US 11,987,887 B2
Method for passivating metallic substances
Holger Grolmes, Erwitte (DE); Christopher Köster, Herdecke (DE); Ingo Klüppel, Bochum (DE); and Marcel Roth, Düsseldorf (DE)
Assigned to Ewald DÖRKEN AG, (DE)
Filed by Ewald DÖRKEN AG, Herdecke (DE)
Filed on Jul. 28, 2020, as Appl. No. 16/940,820.
Claims priority of application No. 19188901 (EP), filed on Jul. 29, 2019.
Prior Publication US 2021/0032757 A1, Feb. 4, 2021
Int. Cl. C23C 22/30 (2006.01); C23C 22/06 (2006.01); C23C 22/34 (2006.01)
CPC C23C 22/06 (2013.01) 15 Claims
OG exemplary drawing
 
1. Method for adjusting a passivation composition for passivation of metallic substrates, the passivation composition including at least one ionic compound of a transition metal which can have several oxidation states, the method comprising:
determining a redox potential for the passivation composition,
adjusting the redox potential of the passivation composition to a predetermined value depending on the determined redox potential,
wherein the passivation composition includes chromium in the form of a chromium (III) compound as transition metal and at least one further transition metal selected from the group of vanadium, molybdenum, tungsten, manganese and mixtures thereof, and
wherein the passivation composition has the form of a dilute aqueous solution or dispersion.