Nondestructive depth profiling of oxidized FeCr alloy by the glancing-incidence and -takeoff X-ray fluorescence method

We have developed the glancing-incidence and -takeoff X-ray fluorescence (GIT-XRF) method for a nondestructive surface analysis at normal air pressure. Since the GIT-XRF method utilizes an X-ray total reflection phenomenon, which occurs on a flat surface, an Fe-20%Cr alloy bulk was carefully polished with a precision-polishing machine. The polished alloyʹs surface was measured by the GIT-XRF method. The experimental results were compared with the calculated curves, and the thickness of the oxide layer and the depth profile were evaluated by fitting the theoretical curve to the data. As a result, it was found that the surface of the Fe-20%Cr alloy oxidized at 873 K for 5 min was covered with Fe oxide. Moreover, when the Fe-20%Cr surface was oxidized at 1323 K for 5 min, it was entirely covered with a Cr oxide film.