Patent ID: 6861160

Claim:
A zinc-base plated steel sheet comprising: a zinc-base plating layer; a composite coating film on the zinc-base plating layer, said composite coating film containing a P ingredient, a N ingredient and at least one metallic element selected from the group consisting of Mg, Al, Ca, Ti, Mn, Fe, Co, Ni, Cu and Mo, as components for structuring the composite coating film; said N ingredient and said at least one metallic element selected from the group consisting of Mg, Al, Ca, Ti, Mn, Fe, Co, Ni, Cu and Mo having a total amount (a), said P ingredient having an amount (b); a molar ratio of (a)/(b) being from 0.2 to 6; the P ingredient being in an amount expressed by a P 2 O 5 conversion value, and the N ingredient being in an amount expressed by an ammonium conversion value; and the composite coating film having a coating weight of 5 to 300 mg/m 2 as the amount of the P ingredient.