elib
DLR-Header
DLR-Logo -> http://www.dlr.de
DLR Portal Home | Imprint | Privacy Policy | Contact | Deutsch
Fontsize: [-] Text [+]

Model-based prediction of the ohmic resistance of metallic interconnects from oxide scale growth based on scanning electron microscopy

Linder, Markus and Hocker, Thomas and Holzer, Lorenz and Friedrich, K. Andreas and Iwanschitz, Boris and Mai, Andreas and Schuler, J. Andreas (2014) Model-based prediction of the ohmic resistance of metallic interconnects from oxide scale growth based on scanning electron microscopy. Journal of Power Sources, 272, pp. 595-605. Elsevier. DOI: [10.1016/j.jpowsour.2014.08.098] ISSN 0378-7753

[img] PDF - Registered users only
2MB

Abstract

The increase of ohmic losses caused by continuously growing Cr2O3 scales on metallic interconnects (MICs) is a major contribution to the degradation of SOFC stacks. Comparison of measured ohmic resistances of chromium- (CFY) and ferritic-based alloy (Crofer) MICs at 850 �C in air with the growth of mean oxide scale thicknesses, obtained from SEM cross section images, reveals a non-trivial, non-linear relationship. To understand the correlation between scale evolution and resulting ohmic losses, 2D finite element (FE) simulations of electrical current distributions have been performed for a large number of real oxide scale morphologies. It turns out that typical morphologies favor nonhomogeneous electrical current distributions, where the main current flows over rather few “bridges”, i.e. local spots with relatively thin oxide scales. These current-“bridges” are the main reason for the non-linear dependence of ohmic losses on the corresponding oxide scale morphology. Combining electrical conductivity and SEM measurements with FE simulations revealed two further advantages: it permits a more reliable extrapolation of MIC-degradation data over the whole stack lifetime and it provides a method to assess the effective electrical conductivity of thermally grown Cr2O3 scales under stack operation.

Item URL in elib:https://elib.dlr.de/91879/
Document Type:Article
Title:Model-based prediction of the ohmic resistance of metallic interconnects from oxide scale growth based on scanning electron microscopy
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Linder, MarkusZHAW Zurich University of Appl. SciencesUNSPECIFIED
Hocker, ThomasZHAW Zurich University of Appl. SciencesUNSPECIFIED
Holzer, LorenzZHAW Zurich University of Appl. SciencesUNSPECIFIED
Friedrich, K. Andreasandreas.friedrich (at) dlr.deUNSPECIFIED
Iwanschitz, BorisHexis AGUNSPECIFIED
Mai, AndreasHexis AGUNSPECIFIED
Schuler, J. AndreasHexis AGUNSPECIFIED
Date:2 September 2014
Journal or Publication Title:Journal of Power Sources
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:272
DOI :[10.1016/j.jpowsour.2014.08.098]
Page Range:pp. 595-605
Publisher:Elsevier
ISSN:0378-7753
Status:Published
Keywords:Solid oxide fuel cell (SOFC), interconnects, Oxide scale morphology, Degradation prediction
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:17 Nov 2014 16:19
Last Modified:10 Jan 2019 15:48

Repository Staff Only: item control page

Browse
Search
Help & Contact
Information
electronic library is running on EPrints 3.3.12
Copyright © 2008-2017 German Aerospace Center (DLR). All rights reserved.