The anodizing of die-casting aluminum has caused great headaches for many suppliers. The aluminum alloy die-casting process, which has lower processing costs than CNC and can directly produce irregular parts, looks beautiful, but its flaw is that it cannot be anodized well to create a beautiful surface. So how do we remove the oxides on the surface of die-casting aluminum? Below, I will briefly introduce the removal method to everyone:

1. Aluminum phosphating

Through the selection of SEM, XRD, potential time curve, and membrane transformation methods, the promoter, fluoride, Mn2+, Ni2+, Zn2+, and PO4 were studied in detail; The influence of Fe2+and other factors on the phosphating process of aluminum materials. Research has shown that guanidine nitrate has the characteristics of good water solubility, low dosage, and rapid film formation, making it a useful promoter for aluminum phosphating. Fluoride can promote film formation, increase film weight, and refine grain size; Mn2+and Ni2+can clearly refine the grain size, making the phosphating film average and dense, and can also 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. As the concentration of Zn2+increases, the film weight increases; The PO4 content has a significant impact on the weight of the phosphating film, increasing the PO4 content. The content increases the weight of the phosphating film.

2. Alkaline electrolytic polishing process for aluminum

We conducted a study on the alkaline polishing solution system and compared the effects of corrosion inhibitors, viscosity agents, and other factors on the polishing efficiency. We successfully obtained an alkaline solution system with good polishing efficiency, and for the first time, we obtained additives that can reduce the operating temperature, extend the service life of the solution, and improve the polishing efficiency. The experimental results indicate that adding appropriate additives to NaOH solution can achieve good polishing effect. Exploratory experiments also found that under certain conditions, the surface reflectance of aluminum material can reach 90% after DC constant voltage electrolytic polishing with NaOH solution of glucose. However, due to unstable factors in the experiment, further research is needed. The feasibility of using DC pulse electrolytic polishing method to polish aluminum under alkaline conditions was explored. The results showed that using pulse electrolytic polishing method can achieve the leveling effect of DC constant voltage electrolytic polishing, but its leveling speed is relatively slow.

3. Environmentally friendly chemical polishing of aluminum and aluminum alloys

We will definitely develop a new environmentally friendly chemical polishing technology using phosphoric acid and sulfuric acid as the base fluid. This technology aims to achieve zero NOx emissions and overcome the quality shortcomings of previous similar technologies. The focus of the new technique is to add some compounds with unique effects to the base liquid to replace nitric acid. For this reason, it is necessary to first analyze the process of tri-acid chemical polishing of aluminum, and increasingly focus on the role of nitric acid. The key role of nitric acid in aluminum chemical polishing is to suppress point erosion and increase polishing brightness. The chemical polishing test integrated in pure phosphoric acid and sulfuric acid suggests that the unique substances added to phosphoric acid and sulfuric acid should be able to suppress point erosion, slow down overall erosion, and have good leveling and brightening effects

The above is the method for removing oxides from the surface of die-casting aluminum, and I hope it can be helpful to you.