Mn coating on AISI 430 ferritic stainless steel by pack cementation method for SOFC interconnect applications

Ebrahimifar, Hadi; Zandrahimi, Morteza

doi:10.1016/j.ssi.2010.12.017

Cited by 37 publications

(14 citation statements)

References 37 publications

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“…Although various techniques have been developed to apply Mn-Co spinel coatings to ferritic stainless steels, the pack cementation method has not been used extensively to produce Mn-Co oxides for SOFC interconnect applications. Very little research has been done on the production of such coatings for SOFC interconnect applications [20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Oxidation and Electrical Behavior of Mn-Co-Coated Crofer 22 APU Steel Produced by a Pack Cementation Method for SOFC Interconnect Applications

Ebrahimifar

Zandrahimi

2015

Oxid Met

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An issue associated with chromia-scale formation on ferritic stainless steels is an associated increase in electrical resistance over time, due to the oxide growth. Further, the migration of chromium via chromia-scale evaporation into solid oxide fuel cell (SOFC) cathodes can result in degradation in cell electrochemical performance. In this research, manganese and cobalt were deposited by the pack cementation method onto Crofer 22 APU ferritic stainless steel. Isothermal and cyclic oxidation was carried out to evaluate the role of coating materials during oxidation. Area-specific resistance (ASR) of the Mn-Co-coated substrates was also tested at 800°C. The results demonstrate that the coating layer transforms to MnCo 2 O 4 , CoFe 2 O 4 , CoCr 2 O 4 , and Co 3 O 4 spinels during oxidation. This scale is protective, and acts as an effective barrier against chromium migration into the outer oxide. Mn-Co oxide and cobalt oxides also cause a reduction in ASR, in comparison to that of bare steel.

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Section: Introductionmentioning

confidence: 99%

Oxidation and Electrical Behavior of Mn-Co-Coated Crofer 22 APU Steel Produced by a Pack Cementation Method for SOFC Interconnect Applications

Ebrahimifar

Zandrahimi

2015

Oxid Met

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“…From Figure 5(c), it is possible to observe that the Monoxide phase, which appears in the intermediate layers, is greatly composed of FeO, with a very small amount of Fe2O3 and Cr2O3. By comparing with experimental observations, one can see that the same predicted phases are found in the oxidized stainless steels [1,7].…”

Section: Methodsmentioning

confidence: 56%

“…The reduction in operating temperature of planar solid oxide fuel cells (SOFCs) to the 600-800ºC temperature range has allowed the use of ferritic stainless steels as replacement for conventional lanthanum chromite ceramics for construction of interconnects in SOFC stacks [1]. Ferritic stainless steels offer many advantages over traditional ceramic interconnects, such as higher thermal and electronic conductivity, reasonable thermal expansion matching, relative ease of fabrication and decreased machining costs.…”

Section: Introductionmentioning

confidence: 99%

Metallic Interconnects for Application in High Temperature Solid Oxide Fuel Cells (Sofcs): Thermodynamic Study of the Oxidation of Ferritic Stainless Steels

Silva¹,

Heck²

2014

ABM Proceedings

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The reduction in SOFC operating temperature due to recent development in materials and fabrication techniques enables the use of ferritic stainless steels as interconnects for SOFCs. Ferritic stainless steels offer many advantages over traditional ceramic interconnects, such as higher thermal and electronic conductivity, as well as relative ease of fabrication. However, the formation of chromium oxide on ferritic stainless steel results in an increase in ohmic resistance and can lead to the loss of cathode catalytic activity (due to Cr volatilization, with cathode poisoning). The oxide growth depends on several factors, such as steel composition, temperature, oxygen partial pressure. In this way, knowing the phase stability, the oxidation behavior of the material and the oxidation kinetics is of great interest. In this context, a thermodynamic study of the oxidation of ferritic stainless steel 430 under oxidizing atmosphere (cathode), at the temperature of 750ºC, is carried out. As one can see, the thermodynamic system can be very complex, involving several phases (chromium oxide, (Fe,Cr,Mn)3O4 Spinel, iron-chromium oxides, etc.). The effect of oxygen partial pressure and alloying elements on phase distribution is evaluated. Thermodynamic modeling is compared with experimental results from literature.

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“…With commonly used characterization methods, ASR measurements are often performed separately. Conventional measurement setups might include symmetrical setups with two coated steel plates, possibly with Pt or Ag paste or LSM pellets in‐between, or one plate coated on both sides with Pt paste . Chromium evaporation is studied on separate samples with the so‐called transpiration method where the volatile chromium is collected downstream of the samples with, for example, denuder tubes in which the volatile chromium reacts with Na 2 CO 3 to form water‐soluble Na 2 CrO 4 , from which the evaporated chromium amount can be analyzed , , .…”

Section: Methodsmentioning

confidence: 99%

Method to Measure Area Specific Resistance and Chromium Migration Simultaneously from Solid Oxide Fuel Cell Interconnect Materials

et al. 2019

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Chromium evaporation is identified as a major degradation mechanism in solid oxide fuel cell (SOFC) stacks. The major chromium source is the commonly used stainless steel interconnects, thus raising a need for protective coatings on the interconnect steel. Ex situ characterization methods of protective coatings involve chromium evaporation measurements, area specific resistance (ASR) measurements and long‐term exposure tests. To replicate stack conditions, commonly used ASR measurement setups should be further developed. This work presents an improved characterization method for steels and coatings and aims to be an extension to state‐of‐the‐art characterization methods. The studied steel samples, bare or coated, are placed adjacent to palladium foils with a screen‐printed lanthanum‐strontium‐cobalt (LSC) layer and the resistivity over the pair is measured. The method offers similar contact materials, chromium migration mechanisms, electrical contacts and chemical interactions, as seen in stacks. Further, it enables post‐test chromium migration analysis with electron microscopy. Demonstration of the method validated that protective coatings hindered both oxidation and chromium migration from the substrate steels. The presented method could aid in accelerating protective coating development.

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Mn coating on AISI 430 ferritic stainless steel by pack cementation method for SOFC interconnect applications

Cited by 37 publications

References 37 publications

Oxidation and Electrical Behavior of Mn-Co-Coated Crofer 22 APU Steel Produced by a Pack Cementation Method for SOFC Interconnect Applications

Oxidation and Electrical Behavior of Mn-Co-Coated Crofer 22 APU Steel Produced by a Pack Cementation Method for SOFC Interconnect Applications

Metallic Interconnects for Application in High Temperature Solid Oxide Fuel Cells (Sofcs): Thermodynamic Study of the Oxidation of Ferritic Stainless Steels

Method to Measure Area Specific Resistance and Chromium Migration Simultaneously from Solid Oxide Fuel Cell Interconnect Materials

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