HIGH-SPEED SILVER PLATING SOLUTION

PURPOSE:To obtain a high-speed silver plating soln. preventing the substitution deposition of silver and reducing the loss of silver by adding an aromatic compound having >NH group in the molecule, a silver alkali cyanide and a salt which improves the electric conductivity of a bath and buffers the bath at a prescribed pH. CONSTITUTION:This high-speed silver plating soln. contains 20-500mg/l aromatic compound having >NH group in the molecule, a silver alkali cyanide such as KAg(CN)2, and a salt which improves the electric conductivity of the bath and buffers the bath at 7.0-9.0pH. The salt includes K2HPO4. Benzotriazole, 5,6- dimethylbenzotriazole or the like is used as the aromatic compound. An Se compound may be added to the plating soln. so as to improve the luster of a plated film and to enable the formation of a thin plated film having no pinholes. It is desirable that the concn. of the free cyanide in the plating soln. is kept at