PLATING LIQUID FOR PREVENTING SULFURATION DISCOLORATION ON SILVER SURFACE

PROBLEM TO BE SOLVED: To provide a plating liquid for preventing sulfuration discoloration on a silver surface capable of completely and stably preventing a surface of a silver solid material product or a silver plated product from sulfuration discoloration.SOLUTION: The plating liquid for preventing sulfuration discoloration on a silver surface includes an elemental indium plating liquid containing 1.0-100.0 g/L of a soluble indium salt as an indium metal content, 20.0-300.0 g/L of salts having conductivity and a buffering ability, 0.005-15.0 g/L of a pyridinecarboxylic amine derivative, 0.1-50.0 g/L of a hexose monosaccharide, and 0.01-10.0 g/L of an anion or amphoteric surface active agent. An elemental indium or indium alloy plating liquid is not only effective to the discoloration prevention of a silver plating film, but also has an extremely good preservation stability of a plating liquid and provides favorable workability and work environment.