Valentyn Tsisar

Compatibility of Ferritic/Martensitic Steel T91 With Flowing LBE Containing 10−7 Mass% Dissolved Oxygen at 450 and 550°C

Corrosion behavior of ferritic/martensitic (F/M) steel T91 with 9 % nominal chromium content was investigated in flowing (2 m/s) Pb-Bi eutectic (LBE) with 10−7 mass% dissolved oxygen at 450 and 550°C for up to 8766 and 2011 h, respectively. The corrosion process and material loss were analyzed. The steel generally shows oxidation consisting of the formation of an Fe-Cr spinel layer. Oxidation resulted in metal recession which does not exceed ∼ 10 μm after 8766 h at 450°C and ∼15 μm after 2011 h at 550°C. Local liquid-metal attack in the form of pits occurs at both temperatures. At 450°C, remarkable liquid-metal attack is observed after 5015 h, while, at 550°C, it is found already after 1007 h. The maximum depth of local attack reaches 960 μm after 8766 h at 450°C, and 190 μm after 1007 h at 550°C.The obtained results are compared with previous experiments at similar testing conditions, except for a higher oxygen concentration of 10−6 mass%.Copyright

Oxidation/Dissolution of Ferritic ODS Steels in Static Lead With Various Oxygen Contents at 650°C

The compatibility of ferritic oxide dispersion strengthened (ODS) steels with static liquid Pb at 650°C was investigated for up to 1750 h. The dependence of corrosion behavior on oxygen concentration in the melt and steel structure was determined. The interaction mode changed from intensive oxidation in the oxygen-saturated melt, accompanied by the formation of a bi-layer magnetite/spinel scale, to formation of a thin Cr-based oxide film in oxygen-doped melt and to the severe steel dissolution in oxygen-free lead. The viability of the in-situ formed Cr-based oxide film, as a promising way to improve the corrosion resistance of steels in the high-temperature (T > 550°C) lead melts is discussed.Copyright