High Thermal Conductivity BiInSn Liquid Metal/Al Composite as High-Performance Thermal Interface Materials

Indium-based liquid metal, such as BiInSn alloy, with a melting point ranging from ∼50 to 80 °C can be easily fabricated into sheet, which has an excellent operability and reusability as the thermal interface material (TIM). However, the thermal conductivity (k) of BiInSn alloy is around 20 W m–1 K–1 and there is still a big gap between the thermal management demand of high-power chips and the leakage after melting, which will result in a serious risk of short circuit. This study utilizes high k and low-cost Al powder as fillers to prepare a series of BiInSn/Al composites. The size and content of the Al particles are carefully optimized to enhance thermal performance. Further investigations reveal that thermal annealing can effectively eliminate voids around the Al particles within the composite sheet, thereby establishing efficient thermal conductive pathways. As a result, the thermal conductivity of the annealed BiInSn/Al composite exceeds 40 W m–1 K–1, representing an 88.5% increase over the original undoped BiInSn sheet, and displays the antileakage performance under higher working temperature.