Bethlehem Steel Corporation

Neal S Berke

Herbert E Townsend

A coated ferrous article with improved properties, e.g., improved overall corrosion resistance and good appearance. The article has a ferrous substrate and a ductile, adherent, corrosion resistant alloy coating metallurgically bonded to the substrate. The alloy coating has a thin intermetallic alloy layer intermediate the substrate and an alloy overlay. The alloy overlay consists essentially of, by weight, magnesium from 3% to 20%, silicon from 3% to 15%, balance aluminum and zinc, where the ##EQU1## is between 1 and 1.5. The metallurgical structure of the overlay is a mixture of (1) cored aluminum-rich dendrites having dendrite arm spacings (DAS) of less than 10.mu., (2) zinc-rich interdendritic regions, and (3) intermetallic phases of zinc, aluminum, magnesium and silicon. The article may be produced by hot dip coating a ferrous substrate in a molten metal bath of the above composition.

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Allentown, PA, United States of America

Neal S Berke