| 摘要 |
The invention relates to a method for treating or pre-treating parts, profiled-pieces, strips, sheet metals and/or wires having metallic surfaces, in which at least 5 % of these surfaces consists of aluminum and/or of at least one aluminum alloy and, optionally, the remaining metallic surfaces can predominantly consist of iron alloys, zinc and/or zinc alloys. The treatment involves the use of an acid aqueous solution, which contains fluoride, zinc and phosphate and which has the following dissolved contents in the phosphatizing solution: sodium virtually none or in a concentration ranging 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 in a concentration ranging from 0.2 to 4 g/L; phosphate in a concentration ranging from 4 to 65 g/L and calculated as PO4; free fluoride in a concentration ranging from 0.03 to 0.5 g/L, and; total fluoride 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/m2.
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