Wettability and thermal contact resistance of thermal interface material composited by gallium-based liquid metal on copper foam

Abstract

As a promising thermal interface material (TIM), gallium-based liquid metal (GBLM) could significantly reduce the thermal contact resistance (TCR) at the solid-solid interfaces, while the leakage of GBLM and the wettability between liquid metal and solid surface restrict further application. In this study, the GBLM was wrapped with a copper foam (CF) skeleton, which prevents leakage and improves the thermal conductivity of the GBLM. Gallium-based liquid metal-copper foam (GBLM-CF) TIM was prepared by the self-wetting of the CF surface through the galvanic corrosion of GBLM. As the concentration of HCl increases from 0 to 5 M, the interfacial tension (IFT) in the HCl solution decreases from 536.80±1.00 mN/m to 481.52±0.49 mN/m, demonstrating that the IFT of the GBLM is inversely proportional to the concentration of HCl. Meanwhile, the decrease of contact angle (CA) by 8° indicates that the presence of CuGa2 on the surface promotes the wettability of GBLM. With the increase of external pressure and the improvement of wettability, the TCR between the GBLM and the copper sheet decreased by 58.28%. The TCR of the sample using GBLM-CF as TIM is 83% lower than that of thermal grease. Moreover, the thermal conductivity of GBLM-CF TIM (51.58±0.01 W/(m·K)) is 212.6% higher than that of GBLM (16.50±0.02 W/(mK)). The GBLM-CF TIM presented in this study can be used for the efficient thermal management of electronic equipment.