Influence of oxide scale thickness on electrical conductivity of coated AISI 430 steel for use as interconnect in solid oxide fuel cells

Ebrahimifar, Hadi; Zandrahimi, Morteza

doi:10.1007/s11581-012-0664-5

Cited by 20 publications

(10 citation statements)

References 26 publications

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“…is the fastest diffusing ion in chromia. The diffusion coefficients for Cr, Fe, and Ni ions are similar, but lower than that for Mn, which could explain why the Mn-rich spinel becomes one of the main oxide phases, even though the steels contain less than 1 % Mn [33][34][35][36]. Figure 10 demonstrates the SEM cross-sectional image (Fig.…”

Section: Oxid Metmentioning

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: Oxid Metmentioning

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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“…9,17,18 The key requirements for a protective coating include dense structure, high electronic conductivity, thermal, mechanical and chemical compatibility with the adjacent components and low diffusion coefficients of Cr and O. Among coating mate-rials, such as reactive element oxides, 11,[19][20][21][22][23][24] 72,73 Although the feasibility of these techniques has been substantiated, individual processes exhibit their characteristic drawbacks along with their advantages. For example, electroplating is suitable for uniformly applying thin film over a complex configuration, but the large negative reduction potential of manganese makes the control of the spinel composition extremely difficult.…”

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confidence: 99%

Highly Dense Mn-Co Spinel Coating for Protection of Metallic Interconnect of Solid Oxide Fuel Cells

Lee

Hong

Kim

et al. 2014

J. Electrochem. Soc.

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The major degradation issues of solid oxide fuel cells (SOFC) are associated with the oxide scale growth and Cr evaporation of the metallic interconnect. To address these challenges, a highly dense spinel oxide coating was fabricated on a ferritic stainless steel interconnect using a cost-competitive ceramic processing route. The nano-scale Mn 1.5 Co 1.5 O 4 spinel powder was synthesized using a glycine-nitrate method, and the particle agglomerates were effectively disintegrated by a high-energy attrition milling process. The spinel protective coating, which was applied by screen printing, was sintered to a nearly full density, without causing damage to the metallic substrate, by a high-temperature annealing process in a reducing environment, followed by re-oxidation at a moderate temperature. The dense spinel coating remarkably reduced the growth rate of chromia scale and restrained the evaporation of chromium species, as verified by area specific resistance (ASR) measurements and analysis on chromium distribution over the cross-section. Strong adhesion between the coating and substrate was confirmed after 500-hour operation. The sintering mechanism involved in reduction-oxidation heat-treatment was studied based on dilatometry measurements and microstructural features. The implication of the ASR change and the chromium migration for stability of practical SOFC stacks was discussed in detail.

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“…9b). Spallation and cracking are the result of the thermal expansion coefficient mismatching of the oxide, or coating layer, with the substrate [16,[36][37][38]. The spalled scale creates a diffusion path for cations and anions.…”

Section: Cyclic Oxidation Behaviormentioning

confidence: 99%

Oxidation and Electrical Behavior of a Ferritic Stainless Steel with a Mn–Co-Based Coating for SOFC Interconnect Applications

Ebrahimifar

Zandrahimi

2015

Oxid Met

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Protective coatings with high electrical conductivity that resist oxide scale growth are required for stainless steel interconnect materials in the long-term durable operation of solid oxide fuel cells. This work evaluates the oxidation and electrical behavior of Crofer 22 APU ferritic stainless steel coated with manganese and cobalt by electrodeposition. Isothermal and cyclic oxidation (800°C in air) tests were done to evaluate the role of the coating layer during oxidation. Area-specific resistance (ASR) of the coated and uncoated substrates was also tested at 800°C in air. Results show that the coating layer transforms into Mn 1.5 Co 1.5 O 4 spinel during oxidation. The mass gain and spallation indicated that the formation of Mn-Co spinel improves the high temperature oxidation. These spinels also cause a reduction in ASR for electroplated substrates (12.42 mX cm 2 ) as compared to uncoated ones (38.74 mX cm 2 ) after 400 h of isothermal oxidation at 800°C.

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Influence of oxide scale thickness on electrical conductivity of coated AISI 430 steel for use as interconnect in solid oxide fuel cells

Cited by 20 publications

References 26 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

Highly Dense Mn-Co Spinel Coating for Protection of Metallic Interconnect of Solid Oxide Fuel Cells

Oxidation and Electrical Behavior of a Ferritic Stainless Steel with a Mn–Co-Based Coating for SOFC Interconnect Applications

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