Solubility and diffusion of metallic iron in liquid Bi metal at 450 °C

Abstract

Lead–bismuth (Pb–Bi) alloy is a candidate for the spallation target material in accelerator-driven system (ADS). If use of liquid metal target presents advantages for their perfect cooling of the target and their heat removal capacity, one of the main drawbacks is the corrosion and the erosion of structural materials which are in direct contact with the liquid metal at high temperatures under high flow velocities. One of corrosion processes is known as dissolution corrosion. The structural material for Pb–Bi target nowadays suggested is the modified Fe–9%Cr (at.%) steel. To evaluate the dissolution corrosion rate, the knowledge of iron solubility and diffusion coefficient in Pb–Bi is necessary. These determinations can be realized using electrochemical methods and mathematical analyzing of resulting data. The aim of this paper is to test a procedure to determine solubility and diffusion coefficient of iron in pure liquid bismuth. The experimental approach and the mathematical analysis are described. It demonstrates that combining electrochemical method and simulation lead to determine the solubility (1.85 ± 0.3 × 10 −5 mol/cm 3) and the diffusion coefficient of iron (1.0 ± 0.2 × 10 −5 mol/cm 3) in liquid Bi at 450 °C.