Hostname: page-component-76fb5796d-dfsvx Total loading time: 0 Render date: 2024-04-26T21:46:24.349Z Has data issue: false hasContentIssue false
  • English
  • Français

Microstructure of the MgH2 Synthesized by Hydriding Chemical Vapor Deposition

Published online by Cambridge University Press:  26 February 2011

Itoko Saita  and
Tomohiro Akiyama
Itoko Saita
Affiliation:
itoko@eng.hokudai.ac.jp, Hokkaido University, Energy Media, CAREM, Kita 13 Nishi 8, Kita-ku, Sapporo, 060-8628, Japan
Tomohiro Akiyama
Affiliation:
takiyama@eng.hokudai.ac.jp, Hokkaido University, Energy Media, CAREM, Sapporo, 060-8628, Japan
Get access

Abstract

It is hardly achieved to prepare highly pure MgH2 by the conventional method of solid-gas reaction between solid magnesium and hydrogen; therefore, we proposed and succeeded to synthesize MgH2 by Hydriding Chemical Vapor Deposition (HCVD). Very interestingly, the HCVDed MgH2 was made of single crystals with fibrous figures; however, further detail of the HCVDed product had not been studied. Therefore the aim of this study was to examine the HCVDed MgH2 in hydrogen storage and to observe the microstructure of the HCVDed MgH2 after the hydrogen desorption and absorption.

As the results of Pressure-Composition-Isotherm (PCT) measurement, the HCVDed MgH2 reversibly absorbed and desorbed 7.6 mass% hydrogen, as much as the theoretical maximum hydrogen capacity of magnesium, without any activation treatment. The equilibrium pressure was slightly lower than the reported value. Before and after the PCT measurement, the HCVDed MgH2 did not showed noticeable difference in figure; however, MgHx, which was prepared dehydriding the HCVDed MgH2 in the PCT, showed significant difference in figure: It had zebra stripes in the SEM observation. This observation showed that the hydrogen storage and release went in the radious direction and the hydrogen diffusion was no more rate-limiting. The phase boundaries of Mg and MgH2 involving strain should affected on the plateau pressure in PCT.

Keywords

chemical vapor deposition (CVD) (deposition)microstructureMg
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 971: Symposium Z – Hydrogen Storage Technologies , 2006 , 0971-Z08-10
Copyright
Copyright © Materials Research Society 2007

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Akiyama, T., Isogai, H. and Yagi, J.: J. Alloys Compd., 252 (1997) L1–L4.Google Scholar
2. Nakamori, Y., Kitahara, G., Orimo, S.: J. Power Sources, 138 (2004) pp. 309–312.Google Scholar
3. Leng, H. Y., Ichikawa, T., Hino, S., Isobe, S., Hanada, N., Fujii, H., J. Power Sources, 159 (2006) 120 Google Scholar
4. Saita, I., Toshima, T., Tanda, S., Akiyama, T.: Materials Transactions, 47 (2006) pp. 931–934 Google Scholar
5. Saita, I., Toshima, T., Tanda, S., Akiyama, T.: J. Alloys Compd., submitted.Google Scholar
6. Vigeholm, B., Kjoller, J., Larsen, B., Pedersen, A. S.: J. Less-common Metals, 89 (1983) pp. 135–144.Google Scholar
7. Stampfer, J. F. Jr, Holley, C. E. Jr, Stuttle, L. F.: J. Am. Chem. Soc, 82 (1960) 3504–3508 Google Scholar