METHOD OF MEASURING FILM THICKNESS OF SURFACE OXIDE FILM OF ZINC-BASED PLATED STEEL SHEET

摘要

It is a main object of the present invention to provide a technique for promptly and accurately measuring the thickness of an oxide film that has a thickness in the range of 10 nm to 100 nm and is formed on a galvanized steel sheet. Furthermore, it is another main object of the present invention to evaluate the press formability of a galvanized steel sheet including the oxide film on the basis of the measured thickness of the oxide film. A method for measuring the thickness of an oxide film formed on a galvanized steel sheet, comprising: irradiating the galvanized steel sheet with an electron beam accelerated to 3-6 kV using an electron probe micro analyzer or a scanning electron microscope equipped with a wavelength dispersive X-ray detector; and measuring the intensity of generated oxygen K± X-rays with the detector and a subsequent pulse height analyzer to eliminate the effect of second order zinc L± and L² X-rays.