Thermal conductivity experiment of interface material based on graphite sheet

Abstract Graphite sheets, recognized for their exceptional thermal conductivity, where in-plane thermal conductivity can surpass 1000 W/m·K, are examined in this study for their impact on the thermal resistance of cooling devices. This investigation focuses on how the installation torque of graphite sheet interface material, along with the contact surface’s roughness and flatness, influences the overall thermal resistance. The findings reveal that integrating a graphite sheet at the interface markedly enhances the interface thermal contact resistance, with increased roughness and flatness further reducing the thermal contact resistance. Specifically, at an installation torque of 0.3 N·m, a flatness of 0.05 mm, and a roughness of 0.8 μm, without filler, using 0.2 mm tin bismuth foil, and 0.2 mm graphite, thermal contact resistance was measured at 2.96, 2.52, and 1.09 K·cm 2 /W, respectively, showing a significant reduction in thermal contact resistance by 1.87 K·cm 2 /W (63.1%) upon adding a graphite sheet. Moreover, when roughness was increased to 12.5 μm, the reduction in contact resistance attributable to the graphite sheet escalated to 82.3%, with the reduction attributable to increased flatness being negligible. The decrease in thermal contact resistance with the graphite sheet reached 87.2%. Furthermore, the study indicates that at a lower installation torque of 0.2 N·m, the graphite sheet effectively fills the interfacial air gaps, thereby enhancing heat dissipation efficiency. These results offer valuable insights for the application of graphite gaskets in high-power components.