Phosphating by spraying with an aqueous acid phosphating solution useful for phosphating metal surfaces

摘要

Phosphating metal surfaces by spraying with an aqueous acid phosphating solution containing (g.liter):Zn ions (0.2-3), phosphate ions (3-50), calculated as PO43-, organic N-oxide as accelerator (0.05-4), and an additional accelerator comprising (mg/liter):hydrogen peroxide (HP) or an equivalent amount of one or more compounds splitting off HP in aqueous acid solution, and nitrobenzene sulfonate ions (20-240).