Microstructures andMechanical Behavior of C/C Composites Prepared by ICVI Using n―propanol asPrecursor

Two dimension needle―punched carbonfiber felts with an initial bulk density of 0.43 g/cm3 weredensified by isothermal―isobaric chemical vapor infiltration (ICVI) at 1050,1100, 1150 and total pressure of 6kPa, using n―propanoldiluted by nitrogen as the precursor of pyrolytic carbon. The bulk density ofC/C composite after densified for 96h were 1.64 g/cm3, 1.68g/cm3and 1.69/cm3, respectively. Bulk densities of the infiltrated sampleswere determined as a function of infiltration time. The flexural strength wasinvestigated by three―point bending test. Texture and fracture surface morphologyof the samples were studied by polarized light microscope (PLM) and scanningelectron microscope (SEM). A layer of midium―textured carbon followed by alayer of high―textured carbon matrix were formed at 1050 and 1150 . WhileC/C composites with pure high―textured pyrolytic carbon matrix was obtained at1100 , with the flexural strength of 199.24MPa. No oxidationtrace was found on the surface of carbon fiber from PLM and SEM observation. Consequently,n―propanol is a promising precursor in CVI process for the densification of high―performanceC/C composites.