Fabrication of Mnsub(1.5)Cosub(1.5)Osub(4) by electrostatic spray deposition for application as protective coating on alloy interconnects for solid oxide fuel cells

Abstract

A Mn1.5Co1.5O4 (MCO) protective coating was deposited by Electrostatic Spray Deposition on the SS446 alloy used as interconnects in Solid Oxide Fuel Cells. The main purpose of this work was to verify the feasibility this technique to inhibit the Cr volatilization and the subsequent SOFC cathode poisoning. Phase crystallization was obtained by thermal annealing at 800 °C in air, after deposition. The corrosion resistance behavior of the uncoated and coated steels was investigated by electric and thermogravimetric measurements. The coated films, 400 nm thick, were found efficient in reducing the oxidation rate, by limiting the outward Cr3+ diffusion. The area specific resistance of the coated SS446 alloy was found to be much lower (6.7 mΩ.cm2 ) and more stable as compared to the uncoated one (80 mΩ.cm2 ), after oxidation for 200 h at 800 °C in ambient air. These results evidence the good performance of the deposition technique for fabricating thin, crack free and dense conductive Mn1.5Co1.5O4 coatings on ferritic alloys.