| abstract |
The present invention provides a composite coated zinc-containing plated steel which is excellent in corrosion resistance, blackening resistance, paint adhesion and alkali resistance, in contrast to plated steel materials treated with conventional chromate replacement techniques. The composite coating zinc-containing plated steel of the present invention is a surface of the plated steel with a treatment solution of pH 7 to pH 14 containing a basic zirconium compound, a vanadil (VO 2 + ) -containing compound, a phosphoric acid compound, a cobalt compound, an organic acid and water. It has a composite film formed by apply | coating and drying, and this composite film has 10-45 mass% of V, 5-100 mass% of P, 0.1-20 mass% of Co, and 10-90 organic acid with respect to 100 mass% of Zr. It is characterized by containing in the ratio of mass%. |