Post-passivation of a phosphatized metal surface
AssigneeHenkel Kommanditgesellschaft auf Aktien
InventorsJan-Willem Brouwer, Peter Kuhm
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Abstract
A process for post-passivation of a phosphated metal surface, characterized in that the phosphated metal surface is treated with an aqueous post-passivation solution which contains from 50 to 500 mg/l of nickel ions and from 200 to 1500 mg/l of phosphate ions. Rinsing water arising which contains constituents of the post-passivation solution may be processed by nanofiltration or reverse osmosis, the retentate being transferred into the phosphating bath, thereby closing the Ni circuit. The post-passivation solution preferably additionally contains a phosphating accelerator.
Claims14
A process for post-passivation of a phosphated metal surface, comprising treating a phosphated metal surface that has been treated with a phosphating solution with an aqueous post-passivation solution that comprises from 50 to 500 mg/l of nickel ions and from 200 to 1500 mg/l of phosphate ions, wherein the phosphated metal surface is contacted with the aqueous post-passivation solution and then rinsed with water or an aqueous solution, and:
- (a) wherein at least a part of the used rinsing water or solution from the rinsing step after the post-passivation treatment is added to the post-passivation solution;
- or
- (b) wherein the phosphated metal surface is rinsed with water or an aqueous solution prior to the post-passivation treatment and is rinsed again with water or an aqueous solution after the post-passivation treatment, and at least part of the used rinsing water or solution from rinsing after post-passivation is added to the rinsing water or solution to be used for rinsing prior to post-passivation.
The process of claim where on the aqueous post-passivation solution has a temperature of between 10° C. and 50° C.
Dependencies are inferred from the claim text.