Method for passivating metallic substances
AssigneeEwald Dörken AG
InventorsHolger Grolmes, Christopher Köster, Ingo Klüppel, Marcel Roth
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Abstract
The present invention relates to a method for adjusting a passivation composition by determining the redox potential of a passivation composition as well as to a method for passivating metallic substrates by treatment with a passivation composition.
Claims15
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.
Method for passivating a metallic substrate by treating the metallic substrate with a passivation composition, 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 based on the redox potential determined,
- providing a metallic substrate for treatment, and
- treating the metallic substrate with the passivation composition, 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.
Method for adjusting the color of a passivation composition and/or the color of a metallic substrate treated therewith, the passivation composition including at least one ionic compound of a transition metal which can have several oxidation states, the method comprising:
- providing a discolored passivation composition and/or a discolored metal substrate,
- determining a redox potential for a discolored passivation composition,
- adjusting the redox potential of the discolored passivation composition to a predetermined value depending on the determined redox potential to provide a passivation composition having an adjusted color and/or treating the discolored substrate with the passivation composition,
- 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.
Dependencies are inferred from the claim text.