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Filler/ Polycarbosilane Systems as CMC Matrix PrecursorsPyrolytic conversion of polymeric precursors to ceramics is accompanied by loss of volatiles and large volume changes. Infiltration of a low viscosity polymer into a fiber preform will fill small spaces within fiber tows by capillary forces, but create large matrix cracks within large, intertow areas. One approach to minimizing shrinkage and reducing the number of required infiltration cycles is to use particulate fillers. In this study, Starfire allylhydridopolycarbosilane (AHPCS) was blended with a silicon carbide powder, with and without dispersant, using shear mixing. The polymer and polymer/particle interactions were characterized using nuclear magnetic resonance, differential scanning calorimetry, thermogravimetric analysis and rheometry. Polymer/particulate slurries and suspensions were used to infiltrate a figidized preform of an eight ply five harness satin CG Nicalon fiber having a dual layer BN/SiC interface coating, and the resulting composites characterized by optical and scanning electron microscopy.
Document ID
19980237188
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Hurwitz, Frances I.
(NASA Lewis Research Center Cleveland, OH United States)
Date Acquired
September 6, 2013
Publication Date
January 1, 1998
Subject Category
Composite Materials
Funding Number(s)
PROJECT: RTOP 523-21-13
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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