In an attempt to reduce the oxidation and Cr evaporation rates of SUS 430 steel as the interconnect for solid oxide fuel cell, FeCoNi (Fe:Co:Ni = 1:1:1, atomic ratio) coating is deposited on bare and 100-h pre-oxidized steel by magnetron sputtering, following by oxidation at 800 degrees C in air to thermally convert to protective and electrically conductive oxide. The thermally converted coating on steel is characterized via a combination of X-ray diffraction, scanning electron microscopy and transmission electron microscopy. It is found that (Fe,Co,Ni)(3)O-4/(Ni,Co)O significantly suppresses the growth of Cr2O3 and reduces the area specific resistance of the surface scale, serving as a diffusion barrier to effectively restrain Cr out-migration. In addition, pre-oxidation treatment for substrate steel prior to the deposition of the FeCoNi coating is advantageous to obtain a Cr-free oxide layer and slightly improves the electrical property of the surface scale.