Non-cyanide silver plating bath composition

Abstract

Disclosed is an electroplating solution for the deposition of silver; said solution containing silver in the form of a complex of silver with hydantoin or a substituted hydantoin compound; said solution also containing an excess of the hydantoin or substituted hydantoin compound employed, together with an effective quantity of a nonprecipitating electrolyte salt, and also an effective quantity of 2,2′ dipyridyl for the purpose of obtaining a mirror-bright to brilliant deposit.

1 . An electroplating solution for the deposition of silver; said solution comprising silver in the form of a complex of silver with hydantoin or a substituted hydantoin compound; said solution also comprising an excess of the hydantoin or substituted hydantoin compound, together with an effective quantity of a nonprecipitating electrolyte salt, and also an effective quantity of 2,2′ dipyridyl for the purpose of obtaining a mirror-bright to brilliant deposit.  
     
     
         2 . The electroplating solution of  claim 1 , further comprising an effective quantity of a pyridine or substituted pyridine compound for the purpose of improving the overall brightness of the deposit obtained.  
     
     
         3 . The electroplating solution of  claim 1  or  2 , further comprising an effective quantity of surface-active material for the purpose of further improving the overall brightness and brilliance of the deposit obtained.  
     
     
         4 . The electroplating solution of  claim 3 , wherein the surface-active material is selected from the group consisting of Hamposyl C, Hamposyl L, Hamposyl O, Blancol, Blancol N, Rhodacal, and Rhodacal N.  
     
     
         5 . The electroplating solution of claims  1  or  2 , wherein the pyridine or substituted pyridine compound is selected from the group consisting of nicotinamide, isonicotinamide, 2-aminopyridine, 3-aminopyridine, nicotinic acid and its salts, and isonicotinic acid and its salts.  
     
     
         6 . The electroplating solution of  claim 4 , wherein the surface-active material is selected from the group consisting of Hamposyl C, Hamposyl L, Hamposyl O, Blancol, Blancol N, Rhodacal, and Rhodacal N.  
     
     
         7 . The electroplating solution of  claim 1  or  2 , wherein the nonprecipitating electrolyte salt is selected from the group consisting of the salts of sulfamic, hydrofluoric, nitric, fluoboric, glycolic, and lactic acids.  
     
     
         8 . The electroplating solution of  claim 3 , wherein the nonprecipitating electrolyte salt is selected from the group consisting of the salts of sulfamic, hydrofluoric, nitric, fluoboric, glycolic, and lactic acids.  
     
     
         9 . The electroplating solution of  claim 4 , wherein the nonprecipitating electrolyte salt is selected from the group consisting of the salts of sulfamic, hydrofluoric, nitric, fluoboric, glycolic, and lactic acids.  
     
     
         10 . The electroplating solution of  claim 5 , wherein the nonprecipitating electrolyte salt is selected from the group consisting of the salts of sulfamic, hydrofluoric, nitric, fluoboric, glycolic, and lactic acids.  
     
     
         11 . The electroplating solution of  claim 6 , wherein the nonprecipitating electrolyte salt is selected from the group consisting of the salts of sulfamic, hydrofluoric, nitric, fluoboric, glycolic, and lactic acids.  
     
     
         12 . A process for the formation of a mirror-bright to brilliant electrodeposit of silver on a substrate comprising the step of: 
 electroplating said substrate in an electroplating solution,    said solution comprising silver in the form of a complex of silver with hydantoin or a substituted hydantoin compound;    said solution also comprising an excess of the hydantoin or substituted hydantoin compound, together with an effective quantity of a nonprecipitating electrolyte salt, and an effective quantity of 2,2′ dipyridyl for the formation of a mirror-bright to brilliant deposit.    
     
     
         13 . The process of  claim 12 , wherein the electroplating solution further comprises an effective quantity of a pyridine or substituted pyridine compound for the purpose of improving the overall brightness of the deposit obtained.  
     
     
         14 . The process of  claim 12  or 13, wherein the electroplating solution further comprises an effective quantity of surface-active material for the purpose of further improving the overall brightness and brilliance of the deposit obtained.  
     
     
         15 . The process of  claim 14 , wherein the surface-active material is selected from the group consisting of Hamposyl C, Hamposyl L, Hamposyl O, Blancol, Blancol N, Rhodacal, and Rhodacal N.  
     
     
         16 . The process of  claim 13 , wherein the pyridine or substituted pyridine compound is selected from the group consisting of nicotinamide, isonicotinamide, 2-aminopyridine, 3-aminopyridine, nicotinic acid and its salts, and isonicotinic acid and its salts.  
     
     
         17 . The process of  claim 16 , wherein the surface-active material is selected from the group consisting of Hamposyl C, Hamposyl L, Hamposyl O, Blancol, Blancol N, Rhodacal, and Rhodacal N.  
     
     
         18 . The process of  claim 12  or  13 , wherein the nonprecipitating electrolyte salt is selected from the group consisting of the salts of sulfamic, hydrofluoric, nitric, fluoboric, glycolic, and lactic acids.  
     
     
         19 . The process of  claim 14 , wherein the nonprecipitating electrolyte salt is selected from the group consisting of the salts of sulfamic, hydrofluoric, nitric, fluoboric, glycolic, and lactic acids.  
     
     
         20 . The electroplating solution of  claim 15 , wherein the nonprecipitating electrolyte salt is selected from the group consisting of the salts of sulfamic, hydrofluoric, nitric, fluoboric, glycolic, and lactic acids.  
     
     
         21 . The electroplating solution of  claim 16 , wherein the nonprecipitating electrolyte salt is selected from the group consisting of the salts of sulfamic, hydrofluoric, nitric, fluoboric, glycolic, and lactic acids.  
     
     
         22 . The electroplating solution of  claim 17 , wherein the nonprecipitating electrolyte salt is selected from the group consisting of the salts of sulfamic, hydrofluoric, nitric, fluoboric, glycolic, and lactic acids.