HIGHLY CONDUCTING/IRRADIATION RESISTANT CARBON-CARBON COMPOSITES FOR FUSION DEVICES

DOE NEEDS TO DEVELOP CARBON-CARBON COMPOSITES TO LINE THE INSIDE WALLS OF FUTURE FUSION DEVICES. THE CARBON-CARBONS SHOULD HAVE THE HIGHEST POSSIBLE RESISTANCE TO FAST NEUTRONSWHILE MAINTAINING HIGH THERMAL CONDUCTIVITY AND GOOD MECHANICAL PROPERTIES. THIS PROJECT WILL FABRICATE A NEW GENERATION BASELINE CARBON-CARBON COMPOSITE WITH VERY RECENTLY DEVELOPED ULTRA HIGH THERMAL CONDUCTING MESOPHASE DERIVED PITCH FIBERS. THESE FIBERS WILL BE USED AS A REINFORCEMENT IN MESOPHASE DERIVED PITCH CARBON MATRICES. PROCESSING WILL INCLUDE DENSIFICATION WITH MESOPHASE PITCH AND PYROLYTIC CARBON AND HEAT TREATMENT ABOVE 2,500 DEGREES CENTIGRADE. THE BASELINE MATERIALS WILL BE FURTHER IMPROVEDBY GROWING FIBER/WHISKER NETWORKS IN THE POROSITY OF A PREFORM AFTER CARBONIZATION. THE NETWORKS WILL BE GROWN BY CHEMICAL VAPOR DEPOSITION AND/OR BY USING A NOVEL FLOW-THROUGH IMPREGNATION PROCESS. "WHISKERED" COMPOSITES WILL BE FURTHER DENSIFIED AND HEAT TREATED TO COMPLETE THEIRPROCESSING. THE PRESENCE OF THE FIBER/WHISKER NETWORKS WILL ENHANCE THROUGH-THE-THICKNESS THERMAL CONDUCTIVITY AND INTERLAMINAR SHEAR AND CROSS-PLANE TENSILE STRENGTHS. ADDITIVES WILL BE IDENTIFIED THAT WILL REDUCE THE SURFACE EROSION (CHEMICAL AND PHYSICAL SPUTTERING) IN A HYDROGEN PLASMA. PHASE I IS EXPECTED TO SHOW THE SUPERIORITY OF THE NEW GENERATION OF CARBON- CARBON COMPOSITES OVER CURRENT STATE-OF-THE-ART MATERIALS. PHASE I WILL PROVIDE THE DATA REQUIRED TO PRODUCE PROTOTYPE COMPOSITES FOR FURTHER PHYSICAL, THERMAL, MECHANICAL, AND IRRADIATION BEHAVIORAL TESTING IN PHASE II.