Patent DE-102009047523-A1 (DE)
Title: Multi-stage method for corrosion-inhibiting pretreatment of metallic components having the surfaces of zinc, comprises subjecting the metallic components with an aqueous treatment solution, and cleaning and degreasing the metal surface
Inventor: BROUWER JAN-WILLEM
IPC: C23C22/73
Filed: 2009-12-04
Abstract: The multi-stage method for corrosion-inhibiting pretreatment of metallic components having the surfaces of zinc, comprises subjecting the metallic components with an aqueous treatment solution, cleaning and degreasing the metal surface, and carrying out a passivation treatment through in-contact-bringing of the metal-surface with an acidic aqueous composition containing a water-soluble compound of the elements such as zirconium, titanium and/or hafnium in a concentration of 5 ppm based on the elements such as zirconium, titanium and/or hafnium, and 1 ppm of copper ions. The multi-stage method for corrosion-inhibiting pretreatment of metallic components having the surfaces of zinc, comprises subjecting the metallic components with an aqueous treatment solution, cleaning and degreasing the metal surface, carrying out a passivation treatment through in-contact-bringing of the metal-surface with an acidic aqueous composition containing a water-soluble compound of the elements such as zirconium, titanium and/or hafnium in a concentration of 5 ppm based on the elements such as zirconium, titanium and/or hafnium, and 1 ppm of copper ions, and carrying out an electroless treatment through in-contact-bringing of the metal surface with an acidic aqueous chromium-free composition containing 100 ppm of nickel ions, less than 10 g/l of zinc ions, and less than 1 g/l of dissolved phosphate calculated as PO 4. The cleaning and/or degreasing of the metal surface is carried out by means of aqueous cleaning solution and is carried out by pickling removal of 0.4 g/m 2>of zinc based on the surface of an electrolytic galvanized steel. The acidic aqueous composition (A) has total 20-1000 ppm of water-soluble compounds of the elements such as zirconium, titanium and/or hafnium based on the elements such as zirconium, titanium and/or hafnium of 5 ppm not more than 100 ppm of copper(II)-ions and/or optionally up to 200 ppm of free fluoride. The composition (B) has a pH value of 3.0-6.5, consists of 2 g/l of nickel ions, 50 ppm of dissolved phosphates, and chelating organic compounds having two functional groups with oxygen- and/or nitrogen atoms selected from carboxyl-, hydroxyl-, amine-, phosphoric acid- or phosphonic acid groups. The chelating organic compounds are contained in a quantity in such a way that the molar excess of zinc ion based on the chelating organic compounds is not greater than 0.5 g/l of zinc ions. The composition (B) consists of 0.5 g/l of zinc ion, and less than 5 ppm of zirconium, titanium or hafnium. The composition (B) additionally consists of copper ions and/or silver ions such as copper ions in a quantity of 1 ppm not more than 100 ppm, and water-soluble compounds, which represent a source for the fluoride ions, where the concentration of the total fluoride in the composition (B) is not greater than 2000 ppm. The metallic component has the surfaces of steel, aluminum and/or pre-phosphating metal surfaces. An independent claim is included for a metal surface of zinc with passive layer system.