Applicability of heat resisting alloys to the separator of planar type solid oxide fuel cell

Kadowaki, Takuya; Shiomitsu, Tohru; Matsuda, Eiji; Nakagawa, Hidemoto; Tsuneizumi, Hiroshi; Maruyama, Toru

doi:10.1016/0167-2738(93)90310-y

Cited by 97 publications

(48 citation statements)

References 2 publications

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“…The second issue encountered with chromia is their potential transformation into volatile chromium species such as CrO 2 (OH) 2 , leading to the loss of their protective properties and the poisoning of the cathode material, and the subsequent degradation in the electrochemical performance of the cell, irrespective of the type of steel used for the construction of SOFC steel interconnects [8,9]. One way to effectively reduce such adverse effects is to deposit active protective and conductive coatings of several conducting perovskite [10][11][12] or spinel [13][14][15][16] layers on the surface of ferritic steels. However, for the coating to be able to act as a barrier against chromium diffusion from the steel and against the formation of volatile Cr(VI) compounds, the inward diffusion coefficient of oxygen ions must be greater than the outward diffusion coefficient of chromium ions [17].…”

Section: Introductionmentioning

confidence: 99%

Mn–Co spinel protective–conductive coating on AL453 ferritic stainless steel for IT-SOFC interconnect applications

Kruk

Stygar

Brylewski

2012

J Solid State Electrochem

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This paper presents research on the synthesis and properties of the Mn 1.5 Co 1.5 O 4 (MC) spinel powder, as well as its application for the preparation of a MC thick film on the AL453 steel to be used for metallic interconnect material in IT-SOFCs. In order to prepare the MC micropowder with excellent homogeneity of the chemical and phase compositions, EDTA gel processes were utilized. In order to improve the contact electrical resistance between an AL453 steel interconnect and the La 0.8 Sr 0.2 FeO 3 (LSF) cathode and protect the cathode from Cr poisoning, the surface of the AL453 steel was coated with a protective manganese cobaltite spinel matrix using screen printing in combination with an appropriate heat treatment. The oxidation of the AL453/MC composite layer carried out in the air-H 2 O gas mixture at 1,073 K for 55 h showed that the spinel coating may serve as an effective barrier against outward Cr diffusion from the AL453 steel and, therefore, significantly inhibit the formation of volatile Cr vapors from the chromia scale. The contact ASR study of the interconnect-cathode interface in the AL453/MC/LSCM/LSF/LSCM/MC/AL453 system carried out in the range of 723−1,073 K in air showed a very large drop in ASR compared to the resistance of the AL453/LSCM/LSF/LSCM/AL453 system without the spinel coating.

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Section: Introductionmentioning

confidence: 99%

Mn–Co spinel protective–conductive coating on AL453 ferritic stainless steel for IT-SOFC interconnect applications

Kruk

Stygar

Brylewski

2012

J Solid State Electrochem

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“…Other ferritic steels, such as JS 3 and Crofer 22 H (Thyssen Krupp VDM GmbH, Germany), ZMG (Hitachi Metals America, Ltd.), SUS 430 (Nippon Seisen Co., Ltd., Japan), and E-Brite (Allegheny Technologies Incorporated, USA), have also been specifically made for interconnect production, but Crofer 22 APU is currently the most studied. However, long-term corrosion and electrical resistance studies in air and H 2 -H 2 O gas mixture atmospheres have determined that despite exhibiting high resistance against oxidation due to the formation of a protective chromium oxide scale on the steel surface, the area specific resistance (ASR) of the steel/scale system gradually increases [4][5][6][7]. This is due to the low electrical conductivity of the Cr 2 O 3 scale [7], the thickness of which increases according to the parabolic rate law [4].…”

Section: Introductionmentioning

confidence: 99%

“…However, long-term corrosion and electrical resistance studies in air and H 2 -H 2 O gas mixture atmospheres have determined that despite exhibiting high resistance against oxidation due to the formation of a protective chromium oxide scale on the steel surface, the area specific resistance (ASR) of the steel/scale system gradually increases [4][5][6][7]. This is due to the low electrical conductivity of the Cr 2 O 3 scale [7], the thickness of which increases according to the parabolic rate law [4]. Moreover, another disadvantage brought about by the scale is its reactivity with the electrode material, especially on the air side of SOFC, which is the result of Cr species vaporization and diffusion into the cathode compartment [8].…”

Section: Introductionmentioning

confidence: 99%

Oxidation properties of the Crofer 22 APU steel coated with La0.6Sr0.4Co0.2Fe0.8O3 for IT-SOFC interconnect applications

