PRODUCTS AND COMPOSITIONS OF LAYERED MATERIAL SYSTEMS FOR FLUXLESS BRAZING OF ALUMINUM OR DISSIMILAR METALS

摘要

A brazing product for fluxless brazing comprises a substrate, which may comprise aluminum or an aluminum alloy, and a filler metal-forming material system applied to the substrate. The filler metal-forming material system forms a liquid filler metal when the brazing product is heated to a brazing temperature. The filler metal-forming material system comprises a liquid-forming layer and a braze-promoting layer. The liquid-forming layer comprises a coating of silicon, a coating of an aluminum-silicon alloy having 20 percent silicon by weight or higher, or a coating comprised of sequential thin layers of aluminum and silicon. The braze-promoting layer comprises one or more metals selected from nickel, cobalt, palladium and iron.