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2216 |
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Tuesday, May 04, 2010, Olivia Room 5:00 PM Power Engineering and SOFC 2 |
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The structure and properties of plasma sprayed Fe-doped manganese cobalt oxide spinel coatings for SOFC metallic interconnectors |
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Jouni Puranen* / Tampere University of Technology, Department of Materials Science, Finland Leo Hyvärinen / Department of Materials Science, Tampere University of Technology, Finland Petri Vuoristo/ Department of Materials Science, Tampere University of Technology, Finland Juha Lagerbom/ Technical Research Centre of Finland, Finland Mikko Kylmälahti/ Department of Materials Science, Tampere University of Technology, Finland |
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Manganese cobalt oxide spinel doped with Fe2O3 was studied as protective coatings on metallic interconnect plates for solid oxide fuel cell applications. These interconnect plates are usually made of ferritic stainless steels containing approximately 11-30 wt% of chromium. The high chromium content causes problems at high operation temperatures in oxidising conditions, on the cathode side of the fuel cell. The formed chromium oxide layer tends to form a thin layer of chromium trioxide or chromium hydroxide which evaporates at certain oxygen partial pressures more easily than chromium oxide and thus poisons the cathodes active area causing the degradation of the solid oxide fuel cell. Moreover, the formed chromium oxide layer on the metal surface increases values of ohmic resistance(area specific resistance (ASR)). Thermal spraying, particularly atmospheric process variations are regarded as a promising and economic way to produce dense and protective layers on top of ferritic steels to lower the degradation processes and extend the lifetime of the SOFC device. In the present work, the ceramic Co-Mn ?oxide spinel coatings were produced by using the atmospheric plasma spray process. The structures and compositions of the coatings were characterized using scanning electron microscopy (SEM). X-ray diffraction (XRD) was used to study the phase structure in as sprayed and heat treated coatings. Coatings with low thickness and microstructurally dense structures were produced by using optimal deposition conditions. |