Preparation of 1D C/C composites with high thermal conductivity

Three kinds of pitches were used as matrix precursors, the self-fabricated mesophase (AR) pitch-based carbon fibers were used as the reinforcing agent, one dimension (1D) carbon/carbon (C/C) composites were prepared by a hot-pressing molding method at about 500°C and subsequent carbonization as well as graphitization treatments. The influence of precursor pitches and heat-treatment temperatures (HTTs) on the thermal conductive properties of the C/C composites were investigated. The morphology and microstructure of graphitized C/C composites were characterized by scanning electron microscope and polarized-light microscope. The results show that both of the thermal diffusivities and the thermal conductivities of C/C composites along the longitudinal direction of fibers gradually increase with HTT. The C/C composite prepared by using AR pitch as a matrix precursor possesses obvious graphite-like layer structure, exhibiting the highest thermal conductivity. The room-temperature thermal conductivity and thermal diffusivity of the C/C composite treated at 3000°C along the longitudinal direction of fibers are 734.4 W/(m·K) and 594.5 mm²/s, respectively.