Composite thermal interface material of gallium-based liquid metal and CuGa2 with high thermal conductivity and long-term stability

Abstract

With the increasing integration density of chips and the consequent rise in surface heat flux, there is a growing demand for thermal interface materials (TIMs) that combine high thermal conductivity and long-term reliability. In this work, CuGa₂ microparticles were synthesized via melt atomization and subsequently incorporated into gallium-based liquid metal to fabricate composite TIMs. Experimental results demonstrate that when the CuGa₂ mass fraction reaches 50%, the composite achieves a maximum thermal conductivity of 74.92 ± 1.04 W/(m·K), approximately 3 times higher than that of conventional gallium-based liquid metal. This enhancement is primarily attributed to metallic bonding at the interface between liquid gallium and the CuGa₂ intermetallic compound, where free electrons serve as the dominant heat carriers across the interface. Furthermore, the addition of CuGa₂ improves the coating ability of the TIM while reducing its fluidity, thereby reducing the risk of leakage. Long-term testing over 35 days revealed no compositional changes or segregation hardening, confirming the excellent stability of the composite. Overall, Ga/CuGa₂ TIMs strengthened by metallic bonding present a promising solution for reliable heat dissipation in high heat flux applications.