Introduction
Aluminum and its alloys are widely used in engineering and commercial product fields, ranging from aviation components, automobile panels and other conventional product applications to energy-saving, environmentally friendly products. Aluminum and its alloys possess excellent mechanical, thermal and electrical properties. However, due to the relatively low surface hardness of aluminum and its alloys, their surfaces are often prone to wear or corrosion, even before they are sold or put into use.
Therefore, it is necessary to improve the surface hardness, corrosion resistance, wear resistance and other properties of aluminum and its alloys by surface treatment in practical applications. Chemical surface treatment of such metals is the most commonly used and effective method. Among the various chemical surface treatment technologies, aluminum chemical polishing technology has become the industry standard for its multiple advantages of wide applicability, easy operation, low cost, large production capacity and excellent treatment effect.
Description
Aluminum chemical polishing (ACP) technology is one of the most important surface cleaning and brightening processes carried out on aluminum and its alloys. Its main principle is electrochemical protection. It is closely related to the immersion solution composition of the aluminum materials. It mainly relies on the electrochemical protection effect between the treated aluminum materials and the immersion solution. It is mainly used for degreasing treatment on aluminum and its alloys before plating, as well as for degreasing treatment and oxide removal treatment on surfaces after aluminum anodic oxidation.
If the thickness of the aluminum oxide film on the aluminum surface is not much, only a brightening effect can be achieved by this technology. But if there is an excessive amount of aluminum oxide film on the aluminum material surface, it is possible to completely remove the oxide film through chemical polishing technology and obtain the best brightening effect.
ACP is widely used in many industries, such as aerospace, automotive, electronics and other industries. Aluminum alloy forgings, fixed parts, precision parts, gold and silver electronic components, etc., can be treated with aluminum chemical polishing.
Process
The aluminum chemical polishing process is mainly composed of two steps: degreasing-brightening.
1. The degreasing process mainly removes the dirt, oil and other impurities on the surface of the aluminum and its alloys, so as to expose the aluminum material to the chemical polishing solution for uniform immersion and reaction.
2. The brightening process is the focus of chemical polishing technology. It is mainly a physical and chemical oxidation-reduction reaction through the action of acid and electrolyte. This reaction will form metal ions and electrons in the metal-immersion liquid interface, which will have a brightening effect on the metal surface.
Take aluminum 6061-T5 as an example. The aluminum chemical polishing process includes the following steps:
1. Clean and wash the surface of the aluminum parts with trichloroethylene, acetone or other cleaning solvent, and then fully dry them.
2. Immerse the aluminum parts in the first tank of the polishing solution. Adopt constant voltage, low current and long time continuous electrolysis. In the electrolysis process, hydrogen bubbles are continuously generated on the surface of the aluminum parts, and the fine surface is polished by this process.
3. After immersing for a certain period of time, take them out and perform second tank electrolysis to obtain a better finish.
4. After the process is completed, take out the aluminum parts and immerse them into water for electrolysis and rinse. Finally, rinse them with acetone or other solvents and clean them with compressed air to obtain excellent chemical polishing effect.
Advantages
1. Wide range of applications. ACP technology is suitable for aluminum and its alloys, including aluminum profile, wrought aluminum, cast aluminum, die-cast aluminum, extrusion aluminum, etc.
2. Easy operation and low cost. ACP technology does not require special technology and facilities. The operation process is relatively simple and low in cost.
3. Large production capacity and good treatment effect. ACP technology can remove aluminum oxide film on aluminum surface in a relatively short time, and obtain uniform and irregular brightening effect and smooth surface.
4. Environmental protection and no special wastage. ACP technology does not need chemical waste, acid and alkali waste water, and it does not produce chemical and environmental pollution during the treatment process.
Conclusion
In summary, aluminum chemical polishing technology has a wide range of applications, low cost, large production capacity, good treatment effect and environmental protection features. It is a mature treatment technology in the aluminum chemical surface treatment process, especially its degreasing-brightening process and other advantages. Therefore, it is widely used in industries such as aerospace, automotive, electronics and other industries, and occupies an important position in aluminum chemical surface treatment technology.
