Electrically Insulating Thermal Putty with High Thermal Conductivity and Low Thermal Resistance through Interface...

Effective heat conduction has become the most urgent technological challenge in the electronics industry. Currently, alumina (Al₂O₃) is widely used as a thermal filler in thermal interface materials (TIMs). However, Al₂O₃-based TIMs generally exhibit relatively low thermal conductivity and high interfacial resistance, which can be attributed to both the low intrinsic thermal conductivity of Al₂O₃ and the significant Kapitza resistance between filler particles. To address this issue, this study introduces fine-sized aluminum nitride (AlN) fillers into spherical Al₂O₃ to enhance the thermal conduction network. Additionally, liquid metal can form a "liquid bridge" between filler particles and optimize the interfacial contact, effectively reducing the interfacial thermal resistance between the filler particles. The resulting TIM with a filler loading of 88.3 vol % exhibits an isotropic thermal conductivity of 14.06 W m^-1 K^-1 and thermal resistance as low as 0.24 K cm² W^-1 under a packaging pressure of 40 psi. Moreover, the composite retains excellent electrical insulation with a volume resistivity of 2.11 × 10¹³ Ω cm. Due to the wetting effect of the LM, the resulting composite demonstrates excellent plasticity properties, making it well-suited for heat transfer applications in complex or irregular packaging structures. The performance test shows that this TIM outperforms current advanced commercial counterparts, highlighting its significant potential for applications in irregular shape thermal management systems.