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A new technique by XAFS (X-ray Absorption Fine Structures) and XANES (X-ray Absorption Near Edge Structures) has been developed for in situ observation of metal corrosion. XAFS and XANES spectra were obtained with a special electrochemical cell to elucidate pitting for stainless steel. A sheet of stainless steel was attached below a reservoir of a specific aqueous environment with thin films. The solution in the reservoir attached to the metal thorough the film, and the solution inside the film corresponds to an artificial pit. X-ray beams pass through the film containing the solution, and XAFS and XANES measurements were performed in a transparent geometry with keeping the specimen at a pitting potential. Measurements were performed for Cr-K, Mo-K, Cl-K and Br-K edges, and changes of concentrations and coordination states of ions were successfully obtained as a function of the distance (d(z)) from the metal/solution interface.Concentrations of chromium and bromide ions inside the artificial crevice of Fe-18Cr-12Ni-2Mo (mass%) alloy shows a linear dependence on the distance d(z). Structures of bromide ion were changed with positions; the distance between bromide ion and the nearest-neighboring ion at a position near the interface was shorter than that at a position far from the interface. This indicates the formation of hydrobromo-complex near the metal/solution interface.The state of molybdenum inside the artificial crevice of Fe-18Cr-20Ni-5Mo (mass%) alloy was investigated using two solutions: LiCl and LiBr. The formation of the [MoO 4 (H 2 O) 2 ] 2Ϫ octahedra was observed in both solutions, but there was observed a significant difference in networking of the octahedral. In LiCl solutions it was similar to that of molybdate ions (MoO 4 2Ϫ ), but in LiBr it was rather different form that of molybdate ions. This shows that the favorable effects of molybdenum can be attributed to the formation of MoO 4 2Ϫ network near the interface.KEY WORDS: crevice corrosion; X-ray absorption fine structure; X-ray absorption near edge structures; stainless steel; bromine; chlorine; chromium; molybdenum; ion coordination.are easily expected to be susceptible to experimental conditions, and in situ observation would be essential for understanding the effects of molybdenum.However, because of experimental difficulties, there have been few reports on direct observation of structures of ions inside pits. Recently X-ray absorption and fluorescence measurement has become one of powerful methods for the in situ study of chemical and physical changes during electrochemical and corrosion processes. It was observed dissolved metal ion concentration inside artificial pit and content of salt films for Type304 SS by using in situ X-ray microprobe technique. 7,8) In this study, we have tried to develop an in situ observation technique by XAFS (X-ray Absorption Fine Structures) and XANES (X-ray Absorption Near Edge Structures) measurements conducted on a special electrochemical cell to elucidate pitting in order to measure a change of concen...

Abstract. Ultrasonic impact treatment(UIT) is a remarkable post-weld treatment, which reduce not only in external stress concentration, but also in residual stress in a welded joints. Internal and surface stresses were investigated on UIT treated welded joints by neutron and X-ray diffraction method. This paper discuses the effect of internal and surface residual stress and surface stress concentration after UIT on fatigue resistance by the comparison of fatigue experiments to predictions calculated with the results of the experimental investigations.

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