Ground-based diffusion experiments on liquid Sn-In systems using the shear cell technique of the satellite mission Foton-M1

This study reported in this paper was aimed at testing the shear cell that was developed for the satellite mission Foton-M1 to measure diffusion coefficients in liquid metals under microgravity (μg)-conditions. Thick Layer diffusion experiments were performed in the system Sn90In10 versus Sn under 1g-conditions. For this system several μg-diffusion results are available as reference data. This combination provides a low, but sufficiently stable, density layering throughout the entire experiment, which is important to avoid buoyancy-driven convection. The experimental results were corrected for the influences of the shear-induced convection and mixing after the final shearing, both of which are typical for the shear cell technique. As the result, the reproducibility and the reliability of the diffusion coefficients in the ground-based experiments were within the limits of error of μg-data. Based on our results we discuss the necessary conditions to avoid buoyancy-driven convection.