Microstructural characteristics of pitch-based carbon-carbon composites

With IK PAN-based carbon fibers as reinforcements and modulated middle-temperature coal-tar pitch as matrix precursor, pitch-based carbon-carbon composites were fabricated under low pressure and high pressure respectively. It was found that there was both domains and mosaics in the carbon matrix, through the examination of the microstructures under polarized light microscope. There were mainly fine-grained mosaics in the green coke. The SEM micrographs of the etched surfaces of samples show that it appears the characteristic of flows in the anisotropic field. The grains of the flow structure had relations with the pressure under which coal-tar pitch carbonized. The higher the carbonization pressure was, the denser and neater the grains were, which indicates a higher degree of orientation of basal planes of the carbon.