Chapter 25. Polymer Derived Nicalon/Si-C-O Composites: Processing and Mechanical Behavior

  1. John B. Wachtman Jr.
  1. Frances I. Hurwitz1,
  2. John Z. Gyekenyesi2 and
  3. Paula J. Conroy2

Published Online: 26 MAR 2008

DOI: 10.1002/9780470310557.ch25

A Collection of Papers Presented at the 13th Annual Conference on Composites and Advanced Ceramic Materials, Part 1 of 2: Ceramic Engineering and Science Proceedings, Volume 10, Issue 7/8

A Collection of Papers Presented at the 13th Annual Conference on Composites and Advanced Ceramic Materials, Part 1 of 2: Ceramic Engineering and Science Proceedings, Volume 10, Issue 7/8

How to Cite

Hurwitz, F. I., Gyekenyesi, J. Z. and Conroy, P. J. (1989) Polymer Derived Nicalon/Si-C-O Composites: Processing and Mechanical Behavior, in A Collection of Papers Presented at the 13th Annual Conference on Composites and Advanced Ceramic Materials, Part 1 of 2: Ceramic Engineering and Science Proceedings, Volume 10, Issue 7/8 (ed J. B. Wachtman), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470310557.ch25

Author Information

  1. 1

    NASA Lewis Research Center Cleveland, OH

  2. 2

    Cleveland State University Cleveland, OH

Publication History

  1. Published Online: 26 MAR 2008
  2. Published Print: 1 JAN 1989

ISBN Information

Print ISBN: 9780470374863

Online ISBN: 9780470310557

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Keywords:

  • chemical vapor infiltration;
  • fiber-matrix reactions;
  • polysilsesquioxane system;
  • hydrolysis;
  • thermogravimetric analysis

Summary

Ceramic matrix composites fabricated using Nicalon fiber and several pofysilsesqui-oxane-derived Si-C-O matrices were characterized by optical and scanning electron microscopy and in four-point bending. Material variables include three Nicalon sizings, poly(vinylacetate), epoxy and DCC-1, two different copofymer compositions, and several pyrolysis schedules. Shrinkage of the matrix during pyrofysis results in a 65% char yield on heating to 1500°C for both the pofyvinylmethylsils-esquioxane and polyphenylmethylsilsesquioxane copofymers studied. In the matrix material linear shrinkages of up to 19% were observed for the vinylmethyl copofymer pyrolyzed to 1200°C, and up to 13% for the phenylmethyl material pyrolyzed to the same temperature, resulting in considerable matrix cracking. Under four-point loading, most composite samples fractured in a brittle manner as the result of strong fiber-matrix bonding. Flexural strengths, moduli, and ultimate strain varied with fiber sizing and processing parameters. Testing and analysis is being applied to promote more fibrous pullout during fracture.