Characterization and thermal performance of Sn-Bi alloy used as a thermal interface material

Abstract. The growing demand for efficient heat dissipation in electronic devices necessitates the development of high-performance TIMs with superior thermal conductivity and mechanical stability. Sn-Bi alloys, known for their low melting points and good wettability, offer alternatives to conventional TIMs. The present study focuses on the microstructural studies, thermal conductivity, hardness and interfacial resistance of Sn-40Bi (alloy 1), Bi-42Sn (alloy 2) and Bi-30.8Sn-29.8Pb (alloy 3) for thermal management applications. Different thicknesses of Sn-Bi and Bi-Sn-Pb alloys were preferred and further, the results are compared. Differential scanning calorimetry (DSC), and scanning electron microscopy (SEM), were used to characterise the alloys. The findings provide insights into the feasibility of Sn-Bi alloys as efficient TIMs. TIM specimen of thickness 0.5 mm exhibited lowest value of TCR for all the alloys. Sn‒40Bi thermal interface alloy exhibited better thermal performance compared to Bi‒42Sn and Bi‒30.8Sn‒29.8Pb.