Ni-Containing Conducting Ceramic as an Oxidation Protective Coating on Metallic Interconnects by Aerosol Deposition
Thick (∼5 m) conducting perovskite LaNiO3 films were deposited on ferritic stainless steel (SS) by aerosol deposition (AD) for use as an oxidation resistance coating layer in the metallic interconnector of a solid oxide fuel cell (SOFC). The microstructural evolution and electrical resistivity of the LaNiO3-coated SS at the SOFC operating temperature (800°C) were examined. The coated oxide layers were fairly dense without pores or cracks, and good adhesion was maintained, even after oxidation at 800°C for 1000 h. The interface oxides formed between LaNiO3 and SS consisted of Ni and Mn-containing spinel and a Cr-rich oxide layer. The initial area specific resistance (ASR) of the LaNiO3-coated SS was 2.68 mΩ·cm2, which was increased to 7.34 mΩ·cm2 after post heat treatment at 800°C for 1000 h. The ASR of the LaNiO3-coated SS was ∼30% lower than that of the (La0.8Sr0.2)MnO3-coated SS post heat treated for the same time. Ni2+ substitution for Mn3+ in the octahedral sites of the spinel structures appears to decrease the resistivity of the interface oxide layer, and increase the long-term stability of the ASR at high temperatures.
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Document Type: Research Article
Affiliations: Functional Ceramics Group, Functional Materials Division, Korea Institute of Materials Science, Gyeongnam 641-831, Korea
Publication date: 2010-06-01