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Ohmic resistance of nickel infiltrated chromium oxide scales in solid oxide fuel cell metallic interconnects

Linder, Markus and Hocker, Thomas and Holzer, Lorenz and Pecho, Omar and Friedrich, K. Andreas and Morawietz, Tobias and Hiesgen, Renate and Kontic, Roman and Iwanschitz, Boris and Mai, Andreas and Schuler, J. Andreas (2015) Ohmic resistance of nickel infiltrated chromium oxide scales in solid oxide fuel cell metallic interconnects. Solid State Ionics, 283, pp. 38-51. Elsevier. DOI: [dx.doi.org/10.1016/j.ssi.2015.11.003] ISSN 0167-2738

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Abstract

Oxide scale formation on metallic interconnects contributes to the overall degradation of solid oxide fuel cell (SOFC) stacks. On the anode side, thermally grown oxide scale might contain additional nickel, nickel oxide, or nickel chromium spinel phases – depending on the applied operation conditions. Ni originates from Ni-meshes, often applied as current collector, from Ni-containing anodes or from Ni-containing coatings. Ni particles released during thermo redox cycles from adjacent Ni-containing components might be interspersed into the oxide scale. This study aims at investigating the influence of Ni on the electrical conductivity of oxide scales. For this purpose pellets of Cr2O3 were mixed with different amounts of Ni and then investigated in-situ under both reducing and oxidizing gas atmospheres at 850 °C. The formed crystals were analyzed using X-ray diffraction, whereas the resulting microstructures were quantified using scanning electron microscopy. During oxidation Ni is converted into NiO, and the latter interacts with Cr2O3 to form a NiCr2O4 spinel phase. Subsequent exposure to reducing conditions leads to an almost instantaneous decomposition of NiCr2O4 spinel, resulting in finely dispersed elementary Ni. This rearrangement of Ni by spinel decomposition leads to a significant improvement of the electrical conductivity of the Cr2O3 pellets compared to their initial state.

Item URL in elib:https://elib.dlr.de/100758/
Document Type:Article
Title:Ohmic resistance of nickel infiltrated chromium oxide scales in solid oxide fuel cell metallic interconnects
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Linder, MarkusZHAW Zurich University of Appl. SciencesUNSPECIFIED
Hocker, ThomasZHAW Zurich University of Appl. SciencesUNSPECIFIED
Holzer, LorenzHexis AGUNSPECIFIED
Pecho, OmarZHAW Zurich University of Appl. SciencesUNSPECIFIED
Friedrich, K. Andreasandreas.friedrich (at) dlr.deUNSPECIFIED
Morawietz, TobiasHochschule EsslingenUNSPECIFIED
Hiesgen, Renaterenate.hiesgen (at) hs-esslingen.deUNSPECIFIED
Kontic, RomanZHAW Zurich University of Appl. SciencesUNSPECIFIED
Iwanschitz, BorisHexis AGUNSPECIFIED
Mai, AndreasHexis AGUNSPECIFIED
Schuler, J. AndreasHexis AGUNSPECIFIED
Date:2015
Journal or Publication Title:Solid State Ionics
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:283
DOI :[dx.doi.org/10.1016/j.ssi.2015.11.003]
Page Range:pp. 38-51
Publisher:Elsevier
ISSN:0167-2738
Status:Published
Keywords:solid oxide fuel cell (SOFC), NiCr2O4 (nickel chromate, spinel), metallic interconnects (MIC), oxide scale formation, Ni-mesh, metallic coating
HGF - Research field:Energy
HGF - Program:Efficient Energy Conversion and Use (old)
HGF - Program Themes:Fuel Cells (old)
DLR - Research area:Energy
DLR - Program:E EV - Energy process technology
DLR - Research theme (Project):E - Electrochemical Processes (old)
Location: Stuttgart
Institutes and Institutions:Institute of Engineering Thermodynamics > Electrochemical Energy Technology
Deposited By: Friedrich, Prof.Dr. Kaspar Andreas
Deposited On:10 Dec 2015 08:59
Last Modified:31 Jul 2019 19:57

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