Chapter 25. The Microstructures of Scs-6 and Scs-8 Sic Reinforcing Fibers

  1. John B. Wachtman Jr.
  1. M. L. Sattler1,
  2. J. H. Kinney1,
  3. E. Zywicz1,
  4. R. Alani2 and
  5. M. C. Nichols3

Published Online: 26 MAR 2008

DOI: 10.1002/9780470313954.ch25

Proceedings of the 16th Annual Conference on Composites and Advanced Ceramic Materials, Part 1 of 2: Ceramic Engineering and Science Proceedings, Volume 13, Issue 7/8

Proceedings of the 16th Annual Conference on Composites and Advanced Ceramic Materials, Part 1 of 2: Ceramic Engineering and Science Proceedings, Volume 13, Issue 7/8

How to Cite

Sattler, M. L., Kinney, J. H., Zywicz, E., Alani, R. and Nichols, M. C. (1994) The Microstructures of Scs-6 and Scs-8 Sic Reinforcing Fibers, in Proceedings of the 16th Annual Conference on Composites and Advanced Ceramic Materials, Part 1 of 2: Ceramic Engineering and Science Proceedings, Volume 13, Issue 7/8 (ed J. B. Wachtman), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470313954.ch25

Author Information

  1. 1

    Lawrence Livermore National Laboratory, Livermore, CA 94550

  2. 2

    Gatan Incorporated, Pleasanton, CA 94588

  3. 3

    Sandia National Laboratories, Livermore, CA 94550

Publication History

  1. Published Online: 26 MAR 2008
  2. Published Print: 1 JAN 1994

ISBN Information

Print ISBN: 9780470375174

Online ISBN: 9780470313954

SEARCH

Keywords:

  • microscopy;
  • microstructure;
  • electron;
  • modulus;
  • carbon

Summary

The microstructures of SCS-6 and SCS-8 SiC fibers have been examined and analyzed using high resolution transmission electron microscopy (HRTEM), microdiffraction, parallel electron energy loss spectroscopy (PEELS), x-ray diffraction and x-ray microscopy. The results of the study confirm findings from earlier studies wherein the microstructure of the fibers have been described as consisting of β-SiC grown upon a monofilament turbostratic carbon core. The present study, however, provides much more detail regarding this microstructure. For example, PEELS spectroscopy and x-ray microscopy indicate that the composition of the SiC varies smoothly from SiC plus free C near the carbon core to SiC at the midradial boundary. The SiC stoichiometry is roughly preserved from the midradial boundary to the exterior interface. HRTEM, microdiffraction, and dark field images provide evidence that the excess carbon is amorphous free carbon which is most likely situated at the grain boundaries of the SiC. The x-ray microscopy results are also consistent with the presence of two phases near the core which consist of SiC and free carbon having density less than graphite (2.25 g/cc). This complex microstructure may explain the recent observations of non-planar failure in composites fabricated with SCS fibers.