Chapter 60. Influence of Fiber Coatings on the Oxidation of Fiber-Reinforced SiC Composites
- John B. Wachtman Jr.
Published Online: 28 MAR 2008
Copyright © 1993 The American Ceramic Society
Proceedings of the 17th Annual Conference on Composites and Advanced Ceramic Materials, Part 1 of 2: Ceramic Engineering and Science Proceedings, Volume 14, Issue 7/8
How to Cite
Tortorelli, P. F., Nijhawant, S., Riester, L. and Lowden, R. A. (1993) Influence of Fiber Coatings on the Oxidation of Fiber-Reinforced SiC Composites, in Proceedings of the 17th Annual Conference on Composites and Advanced Ceramic Materials, Part 1 of 2: Ceramic Engineering and Science Proceedings, Volume 14, Issue 7/8 (ed J. B. Wachtman), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470314180.ch60
- Published Online: 28 MAR 2008
- Published Print: 1 JAN 1993
Print ISBN: 9780470375266
Online ISBN: 9780470314180
Thermogravimetric analysis was used to study the reaction kinetics associated with high-temperature air oxidation of graphite- or BN-coated Nicalon fiber-reinforced SiC composites. For those with graphite interlayers, the shapes of the thermogravimetric curves, and the dependencies of weight changes on interfacial layer thickness and exposure temperature, could be explained on the basis of concurrent reactions associated with oxidation of the graphite and the formation of SiO2 on the matrix and fibers. The oxidation resistance of the SiC with BN-coated Nicalon fibers was significantly better. Flexure tests of Nicalon/graphite/SiC previously oxidized in air at 950°C revealed that degradation of fracture resistance can be detected after very short exposure times (less than 1 h). Accordingly, a knowledge of reaction kinetics is important in characterizing environmental effects on fracture and damage and in predicting the rate of properties degradation.