Metallgesellschaft Aktiengesellschaft

Chemetall Gmbh

Jürgen Specht

Peter Schubach

Thomas Kolberg

Hardy Wietzoreck

Olaf Dahlenburg

Joachim Heitbaum

Rüdiger Rein

Peter Claude

Peter Jorns

Margit Fleischhacker-Jeworrek

Ralf Stickler

Michael Lenhard

Michael Deemer

Martin Mrochem

A method for treating or pre-treating parts, profiled-pieces, strips, sheet metals or wires having metallic surfaces, in which at least 5% of these surfaces consists of aluminum or of at least one aluminum alloy with an acid aqueous solution which contains fluoride, zinc and phosphate and which has the following dissolved contents in the phosphatizing solution: sodium virtually none, from 0.04 to less than 2 g/L; potassium virtually none or in a concentration ranging from 0.025 to 2.5 g/L; sodium and potassium in a concentration ranging from 0.025 to 2.5 g/L as sodium, whereby the potassium content is converted to sodium on a molar basis; zinc 0.2 to 4 g/L zinc, 5 to 65 g/L calculated as PO; 0.03 to 0.5 g/L phosphate free fluoride wherein the total fluoride is present in a concentration ranging from 0.1 to 5 g/L. A zinc-containing phosphate layer is thereby deposited onto the metallic surfaces with a layer weight ranging from 0.5 to 10 g/m.

Process for coating metallic surfaces

An aqueous solution contains phosphate for producing layers of phosphate on metal surfaces selected from the group consisting of iron, steel, zinc, zinc alloys, aluminum and aluminum alloys. The solution contains 0.3 to 5 g Zn /1, 0.1 to 2 g nitroguanidine/1 and 0.05 to 0.5 g hydroxylamine/l, with an S-value amounting to 0.03 to 0.3 and the ratio of the weight of Zn to P O &equals;1:5 to 1.30.

Aqueous solution and method for phosphatizing metallic surfaces

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Rodgau, Germany

Jürgen Specht