Composite coated zinc-containing plated steel material superior in corrosion resistance, blackening resistance, coating adhesion, and alkali resistance

A steel material plated with Zn-containing material and having a composite coating formed thereon, superior in corrosion resistance, blackening resistance, coating adhesion, and alkali resistance characterized by having a composite coating formed by coating and drying on the surface of a plated steel material a treatment solution containing:

• a zirconium-containing compound comprising (i) a zirconium-containing anion having an anion comprised of [Zr(CO3)2(OH)2]2− or [Zr(CO3)3(OH)]3− or (ii) an ammonium salt, potassium salt, sodium salt containing the anion, a vanadyl (VO2+)-containing compound, a phosphoric acid compound, a cobalt compound, an organic acid, and water and having a pH of 7 to 14, the composite coating containing, with respect to the Zr element as 100 parts by mass, V in an amount of 10 to 45 parts by mass, P in an amount of 5 to 100 parts by mass, Co in an amount of 0.1 to 20 parts by mass, and the organic acid in an amount of 10 to 90 parts by mass, and wherein an appearance of the plated steel material is not changed after standing in a 70° C. and a relative humidity of 85% atmosphere for 144 hours.