Evaluation of Ni80Cr20/(La0.75Sr0.25)0.95MnO3 dual layer coating on SUS 430 stainless steel used as metallic interconnect for solid oxide fuel cells

Ni80Cr20/(La0.75Sr0.25)0.95MnO3 dual-layer coating is deposited on SUS 430 alloy by plasma spray for solid oxide fuel cell (SOFC) interconnect application. The phase structure, area specific resistance (ASR), and morphology of the coating are studied. A two-cell stack is also assembled and tested to evaluate coating performance in an actual SOFC stack. The NiCr/LSM coating adheres well to the SUS 430 alloy after oxidation in air at 800 °C for 2800 h. The ASR and its increasing rate of coated alloy are 25 mΩ cm2 and 0.0017 mΩ cm2/h, respectively. In an actual stack test, the maximum output power density of the stack repeating unit increases from 0.32 W cm−2 to 0.45 W cm−2 because of the application of NiCr/LSM coating. The degradation rate of the stack repeating unit with no coating is 4.4%/100 h at a current density of 0.36 A cm−2, whereas the stack repeating unit with NiCr/LSM coating exhibits no degradation. Ni80Cr20/(La0.75Sr0.25)0.95MnO3 dual-layer coating can remarkably improve the thermal stability and electrical performance of metallic interconnects for SOFCs.