Thermal conversion process of CuFe2O4 coating on steel interconnect for solid oxide fuel cell applications

Abstract This study reports the thermal conversion process of CuFe2O4 coating as a protective layer on chromia-forming steels. A CuFe1.8 alloy layer is obtained on steel substrate via magnetron sputtering technology, and then sample is exposed to a simulated solid oxide fuel cell (SOFC) cathode atmosphere (in air at 800 °C) for up to 60 min. X-ray diffraction (XRD) and scanning electron microscopy (SEM) reveal that Fe is preferentially oxidized (Fe2O3 externally and Fe3O4 internally). Then, CuO is formed atop Fe2O3, while the CuFeO2 grows within the internal oxidation zone. The CuFe2O4 spinel layer further grows in different ways with increasing time. The Cr2O3 layer forms at the steel/converted oxide layers interface after the alloy layer disappears.