Effects of graphite filler on the thermophysical properties of 3D C/SiC composites

A three-dimensional carbon/silicon carbide (C/SiC) composite was achieved by infiltrating liquid Si into a carbon/carbon composite which was produced by one cycle of infiltration of resin slurry containing graphite particles, hot-pressing curing and pyrolysis. The specific heats of the graphite-modified C/SiC, which increased from 0.92 to 2.33 J K⁻¹ g⁻¹ as the temperature increased from 30 to 1300 °C, were higher than those of the unmodified C/SiC, which increased from 0.74 to 1.89 J K⁻¹ g⁻¹. The through-thickness thermal conductivities of the graphite-modified C/SiC (40.03–55.53 W m⁻¹ K⁻¹) were higher than those of the unmodified C/SiC (20.93–35.46 W m⁻¹ K⁻¹) in the range of 30–1300 °C. The coefficient of thermal expansion of the graphite-modified C/SiC was lower than that of the unmodified C/SiC at each temperature, with average values of 1.69 × 10⁻⁶ and 2.56 × 10⁻⁶ K⁻¹ for the graphite-modified and unmodified C/SiC composites, respectively, along the carbon cloth layer in the range of 25–1300 °C.