Investigation of additional convective transports in liquid metals and semiconductors during diffusion measurements by means of the shear cell technique

Abstract

Abstract Diffusion measurements of metallic and semiconductor melts on earth show highly irreproducible results due to occurrence of unknown convection. Therefore we investigated the influence of different kinds of additional transports. Diffusion experiments with the shear cell technique and numerical simulations have been performed. It could be shown that neither the initial transport due to the shearing at the beginning of an experiment nor the buoyancy driven convection due to horizontal temperature gradients have sufficient strength to explain the high scattering of the experimental results. Instead there is strong evidence that solutal Marangoni convection, if free surfaces cannot be avoided, may be the main reason for the irreproducibility, at least under laboratory conditions.