2001 Fiscal Year Final Research Report Summary
In-Situ Observation on Localized Corrosion of Corrosion - Resistant Alloys by Using Micro-Electrode / Raman Scattering / Ion Chromatography System
| Project/Area Number |
11450267
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Material processing/treatments
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| Research Institution | MURORAN INSTITUTE OF TECHNOLOGY |
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Principal Investigator |
MISAWA Toshihei Muroran Institute of Technology (MIT), Dept. of Materials Science & Engineering, Prof., 工学部, 教授 (70005982)
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| Co-Investigator(Kenkyū-buntansha) |
KOMAZAKI Shin-ichi MIT, Dept. of Materials Science & Technology, Research Assoc., 工学部, 助手 (70315646)
SAKAI Akira MIT, Dept. of Electrical & Electronic Engineering, Assoc. Prof., 工学部, 助教授 (70136422)
TANABE Hiroyoshi MIT, Dept. of Applied Chemistry, Assoc. Prof., 工学部, 助教授 (70125376)
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| Project Period (FY) |
1999 – 2001
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| Keywords | PH micro-sensor / Ir electrode sensor / localized pH measurement / pH decrease (acidification) / Cr hydrolysis product / localized corrosion / in-situ Raman scattering / metal hydride |
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| Research Abstract |
The research results were obtained from the following three kinds of standpoints.
(1) Two kinds of pH micro-sensors of an iridium (Ir) thin wire oxidized by alternating current electrolysis and platinum (Pt) thin wire casted with H^+ iono-fore were at first prepared for measuring localized pH and as a tip of scanning electrochemical microscopy (SECM) on the alloy electrode surface.
(2) Localized pH observed on the anodic dissolved alloy electrodes of Fe-(0-9 mass %)Cr-(B, N) in Na_2SO_4 aqueous solution of pH 8.9 fell down to about 3.9 by acidification of Cr hydrolysis product in Fe-Cr alloy and the addition of B or N in 9Cr steel suppressed the acidification by buffer action. In-situ micro-Raman scattering spectra showed an initial corrosive products of Fe(OH)_2 and Green Rust II on the alloy surfaces.
(3) Localized pH distribution in electrolyte and in-situ micro-Raman scattering investigation under H_2 atmosphere for La-Ni_5 metal hydride were performed to get microscopic information. The results indicates that the catalytic fresh surface area created by cracking plays an important role in the hydride formation.
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