Chapter 8. High Temperature Behavior of Silicon Carbide and Aluminum Oxide Ceramics in Coal and Residual-Oil Slags

  1. William Smothers
  1. V. J. Tennery,
  2. G. C. Wei and
  3. M. K. Ferber

Published Online: 27 MAR 2008

DOI: 10.1002/9780470291115.ch8

Proceedings of the Educational Symposium on Refractories in Sagging Environments: Ceramic Engineering and Science Proceedings, Volume 2

Proceedings of the Educational Symposium on Refractories in Sagging Environments: Ceramic Engineering and Science Proceedings, Volume 2

How to Cite

Tennery, V. J., Wei, G. C. and Ferber, M. K. (1981) High Temperature Behavior of Silicon Carbide and Aluminum Oxide Ceramics in Coal and Residual-Oil Slags, in Proceedings of the Educational Symposium on Refractories in Sagging Environments: Ceramic Engineering and Science Proceedings, Volume 2 (ed W. Smothers), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470291115.ch8

Author Information

  1. Oak Ridge National Lab P.O. Box X, Oak Ridge, Tenn. 37830

Publication History

  1. Published Online: 27 MAR 2008
  2. Published Print: 1 JAN 1981

ISBN Information

Print ISBN: 9780470373927

Online ISBN: 9780470291115

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Keywords:

  • combustion;
  • transversely;
  • siliconized;
  • exposure;
  • structural

Summary

Ceramic tubes made of aluminum oxide, sialon, and several commercial silicon carbides were exposed for ∽500 h at 1200° to 1220°C to the combustion products from either No. 6 fuel oil or a mixture of 10% bituminous coal in No. 6 fuel oil (COM). Air was blown through the tubes while the combustion products flowed transversely over the outside. The linear thermal expansion, helium permeability, and room-temperature fracture strength were measured before and after exposure.

After exposure to combustion products from No. 6 fuel oil, the linear thermal expansion at 1000°C for sintered α-SiC was 17% greater than it was before the experiment. For CVD SiC and siliconized SiC, there was no change. For alumina, it decreased ∽30%.

When exposed to COM combustion products, the thermal expansion of the α-SiC increased slightly, and that of siliconized KT SiC increased ∽16% at 1000°C. Significant thermal expansion differences were observed between the upstream and downstream sides of the tubes for sintered α-SiC, the KT SiC, and the alumina. The strength after exposure for α-SiC decreased ∽4%; the others remained unchanged.

The helium permeability increased after exposure. The greatest increase occurred for tubes exposed only to residual fuel oil. Increases in Permeability and thermal expansion could be detrimental to service.