Unveiling thermal properties and pump‐out blocking in diamond/GaInSn composites as thermal interface materials

Gallium‐based liquid metal, as a high‐performance thermal interface material, can improve the performance and service life of electronic equipment. This study focuses on the use of diamond as a thermal conductivity enhancement phase to improve the thermal conductivity of GaInSn liquid metal and avoid the overflow of liquid metal during application. In this study, diamond/GaInSn composites were prepared by an ultrasonic‐assisted wetting method. The thermal conductivity and contact thermal resistance of diamond/GaInSn composites were characterized by the transient method. The morphology and thermal conductivity of diamond/GaInSn composites were investigated when diamond particles of different diameters were added to GaInSn liquid metal. The addition of large‐sized diamond particles can effectively improve the thermal conductivity of thermal interface materials (TIMs) but will cause liquid metal to pump out. The material reaches a maximum thermal conductivity of 74 W·mK −1 with an added diamond particle size of 120 μm. The equilibrium mechanism between the thermal properties and pumping blockage performance in diamond/GaInSn with different diamond sizes is discussed in this article. The variation in thermal resistance of diamond/GaInSn composites is inconsistent with the variation in thermal conductivity. When the diamond size is 18 μm (800 mesh), the TIM has the lowest thermal resistance and the best heat transfer performance.