A pitting corrosion on copper tube is a serious problem because it may lead to a leak accident. Though the conditions related to the pit initiations on copper were reported ^{1, 2}, the mechanisms associated with the pit initiations on copper have not been clarified yet.

In order to investigate pit initiations on copper, we previously developed a real-time surface observation system with a channel flow double electrode (CFDE) ³. Our group ^4-7 applied the CFDE to investigation of anodic dissolution mechanisms of metals and alloys because metallic ions dissolved from working electrode (WE) can be detected by arranging a detecting electrode (DE) downstream of the WE. The developed system enables us the in-situ surface observation of copper during anodic polarization since a video recording can be carried out during the measurement. In the present study, the pit initiations on coper during anodic polarization was discussed based on the results of the dissolution currents of cupric or cuprous ions and in-situ surface observation of copper surface.

References

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