Scale-up and electrochemical validation of Fe-modified Mn–Cu spinel coatings deposited by electrophoretic deposition for solid oxide cell interconnect applications

Cobalt-free Mn–Cu spinel coatings, with and without Fe modification, were deposited by electrophoretic deposition (EPD) and comparatively evaluated as protective layers for solid oxide cell (SOC) interconnects. The addition of Fe2O3 led to a finer and more uniform microstructure, while XRD and EDS results were consistent with Fe incorporation into the Mn–Cu spinel-based phase after thermal treatment. Electrochemical testing was performed on large-area interconnects under dual-atmosphere operation (850 °C, 10% H2 + 90% H2O/air) for over 1300 h. The MnCuFe-coated Crofer 22 APU exhibited initial area-specific resistance (ASR) values in the range of 10–20 mΩ cm2, followed by a moderate increase during the first few hundred hours and progressive stabilization beyond 1000 h. Post-mortem analyses revealed controlled chromia growth and preserved coating integrity. These results demonstrate the feasibility of scaling up EPD-processed Mn–Cu-based coatings and validate their performance under industrially relevant conditions, positioning them as viable cobalt-free alternatives for SOC interconnect protection