Composition and process for zinc-phosphate coating a metal surface, coated metal surface and a process for painting the coated surface

摘要

An acidic aqueous coating solution containing about 0.4 to about 1 g. I of zinc, about 5 to about 40 g/l of phosphate, optionally about 2 to about 5 g/l of chlorate, and about 0.01 to about 0.2 g/l of nitrite. The solution is useful for forming on metal surfaces zinc phosphate coatings that exhibit excellent adhesion to a paint film and excellent corrosion resistance after painting when used as an undercoat for the cationic electrodeposition of a paint film. The solutions are especially for application by spraying, preferably using an intermittent spray technique, when said chlorate is included.