Hybrid Three-Dimensional SiC/C High Thermal Conductivity Composites--MER Corporation, 7960 South Kolb Road, Tucson, AZ 85706; 520-574-1980
Dr. Witold Kowbel, Principal Investigator
Dr. J. C. Withers, Business Official
DOE Grant No. DE-FG03-99ER82823 Amount: $750,000

To provide improved strength and toughness, continuous fiber reinforced silicon carbide (SiC) composites (SiC-SiC), being developed primarily for advanced aerospace applications, are being examined for fusion reactor applications. Unfortunately, while the thermomechanical properties of SiC-SiC can be improved over that of monolithic SiC, the thermal conductivity is significantly reduced. This project will develop a hybrid three-dimensional SiC/C composite in which a high thermal conductivity carbon fiber (Z direction) is used to improve the thermal conductivity. This system has the potential for improving through-the-thickness thermal conduc-tivity, while maintaining composite properties upon irradiation. In Phase I, an SiC fabric, produced by chemical vapor reaction (CVR), was used for X-Y reinforcement while K-1100 fibers were used as Z-reinforcement. A high conductivity SiC-matrix, fabricated with a hybrid process that combines chemical vapor infiltration with polymer infiltration and pyrolysis, was used. A thermal conductivity of 65meters/milli Kelvin was achieved through the thickness (Z direction) of the matrix. In Phase II, process optimization for CVR-SiC and S-Nicelon fibers is planned, and irradiation resistance will be optimized.

Commercial Applications and Other Benefits as described by the awardee: The key benefit is for the fusion program. Commercial applications also exist in such energy related fields as heat exchangers.