Characteristics and Verification of a Low Hydrogen Embrittling Zinc-Nickel Electroplate,Developed for Corrosion Protection of High Strength Steels

A coating process is outlined that gives low hydrogen embrittling zinc-nickel binary alloy electroplate for sacrificial corrosion protection of high strength steels, and the physical properties of the coatings produced are presented. The highly corrosion resistant zinc-nickel binary alloy coatings produced by the new process comply fully with the ASTM test requirements for control of hydrogen embrittlement. They are an alternative to the cadmium coatings currently employed for the corrosion protection of high strength steels. The results of hydrogen embrittlement tests and of structural analyses are discussed in light of the structure of the zinc-nickel coating, and of its efficiency in allowing labile hydrogen to diffuse out of the coated high strength steels.