1997 Fiscal Year Final Research Report Summary
Development of Long-Life-Span Coating Films
| Project/Area Number |
07555496
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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 |
Structural/Functional materials
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| Research Institution | The University of Tokyo |
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Principal Investigator |
TSUJIKAWA Shigeo The University of Tokyo, School of Engineering, Professor, 工学系研究科, 教授 (20011166)
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| Co-Investigator(Kenkyū-buntansha) |
OGINO Rikuo Nihon Parkerizing Co., LTD., Central Research Laboratories, Steel Surface Treatm, センター長(研究職)
SHINOHARA Tadashi The University of Tokyo, School of Engineering, Associate Professor, 工学系研究科, 助教授 (70187376)
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| Project Period (FY) |
1995 – 1997
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| Keywords | cathodic protection / titanium oxide / n-type semiconductor / oxide semiconductor / photoelectrochemistry |
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| Research Abstract |
To demonstrate the applicability of cathodic protection of metals by a semiconductor coating under illumination, the photoelectrochemical behaviors of Cu, carbon steel and stainless steel coated with thin TiO_2 film by a sol-gel method have been studied in our laboratory. However, for the adoption of this method as a way of "cathodic protection of metals under sun light", there was a serious problem that still had to be overcome : very frequently, the electrode potential reaches the active region soon after stopping illumination. Nevertheless, some specimens coated with TiO_2 exhibited an interesting phenomenon, which we call "Memory-Effect", where even after stopping illumination, the photovoltage decreases very slowly, and the cathodic potential is kept for several hours. The main objective of this research is to explain the "Memory-Effect", and show that this phenomenon makes possible the cathodic protection of metals by sun light during a whole day.
It was found that the existence of a slow decline of photovoltage in TiO_2 sol-gel coating on type 304 stainless steel was due to the diffusion of Fe from the substrate into the coating. The use of Fe as dopant in the sol solution showed the possibility of the cathodic protection of metals by TiO_2 coating even for night-time.
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