Composition for metal surface treatment, treating liquid for surface treatment, method of surface treatment, and surface-treated metallic material

摘要

An object is to provide a surface treating composition which is capable of depositing a coating having excellent corrosion resistance after further coating on the surface of a metal material such as iron base metal material by using a treating solution which does not contain environmentally harmful components, namely, by using an environmentally less harmful treating solution which had been difficult to obtain in the prior art technology. This object is achieved by a surface treating composition for a metal containing iron and/or zinc comprising the following component (A), component (B), and component (C):
(A) a compound containing at least one element selected from the group consisting of Ti, Zr, Hf, and Si;
(B) a compound containing Y and/or a lanthanoid element; and (c) nitric acid and/or a nitrate compound;
wherein the ratio K1 (=B/A) which is a ratio of the total weight concentration B of the Y and/or the lanthanoid element in the component (B) to the total weight concentration A of the element in the component (A) is in the range of 0.05 ‰¤ K1 ‰¤ 50; and the ratio K2 (=C/A) which is a ratio of the total weight concentration C of nitrogen atom in the component (C) calculated in terms of No 3 to the total weight concentration A is in the range of 0.01 ‰¤ K2 ‰¤ 200.