Tin-lead alloy plating bath.

摘要

A tin-lead alloy plating bath based on a principal plating bath comprising an alkanesulfonic or alkanolsulfonic acid and both bivalent tin and lead salts thereof is characterized by the addition of a guanamine compound having the general formula <CHEM> wherein R1 and R2, which may be the same or different, present each a hydrogen atom, C1-18 straight- or branched-chain alkyl radical, C1-18 straight- or branched-chain alkoxy-lower alkyl radical, or a C3-7 cycloalkyl radical, or R1 and R2 may combine to form a carbon cycle or hetero cycle, and A represents a lower alkylene radical.