1, aluminum phosphating, by using SEM, XRD, potential-time curve, film weight change and other methods, the accelerator,? Fluoride, Mn2+, Ni2+, Zn2+, PO4 and Fe2+ are harmful to aluminum. Effect of phosphating process. Research shows:? 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, which makes? The phosphating film is uniform and compact, which can improve the appearance of 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. The alkaline electrolytic polishing process and alkaline polishing solution system of aluminum were 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: in? Adding proper additives to NaOH solution can produce good polishing effect. ? Exploratory experiments also found that NaOH solution of glucose can be used for DC constant voltage under certain conditions. After electrolytic polishing, aluminum surface? The reflectivity can reach 90%, 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 aluminum 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 adding special substances into phosphoric acid-sulfuric acid should be able to inhibit? Bite corrosion, slow down? All-round corrosion, at the same time, it should have good leveling and bright effect.
4, electrochemical surface strengthening treatment of aluminum and its alloys, aluminum and its alloys in neutral system? Anodic oxidation deposition to form ceramic-like? The process, properties, morphology, composition and structure of amorphous composite film are discussed, and the film forming process and mechanism are also discussed. The results of technological research show that in na2wo 4? In neutral mixed system, the concentration of film-forming accelerator is controlled to be 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 value is? When the current density is 6 ~12a/dm2 and the stirring is weak, a complete, uniform and shiny gray inorganic nonmetallic film can be obtained. Film thickness 5 ~ 10μ m? The microhardness is 300 ~ 540 HV, and the corrosion resistance is excellent. Neutral system has good adaptability to aluminum alloy. Anti-rust aluminum, wrought aluminum and other series aluminum alloys can form films well.