Electrophoretically Deposited Protective Cu-Mn and Mn-Co Spinel Coatings for SOFC Interconnects

Stainless steel interconnects in solid oxide fuel cells can lead to chromium poisoning of the cathode, necessitating the use of protective coatings. Electrophoretic deposition is an efficient method to deposit coatings on substrates with complex microstructures. In this study, four spinel coatings; CuMn2O4, CuNi0.2Mn1.8O4, MnCo2O4, and MnFe0.34Co1.66O4, were deposited by direct-current electrophoretic deposition on flat SUS430 stainless steel substrates. The coatings were evaluated on multiple criteria, including microstructural stability, conductivity, Cr gettering ability, and the ability to act as a diffusion barrier at 700°C and 800°C. It was concluded that CuNi0.2Mn1.8O4 is an excellent candidate at temperatures at and below 700oC, while MnFe0.34Co1.66O4 coatings perform better at higher temperatures.