Improved Method for a metal surface phosphate based on iron, zinc, or combinations of these Metals

摘要

Iron- or zinc-based metal surfaces, especially on a component having both and iron-based surface and a zinc-based surface, for example car bodies, are phosphated by dipping them into an acidic aqueous solution containing: (a) from 0.5 to 1.5 g/l of zinc ion; (b) from 5 to 30 g/l of phosphate ion; (c) from 0.6 to 3 g/l of manganese ion; and (d) a conversion coating accelerator. The phosphated metal surfaces are then suitable especially for electrocoating.