COATING OF CARBON AND SIC FIBERS FOR HIGH TEMPERATURE APPLICATIONS

PLASMATRON HAS DEVELOPED A RF-HOLLOW CATHODE MAGNETRON (RF-HCM) SYSTEM TO UNIFORMLY COAT TOWS OF FIBERS. IN THIS SYSTEM WE HAVE THE PROSITION FOR RF BIASING THE TOW, CONSEQUENTLY THE COATING UNIFORMITY OF THE INDIVIDUAL FIBERS IS SIGNIFICANTLY IMPROVED. ALSO, AT PLASMATRON WE HAVE DEVELOPED THE FABRICATION PROCEDURE FOR CONSTRUCTION OF CYLINDRICAL TARGETS OF KEY HIGH TEMPERATURE MATERIALS, NAMELY SUPER IRON ALLOY FECRALY, TIN, TIC, AND SIC. MONO AND MULTIFILAMENTS OF CARBON AND SIC FIBERS WILL BE COATED WITH FECRALY/SIC, TI/TIN/TI, AND TI/SIC/TI TO PROVIDE A GOOD DIFFUSION BARRIER AND SUFFICIENT ADHESION TO BOTH THE CARBON FIBER AND THE MATRIX (E.G. FECRALY ALLOY OR TI MATRICES). THE DEVELOPED TECHNOLOGY IS SUFFICIENTLY GENERIC SO THAT ALMOST ALL FIBER REINFORCED COMPOSITES COMBINATION CAN BE FABRICATED. EXTENSIVELY THIN FILM CHARACTERIZATION TECHNIQUE WILL BE USED TO INVESTIGATE FILM UNIFORMITY, ADHESION, CHEMICAL AND MECHANICALPROPERTIES. NAMELY SEM-EDX, EMPA, GRAVIMETRIC ANALYSIS; XPS, AND RBS TECHNIQUES WILL BE EMPLOYED. WE ARE PARTICULARLY INTERESTED IN HIGH TEMPERATURE BEHAVIOR OF THE DEPOSITED FIBERS. THE COATED FIBERS WILL BE TESTED AT 800 DEG C AND THE FIBER CROSS SECTION WILL BE CHECKED TO INVESTIGATE ANY DIFFUSTION OF ALUMINUM AND CREATION OF CRACKS DUE TO THERMAL STRESS. FOR SELECTED FINAL PLANAR SAMPLES, A SIMILAR TEST WILL BE PERFORMED WITH 200 HRS INCREMENTS USING RBS TECHNIQUE. THE RBS RESULT WILL ALSO BE EMPLOYED FOR INVESTIGATION OF INTERFACE INTERMIXING.