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

Abstract

As chips become more densely integrated and the surface heat flux increases, there is a growing demand for thermal interface materials (TIMs) that exhibit both high thermal conductivity and long-term reliability. In this study, CuGa₂ microparticles were synthesized via melt atomization and then incorporated into a gallium-based liquid metal to prepare 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)⁻¹, approximately 3 times higher than that of a conventional gallium-based liquid metal. This improvement is primarily due to metallic bonding at the interface between liquid gallium and the CuGa₂ intermetallic compound, where free electrons serve as the main heat carriers across the interface. Furthermore, the addition of CuGa₂ improves the TIM's coating ability 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 applications involving high heat fluxes.