Abstract: A method for forming a zinc oxalate coating on the surface of a strip or sheet of metal covered with a zinc or zinc alloy coating other than zinc/iron coatings, with the aid of an aqueous solution consisting of oxalic acid having a concentration of between 5.10?3 and 0.1 mole/l, and at least one compound and/or ion of an oxidant zinc metal having a concentration of between 10?6 and 10?2 mole/l, and possibly a wetting agent. The inventive method enables sheet metal to be treated at very high speeds without using large amounts of oxidant. It facilitates management of treatment baths. The invention can be used in the lubrication of sheet metal, especially for die stamping.

Abstract: A method for forming a zinc oxalate coating on the surface of a strip or sheet of metal covered with a zinc or zinc alloy coating other than zinc/iron coatings, with the aid of an aqueous solution consisting of oxalic acid having a concentration of between 5.10−3 and 0.1 mole/l, and at least one compound and/or ion of an oxidant zinc metal having a concentration of between 10−6 and 10−2 mole/l, and possibly a wetting agent. The inventive method enables sheet metal to be treated at very high speeds without using large amounts of oxidant. It facilitates management of treatment baths. The invention can be used in the lubrication of sheet metal, especially for die stamping.

Abstract: A bath of pH higher than 4 containing more than 1 mole/liter of Zn.sup.++ ions and at least one polyethylene glycol polymer of the general formula R.sup.1 --O(CH.sub.2 --CH.sub.2 --O).sub.n --R.sup.2, in which n.ltoreq.13 and in which the concentration of polymer in the bath is adapted to incorporate in the coat an organic compound having a content by weight greater than 0.1%, expressed as weight of carbon per unit weight of the coat. The bath is adapted to high current densities, and the coat applied on the steel sheet imparts both a leveling effect and an improvement of corrosion resistance.