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Fabrication of Sic Matrix Composites by Liquid Phase Infiltration with a Polymeric Precursor

Published online by Cambridge University Press:  15 February 2011

Leonard V. Interrante ,
C.W. Whitmarsh  and
W. Sherwood
Leonard V. Interrante
Affiliation:
Department of Chemistry, Rensselaer Polytechnic Institute, Troy, NY 12180-3590
C.W. Whitmarsh
Affiliation:
Starfire Systems, Inc, 877 25th Street, Watervliet, NY 12189
W. Sherwood
Affiliation:
Starfire Systems, Inc, 877 25th Street, Watervliet, NY 12189
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Abstract

A process for the fabrication of SiC matrix composites has been developed which employs aliquid, highly branched, polycarbosilane (AHPCS). This polymer thermosets on heating at 200-400 °C (or at 100 °C with catalyst) and yields an amorphous SiC with low excess C and O content in 60-80% yield on pyrolysis to 1000 °C. Preforms consisting of C-coated Nicalon SiC fiber cloth, unidirectional Textron SiC SCS-6 fiber layups, or Mo boats packed with SiC whiskers, were infiltrated with the polymer, cured in an autoclave, and pyrolyzed to 1000 °C. Five to eight infiltration cycles gave net shape composites with final densities at 85-94 % of theoretical. The results of 4-point flexure tests on the as-prepared Nicalon composites indicate flexure strengths (aver. 378 MPa) that are comparable to or better than similarly reinforced CVI-SiC matrix composites. The whisker and SCS-6 composites showed a small weight loss (10-20%) on heating to 1500 °C in Ar and little or no weight change or obvious embrittlement in air at 1000 °C.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 365: Symposium M – Ceramic Matrix Composites–Advanced High-Temperature Structural Materials , 1994 , 139
Copyright
Copyright © Materials Research Society 1995

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References

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