Chloride-containing bath for the electrodeposition of a zinc-nickel alloy on iron

摘要

A chloride-containing bath for the electrodeposition of a zinc-nickel alloy with 10 to 14% of nickel contains, as brightening additive to increase the corrosion resistance, 1) o-sulphobenzoic acid imide or the Na salt thereof, 2) an aromatic carboxylic acid which may be substituted by 1-3 C1-C4-alkyl groups and/or halogen atoms, 3) a naphthalenesulphonic acid with 1-3 sulpho groups, which may be substituted by 1 or 2 C1-C4-alkyl groups and/or halogen atoms, or a condensation product thereof with formaldehyde, and 4) a polyethyleneimine having a mean molecular weight from 1000 to 8000.