Acid phosphating solution, stable in presence of copper ions

摘要

An acid, aqueous phosphating solution, containing 0.2-3 g/l zinc ions, 3-50 g/l phosphate ions (calculated as PO4<3->) and 0.05-4 g/l organic N-oxide as accelerator. Also claimed is (i) an aqueous concentrate which gives the above solution after diluting by a factor of 10-100 with water and possibly adjusting the pH to a working range of 2.5-3.6; (ii) a process for phosphating steel, galvanised or alloy-galvanised steel and/or aluminium surfaces by spraying and/or dipping for 3 secs. to 8 mins. with the phosphating solution.