Effect of Surface Contamination of the nano-FeTi Hydrogen Storage Alloys on Reaction Rate
| Project/Area Number |
17560623
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Structural/Functional materials
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| Research Institution | Tokai University |
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Principal Investigator |
UCHIDA Hirohisa Tokai University, School of Engineering, Professor (20147119)
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| Co-Investigator(Kenkyū-buntansha) |
HARAKI Takeshi Tokai University, Future Science and Techhnology Jiont, Research Center (70439735)
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| Project Period (FY) |
2005 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥3,350,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥150,000)
Fiscal Year 2007: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2006: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2005: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Keywords | Hydrogen / Nano / Hydrogen storage alloy / FeTi |
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| Research Abstract |
The FeTi intermetallic compound is one of the most conventional hydrogen storage alloys, and much work has been done since the first finding of this interesting feature of FeTi by Reilly and Wiswall. FeTi is an attractive candidate for practical use as a hydrogen storage material because of its relatively inexpensive material costs and a hydrogen storage capacity around H/FeTi =1.9.
As is well known, the surface of FeTi exhibits very inactive behaviour on exposure to hydrogen gas. Cyclic hydrogenation-dehydrogenation is needed for the initial activation of FeTi at high temperatures and hydrogen pressures.
Recent studies on the synthesis of intermetallic compounds by mechanical alloying (MA) have been reported. However, the MA process pronouncedly reduces the hydrogen storage capacity. A similar marked reduction in the maximum hydrogen storage capacity was also found for milled Pd powder. The maximum hydrogen storage capacity does not dramatically recover for those alloys even after annealing treatment.
In this study, we prepared the nano-structured FeTi sample prepared by mechanical grinding (MG). And, we used a Sieverts' type apparatus for the measurement of the rate of hydrogen absorption and-investigated the effect of surface contaminations (low vacuum exposures time : 0min 1h) of the surface of the nano-structured FeTi sample on the hydrogen absorption kinetics.
From the measurement of the pressure dependence of the initial hydrogen absorption rate of the nano-structured FeTi, n was found changed from 1.0 to 0.5 as the surface contamination proceeded with increasing exposure time to low vacuum. This means that the rate determining step changed from the dissociation of H molecules on the alloy surface with 2 relatively thin oxide layers to the permeation of H atoms through grown surface oxide layers.
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Report
(4 results)
Research Products
(27 results)
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[Presentation] Properties of Hydrogen Absorption by Nano-Structured FeTi Alloys2008
Author(s)
T., Haraki, K., Oishi, Y., Miyamoto, M., Abe, T., Kokaji, S., Uchida, H., Uchida
Organizer
International Journal of Materials Research, Issue 2008/05, Cover photograph
Description
「研究成果報告書概要(欧文)」より
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