Chapter 58. Processing of Reaction-Bonded Silicon Carbide Without Residual Silicon Phase
- John B. Wachtman Jr.
Published Online: 28 MAR 2008
Copyright © 1988 The American Ceramic Society, Inc.
Proceedings of the 12th Annual Conference on Composites and Advanced Ceramic Materials, Part 1 of 2: Ceramic Engineering and Science Proceedings, Volume 9, Issue 7/8
How to Cite
Messner, R. P. and Chiang, Y.-M. (1988) Processing of Reaction-Bonded Silicon Carbide Without Residual Silicon Phase, in Proceedings of the 12th Annual Conference on Composites and Advanced Ceramic Materials, Part 1 of 2: Ceramic Engineering and Science Proceedings, Volume 9, Issue 7/8 (ed J. B. Wachtman), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470310496.ch58
- Published Online: 28 MAR 2008
- Published Print: 1 JAN 1988
Print ISBN: 9780470374801
Online ISBN: 9780470310496
Reaction bonded silicon carbide free of the residual silicon phase that has previously limited upper use temperatures and mechanical properties has been synthesized by the infiltration of carbonaceous preforms using alloyed silicon melts. In this approach, rejection of the alloying components from the primary reacted silicon carbide phase into the remaining liquid forms a secondary refractory silicide, in a potentially broad and controllable range of volume fractions. The Si-Mo melt system has been used as a model. Dense SiC-MoSi2 materials free of residual silicon and residual carbon have been synthesized. In addition to a fully-infiltrated monolith, surface coatings on a carbon body have been synthesized by control of processing parameters. In each, the absence of free silicon and incorporation of the secondary phase is expected to improve mechanical properties, since (1) the composite materials that are formed contain no phases which decompose below 1830°C; and (2) the secondary MoSi2phase is known to undergo a brittle-to-ductile transition at 1000°C and should thus act as a ductile dispersed toughening phase at elevated temperatures.