Correspondence Between Electrochemical Fluctuations And Phenomenon For Localized Corrosion Of Less-Noble Metals

摘要

The application of electrochemical noise (Fluctuation) analysis for localized corrosion have been studied. Foils of zinc, aluminum and magnesium were used as specimens for electrochemical cell simulating localized corrosion. Time variations of short circuited potential and current were measured in these solutions, and simultaneously the surfaces of specimens were observed using microscope with television monitor. Two types fluctuation were detected. In the case of aluminum and magnesium, It was seemed that the fluctuations result from hydrogen evolution on the active site in the crevice. In the case of magnesium, fluctuations appeared on the trendy component of the corrosion potential. And that was random one. It was seemed that these fluctuations result from the hydrogen evolution on the active site in the crevice of magnesium from the microscopic observation. In the case of zinc, It was seemed that the fluctuations result from the dissolution on the active site in the crevice and generation of corrosion products on the cathodic site on the outer site.