Method of applying phosphate coatings to metal surfaces

US5904786A · kind A · utility

Assignee

• Metallgesellschaft AG · DE

Inventors

• Thomas Wendel · Schwalbach, DE
• Hardy Wietzoreck · Frankfurt am Main, DE
• Klaus Bittner · Frankfurt am Main, DE
• Peter Schiefer
• Marcus Schinzel · Eppstein, DE
• Helmut Hulsmann · Kreuztal, DE

Key dates

• Filing date: Jun 6, 1997
• Grant date: May 18, 1999
• Expiry date: Jun 6, 2017

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C23C22/365
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

A method is disclosed for applying phosphate coatings to surfaces of zinc, iron, aluminum, and the alloys thereof by wetting with a phosphatizing solution containing divalent cations and phosphate to form a liquid film, and subsequently drying on the liquid film wherein the metal surfaces are wetted with a phosphatizing solution, which is free from elements of sub-groups 5 and 6 of the Periodic Table, said phosphatizing solution containing: PA1 0.5 to 8 g/l nickel; PA1 2 to 20 g/l manganese; PA1 18 to 170 g/l of phosphate (calculated as P.sub.2 O.sub.5); and has an acid number of 0.4 to 0.8, such that after drying on, a phosphate layer having a weight per unit area of 0.3 to 3.0 g/m.sup.2, is obtained, where in the case of phosphatizing surfaces of iron, aluminum or the alloys thereof, the phosphatizing solution necessarily contains 0.5 to 5 g/l of zinc, and in the case of phosphatizing surfaces of zinc or zinc alloys the phosphatizing solution either contains zinc or is free from zinc.