METHOD FOR TREATING METAL SURFACES BY CARBOXYLATION

摘要

The invention relates to a method for treating a metal surface by carboxylation before forming, said metal being selected from zinc, iron, aluminium, copper, lead and the alloys thereof as well as copper-coated, aluminium-coated, galvanised steels. Said method is carried out in oxidising conditions in relation to the metal by bringing said metal into contact with an aqueous, organic or hydro-organic bath comprising at least one organic acid in free form or in salt form. The inventive method is characterised in that: the organic acid is a saturated or unsaturated aliphatic monocarboxylic or dicarboxylic acid; the organic acid is in solution and/or emulsion in the bath at a concentration greater than 0.1 mole/litre; the pH of the bath is acid.