Przybylski

Brylewski

Durda

et al. 2014

J Therm Anal Calorim

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The La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 (LSCF48) cathode material was used as a protective-conducting coating on an interconnect made of Crofer 22 APU ferritic steel intended for application in intermediate-temperature solid oxide fuel cell (IT-SOFC) stacks. The LSCF48 coating was deposited on the surface of the steel via screen-printing followed by appropriate thermal treatment. The oxidation kinetics of the Crofer 22 APU steel-uncoated and coated with LSCF48-approximately obeys the parabolic rate law in air at 1,073 K under isothermal and cyclic oxidation conditions. The oxidation rate for uncoated steel is higher than that for coated steel. SEM-EDS and XRD investigations showed that the LSCF48 coating interacts with the steel during long-term oxidation in the afore-mentioned thermal conditions, and an intermediate multilayer interfacial zone is formed. This intermediate layer leads to lower area specific resistance in air at 1,073 K in comparison to the Crofer 22 APU steel without surface modification.

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“…The interconncect must possess high chemical stability in both reducing and oxidizing environments, high electronic conductivity, good stability, a thermal expansion coefficient similar to the adjacent components, and significant strength to support the other cell components, particularly in the planar design [2~4]. The alkaline-earth-doped lanthanum chromites are the most promising ceramic candidate materials [5,6], although there is some recent work that suggest that metallic or metal/ceramic composites may replace these systems in the near future [7,8]. In the ceramic systems, all but a few have the required properties for consideration.…”

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confidence: 99%

Effect of anode atmosphere on the mechanical properties of doped lanthanum chromite

Sammes

Ratnaraj

1996

J Mater Sci Lett

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In the planar design of the solid oxide fuel cell (SOFC), the interconnect, or bipolar plate, is an important component which allows single cells to be stacked in multi-cellular units [1]. The interconncect must possess high chemical stability in both reducing and oxidizing environments, high electronic conductivity, good stability, a thermal expansion coefficient similar to the adjacent components, and significant strength to support the other cell components, particularly in the planar design [2~4]. The alkaline-earth-doped lanthanum chromites are the most promising ceramic candidate materials [5,6], although there is some recent work that suggest that metallic or metal/ceramic composites may replace these systems in the near future [7,8]. In the ceramic systems, all but a few have the required properties for consideration. Strontium-doped lanthanum chromite (LSC) has been chosen as the interconnect material in this study, because of its superior electronic conductivity and high temperature stability [9].We have shown that a high sintered density (96% theoretical) can be achieved for LSC, when sintered at 1700°C [10]. For practical applications, under such extreme temperatures, fabrication is uneconomical and detrimental to other cell components which may have to be co-sintered with the interconnect. Our recent investigation [11] on lanthanum chromites, showed that doping onto the B-site,. with Co, significantly reduces the sintering temperature. For example, 96% theoretical density was obtained for La0.sSr0.2Cr0.9Co0.103 (LSCC) when sintered at 1500 °C.This work investigates the effect of anode (fuel) atmosphere on the mechanical properties of LSC and LSCC. Non-agglomerated LSC and LSCC powders were synthesized using a modified Pechini method, described elsewhere [12]. The powders were then calcined at 900 °C for 5 h. Powder X-ray diffraction, using a Philips X-ray diffractometer, revealed the materials to have a perovskite structure, with no other discernible peaks present. The powders were pressed into 30 mm × 10 mm × 2 mm bars, compacted using a die press at 400 kg cm -2, and sintered for 5 h at 1700 °C for the LSC sample and at 1500 °C for the LSCC sample, see reference [11]. Bulk density measurements indicated that both the LSC and the LSCC samples had sintered densities of greater than 96% theoretical. The bars were then exposed to the anode (H2) atmosphere using the following regime. The bars were initially placed into a tube furnace and heated to 1000 °C at a rate of 5 °C/min. On reaching 0 2 6 1 -8 0 2 8 © 1996 Chapman & Hall 1000 °C, the samples were purged with argon for 15 min and then exposed to the hydrogen atmosphere. After the desired time, argon was reintroduced and the sample cooled to room temperature. The samples were surface ground and polished, using SiC and synthetic diamond compound, prior to testing, to remove any surface defects that may affect the results. The fracture strength was then measured using a three-point bend test, with a distance of 24 mm between the points of contact, us...

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Applicability of heat resisting alloys to the separator of planar type solid oxide fuel cell

Cited by 97 publications

References 2 publications

Mn–Co spinel protective–conductive coating on AL453 ferritic stainless steel for IT-SOFC interconnect applications

Mn–Co spinel protective–conductive coating on AL453 ferritic stainless steel for IT-SOFC interconnect applications

Oxidation properties of the Crofer 22 APU steel coated with La0.6Sr0.4Co0.2Fe0.8O3 for IT-SOFC interconnect applications

Effect of anode atmosphere on the mechanical properties of doped lanthanum chromite

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