In actual production, many aluminum alloy casting companies will encounter the confusion of the ugly or rough surface of the castings. Today, I have sorted out the dry goods skills of the surface treatment of aluminum alloy die castings. Learn the following four tricks. The surface treatment of the castings is easy and simple!
1. Phosphating Aluminum
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 grains; 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.
2. Alkaline Electrolytic Polishing Process Of Aluminum
Conducted research on alkaline polishing solution system, compared the effects of corrosion inhibitors, viscosity agents, etc. on the polishing effect, and successfully obtained an alkaline solution system with good polishing effects, and for the first time obtained the ability to reduce the operating temperature and prolong the use of the solution. Additives that improve the longevity and polishing effect at the same time. The experimental results show that adding appropriate additives to the NaOH solution can produce a good polishing effect. Exploratory experiments also found that after DC constant voltage electrolytic polishing with glucose NaOH micro manufacturing solution under certain conditions, the reflectivity of the aluminum surface can reach 90%, but due to the unstable factors in the experiment, further research is needed. The feasibility of using 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.
3. Environmentally-Friendly Chemical Polishing Of Aluminum And Alloys
It is determined to develop a new environmentally-friendly chemical polishing technology based on 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 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-sulfuric acid, it is believed that the special substances added in phosphoric acid-sulfuric acid should be able to inhibit pitting corrosion and slow down general 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, and the film formation process and mechanism of the coating were 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/, the concentration of complexing film agent is 1.5~3.0g/, and the concentration of Na 2WO_ 4 is 0.5~0.8g /l, peak current density is 6~12A/dm~2, weak agitation, a complete and uniform gray series inorganic non-metallic film with good gloss can be obtained. 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.
