instruments and radio equipment, daily necessities and architectural decoration.

Ⅱ Anodizing type

Ⅲ Anodizing process flow

1.preconditioning

Pretreatment mainly includes the cleaning of the workpiece surface and chemical treatment. Grease, oil and other impurities can cause surface defects or color differences in anodized products, so the surface must be thoroughly cleaned. If necessary, the surface can be chemically eroded to ensure that the workpiece surface does not contain defects.

2.anodizing

The selection of anodizing processes is mainly based on the chemical composition and microstructure of aluminum alloys. In addition, the workpiece's metallurgical processing history (such as cast state, forged state, heat treatment state and whether it contains welds, etc.) is also an important consideration. The process parameters of anodic oxidation include electrolyte temperature, current density, voltage and oxidation time.

3.tint

After the acidic electrolyte anodizing treatment, the surface layer of the workpiece will form a porous oxide layer. This porous structure can absorb other materials like a sponge and change the state of the workpiece surface. Because the oxide layer itself is colorless, the surface of the workpiece shows different colors after adsorbing dyes or dyes.

4.seal

Sealing is the final step in the anodizing process, and its role is to close the pores of the oxide layer from the outside to ensure that the workpiece surface is in a more stable state. After sealing, the anodized workpiece is improved in terms of corrosion resistance, wear resistance and color stability.

Ⅳ Advantages of anodizing

Improved corrosion resistance

The oxide film formed by anodic oxidation has high density and stability, which can effectively block the erosion of water and corrosive media on the matrix, and improve the corrosion resistance of aluminum and its alloys.

Improved wear resistance

The anodized film has higher hardness and good wear resistance, which can improve the wear resistance of aluminum and its alloys and extend its service life.

Improve decoration

By adjusting the composition and process parameters of the electrolyte, anodic oxidation films of different colors and textures can be prepared to improve the decorative performance of aluminum and its alloys.

Excellent insulation performance

under certain conditions, the anodic oxide film can have good insulation performance, which is used for the preparation of insulating materials and electronic devices.

Strong adsorption capacity

the anodic oxide film has a porous structure, which gives it a strong adsorption capacity. Various pigments, lubricants, resins and other substances can be filled in the pores of the oxide film to further improve the protection, decorative performance or other special functions of the metal material.

The process is simple and easy to operate

the anodizing process is relatively simple, the equipment requirements are not high, the operation is convenient and easy to master. And by adjusting the process parameters, such as electrolyte composition, current density, temperature, time, etc., to control the thickness, hardness, color and other properties of the oxide film to meet different application needs.

Relatively good environmental protection

compared with some traditional surface treatment processes, such as electroplating, anodizing process does not need to use toxic and harmful chemicals, such as cyanide, heavy metals, etc., and has less pollution to the environment.

Can maintain the accuracy of the workpiece

Anodizing is the process of forming an oxide film on the surface of the metal material, which will not have a significant impact on the internal structure and size of the metal material, so the accuracy of the workpiece can be well maintained.

Ⅴ Anodizing application

Aerospace: Used for surface treatment of aircraft structural parts, engine parts, etc., to improve corrosion resistance, wear resistance and corrosion resistance.

Automotive industry: Used for the surface treatment of automotive wheels, decorative strips, grilles and other parts to enhance their corrosion resistance and beauty.

Construction field: Used for the surface treatment of aluminum alloy doors and Windows, curtain walls, stair handrails and other building materials to improve their corrosion resistance and beauty.

Electronic products: Used in the production of mobile phones, tablets, TV and other electronic products shell, enhance its scratch resistance and durability.

Household items: aluminum alloy furniture frame, table and chair legs, kitchen and bathroom hardware accessories, such as faucets, handles surface treatment.

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