Electrolytic polishing of aluminum is a method of aluminum surface finish with great application value. Experiments have been conducted on industrial pure aluminum under alkaline conditions, and the mechanism of aluminum surface finish has been briefly analyzed. The main contents and conclusions are as follows:
The alkaline polishing solution system has been studied, and the effects of corrosion inhibitors and viscosity agents on the polishing effect have been compared. An alkaline solution system with good polishing effects is successfully obtained, and for the first time, it is possible to obtain the additives that can reduce the operating temperature, prolong the use of the solution, and improve the longevity of the 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 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 conduct aluminum surface finish under alkaline conditions can be explored. The results show that the pulse electrolytic polishing method can achieve the leveling effect of the DC constant voltage electrolytic polishing, but its leveling speed is slow.
It is determined to develop a new environmentally friendly chemical polishing technology with the phosphoric acid - sulfuric acid as the base fluid, which achieves zero emission of NOx and overcomes the quality defects of similar technologies in the past. The key to the new technology is to add some special compounds to the base fluid instead of 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 surface finish 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 better leveling and brightening effect.