High-Temperature Thermophysical Properties of Carbon–Carbon Composite Materials Based on Needle-Punched Carbon Framework with Two Types of Sealing

The thermal diffusivity of samples cut from two types of carbon–carbon composite materials along and across their main reinforcement direction is measured using the plane temperature wave method. A needle-punched frame based on carbon biaxial fabric of the ACM C400B grade made of high-strength carbonized fiber. For the first type of carbon–carbon composite material, the reinforcing component is densified with a pyrocarbon matrix, while for the second, with a coke matrix. The density of the studied materials was 1.77 and 1.95 g/cm³, respectively. Based on the results of measuring thermal diffusivity in the range 600–1700 K, the temperature dependences of the thermal conductivity are calculated, allowing us to estimate the thermal conductivity of the studied materials depending on the direction of reinforcement (anisotropy axis). The difference in the thermal conductivity both in magnitude and in the shape of the polytherms is shown depending on the method of compaction of needle-punched carbon frames of carbon-carbon composite materials. The mechanism of thermal conductivity in carbon-carbon composite materials is discussed.