Corrosion of uncoated and alumina coated steel X20CrMoV12-1 in H2O–CO2–O2 and air at 600°C

Schulz, Wencke; Nofz, Marianne; Feigl, Michael; Dörfel, I.; Neumann, R. Saliwan; Kranzmann, Axel

doi:10.1016/j.corsci.2012.10.031

Cited by 22 publications

(17 citation statements)

References 20 publications

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“…On a bare steel surface both chromia scale and Mn sulfides (or mixed Mn/Cr sulfides) would coexist. Yu et al had proven, that this scale oppresses the internal carburization, but Fe dissolution in these Mn species finally leads to breakaway oxidation . The advantageous affinity of Mn to S and its ability to prevent the steel from formation of other crack initiating metal sulfides (like Cr 2 S 3 and FeS) holds for minor Mn concentration in the alloy only, which also applies for P92 with about 0.5 wt%.…”

Section: Resultsmentioning

confidence: 99%

“…Another option is the deposition of oxide coatings (TiO 2 , Al 2 O 3 , SiO 2 ) using chemical vapor deposition (CVD), physical vapor deposition (PVD), sol‐gel, or other techniques . The coatings must exhibit good chemical and microstructural compatibility with the substrate, high mechanical strength for long‐time service, a similar thermal expansion coefficient as the substrate, and due to interdiffusion good chemical resistance.…”

Section: Introductionmentioning

confidence: 99%

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Exposition of sol‐gel alumina‐coated P92 steel to flue gas: Time‐resolved microstructure evolution, defect tolerance, and repairing of the coating

Wollschläger

Nofz

Dörfel

et al. 2017

Materials & Corrosion

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Technically relevant P92 steel (9% Cr) was coated with a micron‐thick porous alumina layer prepared by sol‐gel technique and treated with flue gas (60 CO2‐30 H2O‐2 O2‐1 SO2‐7 N2 (mole fraction in %)) at 650 °C to mimic an oxyfuel‐combustion process. Local defects in the coating were marked using focused ion beam (FIB) technique and were inspected after exposition to hot flue gas atmosphere at 300, 800, and 1300 h, respectively. Local defects like agglomerated alumina sol particles tend to spall off from the coating uncovering the underlying dense chromia scale. Re‐coating was found to restore the protection ability from oxidation when repeatedly treated with hot flue gas. Cracks and voids did not promote the local oxidation due to the formation of crystalline Mn/S/O species within and on top of the coating. The protective character of the steel‐coating system is a result of (i) the fast formation of a dense chromia scale at the surface of sol‐gel alumina‐coated P92 steel bars in combination with (ii) the porous alumina coating acting as diffusion barrier, but also as diffusion partner in addition with (iii) fast Mn outward diffusion capturing the S species from flue gas.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Exposition of sol‐gel alumina‐coated P92 steel to flue gas: Time‐resolved microstructure evolution, defect tolerance, and repairing of the coating

Wollschläger

Nofz

Dörfel

et al. 2017

Materials & Corrosion

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“…As reported by Schulz et al and Nofz et. al., Al 2 O 3 sol-gel coatings were able to protect steels in high-temperature flue gas [24,27]. Al 2 O 3 sol-gel coatings were also proven to be protective in NaCl-containing environments [25,28].…”

Section: Introductionmentioning

confidence: 99%

“…Based on the sintering temperature, the boehmite precursor transforms to γ-Al 2 O 3 between 300-600 • C, to δ-Al 2 O 3 between 700-800 • C, and to θ-Al 2 O 3 between 900-1000 • C, which can also be formed concurrently depending on the synthesis method [30]. This study focuses on the use of γ-Al 2 O 3 formed by sintering at 600 • C, as this polymorph has been proven to be protective in different corrosive environments [25,27]. According to the Pourbaix diagram, Al 2 O 3 is stable in room temperature aqueous solutions with pH between 4−9 [31].…”

Section: Introductionmentioning

confidence: 99%

Study of Al2O3 Sol-Gel Coatings on X20Cr13 in Artificial North German Basin Geothermal Water at 150 °C

et al. 2021

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Al2O3 has been widely used as a coating in industrial applications due to its excellent chemical and thermal resistance. Considering high temperatures and aggressive mediums exist in geothermal systems, Al2O3 can be a potential coating candidate to protect steels in geothermal applications. In this study, γ-Al2O3 was used as a coating on martensitic steels by applying AlOOH sol followed by a heat treatment at 600 °C. To evaluate the coating application process, one-, two-, and three-layer coatings were tested in the artificial North German Basin (NGB), containing 166 g/L Cl−, at 150 °C and 1 MPa for 168 h. To reveal the stability of the Al2O3 coating in NGB solution, three-layer coatings were used in exposure tests for 24, 168, 672, and 1296 h, followed by surface and cross-section characterization. SEM images show that the Al2O3 coating was stable up to 1296 h of exposure, where the outer layer mostly transformed into boehmite AlOOH with needle-like crystals dominating the surface. Closer analysis of cross-sections showed that the interface between each layer was affected in long-term exposure tests, which caused local delamination after 168 h of exposure. In separate experiments, electrochemical impedance spectroscopy (EIS) was performed at 150 °C to evaluate the changes of coatings within the first 24 h. Results showed that the most significant decrease in the impedance is within 6 h, which can be associated with the electrolyte penetration through the coating, followed by the formation of AlOOH. Here, results of both short-term EIS measurements (up to 24 h) and long-term exposure tests (up to 1296 h) are discussed.

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“…Materials that comply with these requirements are steels with high content of chromium (e.g. X20Cr13-1.4021) [1][2][3][4][5]. These steels are widely implemented to manufacture elements used in power plants [6][7] and they are characterized by high resistance to harmful impact of environmental factors [8].…”

Section: Introductionmentioning

confidence: 99%

Microstructure and Chemical Composition of Fe-Cr Alloy Tempered in High Temperature and Atmosphere Containing Ar-SO2

Radziszewska¹,

Kranzmann²,

Dörfel³

et al. 2016

Archives of Metallurgy and Materials

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MIcrostructure and cheMIcal coMposItIon of fe-cr alloy teMpered In hIgh teMperature and atMosphere contaInIng ar-so2The paper presents the microstructure, chemical and phase composition of thin scale, obtained as a result of hightemperature corrosion of X20Cr13 stainless steel. Samples were exposed to gas atmosphere of the following composition: 0.25 vol.% of SO2 and 99.75 vol.% of Ar at 600 °C for 5 h. As a consequence, thin compact scale was formed on steel surface. This scale consisted of three different zones. An amorphous zone was formed close to steel surface. Then, nanocrystalline zone could be observed. Finally, larger grains were formed during the corrosion process. The analysis of the chemical composition revealed higher concentration of chromium near steel surface. In contrast, to chromium, the content of iron, increased near the scale surface. It was found out that the (Cr, Mn, Fe)5O12 phase appeared in the thin scale.

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Corrosion of uncoated and alumina coated steel X20CrMoV12-1 in H2O–CO2–O2 and air at 600°C

Cited by 22 publications

References 20 publications

Exposition of sol‐gel alumina‐coated P92 steel to flue gas: Time‐resolved microstructure evolution, defect tolerance, and repairing of the coating

Exposition of sol‐gel alumina‐coated P92 steel to flue gas: Time‐resolved microstructure evolution, defect tolerance, and repairing of the coating

Study of Al2O3 Sol-Gel Coatings on X20Cr13 in Artificial North German Basin Geothermal Water at 150 °C

Microstructure and Chemical Composition of Fe-Cr Alloy Tempered in High Temperature and Atmosphere Containing Ar-SO2

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