Aluminum phosphating(aluminum alloy die casting）
The effects of accelerator, fluoride, Mn2 +, Ni2 +, Zn2 +, PO4 and Fe2 + on the phosphating process of aluminum were studied in detail by means of SEM, XRD, potential time curve and film weight change. The results show 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 + and Ni2 + can obviously refine the grain, make the phosphating film uniform and compact, and improve the appearance of the phosphating film; When Zn2 + concentration is low, the film cannot be formed or the film formation is poor. With the increase of Zn2 + concentration, the film weight increases; PO4 content has a great influence on the weight of phosphating film, and PO4 can be increased. The content increases the weight of phosphating film.
Alkaline electrolytic polishing process of aluminum alloy die casting
The alkaline polishing solution system was studied, and the effects of corrosion inhibitor and viscosity agent on the polishing effect were compared. The alkaline solution system with good polishing effect was successfully obtained, and the additives that can reduce the operating temperature, prolong the service life of the solution and improve the polishing effect were obtained for the first time. The experimental results show that adding appropriate additives to NaOH solution can produce good polishing effect. The exploratory experiment also found that after DC constant voltage electrolytic polishing with NaOH solution of glucose under some conditions, the surface reflectivity of aluminum can reach 90%, but there are still unstable factors in the experiment, which need to be further studied. The feasibility of polishing aluminum under alkaline conditions by DC pulse electropolishing method is explored. The results show that the leveling effect of DC constant voltage electropolishing can be achieved by pulse electropolishing method, but its leveling speed is slow.