Ni-cu alloy electroplating is described using a bath consisting essentially of an aqueous solution of nickel acetate, copper acetate, and boric acid. Anodes can be of ni, cu, or ni-cu alloys and the cathode can be al, mg, zn, or their alloys with the preferred cathode being zincated aluminum or magnesium (e.g., Al or Mg to which a layer of zn 0.02-0.04 micrometers thick is applied by chemical means by immersing in zincate solution). Thus, in a cell with 2 parallel nickel anodes (5 cm w x 15 cm l) with a zincated al sheet cathode positioned between the anodes, electrolysis was conducted for 1 min using a bath containing ni(oac)2 125, cu(oac)2 10, h3bo3 15.5 G/l at ph 5.5, 30 Deg c, and a current density 50 ma/cm2. Ni-cu alloy electroplates were deposited which contained approximately 70 pct ni and were approximately 1 micrometer thick. After buffing, these electroplates were bright and exhibited excellent corrosion resistance after exposure for 2 weeks in a chamber at 60 deg c and 100 pct humidity. Electroplating with baths containing chloride or sulfate salts resulted in deposits which were inferior in adherence, appearance, or corrosion resistance compared with deposits from the baths containing acetates.
U.S. Pat. 4,167,459; Sept. 11, 1979; Chem. Abstr. 91:165,622W