CARBON-CARBON COMPOSITES TECHNOLOGY PROGRAM

SEVERAL GOVERNMENT ADVANCED TECHNOLOGY PROGRAMS (ELITE, TAV, BGV), ETC.) ARE PROPOSING SYSTEMS WHICH REQUIRE STRUCTURAL COMPONENTS CAPABLE OF SUSTAINING OPERATIONAL LOADS AT EXPOSURE TEMPERATURES OF 3000 DEG F AND HIGHER. THE MOST PROMISING MATERIAL SOLUTION FOR THESE HOT STRUCTURE APPLICATIONS IS COMPOSITE CARBON-CARBON. THE SUCCESSFUL APPLICATION OF THIS CLASS OF MATERIALS HAS BEEN WELL DEMONSTRATED BY EXAMPLES SUCH AS SPACE SHUTTLE, ROCKET NOZZLE THROATS AND EXIT CNES, JET ENGINE AFTERBURNER SECTIONS AND GAS TURBINE ENGINE COMPONENTS. HOWEVER, TWO MAJOR MATERIAL DEFICIENCIES EXIST; LOW MATRIX MECHANICAL PROPERTIES (INTERLAMINAR SHEAR AND CROSS-PLY TENSILE STRENGTHS AND STIFFNESSES) AND COATING COMPATIBILITY (OXIDATION PROTECTION). PDA ENGINEERING PROPOSES A NEW MATERIAL DEVELOPMENT AND EVALUATION PROGRAM THAT WILL ATTEMPT TO TOUGHEN THE COATING AGAINST THERMAL CYCLE CRACK PROPAGATION WHILE SIMULTANEOUSLY IMPROVING THE SUBSTRATE MATRIX PROPERTIES.