DEVELOPMENT OF SILICON CARBIDE CERAMIC COMPOSITES FOR FUSION REACTOR APPLICATIONS

CERAMIC COMPOSITES SUCH AS SILICON CARBIDE (SIC) MATRIX/SIC FIBER ARE BOTH ENABLING AND ENHANCING TECHNOLOGY FOR A VARIETY OF ADVANCED SYSTEMS, INCLUDING NUCLEAR FUSION APPLICATIONS. HOWEVER, CURRENTLY AVAILABLE SIC FIBERS DO NOT POSSES THE CHEMICAL AND MICROSTRUCTURAL STABILITY AT HIGH TEMPERATURES FOR APPLICATIONS OF SUCH COMPOSITES. THE PROCESSES OF SIC MATRIX FORMING GENERALLY RESULT IN HIGH POROSITY AND ALSO IMPEDE THE APPLICATION OF SIC/SIC COMPOSITES. RECENTLY, A PROCESS THAT CONVERTS GRAPHITE FIBER TO SIC FIBER HAS DEMONSTRATED VERY HIGH PURITY SIC WITH CHEMICAL AND MICROSTRUCTURAL STABILITY IN THE RANGE OF 1,600 DEGREES TO 1,900 DEGREES CENTIGRADE. THE CONVERSION PROCESS CAN ALSO CONVERT GRAPHITE ARCHITECTURES TO THE SAME SIC ARCHITECTURE. IN PHASE I, THIS NEW SIC FIBER IS BEING UTILIZED, AND VARIOUS SIC MATRIX-FORMING PROCESSES ARE BEING INVESTIGATED TO PRODUCE HIGH TEMPERATURE, THERMALLY STABLE SIC/SIC COMPOSITE IN NEAR-NET SHAPES WITH SUBSTANTIALLY IMPROVED MECHANICAL PROPERTIES AS WELL AS RADIATION STABILITY. MECHANICAL PROPERTY MEASUREMENTS ARE BEING USED TO IDENTIFY THE BEST COMPOSITE.