Coated steel sheet having excellent corrosion resistance and method for producing the same

A coated steel sheet having corrosion resistance comprising:

• a zinc or a zinc alloy plated steel sheet or an aluminum or an aluminum alloy plated steel sheet;
• a composite oxide coating formed on the surface of the plated steel sheet;
• an organic coating formed on the composite oxide coating;
• said composite oxide coating containing:
• (α) oxide particles;
• (β) at least one metal selected from the group consisting of Mg, Ca, Sr and Ba, or said metal in a form of at least one of a compound and a composite compound;
• and
• (γ) at least one of a phosphoric acid and a phosphoric acid compound,
• the composite oxide coating has a thickness of from 0.005 to 3 μm, or has a total coating weight of the component (α), the component (β) converted to said metal, and the component (γ) converted to P2O5, of from 6 to 3,600 mg/m2;
• said organic coating comprising a product of a reaction between a film-forming organic resin (A) and an active-hydrogen-laden compound (B), a part or whole of which compound (B) comprises a hydrazine compound (C) containing active hydrogen, wherein the hydrazine compound (C) containing active hydrogen is at least one compound selected from the group consisting of an active-hydrogen-laden pyrazole compound and an active-hydrogen-laden triazole compound;
• and
• the organic coating having a thickness of from 0.1 to 5 μm.