1987 Volume 73 Issue 16 Pages 2306-2313
The angular distribution measurement of X-ray photoelectron spectroscopy (XPS) proposed by FADLEY et al. is one of the techniques which enable in-depth analysis without ion sputter etching. This technique has been applied mainly to well-defined samples such as vacuum deposits.
This paper describes the application of this technique to the surface analysis of steels : oxide films formed on a low carbon steel and chromate layer on Cr plated steel.
When the oxide films are analyzed by using conventional Ar+ion etching, both of the intensity ratios of Fe2p3/2 to O 1s and the binding energies of Fe2p3/2 obtained for various kinds of iron oxide converge to certain values with the increment of ion dose, which makes it impossible to identify the structure of oxide films. Meanwhile the angular distribution measurement can identify the layered structure of oxide films by adopting a precise elimination of surface contaminants and correction of binding energy of XPS peaks.
In the application of the angular distribution measurement to chromate layers on Cr plated steel, marked effects of the thickness of oxidized layer and the roughness of steel surface are found. It isshown that the effect of thickness is independent of take-off angle, and that the effect of roughness can be eliminated by using an empirical equation.
