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The control of gas phase kinetics to maximize densification during chemical vapor infiltration

Published online by Cambridge University Press:  31 January 2011

Brian W. Sheldon
Affiliation:
Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6063
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Abstract

A serious problem during the fabrication of composite materials by isothermal chemical vapor infiltration is that the matrix forms more rapidly at the external edges of the body and traps a large amount of porosity inside. In theory, this problem can be eliminated by controlling the gas-phase kinetics to obtain densification which is more rapid in the center of a preform than at its outer surfaces. An analysis of a first-order gas-phase reaction followed by a first-order deposition reaction indicates that improved infiltration is possible under a relatively narrow range of conditions.

Type
Articles
Copyright
Copyright © Materials Research Society 1990

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References

REFERENCES

1Fitzer, E. and Gadow, R., Am. Ceram. Soc. Bull. 65, 326 (1986).Google Scholar
2Stintoti, D. P., Caputo, A. J., and Lowden, R. A., Am. Ceram. Soc. Bull. 65, 347 (1986).Google Scholar
3Sheldon, B.W. and Haggerty, J.S., Ceram. Eng. Sci. Proc. 9, 1061 (1988).Google Scholar
4Sheldon, B.W., “The Formation of Reaction Bonded Silicon Nitride from Silane Derived Silicon Powders”, Sc.D. Thesis, Massachusetts Institute of Technology, Cambridge, MA (1989).Google Scholar
5Middleman, S., J. Mater. Res. 4, 1515 (1989).CrossRefGoogle Scholar
6Satterfield, C. N., Mass Transfer in Heterogeneous Catalysis (M.I.T. Press, Cambridge, MA, 1981).Google Scholar