Corrosion of metallic materials in flowing liquid lead-bismuth

Abstract
Corrosion tests of martensitic and austenitic steels were performed in a forced liquid eutectic Ph-Bi circulation loop. Experiments were carried out at 470°C and 600°C. Two oxygen concentrations in Pb-Bi were studied: 10^-6 wt% and 10^-7-10^-8 wt%. The results showed that at 470°C, all the tested steels have a satisfying corrosion behaviour for both oxygen contents. An oxide layer is formed on martensitic steels (T91 and EM10); its thickness depends on the oxygen content. It is constituted of an outer layer of magnetite and an inner (Fe, Cr) ₃O ₄ spinel layer. Austenitic steel 316L is protected by a very thin oxide layer ( < 1  m). At 600°C, martensitic steels (T91 and EM10) undergo an important oxidation for both oxygen contents (after 1000h, the thickness of the oxide layer varies from 10-15 m to 20-25 m depending on the oxygen content). The oxide layer is constituted of (Fe, Cr) ₃O ₄ spinel and appears porous. Austenitic 316L undergoes severe dissolution at the lowest oxygen content in Ph-Bi and partial dissolution and oxidation at the highest oxygen concentration. Erosion phenomena were observed on all the steels.