Alloy Aluminum Tube Commonly Used In A Variety Of Passivation Process Price
Sewage treatment has brought trouble a few years ago Although some people have suggested the use of low-chromium blunt flowers, tannic acid treatment galvanized layer galvanized layer of the current anti-corrosion treatment method is basically chrome salt passivation treatment. In order to solve the problem of sewage discharge, but because of its immaturity or there are some aspects of its lack, has not yet widely widely used. A recent study, Japan has been tested 1% tannic acid aqueous solution of galvanized sense of its resistance to corrosion has improved, and alloy aluminum tube tannic acid treatment after the fly and then paint the bonding force than the chromium salt passivation film Paint the binding force is much better. Usually at room temperature for 30 seconds. Tannic acid composition is very complex, its main ingredient is twice tannin 70%, gallic acid 20%, between the two gallic acid 7%, the rest is three gallic acid and some unmeasured acid. It can be said that the complex structure of the diclofenac is the membrane of the skeleton, to protect the dissolution of zinc. The structure of the diclofenac is as follows: The formation of tannic acid on the surface of zinc is formed by condensation polymerization or associative polymerization.
The amount of film formation is proportional to time, but it is greatly influenced by temperature. From the Aluminum Tube galvanized layer passivation is widely used in metallurgy, transportation, construction, machinery, aviation and power and other fields, the most commonly used passivation process for chromate passivation. Because of its generated passive film has good shielding performance and self-repair effect, it has excellent corrosion resistance. However, the chromium chromium contained in the chromium has a high toxicity, the human body and the ecological environment has a greater harm. To this end the EU issued ROHS directive, since July 1, 2006, put the EU market of electrical and electronic products shall not contain mercury, cadmium, lead, hexavalent chromium, polybrominated biphenyls (PBB polybrominated diphenyl ether (PBDE 6 kinds of harmful (Ⅵ) passivation technology is divided into: inorganic passivation, organic passivation and inorganic - organic compound passivation , Involving trivalent chromium (Ⅲ) salts, molybdates, tungstates, silicates, rare earth metal salts, titanium salts and organic substances (such as tannic acid, phytic acid), and modified silicate , Inorganic silane passivation, organosilane passivation, and inorganic-organic complex passivation studies have progressed considerably.2 Inorganic passivation The 21VIB elemental passivation usually has similar chemical properties with homozygous elements and is therefore characterized by molybdenum and tungsten As a substitute for the attempt.In addition, chromium has a variety of valence, so trivalent chromium also has a good alternative prospects.