Enabling inexpensive metallic alloys as SOFC interconnects: An investigation into hybrid coating technologies to deposit nanocomposite functional coatings on ferritic stainless steels

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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“…8). A similar effect of the (Mn, Co) 3 O 4 spinel coating was observed in studies by other authors [38,39].…”

Section: Methods Of Sample Characterizationsupporting

confidence: 87%

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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“…LAFAD and FA-EBPVD processes were carried out by Arcomac Surface Engineering, using equipment described elsewhere [17,18]. For LAFAD processes, NiO/YSZ anode substrates (2.5 cm dia) were fixed on stainless steel plates and placed on a rotating substrate carousel in front of the dual LAFAD sources, which were equipped with Zr-Y (82-18 wt%) alloy targets.…”

Section: Methodsmentioning

confidence: 99%

Thin film YSZ coatings on functionally graded freeze cast NiO/YSZ SOFC anode supports

et al. 2008

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Intermediate temperature (600-800°C) solid oxide fuel cell (SOFC) technology is often limited by inadequate gas transport in electrodes, and high ion transport resistance electrolytes. In this study, large area filtered arc deposition (LAFAD) and hybrid filtered arc-assisted e-beam physical vapor deposition (FA-EBPVD) technologies, in combination with freeze-tape-casting, were used to fabricate SOFC anode/electrolyte bi-layers with functionally graded porous anode microstructures and thin film electrolytes favorable for both gas transport and low resistance. Traditionally-processed NiO/YSZ in addition to freeze-tape-cast NiO/YSZ anode substrates were fabricated and subsequently coated with thin film (\1-20 lm) YSZ via LAFAD and FA-EBPVD. LAFAD was found to be effective in applying thin (*1 lm) dense YSZ films on porous substrates at *400°C. FA-EBPVD produced relatively thick (*10-20 lm) dense YSZ coatings on porous substrates, with columnar morphology and nano-metrical grain size. A *10 lm FA-EBPVD YSZ coating was observed to bridge NiO/YSZ surface pores of *10 lm, which typically requires pre-filling prior to conventional thin film coating processes. Coated substrates exhibited negligible curvature, yielding flat anode/electrode bi-layers up to 2.5 cm in diameter. These results are presented with conderations for future SOFC development discussed.

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“…Several types of coatings have been studied and proposed, but the most common type of coatings today is manganese (Mn)-and cobalt (Co)-based spinel coatings (MCO). These coatings can be applied with a variety of coating methods, such as in powder form [14][15][16][17], by plasma spraying [18,19], or by physical vapour deposition (PVD) [20], to mention a few. An alternative coating process is to coat the steel with a metallic Co layer that is rapidly converted to Co 3 O 4 when heated in air [12,[21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, the electrical resistance of the well-conducting (Co,Mn) 3 O 4 coating is not expected to contribute any significant amount to the total resistance of the oxide scale. Instead, focus has been on improving corrosion resistance and limiting the Cr 2 O 3 scale thickness in order to keep the electrical resistance as low as possible [20,29,[32][33][34]. However, as the SOFC operating temperature decreases and, as a consequence, the thickness of the Cr 2 O 3 scale is reduced, the contribution of the coating to the electrical resistance may be more relevant.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Metallic Co-Coating Thickness on Ferritic Stainless Steels Intended for Use as Interconnect Material in Intermediate Temperature Solid Oxide Fuel Cells

et al. 2017

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The effect of metallic Co-coating thickness on ferritic stainless steels is investigated. This material is suggested to be used as interconnect material in intermediate temperature solid oxide fuel cells. Uncoated, 200-, 600-, 1000-, and 1500-nm Co-coated Sanergy HT is isothermally exposed for up to 500 h in air at 650°C. Mass gain is recorded to follow oxidation kinetics, and area-specific resistance (ASR) measurements are conducted on samples exposed for 168 and 500 h. The microstructure of the thermally grown oxide scales is characterized utilizing scanning electron microscopy and energy-dispersive X-ray analysis on broad ion beam-milled cross sections. A clear increase in ASR as a function of Cocoating thickness is observed. However, the increase in ASR, as an effect of a thicker Co-coating, is correlated with thicker (Cr,Fe) 2 O 3 scales formed on these materials and not to an increase in Co spinel top layer thickness.

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Enabling inexpensive metallic alloys as SOFC interconnects: An investigation into hybrid coating technologies to deposit nanocomposite functional coatings on ferritic stainless steels

Cited by 59 publications

References 8 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

Thin film YSZ coatings on functionally graded freeze cast NiO/YSZ SOFC anode supports

The Effect of Metallic Co-Coating Thickness on Ferritic Stainless Steels Intended for Use as Interconnect Material in Intermediate Temperature Solid Oxide Fuel Cells

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