Thermophysical properties of three-dimensional ceramic-filler-modified carbon/carbon composites

SiC and B4C fillers were introduced into three-dimensional, needled, integrated fibre felts by one-shot infiltration to produce ceramic-modified carbon/carbon (C/C) composites, B4C-C/C and SiC-C/C, and the effects of ceramic fillers on thermophysical properties were investigated. The specific heats of B4C-C/C, SiC-C/C and C/C increased from 1.08 to 3.14 J K-1 g(-1), 0.93 to 2.37 J K-1 g(-1) and 1.04 to 3.08 J K-1 g(-1), respectively, as the temperature increased from 30 to 1400 degrees C. Introducing a ceramic filler to the C/C composites improved the thermal conductivity while maintaining a low thermal expansion. The thermal conductivities perpendicular to the carbon cloth layer of B4C-C/C (44.06-56.35 W m(-1) K-1) and SiC-C/C (40.02-52.81 W m(-1) K-1) were higher than those of C/C (37.84-46.59 W m(-1) K-1) in the temperature range of 30-1400 degrees C. B4C-C/C, SiC-C/C and C/C have average thermal expansion coefficients of 1.9 x 10(-6), 1.8 x 10(-6) and 1.6 x 10(-6) K-1, respectively, along the carbon cloth layer from 25 to 1300 degrees C.