High serving temperature GaSn-based thermal interface material added with Cu@Ni core-shell particles featuring proper fluidity and thermal performance

Purpose This paper aims to develop a novel thermal interface material (TIM) that combines the high thermal conductivity of liquid metals (LMs) with suitable fluidity and serving temperature, addressing the leakage issue associated with Ga-based LM. Design/methodology/approach A composite TIM was fabricated using Cu@Ni core-shell powder and GaSn eutectic LM, named GaSn-Cu@Ni. The Cu@Ni core-shell powder was prepared by electroless Ni plating on spherical Cu powder. The GaSn-Cu@Ni composite was obtained by mixing the GaSn eutectic alloy with the Cu@Ni powder under vacuum. The microstructure, viscosity, hardness and thermal conductivity of the composite were characterized and compared with a GaSn-Cu composite. Findings In comparison with the pure Cu powder added one (GaSn-Cu) that has a short process time, the GaSn-Cu@Ni composite can remain in a flowing state with a low viscosity for up to 1.5 h after being fabricated at 25 °C. Additionally, the liquid–solid transition at 60 °C can be accomplished within 192 h along with increasing heat-conducting capabilities due to the generation of CuGa2 phase, and the thermal conductivity of solidified GaSn-Cu@Ni composite can reach 76.1 W/(m·K). Moreover, the serving temperature of the solidified composite can reach as high as 159.9 °C. Originality/value The above findings inspire a promising way for developing novel and highly reliable LM-based TIMs in electronic industry.