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Abstract

An improved fluxing method for the galvanization of steel, particularly batch galvanization, is disclosed. In this process, a metallic element is deposited (for example, by electroless plating) on the surface of the steel sheet or other article prior to its being dipped in the galvanization bath. Preferred metals for use in this fluxing process are tin, copper, nickel, with tin being more preferred, and mixtures of copper and tin being most preferred. This metallic film layer has a thickness between about 5 and about 50 nm. The process of the present invention provides a number of benefits when compared to conventional fluxing processes: for example, it is compatible with the inclusion of aluminum in the galvanization bath; it permits a greater time delay between the fluxing and galvanization operations; and it eliminates the formation of hydrogen chloride or other toxic fumes when the fluxed article is dipped in the molten zinc galvanization bath. Additionally, the present process permits the combination of the fluxing and pickling steps into a single step, providing a shorter and more efficient galvanization process than is conventionally used. The fluxing method may also be used in a continuous galvanization process.

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First Claim