Oxidation Kinetics of Manganese Cobaltite Spinel Protection Layers on Sanergy HT for Solid Oxide Fuel Cell Interconnect Applications

Alvarez, Estefania; Meier, Alan; Weil, K. Scott; Yang, Zhenguo

doi:10.1111/j.1744-7402.2009.02421.x

Cited by 18 publications

(10 citation statements)

References 17 publications

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“…At lower temperatures, the (Mn,Co)Cr 2 O 4 layer A becomes more dominant, which is desirable for reducing chromium volatilization. The squared thickness of the layer A increased linearly with the time, which indicates that the growth of the layer A was controlled by solid state diffusion and thus followed a parabolic law .

x^{2} = k_{p} t,

where k p is the parabolic rate constant, which was determined to be 6.2 × 10 −3 , 2.6 × 10 −3 , 3.2 × 10 −4 , 6.9 × 10 −5 , and 2.2 × 10 −5 μm 2 /s at 1200°C, 1100°C, 1000°C, 900°C, and 800°C, respectively.…”

Section: Resultsmentioning

confidence: 94%

Interactions Between SOFC Interconnect Coating Materials and Chromia

2011

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Manganese cobalt oxides are promising coating materials for reducing chromium volatilization, and thus the associated cathode poisoning, from interconnect alloys in solid oxide fuel cells (SOFCs). Interaction between this coating and the oxide scale formed on the alloy during fuel cell operation can lead to changes in the coating composition and thus its performance. In this study, the properties of manganese cobalt spinel oxides and the reaction between manganese cobalt spinel oxides and chromia were investigated. The reaction product consists of two layers: a layer in contact with chromia that grows by the diffusion of cobalt and manganese from (Mn,Co) 3 O 4 toward the chromia and an intermediate layer that grows by the diffusion of chromium through the reaction layer. The effect of dopants on the coating performance was also investigated. With the addition of iron or titanium, the rate of reaction between the spinel coating and the chromia scale can be decreased significantly, which would reduce the risk of scale spallation and provide an increase in the lifetime of the interconnect and thus the fuel cell. II. Experimental ProcedureSpinel oxides were synthesized by solid state reaction of Co 3 O 4 (99.83%, Fisher, Pittsburgh, PA), MnO (99%, Alfa Aesar, Ward Hill, MA), Fe 3 O 4 (99.999%, Aesar), TiO 2 (99.17%, Fisher), and Cr 2 O 3 (99%, Acros, Geel, Belgium). The relevant oxide powders were carefully weighed to produce the appropriate stoichiometric mixtures for the spinels of interest. Weighed powders were pre-mixed by ball milling J. Stevenson-contributing editor Manuscript No. 29472.

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x^{2} = k_{p} t,

Section: Resultsmentioning

confidence: 94%

Interactions Between SOFC Interconnect Coating Materials and Chromia

2011

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“…According to these results, the CeO 2 -free (Co,Mn) 3 Depending on the type of substrate alloy, the treatment of substrate surface prior to coating, the coating process, the spinel stoichiometry, and the oxidation condition, an increase [12,27], decrease [3,4,12,[28][29][30], or no change [31] in the oxidation rate of the metallic interconnect has been reported with the spinel coating. With regard to the oxidation behavior of (Co,Mn) 3 O 4 -coated Crofer 22 APU, it is generally agreed that the coating reduces the oxidation rate of this alloy as the coating provides some barrier against the oxygen transport to the alloy surface, even though the degree of reduction is debatable.…”

Section: Microstructures Before and After Thermal Conversionmentioning

confidence: 87%

CeO2-doped (Co,Mn)3O4 coatings for protecting solid oxide fuel cell interconnect alloys

Zhu

Lewis

et al. 2015

Thin Solid Films

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Reactive element-doped (Co,Mn) 3 O 4 spinel is considered as the most promising coating system to protect ferritic alloys for solid oxide fuel cell interconnect application. In this paper, a CeO 2 -doped (Co,Mn) 3 O 4 coating was synthesized on a Crofer 22 APU alloy substrate via electrolytic codeposition of a composite layer consisting of a Co matrix and embedded Mn 3 O 4 /CeO 2 particles, followed by thermal conversion of the deposited layer in air at elevated temperatures. After oxidation at 800°C in air for 250 h, no Cr penetration was detected in both the CeO 2 -doped and CeO 2 -free spinel coatings. However, CeO 2 doping significantly reduced the Cr 2 O 3 scale growth at the coating/substrate interface. An area specific resistance of 8 m ·cm 2 at800°C was achieved for the CeO 2 -doped coating sample, which was much lower than that of the CeO 2 -free coating sample (13 m ·cm 2 ) or the bare substrate (24 m ·cm 2 ) at the same temperature.CeO 2 doping in the spinel coating also improved the performance stability of the anode-supported cell in contact with the alloy interconnect.

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“…Efforts have been made by various groups to demonstrate that a (Mn,Co) 3 O 4 spinel could be a promising barrier for interconnect applications in SOFCs. For example, Yang et al .…”

Section: Introductionmentioning

confidence: 99%

“…It also minimizes the interfacial contact area-specific resistance (ASR) between cathode and interconnect by limiting the growth of the Cr-based oxide scale, which has relatively low conductivity. 7 Efforts have been made by various groups [20][21][22][23][24][25][26][27][28] to demonstrate that a (Mn,Co) 3 O 4 spinel could be a promising barrier for interconnect applications in SOFCs. For example, Yang et al 25 found that Mn 1.5 Co 1.5 O 4 spinel coatings (prepared by a slurry screen-printing method) were effective in reducing the contact resistance and providing high electrical conductivity.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of Mn–Co Spinel Coatings on Crofer 22 APU Stainless Steel by Electrophoretic Deposition for Interconnect Applications in Solid Oxide Fuel Cells

Zhang

Javed

Zhou

et al. 2013

Int J Applied Ceramic Tech

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This study investigates the microstructure, oxidation kinetics, and electrical behavior of Mn–Co spinel coating for interconnect applications in solid oxide fuel cells. A relatively dense, uniform, and well‐adherent Mn–Co (Mn1.5Co1.5O4) spinel coating with good oxidation resistance and stable conductivity was successfully prepared on the surface of Crofer 22 APU stainless steel using electrophoretic deposition followed by sintering at 1150°C. During further thermal treatment at 800°C, the chromium oxide (Cr2O3) sublayer formed at the substrate/coating interface during sintering showed a very slow growth, and no chromium penetration was detected in the Mn–Co coating. The oxidation kinetics of the Mn–Co‐coated substrate obeyed the parabolic law with the a parabolic rate constant kp of 5.20 × 10−15 g2/cm4/s, which was 1–2 orders of magnitude lower than that of the uncoated Crofer 22 APU stainless steel substrate. For oxidation (at 800°C) times ≥50 h, the area‐specific resistance of the Mn–Co‐coated Crofer 22 APU substrate became ~17 mΩ·cm2 and was almost constant after further oxidation.

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Oxidation Kinetics of Manganese Cobaltite Spinel Protection Layers on Sanergy HT for Solid Oxide Fuel Cell Interconnect Applications

Cited by 18 publications

References 17 publications

Interactions Between SOFC Interconnect Coating Materials and Chromia

Interactions Between SOFC Interconnect Coating Materials and Chromia

CeO2-doped (Co,Mn)3O4 coatings for protecting solid oxide fuel cell interconnect alloys

Fabrication of Mn–Co Spinel Coatings on Crofer 22 APU Stainless Steel by Electrophoretic Deposition for Interconnect Applications in Solid Oxide Fuel Cells

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