2002 Fiscal Year Final Research Report Summary
New Utilization of Nitrogen using Metal Nitrides
| Project/Area Number |
12450352
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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 |
無機工業化学
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| Research Institution | Osaka University |
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Principal Investigator |
MACHIDA Ken-ichi Osaka University, Collaborative Research Center for Advanced Science and Technology, Professor, 先端科学技術共同研究センター, 教授 (00157223)
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| Co-Investigator(Kenkyū-buntansha) |
ITOH Masahiro Osaka University, Collaborative Research Center for Advanced Science and Technology, Assistant Professor, 先端科学技術共同研究センター, 助手 (90343243)
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| Project Period (FY) |
2000 – 2002
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| Keywords | Intermetallic compounds / Atomic nitrogen / Nitrogen absorption-desorption / Ammonia synthesis / Rare earth metal |
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| Research Abstract |
In this study, the nitrogen absorption and desorption properties of the iron based intermetallic compounds were investigated. Furthermore, the fabrication of functional material by the change of structure and electronic state was performed on Fe_3N/Y_2O_3 nanocomposite for the microwave absorption. The summary is as followed.
Nitrogen absorption and desorption characteristics on rare earth-iron intermetallic compounds, R_2Fe_<17> and RFe_7, were performed. The nitrogen absorption and desorption properties of RFe_7 was superior to that of R_2Fe_<17> because of the ease of nitrogen diffusion due to the difference of crystal structure between them.
Y_2Fe_<17> transforms from crystalline to amorphous state by absorption of nitrogen into its crystal lattice. The calculation by the DV-Xα cluster method revealed that the insertion of nitrogen into the crystal lattice unstabilizes the Y-Fe and Fe-Fe bond strength around the nitrogen atom in octahedral Y_2Fe_4 or tetrahedral Y_2Fe_2 unit.
The fine composite powders of Fe-Mox (M=Ce, Al, Si, Sr, and Zr) were prepared. High catalytic activity of ammonia decomposition was observed on Fe-(Ce, Zr)O_2. This result is ascribable to the enhancement of surface area and solid acidity of(Ce, Zr)O_2 to adsorb ammonia and increase the reaction probability.
The electromagnetic wave absorption properties of Fe_3N/Y_2O_3 nanocomposites were characterized. The resin composites with 80 wt% Fe_3N/Y_2O_3 powders exhibited excellent electromagnetic wave absorption properties (RL<-20 dB) in a frequency range of 0.6-4.4 GHz, with thickness of 3.3-19.3 mm.
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Research Products
(8 results)
