Aluminum alloy die-casting products are mainly used in electronics, automobiles, motors, home appliances and some communications industries. Some high-quality aluminum alloy die-casting products with high performance, high precision and high toughness are also used in industries with high requirements such as large aircraft and ships. middle. The main use is still in the parts of some equipment.

    Features of aluminum alloy die casting:

    1. Wide range of die casting

    2. Castings have high dimensional accuracy and low surface roughness

　　3, high productivity

　　4, high metal utilization

　　5, high casting strength and surface hardness

　　一、Aluminum phosphating

    The effects of accelerators, fluorides, Mn2+, Ni2+, Zn2+, PO4 and Fe2+ on the phosphating process of aluminum have been studied in detail by using methods such as SEM, XRD, potential-time curve, and film weight change. Fluoride can promote film formation, increase film weight, and refine crystal grains; Mn2+ and Ni2+ can significantly refine crystal grains, make the phosphating film uniform and dense, and improve the appearance of the phosphating film; when the concentration of Zn2+ is low, the film cannot be formed Or the film formation is poor. With the increase of Zn2+ concentration, the film weight increases; the content of PO4 has a greater impact on the weight of the phosphating film, increasing PO4. The content increases the weight of the phosphating film.

　　 2. Alkaline electrolytic polishing process for aluminum

Conducted research on alkaline polishing solution system, compared the effects of corrosion inhibitors, viscosity agents, etc. on the polishing effect, successfully obtained an alkaline solution system with good polishing effect, and obtained for the first time that it can reduce the operating temperature and prolong the use of the solution. It is an additive that can improve the longevity and polishing effect at the same time. The feasibility of using the DC pulse electrolytic polishing method to polish aluminum under alkaline conditions is explored. The results show that the pulse electrolytic polishing method can achieve the leveling effect of DC constant voltage electrolytic polishing, but its leveling speed is slow.

　　 Three, aluminum and aluminum alloy environmentally friendly chemical polishing

　　 Determined to develop a new environmentally friendly chemical polishing technology using phosphoric acid-sulfuric acid as the base fluid. 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 good leveling and brightening effect.

　　 4. Electrochemical surface strengthening treatment of aluminum and its alloys

　　The process, performance, 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. The film formation process and mechanism of the film have been preliminarily discussed. The neutral system has good adaptability to aluminum alloy die-casting, and can form a good film on various series of aluminum alloy die-casting products such as rust-proof aluminum and forged aluminum.