Study on Thermal Reliability of Ga-Based Liquid Metal as Thermal Interface Material Encapsulated with Fluororubber

Ga-based liquid metal (LM) with high thermal conductivity is considered to be a promising thermal interface material (TIM) for electronic thermal devices; however, its pump-out and easy oxidation hinder its popularization. Herein, fluororubber (FKM) was selected as the sealing material to prevent the pump-out of eutectic Ga-In-Sn (EGaInSn) and reduce its oxidation during long-term extreme service conditions. After being placed in an oil bath at 125°C for 4 weeks, the FKM soaked in EGaInSn could still hinder the penetration of EGaInSn and maintain good elasticity and plasticity. When EGaInSn was applied to a radiator cap as TIM, the maximum radiator temperature at full load was 47% lower than that without TIM, and 14% lower than that with commercial thermal grease. Moreover, after experiments including 1000 h of high-temperature aging, 1000 h of constant temperature and humidity, and 1000 thermal shocks, there was no pump-out or apparent oxidation in the sealing structure with FKM.