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 °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 °C. B₄C-C/C, SiC-C/C and C/C have average thermal expansion coefficients of 1.9 × 10⁻⁶, 1.8 × 10⁻⁶ and 1.6 × 10⁻⁶ K⁻¹, respectively, along the carbon cloth layer from 25 to 1300 °C.