摘要
•Entropy stabilized coating for SOFC application has been demonstrated.•The High-Entropy system can promote formation of single-phase spinel oxide.•The complex spinel coating can provide effective oxidation protection.•The complex spinel coating can exhibit low ASR value.•The complex spinel coating can prevent Cr evaporation effectively.
This study investigates spinel oxide coatings derived from medium- to high-entropy alloy systems for solid oxide fuel cell interconnect applications. Alloy coatings of Fe-Mn-Co, Fe-Mn-Co-Cu, and Fe-Mn-Co-Cu-Ni are deposited on SUS430 stainless steel substrates utilizing a magnetron sputtering system and subjected to isothermal oxidation at 650 °C. Microstructural and phase analyses reveal the anomalous formation of hematite layers and Cr-Fe mixed oxide structures in Fe-Mn-Co and Fe-Mn-Co-Cu coatings, which indicates greater Fe diffusion at the substrate/coating interface during the early stage of oxidation comparing to that of Fe-Mn-Co-Cu-Ni coating. Theoretical calculations confirm that the hematite and Cr-Fe oxides significantly increase the area specific resistance of Fe-Mn-Co and Fe-Mn-Co-Cu coated steels at 650 °C. Notably, the Fe-Mn-Co-Cu-Ni coating can exhibit superior electrical conductivity, and resistances to oxidation and Cr-evaporation. This study demonstrates that entropy-engineered composition can promote the formation of single phase spinel, enhance phase stability, and can potentially be beneficial for long-term performance of solid oxide fuel cell as coating material for interconnects.