Determination of film thickness of plating layers (zinc, cadmium or tin) on iron by fluorescent X-rays

Abstract

The film thickness of various platings on iron plate is determined by the measurement of fluorescent X-ray intensity of FeKα from the substrate iron. The results on Zn platings are shown in Figs. 2 and 3, and those on Cd and Sn platings are, respectively, in Figs. 4 and 5. The examinations of the slopes of full lines in those figures indicate that the absorption of primary X-rays by plating films, namely, μ1 in the equation(2), is almost negligible, not equal to one4) corresponding to the absorption edge wavelengths of the substrate metals. Therefore, provided that the mass absorption coefficient of FeKα by plating films, the radiation angle (θ2) of fluorescent X-rays and the density of the plating metals are known or measurable, the thickness of plating film is calculated from the equation(4) by the comparison of FeKα intensities on pure and electroplated iron plates. However, to obtain much higher accuracy, considerations on absorption and enhancement effects of primary X-rays are necessary. © 1965, The Japan Society for Analytical Chemistry. All rights reserved.