Alcoa Closed Warrick Aluminium Factory
1, aluminum phosphide
By means of SEM, XRD, potential time curve, membrane method such as heavy change promoter was studied in detail, fluoride, Mn2 + and Ni2 +, Zn2 +, PO4; And Fe2 + etc. The influence of the process of aluminium phosphide. Research shows that: guanidine nitrate with good water solubility, low dosage, fast film forming characteristics, is an effective promoter of aluminium phosphide: fluoride can promote film-forming, weight increase membrane, refine the grain size; Mn2 + and Ni2 + can significantly refine grain, make the phosphating coating is compact and uniform and can improve the look of the phosphating film; Zn2 + concentration is low, can’t film or film is poor, with Zn2 + concentration increased, film weight increase content of phosphating film m1 weight, improve the PO4. Content increase heavy phosphating film.
Alkaline electropolishing technology of 2, aluminum
The alkaline polishing solution study, compared the corrosion inhibitor, viscosity agent on the polishing effect, successfully obtained the polishing effect is very good system of alkaline solution, and got to reduce the operating temperature for the first time, lengthen the service life of the solution, but also can improve the polishing effect of additives. The experimental results show that adding proper additive in NaOH solution can produce a good polishing effect. Exploratory experiment also found that: with NaOH solution under certain conditions of glucose after dc constant voltage electrolytic polishing, aluminum surface reflectance can reach 90%, but as a result of the experiment also exists instability, needs further research. Explores the dc pulse electrochemical polishing method, the feasibility of polished aluminium in alkaline conditions, the results show that the pulse electrochemical polishing method can achieve dc constant voltage electrolysis polishing leveling effect, but the leveling speed slower.
3, aluminium and aluminium alloy and environmentally friendly chemical polishing
Determine the development of a sulfuric acid phosphate as base fluid and environmentally friendly new technology of chemical polishing, the technology to realize zero emission of NOx and overcome quality defects existing in the previous similar technology. New technology is the key in the base to add some compounds with special function instead of nitric acid. To do this you will first need to analyze the three acid polishing process of aluminium, especially focuses on the role of nitric acid. Aluminum nitrate in the main role in the chemical polishing corrosion inhibition and improve polishing brightness. In pure chemical polishing experiments in a sulfuric acid, phosphate think add special material should be in a sulfuric acid phosphate can inhibit corrosion, reduce total corrosion, and must have a better effect on the whole peaceful and bright
4, electrochemical surface strengthening treatment of aluminum and its alloys
Aluminum and its alloy anodic oxidation deposit formed in neutral system class ceramic conversion of amorphous composite membrane process, properties, morphology, composition and structure, preliminary discussion on the film-forming process and the mechanism of the film. Technology research results show that in Na_2WO_4 neutral mixed system, control film promoter concentration is 2.5 ~ 3.0 g/l, complexing film-former concentration is 1.5 ~ 3.0 g/l, Na_2WO_4 concentration is 0.5 ~ 0.8 g/l, the peak current density for 6 ~ 12 a/dm ~ 2, weak stirring, uniform and can get a complete, good gloss gray series of inorganic non metal film layer. The film thickness is 5 ~ 10 microns, microhardness is 300 ~ 540 hv, excellent corrosion resistance. The neutral system for aluminum alloy has good adaptability, anti-rust aluminum, forging and other series of aluminum alloy can be well on the film.
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