Development of low-temperature sintered Mn–Co spinel coatings on Fe–Cr ferritic alloys for solid oxide fuel cell interconnect applications

To reduce the sintering temperature of spinel coatings to a safe temperature for Fe–Cr ferritic alloys, an MnCo2O4–MnO2 bicomponent coating has been prepared on SUS430 ferritic alloy by slurry coating, followed by air sintering at a temperature of 800 °C. The resultant coating is stable during cyclic oxidation tests and is effective at improving the oxidation resistance of SUS430 alloy. The area-specific resistance of coated samples remains nearly constant during long-term oxidation at 800 °C and is less than 6 mΩ cm2 even after oxidation for 1000 h. These results indicate that the low-temperature sintered MnCo2O4–MnO2 coating is a promising protective material for Fe–Cr ferrite alloys, especially SUS430, which are seriously oxidized at temperatures ≥850 °C.

► We develop a low-temperature sintered coating for SOFC metallic interconnects. ► The bicomponent coating material MnCo2O4–MnO2 can be air sintered at 800 °C. ► MnCo2O4–MnO2 coating greatly improves the oxidation resistance of SUS430 alloy. ► MnCo2O4–MnO2 coating is well conductive and stable during long-term oxidation. ► Cr exhaustion of SUS430 alloy is inhibited by MnCo2O4–MnO2 coating.