Effect of NiFe2 coating thickness on high temperature oxidation and electrical behavior of coated steel interconnect.

NiFe 2 coating with thickness of 3.5, 6.5 and 9.5 μm was deposited on SUS 430 steel by magnetron sputtering 2 h, 4 h and 6 h, respectively, for application as protective coating of solid oxide fuel cell (SOFC) interconnects. Oxidation and electrical behavior of the coated steels were evaluated in air at 800 °C for durations of up to 15 weeks to investigate the effect of coating thickness. It is found that 4 h and 6 h samples showed better oxidation resistance and Cr-blocking effectiveness compared to 2 h sample. The lowest area specific resistance (ASR) after 15-week oxidation was achieved for 4 h sample. Results suggest that 6.5 μm NiFe 2 coating of 4 h sample exhibited an appropriate thickness for effectively inhibiting Cr out-diffusion and improving the oxidation resistance while maintaining a low scale ASR. • NiFe 2 coatings with different thickness was sputtered on interconnect steel. • Increase of coating thickness enhanced the inhibition against Cr out-migration. • The lowest scale area specific resistance was achieved for 6.5 μm NiFe 2 coated steel. • NiO layer exhibited superior ability to prevent both Cr and Mn out-migration. [ABSTRACT FROM AUTHOR]