Application of sputtered NiFe2 alloy coating for SOFC interconnect steel

NiFe2 alloy coating was applied on SUS 430 steel substrate for solid oxide fuel cell (SOFC) interconnects via magnetron sputtering technology. The coated steel was exposed for 15 weeks in air at 800 °C. SEM/EDS and XRD analysis results indicated that NiFe2O4 spinel layer atop chromia sub-layer was obtained on the coated steel. The top NiFe2O4 spinel layer not only suppressed chromia layer growth, but also exhibited excellent effect on retention of out-migration Cr species. The long term durability of the double-layered scale was demonstrated by the distinct adhesion of the steel/chromia and chromia/spinel interfaces. An area specific resistance (ASR) of 49.25 mΩ cm2 was achieved for NiFe2 coated steel after 15 weeks exposure. NiFe2O4 spinel thermally developed from sputtered NiFe2 coating is promising for the FSS interconnects application.