Patent ID: 8349092
Filing Date: 2013-01-08
Classification: C23C

Abstract:
1. A process comprising: applying an aqueous, acidic phosphating solution comprising dissolved contents to a metallic surface, said metallic surface comprising at least 5% by weight of at least one of aluminum or an aluminum alloy, wherein the dissolved contents in the phosphating solution comprise: having a combined sodium and potassium content in the range of 0.3 to 1.8 g/L as sodium, the potassium content being converted to sodium on a molar basis; zinc in a concentration range of 0.2 to 4 g/L; phosphate in a concentration range of 4 to 65 g/L, calculated as PO free fluoride in a concentration range of 0.03 to 0.5 g/L; total fluoride in the concentration range of 0.1 to 5 g/L; silver in the concentration range of 0.001 to 0.080 g/L; wherein a zinc-containing phosphate film is deposited on the metallic surface and has a coating weight in the range of 0.5 to 10 g/m wherein the content based on hydroxylamine is virtually none, and wherein no copper is added.