It was noted that diffusion measurements of metallic melts on Earth exhibited highly irreproducible results due to the occurrence of unknown convection effects. Thereforethe influence of various types of additional transport were investigated. Diffusion experiments were performed by using the shear cell technique and numerical simulations. It could be shown that neither the initial transport due to shearing at the beginning of an experiment nor the buoyancy-driven convection due to horizontal temperature gradients had sufficient strength to explain the high scatter in the experimental results. There was instead strong evidence that solutal Marangoni convection, if free surfaces could not be avoided, could be the main reason for the irreproducibility; at least under laboratory conditions.

Investigation of Additional Convective Transports in Liquid Metals and Semiconductors during Diffusion Measurements by Means of the Shear Cell Technique. H.Müller, G.Müller-Vogt: Crystal Research and Technology, 2003, 38[7-8], 707-15