PRETREATING SOLUTION FOR SILVER PLATING AND SILVER PLATING SOLUTION

摘要

PURPOSE:To prevent the substitution deposition of silver on a copper sheet and to improve the wettability of the surface of the sheet and the adhesion of a plating film by successively treating the sheet with a pretreating soln. and a silver plating soln. each contg. a prescribed heterocyclic thion compd., a prescribed amine compd. and a surfactant. CONSTITUTION:The pretreating soln. for silver plating and the silver plating soln. each contg. the heterocyclic thion compd., the amine compd. and the surfactant are prepd. The thion compd. may be 3-aminorhodanine, 3-thiourazol or 2-thiouracil and acts as an inhibitor for inhibiting the substitution deposition of silver. The amine compd. is represented by general formula I (wherein n=-10), II (where n=1-10) or III (where each of R and R' is H or <=5C alkyl) and reduces the surface tension of the soln. The surfactant also reduces the surface tension. A silver plated product having satisfactory adhesion and fine appearance is obtd. by using the solns.