(1. The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, China) (2. Key Laboratory of Hubei Province for Coal Conversion and New Carbon Materials, Wuhan University of Science and Technology, Wuhan 430081, China)
The rapid development in the fields of microelectronics and communication technologies has put forward higher requirements for thermal management materials, and there is an urgent need for designing and developing carbon materials with high-oriented thermal conductivity. High-oriented carbon materials possess typical anisotropic and high thermal conductivities, owing to their high crystallinity and graphitization degree as well as orderly stacking of graphene sheets. Although powdery carbon materials, such as flake graphite, vapor-grown carbon fiber, carbon nanotube, graphene, etc. have high thermal conductivities, the thermal conduction of composites using powdery carbon materials as thermal conductive fillers is not well-performed. Therefore, their application will be subject to certain restrictions in the field of thermal dissipation of large integrated devices with high power. It is critical to achieve high-oriented thermal conductive performance for carbon materials by controlling the size, orientation and orientation continuity of graphite microcrystal. Macro-sized carbon materials, such as flexible graphite, natural flake graphite-molded block, high-oriented pyrolytic graphite, polyimide graphite film/block, mesophase pitch-based continuous carbon filament and its composite, etc. can be obtained via choosing suitable carbonaceous precursors, forming processes and heat treatment conditions, as well as controlling the continuous orientation of graphene sheets. The graphite crystal of macro-sized carbon materials along the (002) crystalline direction maintains high thermal conductive performance, so that their high-oriented, continuous and multi-dimension-tunable thermal conduction will come true. Therefore, the macro-sized carbon materials have a broad application market in the field of thermal management, such as thermal conduction, thermal dissipation and thermal protection, etc.