Colored conversion layers devoid of chrome formed on metal surfaces

US7828911B2 · kind B2 · utility

Assignee

• Henkel AG & Co. KGaA · DE

Inventors

• Pavel Gentschev · Bad Goisern, AT
• Matthias Schweinsberg · Langenfeld, DE
• Marco Bastian · Goldkronach, DE
• Ulrich Jueptner · Hilden, DE

Key dates

• Filing date: May 4, 2006
• Grant date: Nov 9, 2010
• Expiry date: Dec 30, 2026

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C23C22/73
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

A method for producing coloured layers on zinc, aluminium, magnesium or alloy surfaces. The surfaces are brought into contact with an aqueous treatment solution which is devoid of chrome, said solution containing, in total, 3-35 g/l persulfate ions and/or peroxodisulfate ions and not more than 10 g/l ammonia or ammonium ions, it has a pH value in the region of between 10-12 and a temperature in the range of between 30-80 ° C. The surfaces are brought into contact with the treatment solution for a period in the region of 0.5-5 minutes and optionally, they are covered with a coating based on organic polymers. The invention further relates to metal parts treated according to said method.