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Microwave Processing of Ceramics: Guidelines Used at the Oak Ridge National Laboratory

Published online by Cambridge University Press:  25 February 2011

Mark A. Janney
Affiliation:
Oak Ridge National Laboratory P.O. Box 2008 Oak Ridge, Tennessee 37831-6087
Hal D. Kimrey
Affiliation:
Oak Ridge National Laboratory P.O. Box 2008 Oak Ridge, Tennessee 37831-6087
James O. Kiggans
Affiliation:
Oak Ridge National Laboratory P.O. Box 2008 Oak Ridge, Tennessee 37831-6087
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Abstract

To make meaningful comparisons between conventional and microwave processing of materials, one must conduct experiments that are as similar as possible in the two environments. Particular attention must be given to thermal conditions, sample parameters, and furnace environment. Under thermal conditions, one must consider temperature measurement (pyrometer or thermocouple, sheath type, and arcing of thermocouples), thermal history (heating and cooling rates, thermal gradients), and exothermic reactions. Regarding sample parameters, one must. consider sample size, and packing powders and insulation systems. With respect to furnaces, one must consider differences in atmosphere, impurities, and uniformity of heating. Examples will be drawn from diffusion, grain growth, sintering, nitridation, and drying experiments conducted at the Oak Ridge National Laboratory (ORNL) over the past six years.

Type
Research Article
Copyright
Copyright © Materials Research Society 1992

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References

REFERENCES

1. Janney, M. A. and Kimrey, H. D., “Microwave Sintering of Alumina at 28 GHz,” Ceramic Powder Science, II, pp 919924, Messing, G. L., Fuller, E. R., and Hausner, H., eds., American Ceramic Society, Westerville, Ohio, 1988.Google Scholar
2. Janney, M. A., Calhoun, C. D., and Kimrey, H. D., “Microwave Sintering of Solid Oxide Fuel Cell Materials, I: Zirconia-8 mol% Yttria,” J. Am. Ceram. Soc., 75 [2] 341–6 (1992).Google Scholar
3. Janney, M. A., Kimrey, H. D., Schmidt, M. A., and Kiggans, J. O., “Alumina Grain Growth in a Microwave Field,” J. Am. Ceram. Soc., 74 [7] 1675–81 (1991).Google Scholar
4. Janney, M. A. and Kimrey, H. D., “Diffusion-Controlled Processes in Microwave-fired Ceramics,” Microwave Processing of Materials, 11, Proc. Mater. Res. Soc., Vol. 189, 215–27 (1991).Google Scholar
5. Lewis, D., “Review of Polymer Processing with Microwaves,” this proceedings.Google Scholar
6. Giguerre, R., “Review of Organic Synthesis Using Microwaves,” this proceedings.Google Scholar
7. Marquardt, P., Nimitz, G., Heite, G., and Peters, H., “Microwave Evidence for a Size-Induced Metal-Insulator Transition in Mesoscopic Conductors,” Microwave Processing of Materials, I, Proc. Mater. Res. Soc., Vol. 124, pp. 155160 (1989)Google Scholar
8. Nishitani, T., Method for Sintering Refractories and an Apparatus Therefore, U. S. Patent 4,147,911; filed Aug. 10, 1976; issued Apr. 3, 1979.Google Scholar
9. Holcombe, C. E.; personal communication.Google Scholar
10. Janney, M. A. and Kimrey, H. D., “Microwave Sintering of Solid Oxide Fuel Cell Materials, II: Lanthanum Chromite,” submitted to J. Am. Ceram. Soc. Google Scholar
11. Holcombe, C. E. and Dykes, N. L., “Importance of ‘Casketing’ for Microwave Sintering of Materials,” J. Matl. Sci. Lett., 9, 425–8 (1990).CrossRefGoogle Scholar
12. Holcombe, C. E. and Dykes, N. L., ““Ultra” High-Temperature Microwave Sintering,” Ceramic Trans., Vol. 21, 375–85, 1991.Google Scholar
13. Kiggans, J. O. and Tiegs, T. N., “Characterization of Silicon Nitride Synthesized by Microwave Heating,” Ceramic Trans., Vol 21, 403410, 1991.Google Scholar
14. Kimrey, H. D., “A Quasi-Optical Model for Microwave Processing,” this proceedings.Google Scholar
15. Kimrey, H. D., Kiggans, J. O., Janney, M. A., and Beatty, R. L., “Microwave Sintering of Zirconia-Toughened Alumina Composites,” Microwave Processing of Materials, II, Proc. Mater. Res. Soc., Vol. 189, 243–55 (1991).Google Scholar
16. Peterson, R. A., Microwave Heating Temperature Control, U. S. Patent 3,859,493; filed Nov. 21, 1973; issued Jan. 7, 1975.Google Scholar
17. Sutton, W. H. and Johnson, W. E., Method of Improving the Susceptibility of a Material to Microwave Energy Heating, U. S. Patent 4,219,361; filed Jun. 9, 1978; issued Aug. 26, 1980.Google Scholar
18. Johnson, D. L., “Microwave Heating of Grain Boundaries in Ceramics,” J. Am. Ceram. Soc., 74[4]849–50(1991).Google Scholar
19. Clark, D. E. and Foltz, D.C., “Microwave Processing Activities at the University of Florida,” Ceramic Trans., Vol. 21, 2934, 1991.Google Scholar
20. Kiggans, J. O. and Tiegs, T.N., “Microwave Processing of RBSN and SRBSN Silicon Nitrides,” this proceedings.Google Scholar
21. James, C.R., Tinga, W.R., and Voss, W.A.G., “Energy Conversion in Closed Microwave Cavities,” in Okress, E. C., ed., Microwave Power Engineering, Vol. 2, Academic Press, N.Y., 1973 Google Scholar
22. McDonald, A.D., Microwave Breakdown in Gases, J. Wiley and Sons, 1966.Google Scholar