GB662217A - Improvements in or relating to the electrodeposition of copper - Google Patents

Abstract

662,217. Electrodeposition of copper. WESTINGHOUSE ELECTRIC INTERNATIONAL CO. Sept. 20, 1949 [Oct. 13, 1948], No. 24159/49. Drawings to Specification. Class 41] An aqueous acid copper sulphate electrolyte, for the electrodeposition of copper, contains between 0.5 and 0.005 ozs per U.S. gallon of a metal from the groups consisting of zinc and cadmium. The zinc or cadmium may be added to the electrolyte as salts, for example, cadmium sulphate or oxide, or zinc sulphate or oxide. Alternatively the metal may be added as an anode of zinc or cadmium or an alloy of the two, a deplating current being applied to cause the anode to dissolve in the electrolyte. A small amount of a wetting agent may be present in the electrolyte. In the electrodeposition, there may be used a periodically-reversed current somewhat as in the process described in Specification 630,165. For example, the member to be plated may be subjected in the electrolyte to a plating current as cathode for a period of between 40 seconds and 0.01 seconds, then to a deplating current as anode for a period between 20 seconds and 0.002 seconds, the magnitude and time of application of the deplating current being sufficient to apply between 10 and 75 per cent of the Coulombs of current applied during the preceding plating period, alternate plating and deplating continuing until a deposit of copper of desired thickness has been applied. The anode may be an alloy of copper containing at least 95 per cent by weight of copper and between 0.005 and 5 per cent by weight of at least one metal from the group consisting of cadmium and zinc. Specification 633,780 is referred to.