Fabrication of high thermal conductivity C/C composites reinforced by graphite films with hexagonal pits

High thermal conductivity graphite films (GFs) have been widely used in the field of heat dissipation. However, due to their extremely smooth surface and low surface energy, it is difficult for them to be used as the reinforcement of composites. In this study, hexagonal pits and channels were prepared on the surface of GFs by high-temperature air etching treatments. The morphology and reason of pits and channels prepared in the air were investigated. The pits and channels enable the mechanical interlocking effect between the GFs and the carbon matrix and enhance the mechanical and thermal properties of the carbon/carbon (C/C) composites. The GFs-reinforced C/C composites with high thermal conductivity were fabricated through impregnation-carbonization cycles. The results show that, with the increase in etched GFs volume fraction, the horizontal thermal conductivity was increased from 148 to 412 W/(m K). Moreover, compared with pristine GFs-reinforced C/C composites, etched GFs-reinforced C/C composites show an increase of 165% in flexural strength. Overall, etched GFs-reinforced C/C composites with superior properties have a broad prospect in the fields of heat dissipation.