Cr diffusion coatings on a ferritic-martensitic steel for corrosion protection in KCl-rich biomass co-firing environments

Meißner, T.M.; Montero, X.; Fähsing, Diana; Galetz, Mathias C.

doi:10.1016/j.corsci.2019.108343

Cited by 32 publications

(17 citation statements)

References 41 publications

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“…In particular, the S1 deposit, which has the highest concentration of chlorides, is the most aggressive (59.6 mg/cm 2 ) followed by the deposits S3 and S2 (42.7 and 34.1 mg/cm 2 , respectively). Different authors have demonstrated that the presence of chlorides causes severe damage and also accelerates corrosion through a mechanism usually called chlorine-induced "active oxidation" [24][25][26]. Although during the first steps of isothermal test the Na-containing S2 salt is more aggressive, the trend changes after 90 h. The K-rich S3 deposit is in contrast more aggressive after 360 h of test.…”

Section: Characterization Of the Starting Materialsmentioning

confidence: 99%

Fireside corrosion on T24 steel pipes and HVOF NiCr coatings exposed to different salt mixtures

et al. 2020

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Fireside corrosion of T24 steel and HVOF NiCr-coated counterparts is investigated. The samples were exposed to different deposits of NaCl, KCl, Na2SO4 and K2SO4 at 650 ºC for 360 h in dry air. The deposit with the highest chloride content (NaCl-KCl) was the most aggressive followed by the ones combining chlorides and sulfates. In contrast, the sulfate-based salts did not produce severe damage. The NiCr coating maintained the integrity of the substrate but the chlorides induced a great attack on the coating. The formation of K2CrO4 and the penetration of chlorides are identified as the main factors of this attack.

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Section: Characterization Of the Starting Materialsmentioning

confidence: 99%

Fireside corrosion on T24 steel pipes and HVOF NiCr coatings exposed to different salt mixtures

et al. 2020

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“…The creation of layers in the process of carburizing with metallization may take place for the hard carbides to form on the surface [6,8]. A similar effect can be obtained by other methods such as pack cementation process [9], TRD process [10,11], or thermal diffusion of chromium on grey cast iron [12]. The first example is based on the formation of a carbide layer on the steel surface during the pack cementation process-a chromium carbide layer, composed of Cr 23 C 6 , is formed in the area above the chrome layer.…”

Section: Introductionmentioning

confidence: 77%

“…The first example is based on the formation of a carbide layer on the steel surface during the pack cementation process-a chromium carbide layer, composed of Cr 23 C 6 , is formed in the area above the chrome layer. [9]. Further examples relate to the occurrence of reactive diffusion for iron-based alloys.…”

Section: Introductionmentioning

confidence: 99%

The Hybrid Process of Low-Pressure Carburizing and Metallization (Cr + LPC, Al + LPC) of 17CrNiMo7-6 and 10NiCrMo13-5 Steels

et al. 2021

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This paper presents the concept of modification of physicochemical properties of steels by simultaneous diffusion saturation with carbon and chromium or aluminum. The application of a hybrid surface treatment process consisting of a combination of aluminizing and low-pressure carburizing (Al + LPC) resulted in a reduction in the amount of retained austenite in the surface layer of the steel. While the use of chromium plating and low-pressure carburizing (Cr + LPC) induced an improvement in the corrosion resistance of the carburized steels. It is of particular importance in case of vacuum processes after the application of which the active surface corrodes easily, as well as in case of carburizing of low-alloy steel with nickel, where an increased content of retained austenite in the surface layer is found after carburizing.

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“…Cr and Ni + Cr coatings were then applied onto the remaining X20CrMoV12-1 specimens. The coating manufacturing is presented here in short because both coatings were described in detail in our previous publication . The coatings are based on the pack cementation process using Cr as the diffusion element (temperature: 1050 °C, holding time: 2 h, atmosphere: Ar + 5 vol % H 2 ). − In the case of the Ni + Cr coating, a Ni layer was deposited on X20CrMoV12-1 by conventional electrochemical methods prior to the chemical vapor deposition process.…”

Section: Materials and Methodsmentioning

confidence: 99%

“…Additionally, the change of corrosivity of the environment due to the combustion of increasing amounts of biomass as secondary fuel together with coal and its influence on degradation of superheater tube materials is in the spotlight of this study. In a previous paper, the same coatings were investigated under highly accelerated corrosion conditions using artificial, undiluted sulfate as well as sulfate–chloride deposits, which allowed us to compare them after only short exposure times …”

Section: Introductionmentioning

confidence: 99%

Long-Term Corrosion Behavior of Cr Diffusion Coatings on Ferritic–Martensitic Superheater Tube Material X20CrMoV12-1 under Conditions Mimicking Biomass (Co-)firing

et al. 2020

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Co-firing of biomass is currently attracting more attention because it is a major step toward reducing CO2 emissions from power generation and can be directly realized within existing plants. Despite its many benefits, considerable challenges in terms of corrosion prevention and durability of the plant components arise because of highly increased amounts of chlorine and alkali species inside the steam generator. Ferritic–martensitic superheater tube steels are particularly challenged and subjected to rapid degradation with the pursuit of achieving higher biomass-to-coal firing ratios. In order to improve the corrosion behavior of such structural materials in environments relevant for biomass (co-)firing, the present paper suggests enrichment of Ni (against chlorine-induced attack) and Cr (against sulfur-induced attack) in the surfaces of the metallic tubes. For this purpose, a Cr and a combined Ni + Cr diffusion coating were manufactured on ferritic–martensitic X20CrMoV12-1 steel and investigated in environments simulating pure coal, co-firing, as well as pure biomass firing (straw). Exposure tests were conducted at 650 °C for up to 1900 h in SO2- and/or HCl-containing atmospheres with specimens embedded in real power plant combustion ashes. Pure biomass firing clearly accelerated the corrosion attack compared to partial substitution of coal and pure coal firing. However, the Ni + Cr coating performed very well and increased the corrosion resistance of the ferritic–martensitic substrate. As far as degradation mechanisms are concerned, the first stage of the attack turned out to be dominated by chlorine followed by a shift toward sulfur-induced corrosion.

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Cr diffusion coatings on a ferritic-martensitic steel for corrosion protection in KCl-rich biomass co-firing environments

Cited by 32 publications

References 41 publications

Fireside corrosion on T24 steel pipes and HVOF NiCr coatings exposed to different salt mixtures

Fireside corrosion on T24 steel pipes and HVOF NiCr coatings exposed to different salt mixtures

The Hybrid Process of Low-Pressure Carburizing and Metallization (Cr + LPC, Al + LPC) of 17CrNiMo7-6 and 10NiCrMo13-5 Steels

Long-Term Corrosion Behavior of Cr Diffusion Coatings on Ferritic–Martensitic Superheater Tube Material X20CrMoV12-1 under Conditions Mimicking Biomass (Co-)firing

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