Hostname: page-component-cd9895bd7-jkksz Total loading time: 0 Render date: 2024-12-28T00:42:57.781Z Has data issue: false hasContentIssue false

Hydrogen storage characteristics of mechanically alloyed amorphous metals

Published online by Cambridge University Press:  31 January 2011

J. H. Harris
Affiliation:
BP America, Warrensville Research Center, 4440 Warrensville Center Road, Cleveland, Ohio44128
W. A. Curtin
Affiliation:
BP America, Warrensville Research Center, 4440 Warrensville Center Road, Cleveland, Ohio44128
L. Schultz
Affiliation:
Siemens AG, Research Laboratories, D-8520 Erlangen, Federal Republic of Germany
Get access

Abstract

The hydrogen storage properties of a series of mechanically alloyed (MA) amorphous Ni1xZrx alloys are studied, using both gas phase and electrochemical techniques, and are compared to H storage of rapidly quenched (RQ) amorphous Ni1−xZrx. In the MA alloys, hydrogen resides in the Ni4−nZrn (n = 4,3,2) tetrahedral interstitial sites, with a maximum hydrogen-to-metal ratio of 1.9(4 n)xn(1 − x)4 − n. These features are identical to those of the RQ alloys and indicate that the topological and chemical order of the MA and RQ materials are essentially the same. However, the typical binding energy of hydrogen in a Ni4−nZrn site, En, is shifted in the MA alloys relative to the RQ alloys and the distribution of binding energies centered on En is significantly broader in the MA samples. Thus, the MA and RQ alloys are not identical and sample annealing does not alter this subtle distinction. The sensitivity of H storage to the presence of chemical order in binary alloys are analyzed theoretically and the data are found to be most consistent with little or no chemical order (random alloys).

Type
Articles
Copyright
Copyright © Materials Research Society 1988

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

1Hellstern, E. and Schultz, L., Appl. Phys. Lett. 48, 124 (1986).CrossRefGoogle Scholar
2Bruening, R., Altounian, Z., Strom-Olsen, J. O., and Schultz, L., in the Proceedings of the 6th International Conference on Rapidly Quenched Metals (Elsevier, New York, 1988).Google Scholar
3Weeber, A. W., Meer, K. Van der, Bakker, H., deBoer, F. R., Thijsse, B. J., and Jongste, J. F., J. Phys. F: Met. Phys. 16, 1897 (1986).CrossRefGoogle Scholar
4Schultz, L., Hellstern, E., and Thomae, A., Europhys. Lett. 3, 921 (1987).CrossRefGoogle Scholar
5Hellstern, E. and Schultz, L., Appl. Phys. Lett. 49, 1163 (1986).CrossRefGoogle Scholar
6Koch, C. C., Cavin, O. B., McKamey, C. G., and Scarbrough, J. O., Appl. Phys. Lett. 43, 1017 (1983).CrossRefGoogle Scholar
7Dolgin, B. P., Vanek, M. A., McGory, T., and Ham, D. J., J. NonCryst. Solids 87, 281 (1986).CrossRefGoogle Scholar
8Harris, J. H., Curtin, W. A., and Tenhover, M. A., Phys. Rev. B 16, 5784 (1987).CrossRefGoogle Scholar
9Curtin, W. A. and Harris, J. H., in Ref. 2.Google Scholar
10Luedecke, C. M., Deublein, G., and Huggins, R. A., J. Electrochem. Soc. 132, 52 (1985).CrossRefGoogle Scholar
11Aoki, K., Horata, A., and Masumoto, T., in Proceedings of the 4th International Conference on Rapidly Quenched Metals, edited by Masumoto, T. and Suzuki, K. (Japan Institute of Metals, Sendai, 1982), p. 1649.Google Scholar
12Kirchheim, R., Acta Met. 29, 835 (1981).CrossRefGoogle Scholar
13Cowley, J. M., Diffraction Physics (North-Holland, Amsterdam, 1975).Google Scholar
14As discussed in Ref. 8 for the random alloy model, it is extremely important to show that blocking interactions considerably alter the number of A4–n Bn sites which can be occupied, but only in an x- and n-independent manner. Thus, the random alloy statistics xn (1 – x)4–n are preserved but with a prefactor Neff ≃ 1.9 that is much smaller than the total number of tetrahedral interstitial sites per atom, which is in the range of 5-6. With CSRO, the total number of A4–n Bn sites is altered and, in principle, the detailed blocking effects are also modified, which could partially cancel CSRO effects on the H storage. Our simulation results on H storage in the tetrahedral sites of bcc A1–x Bx alloys show blocking effects to be modified only very slightly in comparison to the variations in the total number of tetrahedra. Hence, modification to H storage from modified blocking at finite α are neglected in our analysis.Google Scholar
15Lee, A., Etherington, G., and Wagner, C. N. J., J. Non-Cryst. Solids 61 and 62, 343 (1984).Google Scholar