Reduction of Convection in Diffusion Measurement using the Shear Cell by Stabilization of Density Layering on the Ground

Abstract

An inter-diffusion experiment between a ternary alloy of SnBiIn and pure Sn was performed using the shear cell technique on the ground. The capillary was set vertically and the SnBiIn sample was set in the lower side of the capillary. The obtained concentration profiles were smooth and were able to be fitted by theoretical functions. The diffusion coefficients of In and Bi obtained by fitting and corrections for the shear convection and the averaging effect agreed well with those obtained in a microgravity experiment performed in Foton-M2. Under assumption of the power law, the obtained data were lying on the same curves of temperature dependence as other available reference data of inter-diffusion of SnIn-Sn and SnBi-Sn. It was found that the addition of Bi to SnIn does not bother the diffusion of In and stabilizes the density layering to suppress convection in an experiment on the ground.