| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for easily evaluating grain boundary corrosion sensitivity in stainless steel in its environment, without performing long-time dipping tests. SOLUTION: An evaluation method of grain boundary corrosion sensitivity includes a surface-polishing process for polishing the measurement surface of stainless steel, a potential stabilization process for installing the stainless steel in a liquid phase cell under nearly the same conditions as specific usage environment, providing an electrode in each cell, and then stabilizing potential within 10 minutes to 5 hours, a film thickness calculation process for measuring reflected light to incidence light by microscope ellipsometry, having a resolution of up to 20μm using a CCD camera, and calculating the film thickness in a grain boundary film and a film in a grain formed on the surface of the stainless steel, and a sensitivity evaluation process for changing potential at least two times, then repeating the film thickness calculation process for a total of at least three times, and then plotting the film thickness in the grain boundary and inside the grain with respect to the potential change.
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