A study on the oxidation and electrical behavior of crofer 22 APU solid oxide fuel cell interconnects with Ni-Co-CeO2 composite coating

A protective/conductive coating can be used to limit the formation of chromia in ferritic steel interconnects in solid oxide fuel cells (SOFCs). One of the most promising candidates for restricting chromia formation is the addition of reactive elements oxides to the coating. Here in, Ni-Co-CeO2 composite coating was applied to Crofer 22 APU alloy via the electroless method. The oxidation and electrical behavior of uncoated and coated samples were evaluated at 800 °C. The coating structure was examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Results showed Cr2O3-scale thicknesses, and a reduction in oxidation rates for Ni-Co-CeO2-coated samples compared to uncoated samples. Also, area specific resistance (ASR) results indicated that the formation of NiFe2O4, (Mn,Ni)2O4, Co3O4, and CoFe2O4 compositions and the presence of CeO2 reduced ASR. The ASR values of Ni-Co-CeO2 coated and uncoated Crofer 22 APU alloy after 300 h of isothermal oxidation at 800 °C was 11.8 mΩ cm2 and 35.7 mΩ cm2, respectively.