Phosphating method accelerated by N-oxides

US6379474B1 · kind B1 · utility

Assignee

• Henkel Kommanditgesellschaft auf Aktien · DE

Inventors

• Bernd Mayer · Graz, AT
• Peter Kuhm · Hilden, DE
• Pietro Balboni · Bologna, IT
• Markus Senner · Goldkronach, DE
• Horst-Dieter Speckmann · Langenfeld, DE
• Juergen Geke · Goldkronach, DE
• Jan-Willem Brouwer · Willich, DE
• Annette Willer · Neuss, DE

Key dates

• Filing date: Jan 10, 2001
• Grant date: Apr 30, 2002
• Expiry date: Jan 10, 2021

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C23C22/12
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

An acidic aqueous phosphating solution is presented having 0.2 to 3 g/l of zinc ions, 3 to 50 g/l of phosphate ions expressed as PO4−3, and 0.05 to 4 g/l of an organic N-oxide containing a saturated, unsaturated or aromatic 5- or 6-membered ring system, where the N atom of the N-oxide is part of said ring system, and where the ratio by weight of phosphate ions to zinc ions is from 3.7 to 30:1. The solution is free of hydroxylamine and useful in phosphating metal surfaces.