Investigation of Electrodeposited Mn–Co–Y₂O₃ Coating on Crofer 22 APU for the SOFC Interconnect Application

The electrodeposition technique was successfully used for the co-deposition of Mn and Co metals and Y₂O₃ particles on Corofer 22 APU interconnects. The uncoated and Mn–Co–Y₂O₃-coated samples were oxidized in an electric furnace for 500 h at 800°C. The surface morphology and phase structure of these samples were examined by field emission scanning electron microscopy (FESEM) and XRD analysis, respectively. The electrical conductivity of the samples was investigated by measuring area specific resistance. The results showed that the weight gain of uncoated and Mn–Co–Y₂O₃-coated samples after isothermal oxidation for 500 h was 0.52 and 0.4 mg cm^–2, respectively. Microscopic investigations demonstrated that a non-continuous thin oxide scale forms underneath the applied coating, while high outward diffusion of Fe, Mn, and Cr occurred in uncoated steel after 500 h of oxidation at 800°C. Findings also implied that the applied coating significantly improve the electrical conductivity of steel interconnects after long-term oxidation at high temperatures.