Sputtered Fe1·5CoNi0.5 coating: An improved protective coating for SOFC interconnect applications

Abstract

In an attempt to optimize the properties of FeCoNi coating for planar solid oxide fuel cell (SOFC) interconnect application, the coating composition is modified by increasing the ratio of Fe/Ni. An Fe 1·5 CoNi 0.5 (Fe:Co:Ni = 1.5:1:0.5, atomic ratio) metallic coating is fabricated on SUS 430 stainless steel by magnetron sputtering, followed by oxidation in air at 800°C. The Fe 1·5 CoNi 0.5 coating is thermally converted to (Fe,Co,Ni) 3 O 4 and (Fe,Co,Mn,Ni) 3 O 4 without (Ni,Co)O particles. After oxidation for 1680 h, no further migration of Cr is detected in the thermally converted coating region. A low oxidation rate of 5.9 × 10 −14 g 2 cm −4 s −1 and area specific resistance of 12.64 mΩ·cm 2 is obtained for Fe 1·5 CoNi 0.5 coated steels. • Fe 1·5 CoNi 0.5 coating is deposited on SUS 430 stainless steel by magnetron sputtering. • The tri-layer oxide scale is thermally formed on the Fe 1·5 CoNi 0.5 coated steel. • The oxidation resistance of the steel substrate is improved. • The out-migration of Cr is effectively inhibited. • A low ASR of 12.64 mΩ·cm 2 is exhibited.