Hits:Updated:2016-08-04 14:08:20【Print】
| With the development of automobiles, aircraft, ships, home appliances and other industries, on the surface of metal parts corrosion-resistant, high temperature, wear, anti-oxidation, anti-fatigue, anti-radiation, electrical conductivity, magnetic, insulation, decorative and other special performance requirements more extensive , prompting the metal surface treatment technology developed rapidly. Domestic primary method for metal surface treatment are phosphate method, since the method phosphide high energy consumption, high pollution, high cost, is gradually substituted silane surface treatment technology, the silane processing techniques are constantly being developed, and sophisticated applications. Silane treated with traditional phosphate method has the following advantages: no harmful heavy metals, phosphorus, and silane without heating process does not produce sediment, the processing time is short, easy to control; eliminating the need for surface conditioning step bath may reuse; effectively improve the adhesion of the coating to the substrate; collinear can handle a variety of substrates iron, galvanized steel, aluminum and the like. Thus, the new environmental protection, energy saving, low emissions, low cost silane metal surface treatment technology and technical personnel at home and abroad has become the focus of research. Silane coupling agents are a class of organic silicon-containing compound having a functional group. Its molecular formula represented by the formula Y (CH2) nSiX3 represented, where n = 0-3; X is typically chloro, methoxy, ethoxy, methoxyethoxy, acetoxy, etc., these groups upon hydrolysis generating silanols i.e., combine with the inorganic material to form a silicone. Y is a vinyl group, an amino group, an epoxy group, methacryloxy group, a mercapto group or a ureido group, an organic functional groups which can react with organic material. When the hydrolysis of silicon functional group, the Si-X is converted to Si-OH, and by-product HX. Si-OH and Si-OH either Si-OH or other molecules in the surface of the treated substrate dehydration condensation reaction to form Si-O-Si bond, and even with some oxides (e.g. aluminum oxide, iron, tin oxide, zirconium oxide, titanium oxide, nickel, etc.) to produce stable Si-O bond, so that the silane and inorganic or metal to connect. Silane of this feature, it can be applied to metal rust and oxidation, Mg, Al, Cr, Fe, Zn and other metals after silane treatment, can greatly improve the corrosion resistance. Silane treatment technology is the use of the special properties of the silane coupling agent. During film formation, the metal surface is: (1) a silane coupling agent after hydrolysis, forming silanol groups with hydrophobic and hydrophilic structures; (2) formed by intermolecular dehydration condensation ordered oligomer; (3) hydroxyl groups on the oligomer to form hydrogen bonds with the metal surface; (4) Since the intramolecular dehydration, part form a covalent bond, tightly arranged in a metal surface, forming a dense film of silane. |
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