The compatibility of austenitic materials with liquid Pb–17Li

Abstract Mass transfer experiments in liquid Pb–17Li were performed in an anisothermal container with pure metals (Fe, Ni and Cr) and with four austenitic materials. These experiments evidenced a corrosion rate of pure nickel two orders of magnitude higher than the chromium one and about three orders of magnitude higher than the iron one. Concerning the austenitic materials, a porous corrosion layer mainly constituted of ferrite but containing also for two of them small amounts of chromium-rich phase was observed. A mechanism of corrosion for austenitic steels was proposed and discussed below. The first step of our mechanism is the nickel and the chromium superficial dissolution. The second step results from the phase transformation of the austenite matrix (γ structure) into ferrite (α structure) with porosity. And finally, the diffusion of the dissolved species occurs in the liquid metal channels and in the diffusion boundary layer of liquid Pb–17Li. The chromium diffusion in the liquid alloy is the limiting step for the whole mechanism.