FABRICATION OF CARBON-CARBON COMPOSITES BY FORCED FLOW-THERMAL GRADIENT CHEMICAL-VAPOR INFILTRATION

Carbon fiber-carbon matrix composites were fabricated using the forced flow-thermal gradient chemical vapor infiltration (FCVI) process. The preforms for the infiltration were prepared by stacking 40 layers of carbon cloth in a graphite holder. The preforms were infiltrated with carbon using propylene or methane as a reactant, with hydrogen as a diluent. Composites with porosities as low as 7% have been processed within 8-12 h. The highest deposition rate obtained in the present study was similar to 3 mu m/h, which is more than an order of magnitude faster than the typical value of 0.1-0.25 mu m/h for the isothermal infiltration process.