title: Visualizing Nanoscale Distribution of Corrosion Cells by Open-Loop Electric Potential Microscopy.
abstract: Corrosion is a traditional problem but still one of the most serious problems in industry. To reduce the huge economic loss caused by corrosion, tremendous effort has been made to understand, predict and prevent it. Corrosion phenomena are generally explained by the formation of corrosion cells at a metal-electrolyte interface. However, experimental verification of their nanoscale distribution has been a major challenge owing to the lack of a method able to visualize the local potential distribution in an electrolytic solution. In this study, we have investigated the nanoscale corrosion behavior of Cu fine wires and a duplex stainless steel by in situ imaging of local corrosion cells by open-loop electric potential microscopy (OL-EPM). For both materials, potential images obtained by OL-EPM show nanoscale contrasts, where areas of higher and lower potential correspond to anodic areas (i.e., corrosion sites) and cathodic areas, respectively. This imaging capability allows us to investigate the real-time transition of local corrosion sites even when surface structures show little change. This is particularly useful for investigating reactions under surface oxide layers or highly corrosion-resistant materials as demonstrated here. The proposed technique should be applicable to the study of other redox reactions on a battery electrode or a catalytic material. The results presented here open up such future applications of OL-EPM in nanoscale electrochemistry.
authors.affiliation: Division of Electrical Engineering and Computer Science, Kanazawa University , Kakuma-machi, 920-1192 Kanazawa, Japan.|Research and Development Group, Center for Technology Innovation - Materials, Hitachi, Ltd. , 319-1292 Hitachi, Japan.
authors.forename: Kyoko
authors.initials: K
authors.lastname: Honbo
authors.affiliation: Division of Electrical Engineering and Computer Science, Kanazawa University , Kakuma-machi, 920-1192 Kanazawa, Japan.
authors.forename: Shoichiro
authors.initials: S
authors.lastname: Ogata
authors.affiliation: Division of Electrical Engineering and Computer Science, Kanazawa University , Kakuma-machi, 920-1192 Kanazawa, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Kitagawa
authors.affiliation: Division of Electrical Engineering and Computer Science, Kanazawa University , Kakuma-machi, 920-1192 Kanazawa, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Okamoto
authors.affiliation: Division of Electrical Engineering and Computer Science, Kanazawa University , Kakuma-machi, 920-1192 Kanazawa, Japan.
authors.forename: Naritaka
authors.initials: N
authors.lastname: Kobayashi
authors.affiliation: Research and Development Group, Center for Technology Innovation - Materials, Hitachi, Ltd. , 319-1292 Hitachi, Japan.
authors.forename: Itto
authors.initials: I
authors.lastname: Sugimoto
authors.affiliation: EBARA Corporation , 144-8510 Tokyo, Japan.
authors.forename: Shohei
authors.initials: S
authors.lastname: Shima
authors.affiliation: EBARA Corporation , 144-8510 Tokyo, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Fukunaga
authors.affiliation: EBARA Corporation , 144-8510 Tokyo, Japan.
authors.forename: Chikako
authors.initials: C
authors.lastname: Takatoh
authors.affiliation: Division of Electrical Engineering and Computer Science, Kanazawa University , Kakuma-machi, 920-1192 Kanazawa, Japan.|ACT-C, Japan Science and Technology Agency , Honcho 4-1-9, 332-0012 Kawaguchi, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Fukuma
keywords: atomic force microscopy; copper; local corrosion cell; open-loop electric potential microscopy; stainless steel