Thermophysical properties of densified pitch based carbon/carbon materials—II. Bidirectional composites Original Research Article

Bidirectional carbon/carbon composites were developed using high-pressure impregnation/carbonization technique with PAN based carbon fabric as reinforcement and coal tar and synthetic pitches as matrix precursors. Microstructure of these composites has been evaluated using scanning electron microscope and polarized light optical microscope. Thermophysical properties i.e. thermal conductivity and specific heat have been evaluated both at room temperature and between 40 and 300 °C. The temperature dependence of thermal diffusion, specific heat and thermal conductivity has been studied and correlated with microstructure of carbon/carbon composites. It is found that the specific heat of carbon/carbon composites shows increase with temperature with an inverse slope in the temperature range of 150–200 °C. Accordingly, though the thermal conductivity decrease with temperature due to increased phonon interactions, it shows reversible action between 150 and 200 °C.