Preparation and performance of SUS430-Sr₂Fe_1.5Mo_0.5O_6‒δ stainless steel-ceramic composite interconnect materials for solid oxide fuel cell

The SUS430-Sr₂Fe_1.5Mo_0.5O_6−δ (SUS430-SFM) stainless steel-ceramic composite connector materials for solid oxide fuel cell (SOFC) were prepared by a compaction-sintering-coating method, using SUS430 stainless powders and Sr₂Fe_1.5Mo_0.5O_6−δ (SFM) ceramic powders as the raw materials. Microstructure, oxidation resistance, and electrical conductivity of the sintered SUS430 and SUS430-SFM samples were characterized. The results show that the SFM coating and the SUS430 substrate show a matching thermal expansion coefficient (TEC), and there is a good combination between the coating and the substrate. The oxidation rate constant of the SUS430-SFM sample is about 3.66×10⁻¹⁴ g²∙cm⁻⁴∙s⁻¹ after oxidation at 800 ℃ for 140 h in air, which is about 50% lower than that of the SUS430 sample (2.42×10⁻¹⁴ g²∙cm⁻⁴∙s⁻¹). The area specific resistance (ASR) of the SUS430-SFM sample also reduces from 81 mΩ∙cm² (SUS430 sample) to 2.6 mΩ∙cm². The present work indicates that the SFM coating can effectively improve the oxidation resistance and the electrical conductivity of the SUS430 stainless substrate.