Diffusion measurements of metallic and semiconductor melts on earth exhibited highly irreproducible results due to occurrence of unknown convection. Therefore, the influence of various types of additional transport were investigated. Diffusion experiments were performed by using the shear cell technique and numerical simulation. 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 had sufficient strength to explain the high scattering of the experimental results. Instead there was strong evidence that solutal Marangoni convection, if free surfaces could not be avoided, may 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