Ni/NiFe2 dual-layer coating for SOFC steel interconnects application

Abstract

Ni/NiFe2 dual-layer coating is fabricated on SUS 430 stainless steel by magnetron sputtering for solid oxide fuel cells (SOFCs) interconnect application. Ni/NiFe2 coated steels are exposed to air at 800 °C for duration of up to 10 weeks in comparison with NiFe2 coated steels. Ni/NiFe2 coating is thermally converted to an oxide structure with an inner NiO layer and an outer NiFe2O4 spinel layer. NiO/NiFe2O4 oxide layer is more effective in blocking Cr migration and reducing oxidation rate during long-term exposure than a single NiFe2O4 layer converted from NiFe2 coating. Enhancements on oxidation resistance and Cr-blocking capability are attributed to NiO layer serving as a diffusion barrier between Cr2O3 and NiFe2O4.

Keywords

• Steel interconnect
• Diffusion barrier
• NiO
• NiFe2O4 spinel