Post-passivation of a phosphatized metal surface

US6645316B1 · kind B1 · utility

Assignee

• Henkel Kommanditgesellschaft auf Aktien · DE

Inventors

• Jan-Willem Brouwer · Willich, DE
• Peter Kuhm · Hilden, DE

Key dates

• Filing date: Nov 28, 2001
• Grant date: Nov 11, 2003
• Expiry date: Nov 28, 2021

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02A20/131
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

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.