Enhancing Thermal Conductivity and Tribological Performance of Paper‐Based Friction Materials via One‐Dimensional/Two‐Dimensional Carbon Nanoparticle Composite Coatings

Paper‐based friction materials are porous materials suitable for oil environments and serve as core components in transmission systems. Currently, friction materials face significant challenges, such as thermal fading and unstable friction coefficients under high pressure. Carbon nanofibers (CNFs), carbon microfibers (CF), and graphene nanoparticles (GNPs) are commonly used as surface coatings to improve the thermal and tribological performances of composite materials. Therefore, this study investigated the effect of the blending ratio on the performance of friction materials by applying hybrid carbon nanoparticles to fiber composites. The results indicate that GNPs and CF exhibit a mechanical interlocking effect, whereas CNFs and CF exhibit a size‐dependent composite effect. The CNFs and GNPs form a three‐dimensional network framework. At a GNPs/CF ratio of 1:9, paper‐based friction materials exhibit a plane thermal conductivity of 1.037 W/(m·K) and through‐plane thermal conductivity of 0.286 W/(m·K). The dynamic friction coefficient was determined to be 0.137. Compared with the GNPs coatings, the thermal conductivity increased by 13.45% and 30.59%, respectively, whereas the friction coefficient increased by 11.38%. Consequently, the GNPs/CF composite coatings are far superior to the GNPs coatings.