Improvements relating to the electrodeposition of copper
633,780. Electrodeposition of copper. GENERAL MOTORS CORPORATION. July 18, 1947, No. 19248. Convention date, May 24, 1941. [Class 41] An electrolyte for electrodeposition of copper comprises an aqueous solution of copper sulphate, free sulphuric acid, and a thiourea in an amount between .002 and 5 grams per litre of solution. The electrolyte may also contain a small amount, for example, between .01 and 5 grams per litre, of a control agent of the organic sulphonate type, effective to widen the plating range and improve the distribution of brightness. In addition, or alternatively, there may also be added to the bath a metallic salt, for example, a sulphate of cadmium, zinc or cobalt, or a phosphate of nickel. The Specification as open to inspection under Sect. 91 describes also the use, in place of thiourea, of one or more compounds of the group, including isothiocyanates, thioacetamides, xanthates, mercaptans and cyanamides. This subject-matter does not appear in the Specification as accepted.