Patent ID: 7070689

Claim:
An acidic aqueous solution devoid of ammonium ion, of fluoroborate ion and of citrate ion and comprising, per liter, from 10 to 60 g of Zn 2+ ions, from 20 to 100 g of Mn 2+ ions, a buffering agent, and an agent for bringing closer the potentials for deposition of a Zn/Zn 2+ couple and of a Mn/Mn 2+ couple that is a compound of formula R 1 —(CH 2 —CH 2 —O) n —R 2 0<n<25 wherein R 1 =aryloxy group, aryloxyalkoxy group, alkylaryl group, alkylaryloxy group, or alkylaryloxyalkoxy group, R 2 =-H, —(CH 2 ) m −SO 3 − M + , where m =0 to 5, —(CH 2 ) 2 —PO 3 2− M + 2 , -where z =0 to 2, or —CH 2 —COO − M + , where M + =Na + , K + or NH 4 + or aryl, present in a concentration of 0.5 to 15 g/l.