Journal Article

PreJuSER-15819

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Interaction of sealing material mica with interconnect steel for solid oxide fuel cells application at 600 degrees C

Bram, M.FZJ* ; Niewolak, L.FZJ* ; Shah, N.FZJ* ; Sebold, D.FZJ* ; Buchkremer, H. P.FZJ*

2011
Elsevier New York, NY [u.a.]

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Please use a persistent id in citations: doi:10.1016/j.jpowsour.2011.02.086

Abstract: In the last few years, a lot of effort has been undertaken to reduce the operation temperature of solid oxide fuel cells (SOFCs). Intermediate temperatures in the range of 600-650 degrees C are thought to be highly attractive due to the expected reduction of high-temperature corrosion and interdiffusion phenomena. Furthermore, each stack operated at higher temperatures has to pass this temperature range during thermal cycling. In this work, a study has been carried out to investigate the interaction between interconnect steel (DIN 1.4760) and vermiculite mica paper filled with talc at 600 degrees C. Mica paper has been implemented recently as a new sealing material for SOFC stacks, aiming to replace established but brittle glass ceramics. Corrosion experiments were conducted at 600 degrees C under dual gas atmosphere conditions as well as in air. The interconnect steel showed the formation of non-protective oxide scales in contact with mica, especially in the presence of air. The morphology of oxide scales was investigated by SEM/EDX. Possible reasons for this unexpected result are discussed. The complete encapsulation of mica by embossed and welded sheets made of FeCrAlY-steel (DIN 1.4767) as well as the pre-oxidation of interconnect steel were investigated as solutions to this problem. Pre-oxidation was found to be a promising measure to protect the interconnect steel from breakaway oxidation in contact with mica. (C) 2011 Elsevier B.V. All rights reserved.

Keyword(s): J ; Sealing SOFC (auto) ; Mica (auto) ; Interconnect steel (auto) ; Oxidation (auto) ; Intermediate temperature (auto)

Note: The authors are grateful for financial support from the European Commission under contract No. SES6-2006-020089 (SOFC600). They also would like to thank B. Hausmann for manufacturing composite samples, V. Haanappel for conducting the experiments in the dual environment, M. Kappertz for helping in metallographic preparation, H. Moitroux for taking macro pictures and E. Wessel for SEM/EDX investigations. We would also like to thank W.J. Quadakkers for helpful discussions.

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Contributing Institute(s):

1. Werkstoffsynthese und Herstellverfahren (IEK-1)
2. Werkstoffstruktur und -eigenschaften (IEK-2)

Research Program(s):

1. Rationelle Energieumwandlung (P12)
2. SOFC - Solid Oxide Fuel Cell (SOFC-20140602) (SOFC-20140602)

Appears in the scientific report 2011

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