METHOD OF DEPOSITING TIN-BISMUTH-COPPER ALLOY

摘要

PROBLEM TO BE SOLVED: To provide an electroplating method which does not deposit metal bismuth on an alloy surface by a substitution reaction. SOLUTION: The method of electroplating an alloy containing 93 to 98.5 wt.% tin, 1 to 5 wt.% bismuth and 0.5 to 2 wt.% copper from an acidic electrolytic bath containing one or more kinds of alkyl sulfonic acids and/or alkanol sulfonic acids and/or one or more kinds of soluble tin slats, one or more kinds of soluble bismuth salts and one or more kinds of copper salts, in which the substitution deposition of the bismuth on the surface of the tin-bismuth-copper alloy is prevented by performing the electroplating in the acidic electrolytic bath of a pH<=1.