Electrodeposition of Copper-Nickel Alloys from Citrate Solutions

SYNOPSIS

Sound, adherent deposits of copper-nickel alloys may be produced from solutions containing copper and nickel sulphates and trisodium citrate. The composition of the deposit is dependent on both the composition of the solution and the cathode current density, but is not markedly affected by variations in temperature or by agitation of the solution. In solutions containing a small proportion of chloride the anode efficiency is substantially 100%, but the cathode efficiency varies from 50% to 80%, depending on electrolyte composition, temperature, and current density. The hardness and contractile stress of an alloy deposit containing 55 copper/45 nickel is somewhat greater than that of nickel deposited from a Watts solution. Preliminary throwing-power measurements have indicated that the solution is capable of very uniform metal distribution.