Solution precursor plasma spray process: A promising route for the fabrication of Mn-Co oxide based protective coating for SOFC

摘要

A spinel-based manganese cobaltite (Mn1.5Co1.5O4) surface protective layer which is suitable for SOFC current collectors and bi-polar interconnector plates is developed by solution precursor plasma spraying (SPPS) technique on SS430 flat substrates and meshes. The plasma spray parameters are optimized for getting adherent coatings on SS substrates and meshes. The area specific resistance (ASR) of as sprayed and heat treated (800 degrees C for 72 h) coatings is studied using DC four-probe technique. The diffusion barrier properties of the spinel coating after oxidation studies are analyzed by scanning electron microscopy and energy dispersive X-ray spectroscopy to analyze the chromium diffusion across the coating and at the substrate-coating interface. Significant improvement in oxidation resistance is observed for the spinel coated substrates compared to bare S5430 substrate and Cr diffusion is not observed across the coating. The current collector mesh with protective coating exhibits a stable ASR. The coated current collector mesh has been used in a SOFC button cell and tested. The cell performance is not affected by the use of spinel coated SS430 mesh. This study shows that SPPS is a viable approach for fabricating protective layers as the process is simpler than suspension plasma spraying, economically attractive and can be used for coating larger areas in comparison to sputtering process. (C) 2017 Elsevier B.V. All rights reserved.