Cobalt Coated 460FC-Based Metallic Interconnects for Solid Oxide Fuel Cell

Solid oxide fuel cells (SOFCs) show excellent fuel efficiency, power reliability, lower emission, and inexpensive operating cost, as compared to other electrochemical devices. Recently, 460FC-based Fe-Cr alloy have been developed as metallic interconnect for SOFCs. However, serious problems caused by the diffusion of Cr and the growth of Cr-based oxide of 460FC-based Fe-Cr alloy during oxidation at high temperature reduce the power efficiency of SOFC. Co-based oxide layer can improve the oxidation properties of metallic interconnects at high temperature due to inhibiting the diffusion of Cr and retarding the growth of Cr-based oxide during oxidation at high temperature. Here, Co protective layer was deposited on 460FC-based Fe-Cr alloy by the electroless plating method and then oxidized at high temperature. The oxidation characteristics of Co-coated 460FC-based Fe-Cr alloy at high temperature was analyzed and compared with non-coated 460FC-based Fe-Cr alloy using X-ray photoelectron spectroscopy (XPS), focused ion beam-scanning electron microscope (FIB-SEM)/energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and area specific resistance (ASR). The Co protective layer of Co-coated 460FC-based Fe-Cr alloy was thermally oxidized to Co₃O₄ during oxidation at high temperature, which shows lower resistance than Cr-based oxide. It is confirmed that the presence of continuous Co₃O₄ layer inhibited the diffusion of Cr and retarded the growth of Cr-based oxide effectively during oxidation at high temperature. Therefore it is believed that the oxidation properties of metallic interconnects at high temperature is enough to apply to the SOFC.