Novel Molecular Sources for Dispersing Boron in Carbon-Carbon Composites

摘要

Improving the oxidation resistance of carbon-carbon composites is key toextending the applications of this material system into higher temperature regimes. While molecularly dispersed boron, through addition of carborane, helps to provide oxidation protection to phenolic derived carbon, the moisture affinity of the boria seriously affects composite performance. Substitution of furfuryl and pitch as the resin precursors significantly improved the moisture resistance of the carbon matrix material by stabilizing the boron at low temperatures and minimizing premature boria formation. Carborane addition to a commercial furfuryl/pitch blend (Kaiser Code88A) yielded a carbon char with reduced moisture affinity and improved oxidation resistance. Mechanical properties of the Code88A matrix composites were not significantly affected by the addition of carborane. Although sample size limitations in testing detracted from the demonstration of success, data suggests that the oxidation resistance of carbon-carbons can be significantly enhanced via this approach without detriment to the physical attributes and moisture resistance of the composite. (MM).