In-situ measurement of thermodiffusion in liquid alloys

Abstract

Thermodiffusion in liquid alloys influences the homogeneity of doped semiconductors and grown crystals as well as the microstructure formation during solidification. The calculation of thermodiffusion by molecular dynamic simulation can be very sensitive to the specific potential (Levchenko et al. 2016). There exist several theoretical models attempting to predict binary thermodiffusion, but there is still no comprehensive model able to predict the Soret coefficient for a wider range of systems, as recently shown by (Hoang et al. 2022). Copper and silver are used together with tin in ternary Sn-Ag-Cu (SAC) alloys for soldering, in efforts to replace the toxic lead based solders. The thermodiffusion in liquid Ag–Cu was modeled by Sarder et al. (Sarder et al. 2019), using molecular dynamics (MD) simulations. They found silver to migrate to the cold side, with a Soret coefficient of 1.8 × 10-3 K-1 for liquid Ag62.5Cu37.5 at a temperature of 1100 K. It is the goal of this work to measure the Soret effect in liquid Ag60Cu40 using a specialized shear cell furnace, and compare the measured value with the results from simulations.