Thermal conduction networks formed by thermally conductive fillers are crucial to the thermal conductivity coefficients (λ) of composites. In this paper, paraffin wax (PW) spheres with different sizes are prepared by instantaneous cooling granulation technology. With graphite coated on their surface by the micro-cladding method, the graphite/PW thermally conductive composites are then fabricated by hot pressing. The formation process of graphite thermal conduction networks at interfaces between the PW phases, and the influences of the density, distribution, and integrity of the networks on the λ of the graphite/PW composites are analyzed in-depth. Besides, an innovative concept of “Density of Thermal Conduction Networks (D_TCN)” is proposed to explain the λ difference among different graphite/PW composites. The D_TCN of the graphite/PW composites have the best value for given graphite loading and molding pressure. The λ of the graphite/PW composites with the same size of PW spheres increases with increasing D_TCN. When the amount of graphite is 10 wt%, the molding pressure is 200 MPa, and the PW spheres size is 2.08 ± 0.08 mm, the graphite/PW composites have the maximum λ (1.81 W/(m·K), the λ enhancement rate per unit mass fraction (E_λ/wt) of graphite is 45, about 6 times of that of pure PW (0.33 W/(m·K)), also obviously higher than that of the freely dispersed R-graphite/PW composites with the same amount of graphite and molding pressure (0.79 W/(m·K), E_λ/wt is 14). The higher D_TCN, the more uniform distribution and integrity of the thermal conduction networks, and ultimately the higher λ of graphite/PW composites.

由导热填料形成的导热网络对复合材料的导热系数 ( λ )至关重要。本文采用瞬时冷却造粒技术制备了不同尺寸的石蜡（PW）球体。通过微包覆法在其表面涂覆石墨，然后通过热压制造石墨/PW导热复合材料。深入分析了PW相界面处石墨热传导网络的形成过程，以及网络的密度、分布和完整性对石墨/PW复合材料λ的影响。此外，“热传导网络密度（D _TCN)”来解释不同石墨/PW复合材料之间的λ差异。对于给定的石墨负载和成型压力，石墨/PW 复合材料的D _TCN具有最佳值。具有相同尺寸 PW 球体的石墨/PW 复合材料的λ随着D _{TCN 的}增加而增加。当石墨用量为10 wt%，成型压力为200 MPa，PW球尺寸为2.08±0.08 mm时，石墨/PW复合材料的λ最大(1.81 W/(m·K)，λ增强每单位质量分数的比率 ( E _λ/wt)的石墨为45，约为纯PW(0.33 W/(m·K))的6倍，也明显高于相同石墨量和成型压力下自由分散的R-graphite/PW复合材料( 0.79 W/(m·K)，E _λ/wt为 14)。D _TCN越高，热传导网络的分布和完整性就越均匀，最终石墨/PW 复合材料的λ也越高。