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A model for microwave processing of compositionally changing ceramic systems

Published online by Cambridge University Press:  03 March 2011

Daniel J. Skamser ,
Jeffrey J. Thomas ,
Hamlin M. Jennings  and
D. Lynn Johnson
Daniel J. Skamser
Affiliation:
Department of Materials Science and Engineering, Northwestern University, 2225 North Campus Drive/MLSF 2036, Evanston, Illinois 60208-3108
Jeffrey J. Thomas
Affiliation:
Department of Materials Science and Engineering, Northwestern University, 2225 North Campus Drive/MLSF 2036, Evanston, Illinois 60208-3108
Hamlin M. Jennings
Affiliation:
Department of Materials Science and Engineering, Northwestern University, 2225 North Campus Drive/MLSF 2036, Evanston, Illinois 60208-3108
D. Lynn Johnson
Affiliation:
Department of Materials Science and Engineering, Northwestern University, 2225 North Campus Drive/MLSF 2036, Evanston, Illinois 60208-3108
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Abstract

A finite-difference model was used to simulate the temperature and composition distributions produced inside a specimen heated with microwave energy during a process involving a change in composition. The dielectric properties of the specimen change with composition, resulting in nonuniform microwave power absorption and steady-state temperature gradients. When the specimen becomes less lossy as it reacts, or if the changes in the microwave heating properties are gradual, the reaction proceeds relatively uniformly and the volumetric microwave heating creates an inside-out reaction profile leading to increased conversions for processes such as reaction bonding and chemical vapor infiltration (CVI). If the specimen becomes more lossy as it reacts, then the reaction proceeds nonuniformly with rapid reaction rates in the hottest parts of the specimen and little or no reaction in the cooler areas. The process may then occur as a reaction front which moves along the specimen, as with combustion synthesis. This type of processing has potential advantages and disadvantages depending on the system.

Type
Articles
Information
Journal of Materials Research , Volume 10 , Issue 12 , December 1995 , pp. 3160 - 3178
Copyright
Copyright © Materials Research Society 1995

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References

REFERENCES

1Various references include Microwaves: Theory and Application in Materials Processing I and II, in Ceram. Trans. Vols. 21 and 36 from The American Ceramic Society and Microwave Processing of Materials I–IV in MRS Proceedings, Vols. 124, 189, 269, and 347 from the Materials Research Society.Google Scholar
2Sutton, W. H., Am. Ceram. Soc. Bull. 68, 376–386 (1989).Google Scholar
3De', A., Ahmad, I., Whitney, E. D., and Clark, D. E., in Microwave Processing of Materials II, edited by Snyder, W. B. Jr., Sutton, W. H., Iskander, M. F., and Johnson, D. L. (Mater. Res. Soc. Symp. Proc. 189, Pittsburgh, PA, 1991), pp. 283–288.Google Scholar
4Janney, M. A., Calhoun, C. L., and Kimrey, H. D., J. Am. Ceram. Soc. 75, 341–346 (1992).Google Scholar
5Spotz, M. S., Skamser, D. J., and Johnson, D. L., J. Am. Ceram. Soc. 78, 1041–1048 (1995).CrossRefGoogle Scholar
6Skamser, D. J., Day, P. S., Jennings, H. M., and Johnson, D. L., in Advances in Ceramic Matrix Composites II, edited by Singh, J. P. and Bansal, N. P. (American Ceramic Society, Westerville, OH, 1994), pp. 143–154.Google Scholar
7Thomas, J. J., Christensen, R. J., Johnson, D. L., and Jennings, H. M., J. Am. Ceram. Soc. 76, 1384–1386 (1993).CrossRefGoogle Scholar
8Thomas, J. J., Ph. D. Dissertation, Northwestern University (1994).Google Scholar
9Dalton, R. C., Ahmad, I., and Clark, D. E., Ceram. Eng. Sci. Proc. 11, 1729–1742 (1990).CrossRefGoogle Scholar
10Ahmad, I., Dalton, R., and Clark, D. E., J. Microwave Power and Electromagnetic Energy 26, 128–138 (1991).Google Scholar
11Willert-Porada, M. A., in Microwaves: Theory and Application in Materials Processing II, edited by Clark, D. E., Laia, J. R., and Tinga, W. R. (The American Ceramic Society, Westerville, OH, 1993), pp. 277–286.Google Scholar
12Willert-Porada, M. A., Fisher, B., and Gerdes, T., in Microwaves: Theory and Application in Materials Processing II, edited by Clark, D. E., Laia, J. R., and Tinga, W. R. (The American Ceramic Society, Westerville, OH, 1993), pp. 365–375.Google Scholar
13Thomas, J. J., Skamser, D. J., and Johnson, D. L., in A Forum on Electromagnetic Technology & Applications from Around the World, edited by Lewis, D. A. and McCutchan, M. D. (International Microwave Power Institute, Manassas, VA, 1994), pp. 140–143.Google Scholar
14Neelakanta, P. S. (private communication).Google Scholar
15Carslaw, H. S. and Jaeger, J. C., Conduction of Heat in Solids, 2nd ed. (Clarendon Press, Oxford, 1989).Google Scholar
16Atkinson, A., Leatt, P. J., and Moulson, A. J., Proc. Brit. Ceram. Soc. 22, 253 (1973).Google Scholar
17Abbasi, M. H. and Evans, J. W., AIChEJ. 29, 617 (1983).Google Scholar
18Watters, D. G., Ph. D. Dissertation, Northwestern University (1989).Google Scholar
19Metaxas, A. C. and Meredith, R. J., Industrial Microwave Heating (Peter Peregrinus Ltd., London, 1983).Google Scholar
20Neelakanta, P. S., J. Phys.: Condens. Matter. 2, 4935–4947 (1990).Google Scholar
21Moulson, A. J., J. Mater. Sci. 14, 1017 (1979).Google Scholar
22Ziegler, G., Heinrich, J., and Wotting, G., J. Mater. Sci. 22, 3041 (1987).Google Scholar
23Rossetti, G. A. and Denkewicz, R. P., J. Mater. Sci. 24, 3081 (1989).Google Scholar
24Patankar, S. V., Numerical Heat Transfer and Fluid Flow (Hemi-sphere Publishing Corp., New York, 1980).Google Scholar
25Tiegs, T. N., Kiggans, J. O. Jr., and Kimrey, H. D. Jr., in Microwave Processing of Materials II, edited by Snyder, W. B. Jr., Sutton, W. H., Iskander, M. F., and Johnson, D. L. (Mater. Res. Soc. Symp. Proc. 189, Pittsburgh, PA, 1991), pp. 267–272.Google Scholar
26Kiggans, J. O. Jr. and Tiegs, T. N., in Microwave Processing of Materials III, edited by Beatty, R. L., Sutton, W. H., and Iskander, M. F. (Mater. Res. Soc. Symp. Proc. 269, Pittsburgh, PA, 1992), pp. 285–300.Google Scholar
27Tiegs, T. N., Kiggans, J. O. Jr., Lin, H. T., and Willkens, C. A., in Microwave Processing of Materials IV, edited by Iskander, M. F., Lauf, R. J., and Sutton, W. H. (Mater. Res. Soc. Symp. Proc. 347, Pittsburgh, PA, 1994), pp. 501–506.Google Scholar
28Johnson, D. L., Skamser, D. J., and Spotz, M. S., in Microwaves: Theory and Application in Materials Processing II, edited by Clark, D. E., Tinga, W. R., and Laia, J. R. Jr. (American Ceramic Society, Westerville, OH, 1993), pp. 133–146.Google Scholar