Long-term corrosion performance of T91 ferritic/martensitic steel at 400 °C in flowing Pb-Bi eutectic with 2 × 10−7 mass% dissolved oxygen

Environmental degradation of structural materials in liquid lead- and lead-bismuth eutectic-cooled reactors

“…This difference suggests that a higher Cr content in the "T91-A" steel promoted the formation of more stable oxides (e.g., Cr-based oxides), resulting in a better steel resistance to dissolution 'pitting'. Interestingly, under similar exposure conditions, the severe localised dissolution corrosion damage was not observed in T91 (8.99 wt%) F/M steels tested in the CRAFT loop (SCK CEN), after even a longer exposure up to ~20,000 h. This may result from different local flow patterns in the two forced convection loops [190]. In addition to the steel Cr content, the severity of dissolution 'pitting' relies heavily on the test temperature and LBE oxygen content [101].…”

“…The oxide residues on the steel surface tend to capture the steel alloying elements (Cr, Fe) that diffuse outwards as well as the oxygen that tries to diffuse inwards, promoting rather than decelerating the growth of the 'pit'. Locally enhanced dissolution corrosion was reported in 9Cr F/M steels, including the T91, T92, E911, and EUROFER grades with slight differences in chemical composition, e.g., in the Cr and Si contents [101,181,182,190]. Schroer et al [183] reported very severe localised dissolution corrosion damage (depth: ~1190 μm) in a "T91-B" steel (8.99 wt% Cr) exposed to oxygen-containing (C O ≈ 1 × 10 − 7 wt%), flowing LBE (v ≈ 2 m/s) at 400 • C for 13,172 h in the CORRIDA loop (KIT), while a "T91-A" steel with a relatively high Cr content (9.44 wt%) did not suffer such extreme LMC damage under identical exposure conditions.…”

“…Mechanisms: uniform oxidation (diamonds), uniform dissolution (circles), and locally enhanced dissolution (triangles). [ 92,101,117,180,181,183,187,190,191,[215][216][217]225,227,231,232]. Steel grades: T91, F82H, STBA26, STBA28, EUROFER-97, E911 and P92.…”

Low-temperature oxy-nitriding of 316 L austenitic stainless steel for improved corrosion resistance in liquid lead-bismuth eutectic

“…However, under the same conditions, a dense oxide film containing γlow-N (Layer A) was formed on the surface of the LTON treated sample to effectively protect the steel from contacting corrosive LBE. The structural materials usually form a bilayer structure consisting of the outer magnetite and inner spinel during LBE corrosion [27]. Usually, the spinel was more protective than the magnetite for combating the LBE corrosion [28].…”

A Review of the Surface Modifications for Corrosion Mitigation of Steels in Lead and LBE

“…The oxide layer exhibits a duplex scale, consisting of an inner spinel and an outer magnetite. The layer thickness grows faster for the magnetite oxide than for the spinel oxide [25]. Austenitic stainless steels are much less sensitive to oxidation [26] and sometimes claimed as excellent corrosion resistance materials [27].…”