Abstract
The characteristics of iron (Fe) and nickel (Ni) diffusion in molten lead-bismuth eutectic (LBE) were investigated experimentally by using capillary method. The diffusion coefficients of iron (Fe) and nickel (Ni) were determined from measured axial concentration distributions of Fe and Ni in LBE specimens. The correlation of the diffusion coefficients can be obtained as DFe =3.5×10-3exp (-4.15×10-4/RT) (550°C < T < 650°C) [cm2/s], DNi =1.7×10-3exp (-3.63×10-4/RT) ( 500°C < T < 650°C) [cm2/s]. The diffusion coefficient of Fe in LBE obtained is approximately the same as the result derived by Balboud - Celerier. The result of the diffusion coefficient of Ni is almost in he same order as that of Fe in spite of much higher solubility of Ni than that of Fe in LBE. From microstructure observation by using the scanning electron microscope (SEM) and the energy dispersive X-ray spectroscopy (EDX), it is found that in case of Ni diffusion, some compounds, with 50-60% Ni, 15-20% Pb and 15%-20% Bi, were observed only in the solid specimen. It is probable that the formation of the compounds slowed down the diffusion of Ni into LBE.
