Phosphating solution used as a pre-treatment for metal surfaces contains zinc irons, phosphate ions, hydrogen peroxide or an equivalent amount of a hydrogen peroxide-splitting substance and aliphatic chelate-forming carboxylic acid

摘要

Phosphating solution contains (in g/l) 0.2-3 zinc (II) irons, 3-50 phosphate ions (calculated as PO 4 3 -), 15-50 hydrogen peroxide or an equivalent amount of a hydrogen peroxide-splitting substance and 0.3-15 aliphatic chelate-forming carboxylic acid with 2-7 carbon atoms with a content of free acid of a maximum one point. Independent claims are also included for the following: (1) Aqueous concentrate; and (2) Method for phosphating metal surfaces made from steel, galvanized steel and/or aluminum.