Trivalent chromium plating solution and method for chromium-plating using same

Abstract

A trivalent chromium plating solution having a high plating deposition rate and being practical is provided with a trivalent chromium plating solution containing a trivalent chromium compound, a complexing agent, potassium sulfate and ammonium sulfate as a conductive salt, a pH buffer, and a sulfur-containing organic compound, containing a carboxylic acid having two or more hydroxy groups and two or more carboxy groups or a salt thereof as the complexing agent, and containing a combination of saccharin or a salt thereof and a sulfur-containing organic compound having an allyl group as the sulfur-containing organic compound.

1 . A trivalent chromium plating solution, comprising:
 a trivalent chromium compound,   a first complexing agent,   potassium sulfate and ammonium sulfate as a conductive salt,   a pH buffer, and   a first sulfur-containing organic compound,   wherein the first complexing agent is a carboxylic acid having two or more hydroxy groups and two or more carboxy groups or a salt thereof, and   the first sulfur-containing organic compound is a combination of saccharin or a salt thereof and a sulfur-containing organic compound having an allyl group.   
     
     
         2 . The trivalent chromium plating solution according to  claim 1 , wherein the carboxylic acid having two or more hydroxy groups and two or more carboxy groups or a salt thereof is diammonium tartarate. 
     
     
         3 . The trivalent chromium plating solution according to  claim 1 , wherein the trivalent chromium plating solution has a mass ratio of potassium sulfate and ammonium sulfate ((potassium sulfate)/(ammonium sulfate)) of from 1.0 to 30. 
     
     
         4 . The trivalent chromium plating solution according to  claim 1 , wherein the sulfur-containing organic compound having an allyl group is sodium allylsulfonate and/or allylthiourea. 
     
     
         5 . The trivalent chromium plating solution according to  claim 1 , further comprising:
 a second complexing agent, and   a second sulfur-containing organic compound,   wherein the second complexing agent is a carboxylic acid having two or more carboxy groups having a number of carbon atoms of 4 or more or a salt thereof, and   the second sulfur-containing organic compound is a sulfonic acid having a vinyl group or a salt thereof.   
     
     
         6 . The trivalent chromium plating solution according to  claim 5 , wherein the carboxylic acid having two or more carboxy groups having a number of carbon atoms of 4 or more or a salt thereof is phthalic acid or adipic acid. 
     
     
         7 . The trivalent chromium plating solution according to  claim 5 , wherein the sulfonic acid having a vinyl group or a salt thereof is sodium vinylsulfonate. 
     
     
         8 . The trivalent chromium plating solution according to  claim 1 , wherein the trivalent chromium plating solution comprises substantially no iron and/or cobalt. 
     
     
         9 . A method for chromium-plating on an article, the method comprising:
 electroplating an article with the trivalent chromium plating solution according to  claim 1 .   
     
     
         10 . A chromium-plated product, comprising:
 an article, electroplated with the trivalent chromium plating solution according to  claim 1 .   
     
     
         11 . The chromium-plated product according to  claim 10 , wherein the chromium plating comprises substantially no iron and/or cobalt.