Chapter 6. Degradation Mechanism of Metal Supported Atmospheric Plasma Sprayed Solid Oxide Fuel Cells
- Narottam P. Bansal,
- Andrew Wereszczak and
- Edgar Lara-Curzio
Published Online: 26 MAR 2008
Copyright © 2007 The American Ceramics Society
Advances in Solid Oxide Fuel Cells II: Ceramic Engineering and Science Proceedings, Volume 27, Issue 4
How to Cite
Hathiramani, D., Vaßen, R., Mertens, J., Sebold, D., Haanappel, V. A. C. and Stöver, D. (2008) Degradation Mechanism of Metal Supported Atmospheric Plasma Sprayed Solid Oxide Fuel Cells, in Advances in Solid Oxide Fuel Cells II: Ceramic Engineering and Science Proceedings, Volume 27, Issue 4 (eds N. P. Bansal, A. Wereszczak and E. Lara-Curzio), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470291337.ch6
- Published Online: 26 MAR 2008
- Published Print: 1 JAN 2006
Print ISBN: 9780470080542
Online ISBN: 9780470291337
Sufficient thermal shock resistance, good thermal conductivity, as well as its solderability makes metallic supports highly attractive for SOFCs used in auxiliary power units (APUs). It is known that metallic supported SOFCs based on ferritic steels show high degradation rates during operation. Life times of such SOFCs are in the range of 200 h instead of up to 5000 h required for typical mobile applications. To solve this problem it is important to identify the mechanism responsible for the degradation.
SOFCs were produced by subsequently atmospheric plasma spraying of the anode (NiO/YSZ) and the electrolyte layer (YSZ) on top of porous metallic substrates. The cathode (LSFC) was applied by screen printing. Two different types of alloys were used as metallic substrates, Crofer22APU first (ThyssenKrupp) and the ODS alloy ITM-14 (Plansee). Electrochemical tests were performed for 200 h at 800°C under a constant current load.
Possible degradation mechanisms were listed and systematic experiments were designed to study the individual contribution of each degradation process. From both the characterization of the single cell tests as well as the individual experiments for each degradation mechanism, it can be concluded that chromium diffusion from the metallic support to the anode layer seems to be responsible for the high degradation rates. Other mechanism like degradation of the metallic substrates due to oxidation or the formation of La2Z2rO7 or SrZrO3 along the electrolyte-cathode interface does only play a minor role to the total degradation of the SOFC during the first 200 h.