1, aluminum phosphating

The accelerant, fluoride, Mn2+, Ni2+, Zn2+ and PO4 were studied in detail by means of SEM, XRD, potential-time curve and film weight change. And Fe2+ on the phosphating process of aluminum. The results show that guanidine nitrate has the characteristics of good water solubility, low dosage and fast film formation, and 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 the concentration of Zn2+ is low, no film or film difference can be formed. With the increase of Zn2+ concentration, the weight of the film increased. The content of PO4 has a great influence on the weight of phosphating film, which increases PO4. This content increases the weight of phosphating film.

2. Alkaline electrolytic polishing process of aluminum

The alkaline polishing solution system was studied, and the effects of corrosion inhibitor and tackifier on polishing effect were compared. The alkaline solution system with good polishing effect was successfully obtained, and the additives which 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 the surface reflectivity of aluminum can reach 90% after electrolytic polishing with NaOH solution of glucose under certain conditions, but there are still unstable factors in the experiment, which need further study. The feasibility of polishing aluminum by DC pulse electrolytic polishing under alkaline conditions was explored. The results show that DC pulse electrolytic polishing method can achieve the leveling effect of DC constant pressure electrolytic polishing, but its leveling speed is slow.

3. Environmentally friendly chemical polishing of aluminum and its alloys.

Determined to develop a new environmental protection chemical polishing technology based on phosphoric acid-sulfuric acid, realize zero emission of nitrogen oxides and overcome the quality defects of similar technologies in the past. The key of the new technology is to add some special compounds to the basic solution instead of nitric acid. Therefore, it is necessary to analyze the 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 simple chemical polishing test in phosphoric acid-sulfuric acid, it is considered that the special substances added in phosphoric acid-sulfuric acid should be able to inhibit pitting corrosion and slow down the overall corrosion, and must also have good leveling and bright effect.

4. Electrochemical surface strengthening treatment of aluminum and its alloys.

The process, properties, morphology, composition and structure of ceramic-like amorphous composite conversion film formed by anodic oxidation deposition of aluminum and its alloys in neutral system are discussed, and the film forming process and mechanism are preliminarily discussed. The technological research results show that the concentration of film-forming accelerator is controlled at 2.5 ~ 3.0g/L, the concentration of complexing agent is 1.5 ~ 3.0g/L, the concentration of na2wo 4 is 0.5 ~ 0.8g/L, and the peak current density is 6 ~ 12A/DM. The film thickness is 5 ~10 μ m, and the microhardness is 300～540 HV, so it has excellent corrosion resistance. The neutral system has good adaptability to aluminum alloys, and can form films on various series of aluminum alloys such as antirust aluminum and deformed aluminum.

5. Surface treatment technology of YL 1 12 aluminum alloy

YL 1 12 aluminum alloy is widely used in the structural parts of automobiles and motorcycles. Before application, the material needs surface treatment to improve its corrosion resistance, and form a surface layer that is easy to combine with the organic coating to facilitate the subsequent surface.