Surface treatment of aluminum die casting

Suface treatment is very important for Aluminum die casting parts.We hereby wish to introduce the common finish treatment for the casting parts.

1. Alkaline electrolytic polishing of aluminum

The effects of accelerators, fluorides, Mn2+, Ni2+, Zn2+, PO4; and Fe2+ on the phosphating process of aluminum were studied in detail by using SEM, XRD, potential-time curve, film weight change and other methods. Studies have shown that guanidine nitrate has the characteristics of good water solubility, low dosage, and rapid film formation. It is an effective accelerator for aluminum phosphating: fluoride can promote film formation, increase film weight, and refine grain; Mn2+, Ni2+, can Obviously refine the grains, make the phosphating film uniform and compact, and improve the appearance of the phosphating film; when the Zn2+ concentration is low, the film cannot be formed or the film formation is poor. As the Zn2+ concentration increases, the film weight increases; the PO4 content affects the phosphating film The film weight has a greater impact and increases PO4. The content increases the weight of the phosphating film.

2. Aluminum phosphating

The effects of accelerators, fluorides, Mn2+, Ni2+, Zn2+, PO4; and Fe2+ on the phosphating process of aluminum were studied in detail by using methods such as SEM, XRD, potential-time curve, and film weight change. Research shows that guanidine nitrate has the characteristics of good water solubility, low dosage, and rapid film formation. It is an effective accelerator for aluminum phosphating: fluoride can promote film formation, increase film weight, and refine grain; Mn2+, Ni2+ can be obvious Refine the grains to make the phosphating film uniform and compact and improve the appearance of the phosphating film; when the Zn2+ concentration is low, the film cannot be formed or the film formation is poor. As the Zn2+ concentration increases, the film weight increases; the content of PO4 affects the phosphating film The heavy impact is greater, and the PO4 is increased. The content increases the weight of the phosphating film.

3. Environmentally-friendly chemical polishing of aluminum and aluminum alloys

It is determined to develop a new environmentally friendly chemical polishing technology based on phosphoric acid monosulfuric acid. This technology must achieve zero emission of NOx and overcome the quality defects of similar technologies in the past. The key to the new technology is to add some compounds with special effects to the base fluid to replace nitric acid. For this reason, it is first necessary to analyze the three acid chemical polishing process of aluminum, especially the role of nitric acid. The main function of nitric acid in aluminum chemical polishing is to inhibit pitting corrosion and improve polishing brightness. Combined with the chemical polishing test in simple phosphoric acid-sulphuric acid, it is believed that the special substances added to phosphoric acid-sulphuric acid should be able to inhibit pitting corrosion and slow down overall corrosion, and must have a better leveling and brightening effect.

4. Electrochemical surface strengthening treatment of aluminum and its alloys

The process, properties, morphology, composition and structure of the ceramic-like amorphous composite conversion coating formed by anodic oxidation and deposition of aluminum and its alloys in a neutral system were preliminarily discussed. Process research results show that in the Na_2WO_4 neutral mixing system, the concentration of film-forming accelerator is controlled to be 2.5-3.0g/l, the concentration of complexing film agent is 1.5-3.0g/l, and the concentration of Na_2WO_4 is 0.5-0.8g/l , The peak current density is 6-12A/dm~2, and weak agitation can obtain a complete, uniform, and good-gloss gray series inorganic non-metallic film. The film has a thickness of 5-10μm, a microhardness of 300-540HV, and excellent corrosion resistance. The neutral system has good adaptability to aluminum alloys, and can form a good film on various series of aluminum alloys such as rust-proof aluminum and forged aluminum.

5. YL112 aluminum alloy surface treatment technology

YL112 aluminum alloy is widely used in casting structural parts of automobiles and motorcycles. The material needs to be surface treated before application to improve its corrosion resistance and form a surface layer that is easy to combine with the organic coating to facilitate the subsequent surface.