Rapid Fabrication of C/C-SiC Composites

Abstract

C/C-SiC composites, namely carbon fiber reinforced silicon carbide and pyrocarbon matrices, were fabricated in two steps in this study. Firstly, C/C composites were prepared by a rapid economical densification process of chemical liquid-vaporized infiltration. PAN based felt and 2-Dimensional carbon fibers were chosen as preform, respectively. A liquid hydrocarbon, kerosene, was used as a precursor. The C/C composites were processed in a temperature range of 900-1100°C for 150 minutes. Subsequently, C/C-SiC composites were fabricated from the C/C composites and silicon powder by reactive melt infiltration method. Densities, open porosities of the C/C and the C/C-SiC composites were investigated. Structural properties of the C/C-SiC composites were studied by optical microscopy. X-ray diffraction was used to identify the element and the crystal phase of the composites. It was shown that the density of C/C composite reached to 1.72 g/cm3 based on the 2D carbon fibers by CLVI method. Microstructure observation of the C/C composite revealed that the pyrocarbon is layer concentric around the fibers. It was found that during the RMI processing β-SiC was formed through the reaction only between liquid silicon and pyrocarbon, while carbon fiber was not damaged. Free silicon remains in the C/C-SiC composites because of insufficient reaction with the pyrocarbon.