Hostname: page-component-586b7cd67f-rcrh6 Total loading time: 0 Render date: 2024-11-25T22:24:58.511Z Has data issue: false hasContentIssue false
  • English
  • Français

Nucleation and Growth of MoSi2 Pest During Low Temperature Oxidation

Published online by Cambridge University Press:  01 January 1992

T. C. Chou  and
T. G. Nieh
T. C. Chou
Affiliation:
Lockheed Research and Development Division, O/93-60, B/204, Palo Alto, CA 94304
T. G. Nieh
Affiliation:
Lawrence Livermore National Laboratory, L-350, P. O. Box 808, Livermore, CA 94550
Get access

Abstract

The phenomenon of “MoSi2 pest” has been studied in detail by low temperature oxidation of various polycrystalline MoSi2 monoliths and composites. Single crystalline samples were studied to address the nucleation and growth of pest reaction. Pest of MoSi2 was observed to occur at temperatures between 375 and 500°C. Samples after pest reactions yielded to powdery reaction products of MoO3 whiskers, SiO2 clusters, and residual MoSi2 particles. Although all the samples showed complete disintegration after sufficient oxidation durations were rendered, the kinetics of pest disintegration varied among different samples. By performing interrupted oxidation tests, pest reaction was found to consist of nucleation and growth stages, with the former stage acung as the rate-limiting step. Furthermore, the nucleation of pest reaction was found to be closely related to the formation of MoO3, which was preferentially formed at such defect sites as intergranular boundaries and cracks. Mechanisms leading to the pest disintegration of MoSi2 are discussed in light of the nucleation and growth of pest reaction.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 288: Symposium L – High-Temperature Ordered Intermetallic Alloys V , 1992 , 965
Copyright
Copyright © Materials Research Society 1995

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. Fitzer, Von E., “Molybdenum Disilicide as High-Temperature Material,” Plansee Proc., 2nd Seminar, Reutte/Tyrol, 1955, pp. 56-79 (published in 1956).Google Scholar
2. Schilichting, J., High Temperature-High Pressure, 10, 241 (1978).Google Scholar
3. Searcy, A. W., J. Am. Ceram. Soc. 40, 431 (1957).Google Scholar
4. Berkowitz-Mattuck, J. B. and Dils, R. R., J. Electrochem. Soc. 112, 583 (1965).Google Scholar
5. Wirkus, C. D. and Wilder, D. R., J. Am. Ceram. Soc. 49, 173 (1966).Google Scholar
6. Samsonov, G. V., “Silicides and Their Uses in Engineering,” (Akad. Nauk. Ukr. SSR, Kiev, 1959).Google Scholar
7. Carter, D. H., “SiC Whisker-Reinforced MoSi2,” LA-11411-T (Los Alamos National Laboratory, New Mexico, 1988).Google Scholar
8. Aikin, R. M. Jr., Scripta Met. et Mat. 26, 1025 (1992).Google Scholar
9. Fitzer, E. and Remmele, W., 5th International Conference on Composite Materials (Metallurgical Society Inc., Warrendale, PA, 1985) pp. 515–530.Google Scholar
10. Fitzer, E. and Schmidt, F. K., High Temperature-High Pressure, 3, 445 (1971).Google Scholar
11. Lu, T. C., Evans, A. G., Hecht, R. J., and Merabian, R., Acta Met. 39, 1853 (1991).Google Scholar
12. Meschter, P. J., Met. Trans. A23, 1763 (1992).Google Scholar
13. Rausch, J. J., ARF 2981-4, Armour Research Foundation, August 31, 1961, NSA 15-31171.Google Scholar
14. Westbrook, J. H. and Wood, D. L., J. Nucl. Mater. 12, 208 (1964).Google Scholar
15. McKamey, C. G., Tortorelli, P. F., DeVan, J. H., and Carmichael, C. A., J. Mater. Res. 7, 2747 (1992).Google Scholar
16. Chou, T. C. and Nieh, T. G., Scripta Met. et Mat. 26, 1637 (1992).Google Scholar
17. Chou, T. C. and Nieh, T. G., Scripta Met. et Mat. 27, 19 (1992).Google Scholar
18. Kubaschewski, O. and Alcock, C. B., “Metallurgical Thermochemistry,” 5th edition, (Pergamon Press, New York, 1979), p. 366.Google Scholar
19. Chou, T. C. and Nieh, T. G., J. Mater. Res. (in press).Google Scholar
20. Chou, T. C. and Nieh, T. G., submitted to J. Mater. Res. Google Scholar