Plating bath and method for electroplating tin and/or lead

An aqueous plating bath for electrodeposition of a tin, lead or tin-lead alloy, which plating bath is free of fluoride and fluoborates and comprises

• (A) from about 0.5 to about 350 grams per liter of at least one stannous ion, lead ion or mixture of stannous and lead ions
• (B) from about 10 to about 500 grams per liter of at least one alkane sulfonic acid having the general formula
• RSO.sub.3 H (I)
• or an alkanol sulfonic acid of the general formula ##STR23## wherein R is an aliphatic group containing from 1 to about 6 carbon atoms, n is from 0 to about 10, m is from 1 to about 11 and the sum of m+n is up to about 12,
• (C) from about 0.01 to about 50 grams per liter of at least one nonionic, cationic or amphoteric surfactant,
• (D) an effective amount of at least one primary brightening agent selected from the group consisting of naphthaldehyde and carbonyl compounds having the general formula
• Ar--C(H).dbd.C(H)--C(O)--CH.sub.3 (III)
• wherein Ar is a phenyl, naphthyl, pyridyl, thiophenyl or furyl group, and
• (E) an effective amount of a secondary brightening agent selected from the group consisting of lower aliphatic aldehydes and substituted olefins of the formula ##STR24## wherein R.sub.1 is a carboxy, carboxamide, alkali metal carboxylate, ammonium carboxylate, amine carboxylate or allyl carboxylate, and R.sub.2, R.sub.3 and R.sub.4 are each independently hydrogen or lower alkyl groups.