Lead immersion bath and method of supplificially exchanging a tin layer for a lead layer.

摘要

A lead immersion bath and method of superficially exchanging a tin layer for a lead layer, and a lead-tin alloy layer, respectively, which bath comprises an alkaline solution of a lead (II) compound and a complexing agent, in which the complexing agent has been chosen so that the complex constant of the lead complex in the solution used is smaller than the dissociation constant of hydroxyplumbite ions. The lead-tin alloy layer is obtained by a thermal treatment between 183 DEG C and 232 DEG C.