method of electrolytic solution cuivrage not used.

摘要

A copper-plating bath comprises 0.02-0.25 mols. of a water-soluble copper sa 0.25-2.1 mols. of formaldehyde (or equivalent amount of paraformaldehyde or trioxan); 0.002-0.25 mols., but in amount less than that necessary to complex completely said copper salt, of a copper complexing salt selected from the group consisting of Rochelle salts, sodium gluconate and sodium citrate; alkali metal hydroxide from 5-7 times the number of mols. of the copper complexing salt and sufficient to give the bath a pH of at least 11.0; and water sufficient to give one litre of solution. Before plating, the substrate may be treated in solutions of stannous chloride, fluoborate or sulphate, and palladium chloride or auric chloride. Surfaces which may be copper-plated include plastics,