Acidic, aqueous phosphate-coating solutions for use in a process for phosphate-coating metal surfaces.

摘要

Acidic, aqueous, substantially chlorate-free phosphate solution contains in S/L:- 0.1-1.5 Zn ions; 5-50 phosphate ions; 0.2-4 Mn ions; min 0.05 fluoride ions; less than 0.5 chloride ions; and at least one of the following phosphate accelerators:- 0.01-0.2 nitrite ions; 1-15 nitrate ions; 0.5-5 H2O2 (based on 100% H2O2); 0.05-2 m-nitrobenzene-sulphonate ions; 0.05-2 m-nitrobenzoate ions and 0.05-2 p-nitrophenol.