ISSN:
1662-9752
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Due to the reduction of operating temperature from 1000°C to 800°C, chromia formingalloys are the best candidates for interconnects in Solid Oxide Fuel Cells (SOFCs). Theseinterconnects have to be operational in service conditions, at 800°C in air (cathode side) and inhumidified hydrogen (anode side). The performance of the interconnect stainless steels is limited bythe oxide scale formation (chromia), the low electronic conductivity of this scale and the possiblevolatility of chromium oxides. In the field of high temperature oxidation of metals, it is well knownthat the addition of a nanometric layer made of reactive element oxide such as, La2O3, Nd2O3 andY2O3 by MOCVD (Metal Organic Chemical Vapor Deposition) on alloy surface resulted in animportant improvement in the high temperature oxidation resistance. These coatings are made onmetallic alloys in order to form perovskite oxides such as LaCrO3, NdCrO3 and YCrO3, which areexpected to present a good conductivity at 800°C in air. However, this temperature looks somewhattoo low to guarantee the formation of perovskite oxides and thus to improve the oxidation resistanceand electrical conductivity. In fact, XRD analyses revealed that for Y2O3 coatings, perovskiteoxides were not formed after oxidation in air at 800°C for 100 hours. The goal of this study is toperform pre-oxidation at 1000°C for 2 hours in air under atmospheric pressure on coatedCrofer22APU to pre-form perovskite phases. The so-prepared perovskite were tested in athermobalance in air. Experiments performed in H2/10%H2O under 150 mbar at 800°C validatedthe coating influence from the anode side as well as the cathode side. The corrosion products wereanalyzed after 100 hours ageing at 800°C by SEM, EDX, and XRD. ASR (Area SpecificResistance) was measured for the same times and temperature in air
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/19/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.595-598.753.pdf
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