Chapter 66. Ultrasonic Assessment of Oxidation Damage in SiC/RBSN Composites
- John B. Wachtman Jr.
Published Online: 28 MAR 2008
Copyright © 1994 The American Ceramic Society
Proceedings of the 18th Annual Conference on Composites and Advanced Ceramic Materials - B: Ceramic Engineering and Science Proceedings, Volume 15, Issue 5
How to Cite
Rokhlin, S. I., Chu, Y. C., Lavrentyev, A. I., Baaklini, G. Y. and Bhatt, R. T. (1994) Ultrasonic Assessment of Oxidation Damage in SiC/RBSN Composites, in Proceedings of the 18th Annual Conference on Composites and Advanced Ceramic Materials - B: Ceramic Engineering and Science Proceedings, Volume 15, Issue 5 (ed J. B. Wachtman), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470314555.ch66
- Published Online: 28 MAR 2008
- Published Print: 1 JAN 1994
Print ISBN: 9780470375334
Online ISBN: 9780470314555
- ultrasonic characterization of oxidation dam age;
- matrix porosities;
- ceramic matrix composites;
- RBSN matrix;
- NASA lewis research center.
In this paper we report results on ultrasonic characterization of oxidation damage in ceramic matrix composites as a function of time and temperature of oxidation. Unidirectional SiC/RBSN composites with different fiber fractions and matrix porosities were used. The samples were exposed in a flowing oxygen environment for 0.1, 1, 10 and 100 hours at temperatures 600, 900, 1200 and 1400 °C. For each exposure time and temperature, multiple samples were investigated and their averaged results were used in the analysis. Using multi-phase micromechanical analysis, we found that oxidation of the carbon interphasial layer is the dominant mechanism in the reduction of the composite transverse and shear moduli. Such damage can occur in ceramic matrix composites for even very short exposure to an oxidizing environment. By analyzing the reduction of composite transverse and shear moduli, we can effectively determine the critical exposure time for transition from nondamaged to damaged states at different oxidation temperatures. The comparison of ultrasonic and gravimetric methods and the effect of matrix porosity on oxidation damage are discussed.