| abstract |
A method for phosphating metal surfaces uses phosphating solutions which are essentially free of nickel 0.3 to 1.7 g / l Zn 0.2 to 4.0 g / l Mn 0.001 to 0.030, preferably 0.003 to 0.020 g / l Cu 5 to 30 g / l phosphate (calculated as P₂O₅) contain and in which the concentration of Fe (II) is kept below 0.1 g / l and the pH is adjusted to 3.0 to 3.8 by means of oxygen and / or other oxidizing agents having the same effect. The weight ratio of Cu to P₂O₅ is preferably set to 1: (170 to 30000) and the addition of Cu and P₂O₅ in a weight ratio of 1: (5 to 2000).n n n When used in the spray process, the phosphating solutions should contain 0.3 to 1.0 g / l Zn and when used in the spray / immersion process and immersion process 0.9 to 1.7 g / l Zn.n n n The method is used in particular for the pretreatment of metal surfaces for subsequent painting, in particular electro-dip painting, and the phosphating of steel, galvanized steel, alloy-galvanized steel, aluminum and their alloys. |