TREATING SOLUTION FOR SURFACE TREATMENT OF METAL AND SURFACE TREATMENT METHOD

摘要

Surface treatment of a metal material comprising iron and/or zinc, comprises contacting the metal material with a treating solution for surface treatment comprising (A) a compound containing at least one metal element selected from Ti, Zr, Hf and Si and (B) a fluorine-containing compound as a supply source of HF, where the ratio (K = A/B) of the total mole weight A of the metals, namely Ti, Zr, Hf and Si, in the compounds of the component (A) to the mole weight B of the fluorine-containing compound (B) in terms of the HF obtained by converting all the fluorine atoms in the fluorine-containing compound is in the range of 0.06 less than or equals K less than or equals 0.18, and the total molar concentration of the metals, namely Ti, Zr, Hf and Si, in the compounds of component (A) is in the range of 0.05 to 100 mmol/L. The treating solution for surface treatment optionally further comprises at least one element selected from among Ag, Al, Cu, Fe, Mn, Mg, Ni, Co and Zn. The surface treatment method uses a treating bath free of a component harmful to the environment and can also be employed for depositing a surface treatment film excellent in corrosion resistance after application, on the surface of a metal material containing at least one of iron and zinc.