Structural analysis of passive films on stainless steel by synchrotron radiation

In the development research of stainless steel, the stabilization mechanism of passive film on the stainless steel has not yet been elucidated. The reason for this is that the structural analysis of the passive films is difficult because its thickness is too thin (a few nm) for a standard X-ray diffraction study. In order to develop the technique of the structural analysis of the passive film, we applied the grazing incidence X-ray scattering (GIXS) and total-reflection XAFS to the passive films on SUS304L and SUS316L using SPring-8. The results of GIXS suggested that their atomic structures have the characteristic of spinel-type structure. From the results of total-reflection XAFS, it was indicated that the component of Cr was enriched in the passive films. This paper will review the history of the research of the passive film using synchrotron radiation at first, and report the results of our investigation of the structural analysis method of the passive films on the practical stainless steel mentioned above. (author)