Abstract: An aqueous alkaline cyanide-free bath for the galvanic deposition of zinc or zinc alloy coatings on substrate surfaces is described, which contains in addition to a source of zinc ions and optionally a source of further metal ions, also hydroxide ions and a polymer of the general formula A that is soluble in the bath as well as optionally conventional additives. The bath may furthermore contain a quaternary derivative of a pyridine-3-carboxylic acid of the formula B and/or a quaternary derivative of a pyridine-3-carboxylic acid of the formula C A process for the galvanic deposition of zinc coatings and zinc alloy coatings using the aforedescribed bath is also described. By using the baths according to the invention it is possible to produce coatings that exhibit a uniform layer thickness combined with a high gloss, and which do not exhibit any tendency to exfoliate.

Abstract: Bright zinc plate is obtained from alkaline, cyanide-free zinc plating baths containing at least one linear polyamine obtained by condensing an aliphatic diamine with an aliphatic dihalide. Especially good results are obtained if the bath also contains at least one substituted pyridine compound in the form of a free base or as a quaternised derivative. A brightener composition containing both the linear polyamine and the pyridine compound can be added to alkaline, cyanide-free zinc plating baths.

Abstract: Bright zinc plate is obtained from alkaline, cyanide-free zinc plating baths containing (a) at least one linear polyamine obtained by condensing an aliphatic diamine containing at least one tertiary amino group with a 1,3-dihalopropan-2-ol, and (b) at least one substituted pyridine compound in the form of a free base or as a quaternized derivative. A brightener composition containing the linear polyamine and the pyridine compound can be added to alkaline, cyanide-free zinc plating baths.

Abstract: The mixture present after reaction of an acetylenic diol and less than an equimolar amount of an alkylene oxide or the like oxirane compound, and comprising a proportion of unreacted acetylenic diol starting material together with proportions of the mono-substituted and di-substituted reaction products is used as a nickel-plating bath additive. Preferred ranges for the reaction mixture of diol/oxirane are 1 : 0.5. to 1 : 0.95, and a preferred combination is 2-butyne-1,4-diol and propylene oxide.