Surface Treatment Method and Technology of Aluminum Die Casting

Update:May 09 2017

The effects of accelerators of aluminum die casting, fl […]

The effects of accelerators of aluminum die casting, fluorides, Mn2 +, Ni2 +, Zn2 +, PO4 and Fe2 + on the phosphating process of aluminum were studied by means of SEM, XRD, potential-time curve and membrane 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 phosphating of aluminum: fluoride can promote film formation, increase film weight and refine grain; Mn2 +, Ni2 + can obviously The Zn2 + concentration is low, the film can not be formed or the film is poor. With the increase of Zn2 + concentration, the membrane weight increases; the PO4 content is different from that of the phosphate film Heavy impact greater, improve PO4. The content of phosphating film is increased.

The effect of corrosion inhibitor and viscosity on the polishing effect was compared. The alkaline solution system with good polishing effect was successfully obtained, and the operation temperature was reduced for the first time, and the solution was prolonged. Life, while also improving the polishing effect of the additive. The experimental results show that the addition of the appropriate additives in NaOH solution can produce good polishing effect. The exploratory experiment also found that the surface reflectivity of the aluminum surface can reach 90% after DC constant voltage electrolysis with NaOH solution under certain conditions, but there are still some unstable factors due to the experiment, which needs further study. The feasibility of using DC pulsed electrolytic polishing method to polish aluminum under basic conditions is explored. The results show that the pulsed electrolytic polishing method can achieve the leveling effect of DC constant voltage electrolytic polishing, but its leveling speed is slow.

It is determined that a new technology of environmentally friendly chemical polishing with phosphoric acid monosulfic acid is developed. This technology should achieve zero emission of NOx and overcome the quality defects of similar technologies in the past. The key to new technology is to add some special compounds in the base fluid to replace nitric acid. To this end, the first need for aluminum triac acid chemical polishing process analysis, in particular, to focus on the role of nitric acid. Nitric acid in the aluminum chemical polishing in the main role is to inhibit the point of corrosion, improve the polishing brightness. The addition of special substances in phosphoric acid monosulfuric acid should be able to inhibit point corrosion and slow down the overall corrosion, and must have good leveling and brightening effect.