Nano-Oxide Dispersed Ferritic Stainless Steel for Metallic Interconnects of Solid Oxide Fuel Cells

In this study, we developed novel nano-oxide dispersed ferritic steel alloys and tested their long-term performance as interconnect materials for SOFC application. Physical properties, microstructural and phase analysis of the nano-oxide (i.e. CeO2, La2O3) dispersed stainless steel alloys were examined before the long-term testing in air at 800 degrees C for 1000 h. The electrical properties of the oxide layer were investigated by long-term ASR tests. Post-test analysis of the samples was conducted by SEM, EDS, and XRD techniques. The long-term ASR results show that the dispersion of nano-oxide particles significantly improved the ASR properties of the ferritic stainless steel based alloys. Especially, the total increase in the ASR of nano-CeO2 dispersed ferritic steel during the 1000h long-term test was much less than that of the SUS430. In this work, the electrical and the oxidation behaviors for the long-term test are discussed as related to the microstructure and oxide scale formation mechanism.