Abstract
An electrochemical ellipso-microscopy cell was expanded by combination with a channel flow electrode method. Fe-6 wt% Cr was potentio-dynamically polarized to passive region in acidic 0.15 M Na2SO4 solution. During the polarization, the electrolyte solution was flowed at various flow rates under laminar flow condition, and the Fe-6Cr sample surface was monitored by the ellipso-microscope. Simultaneously, two detector electrodes in the solution downstream were potentio-statically polarized to detect Fe and Cr species dissolved from the sample. Dissolution rates of Fe and Cr species in active region were depended on the flow rate. When AES analysis was conducted after the polarization of Fe-6Cr, depth profiles revealed that Cr enrichment in the outermost layer of passive film. Cr ratio in metal cations on the passive film increased with increaseing in flow rate. These behaviors implied that the corrosion resistance of passive film formed under solution convection was improved by oxidized products generated in active region. In the presentation, Fe-6Cr anodic dissolution behavior and enrichment of Cr species are discussed.