| Project/Area Number |
08555166
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Material processing/treatments
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
SEO Masahiro Hokkaido Univ., Fac.of Eng., Pro., 大学院・工学研究科, 教授 (20002016)
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| Co-Investigator(Kenkyū-buntansha) |
FUJIMOTO Eiji Hokuto Denko CORP,Head Res., 技師長(研究職)
FUSHIMI Koji Hokkaido Univ., Fac.of Eng., Res.Ass., 大学院・工学研究科, 助手 (20271645)
TAKAHASHI Hideaki Hokkaido Univ., Fac.of Eng., Pro., 大学院・工学研究科, 教授 (70002201)
冨土元 英二 北斗電工株式会社, 技師員(研究職)
富士元 英二 北斗電工(株), 技師長
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| Project Period (FY) |
1996 – 1997
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| Project Status |
Completed (Fiscal Year 1997)
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| Budget Amount *help |
¥9,100,000 (Direct Cost: ¥9,100,000)
Fiscal Year 1997: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1996: ¥7,400,000 (Direct Cost: ¥7,400,000)
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| Keywords | Scanning Electrochemical Microscope / Passive Film / Evaluation of Heterogeneity / Redox Reaction / Probe Current Image / Polycrystalline Surface / Iron Electrode / Titanium Electrode / 酸化・還元反応 / 電流像 |
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| Research Abstract |
A scanning electrochemical microscope (SECM) was successfully constructed to evaluate the heterogeneity of passive films. A cross section of Pt wire with a diameter of 10mum sealed into glass tube was used as a scanning probe electrode. A commercial type of potentiostat was improved to a bipotentiostat which is capable of controlling independently the potentials of probe and specimen electrodes. The constructed SECM has a lateral resolution of 20mum, wich is two times as much as a diameter of probe electrode.
Two iron plates embedded in epoxy resin were anodically polarized at different potentials in pH8.4 borate solution to form passive films with different thickness. Afterward, in pH8.4 borate solution containing Fe (CN) _6^<4->, the probe electrode was polarized at the potentioal at which Fe (CN) _6^<4-> can be oxidized to Fe (CN) _6^<3->, whereas the two iron plates were polarized at the potetial at which Fe (CN) _6^<3-> can be reduced to Fe (CN) _6^<4->. The difference in thickness
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between passive films on two iron plates could be distinguished from the probe current image. The heterogeneity of passive film formed on polycrystalline iron electrode with distinct grains was also examined in the same manner. The probe current image depended on the grain orientation and the probe current increased in the order of grain orientation, {100}, {111}, and {110}. This difference in probe current results from the difference in thickness of passive films.
An electropolished titanium specimen was anodically oxidized in pH 8.4 borate solution to form the passive film. The heterogeneity of the passive film was evaluated using the SECM.It is found from the probe current image that the heterogeneity of the passive film increases with increasing anodic potential for film formation above 4 V_<SHE>. This heterogeneity corresponds to the shape of each substrate grain, suggesting that the passive film on each substrate grain differs in thickness and defective structure.
A scanning photoelectrochemical microscope (SPECM) is being developed by attaching an optical fiber to the probe electrode of SECM.SPECM would be useful to evaluate the difference in defective structures of the passive films. Less
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