MUTUAL DIFFUSION COEFFICIENT IN MOLTEN LEAD-BISMUTH MIXTURES

Mutual diffusion coefficients in the molten lead-bismuth system were measured over the whole concentration range at temperatures from 443 to 1068 K using the capillary-reservoir method. Care was taken to avoid turbulence or disturbances liable to occur in the liquid metal system at high temperatures, and also to eliminate the oxide layer or other impurities at the interface. High reliability in the determined diffusion coefficients was realized by confirming the occurrence of molecular diffusion from the observed concentration profiles. The extrapolated diffusion coefficients at infinite dilution of lead or bismuth could well be correlated by Arrhenius-type expressions. The concentration dependency of the ideal diffusion coefficients was found to be nearly linear.