Title: Ohmic resistance of nickel infiltrated chromium oxide scales in solid oxide fuel cell metallic interconnects
Authors : Linder, Markus
Hocker, Thomas
Holzer, Lorenz
Pecho, Omar
Friedrich, Andreas
Morawietz, Thomas
Hiesgen, Renate
Kontic, Roman
Iwanschitz, Boris
Mai, Andreas
Schuler, Andreas
Published in : Solid State Ionics
Volume(Issue) : 283
Pages : 38
Pages to: 51
Publisher / Ed. Institution : Elsevier BV
Issue Date: 2015
Language : Englisch / English
Subjects : Interconnect; Oxidation; Map; SOFC
Subject (DDC) : 621.3: Elektrotechnik, Elektronik
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.
Departement: School of Engineering
Organisational Unit: Institute of Computational Physics (ICP)
Institute of Materials and Process Engineering (IMPE)
Publication type: Beitrag in wissenschaftlicher Zeitschrift / Article in scientific Journal
DOI : 10.1016/j.ssi.2015.11.003
ISSN: 0167-2738
URI: https://digitalcollection.zhaw.ch/handle/11475/1622
Appears in Collections:Publikationen School of Engineering

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