Oxide scale formation on different metallic interconnects for solid oxide fuel cells

The formation of an oxide layer on different metallic samples (i.e., Crofer 22 APU, SS430 and Conicro 4023 W188) treated at 800 °C for 100 and 1000 h in air was investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM/EDX) and thermogravimetric analysis.The results indicate that the oxide scale formed on the metallic interconnect consists of a spinel (Fe, Cr, Mn)3O4 or (Fe, Cr, Ni)3Co2O4 outer layer and a chromia (Cr2O3) inner layer. The Crofer 22 APU and Conicro 4023 W188 samples were determined to be more promising as metallic interconnects than SS430 due to their higher oxidation resistance.

► The oxidation of Crofer 22 APU, SS430 and Conicro 4023 W188 was studied.
► Oxide scales were studied by XRD and SEM after oxidation at 800 °C in air for 1000 h.
► A spinel outer layer and chromia inner layer were formed for all alloys.