Journal article
Electrical Resistance Measurements and Microstructural Characterization of the Anode/Interconnect Contact in Simulated Anode-Side SOFC Conditions
Metallic interconnects in solid oxide fuel cell (SOFC) stacks are often in direct contact with a nickel/yttria stabilized zirconia (Ni/YSZ) cermet anode. Interdiffusion between the two components may occur at the operating temperature of 700–850◦C. The alteration of chemical composition can result in phase transformation of the steel and in formation of oxides with a poor electrical conductivity in the anode.
In this study, the area specific resistance (ASR) of the steel Crofer 22 APU, in contact with a Ni/YSZ anode with and without a tape casted CeO2 barrier layer was measured in simulated SOFC anode conditions at 800◦C. The microstructure in the contact area was characterized using scanning electron microscopy techniques.
The ASR was low for the steel in direct contact with the Ni/YSZ anode. Nickel diffusion into the steel resulted in a fine grained zone, which was identified as ferrite. The zone is austenitic at the exposure temperature but transforms to ferrite during cooling. When a CeO2 nickel diffusion barrier layer was used The ASR was considerably higher.
These results imply that nickel diffusion is not only detrimental: It leads to microstructural instability but also results in a low electrical resistance of the anode/interconnect contact.
Language: | English |
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Publisher: | The Electrochemical Society |
Year: | 2015 |
Pages: | 387-396 |
ISSN: | 19457111 and 00134651 |
Types: | Journal article |
DOI: | 10.1149/2.0381504jes |
ORCIDs: | Alimadadi, Hossein |