Effect of Oxygen Concentration in Static Pb-Bi Eutectic on Corrosion Mode of Aluminum-Alloyed Austenitic Steels at 550 °C for 1000 h

2021 ◽  
Vol 1024 ◽  
pp. 79-85
Author(s):  
Valentyn Tsisar ◽  
Zhang Jian Zhou ◽  
Olaf Wedemeyer ◽  
Aleksandr Skrypnik ◽  
Carsten Schroer
Keyword(s):  
Liquid Metal ◽  
Oxide Film ◽  
Dissolved Oxygen ◽  
Oxygen Concentration ◽  
Corrosion Behavior ◽  
Austenitic Steels ◽  
Ferrite Layer ◽  
Effect Of Oxygen ◽  
Corrosion Mode ◽  
Al Oxide

Corrosion behavior of Fe-18Ni-12Cr-2.30Al and Fe-18Ni-12Cr-2.90Al-Nb-C austenitic steels was investigated in static Pb-Bi eutectic at 550 °C for 1000 h depending on the concentration of dissolved oxygen in the liquid metal. In the concentration range from 1012 to 108 mass % O, both steels underwent corrosion via dissolution resulted in the formation of spongy ferrite layer depleted in Ni and Cr and penetrated by Pb and Bi. In Pb-Bi with 106 mass % O, Fe-18Ni-12Cr-2.90Al-Nb-C steel oxidizes with formation of very thin (≤ 1 μm) Cr/Al oxide film while Fe-18Ni-12Cr-2.30Al steel shows mixed corrosion behavior represented by more intensive oxidation and dissolution. The features of corrosion response are discussed depending on the composition of steels and concentration of dissolved oxygen in the Pb-Bi eutectic.

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

2014 ◽  
Author(s):  
Valentyn Tsisar ◽  
Carsten Schroer ◽  
Olaf Wedemeyer ◽  
Aleksandr Skrypnik ◽  
Jürgen Konys
Keyword(s):  
Liquid Metal ◽  
Dissolved Oxygen ◽  
Oxygen Concentration ◽  
Corrosion Behavior ◽  
Chromium Content ◽  
Martensitic Steel ◽  
Corrosion Process ◽  
Material Loss ◽  
Spinel Layer ◽  
Testing Conditions

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%.

Effect of Structural State and Surface Finishing on Corrosion Behavior of 1.4970 Austenitic Steel at 400 and 500 °C in Flowing Pb-Bi Eutectic With Dissolved Oxygen

2018 ◽  
Vol 4 (4) ◽  
Author(s):  
Valentyn Tsisar ◽  
Carsten Schroer ◽  
Olaf Wedemeyer ◽  
Aleksandr Skrypnik ◽  
Jürgen Konys
Keyword(s):  
Oxide Film ◽  
Dissolved Oxygen ◽  
Corrosion Behavior ◽  
Structural State ◽  
Cold Work ◽  
Surface Finishing ◽  
Polished Surface ◽  
Type Solution ◽  
Corrosion Attack ◽  
Cold Worked

The effect of structural state (solution annealed (SA) and after 40% cold work (CW)) and surface finishing (turning, grinding, and polishing) on the corrosion behavior of austenitic 1.4970 (15-15 Ti) steel in flowing (2 m/s) Pb-Bi eutectic containing 10−7 mass% dissolved oxygen at 400 °C and 10−6 mass% O at 500 °C is investigated. At 400 °C for ∼13,000 h, the corrosion losses are minor for steel in both structural states and for surfaces finished by turning and grinding—a thin Cr-based oxide film is formed. In contrast, the polished surface showed initiation of solution-based corrosion attack with the formation of iron crystallites and preferential propagation along the grain boundaries. The depth of corrosion attack does not exceed 10 μm after ∼13,000 h. At 500 °C for 2000 h, the samples in both structural states showed general slight oxidation. Cold-worked steel underwent a severe groove-type and pit-type solution-based attack of 170 μm in maximum depth, while the SA sample showed only sporadic pit-type corrosion attack to the depth of 45 μm in maximum.

Effect of Temperature and Dissolved Oxygen on the Corrosion Behavior of Carbon Steel in High-Temperature Water

CORROSION ◽  
1991 ◽  
Vol 47 (7) ◽  
pp. 500-508 ◽  
Author(s):  
K. Mabuchi ◽  
Y. Horn ◽  
H. Takahashi ◽  
M. Nagayama
Keyword(s):  
High Temperature ◽  
Carbon Steel ◽  
Oxide Film ◽  
Dissolved Oxygen ◽  
Corrosion Behavior ◽  
Effect Of Temperature ◽  
Oxide Surface ◽  
X Ray ◽  
High Temperature Water ◽  
Temperature Water

Abstract The corrosion behavior of carbon steel in high-temperature water, and the structure and composition of the oxide film were examined as functions of dissolved oxygen concentration (DO), temperature (T), and corrosion time (t). The total amount of iron corroded (WT) was differentiated into the amounts of iron ions in the oxide (WF) and dissolved into the water (WD). The total rate of corrosion (rT), the rate of iron dissolution (rD), and the rate of accumulation of iron in the oxide (rF) were obtained by differentiating the time variations in WT, WF, and WD. The structure and composition of the oxide film were examined by x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), and transmission and scanning electron microscopy. In general, rT increases with increasing DO and T, rD shows T- and DO-dependent minimum, and there is serious localized corrosion at high DO above 500 ppb. Oxide films consist of magnetite except at T=60°C, DO=50 to 200 ppb where a thin layer of hydrous ferric oxide is formed. At DO=500 ppb , the outermost part of the magnetite changes into γ-Fe2O3, and above DO=1.0 ppm, appreciable amounts of α-Fe2O3 cover the magnetite oxide layer. The rT and rD values are not related to the presence of αFe2O3 or Fe3O4 in the surface structure of the oxide, but clearly decrease as the OH−/Fe mole ratio at the oxide surface increases. The mechanism determining the corrosion rate changes is discussed.

Corrosion behavior of austenitic steels 1.4970, 316L and 1.4571 in flowing LBE at 450 and 550 °C with 10−7mass% dissolved oxygen

2014 ◽  
Vol 454 (1-3) ◽  
pp. 332-342 ◽  
Author(s):  
Valentyn Tsisar ◽  
Carsten Schroer ◽  
Olaf Wedemeyer ◽  
Aleksandr Skrypnik ◽  
Jürgen Konys
Keyword(s):  
Dissolved Oxygen ◽  
Corrosion Behavior ◽  
Austenitic Steels

Effect of Physicochemical Variables on Algal Autoflotation

1992 ◽  
Vol 26 (7-8) ◽  
pp. 1769-1778 ◽  
Author(s):  
S.-I. Lee ◽  
B. Koopman ◽  
E. P. Lincoln
Keyword(s):  
Dissolved Oxygen ◽  
Oxygen Concentration ◽  
Retention Time ◽  
Contact Time ◽  
Pilot Scale ◽  
Dissolved Oxygen Concentration ◽  
Physicochemical Variables ◽  
Rise Rate ◽  
Mixing Intensity ◽  
Maximum Rise

Combined chemical flocculation and autoflotation were examined using pilot scale process with chitosan and alum as flocculants. Positive correlation was observed between dissolved oxygen concentration and rise rate. Rise rate depended entirely on the autoflotation parameters: mixing intensity, retention time, and flocculant contact time. Also, rise rate was influenced by the type of flocculant used. The maximum rise rate with alum was observed to be 70 m/h, whereas that with chitosan was approximately 420 m/h. The efficiency of the flocculation-autoflotation process was superior to that of the flocculation-sedimentation process.

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