Temperature‐dependent electrical resistivity in In–Sn alloys with varied phase composition and ternary element levels

The In–Sn alloys which have low melting point are technically important for many applications, especially for those involving cryogenic temperatures. Because electrical resistivity is critical to electronic devices, the resistivity of alloys from the In–Sn system and potential variations that can result from elemental additions require investigation. Resistivity depends on temperature, microstructure, and local composition. By linking solidification paths, phase constitution, and microstructure in binary In–Sn and modified alloys, we show that the resistivity in the β-In 3 Sn phase rises with solute dissolution and that Ga, Ag, and Bi each increase resistivity by different mechanisms. Supported by Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM), CALPHAD, X-Ray Diffraction (XRD), and Electron Backscatter Diffraction (EBSD) data, we show that mechanisms including lattice distortion, precipitation, and boundary-induced scattering affect both the resistivity and the Temperature Coefficient of Resistance (TCR).