Engineering Lamellar Stainless Steel 410S Porous Supports via a Water-Based Tape Casting Method: A Scalable Path for...

Metal-supported solid oxide fuel cells (MS-SOFCs) have garnered increasing attention for advancing energy converter devices owing to their mechanical robustness, fast thermal cycling, and ability to operate with a wide range of fuels such as hydrocarbons and biofuels without contaminations. However, the manufacturing of porous metallic supports (PMSs), a critical component of these cells, still presents significant challenges, particularly regarding oxidation resistance, mismatch in thermal expansion coefficients (CTEs), gas diffusion issues, and synthesis reproducibility. In this work, we report a reproducible water-based tape casting methodology for PMS fabrication using commercially available 410S stainless steel powder. This alloy was selected due to their CTE compatibility with MS-SOFC ceramic layer components and due to its excellent chromium content (11.5-14.5%) to improve corrosion resistance. The optimized slurry formulation, containing tailored amounts of water-soluble binders and plasticizers, offers flexible and defect-free green tapes. Rheological characterization confirmed pseudoplastic and thixotropic behavior with high recovery (91.5%) after shear, ensuring stability during casting. Thermal gravimetric analysis (TGA) guided the debinding profile to prevent structural damage, and sintering was conducted under air and argon atmospheres. Argon sintering preserved the metallic structure and chromium content, while air sintering led to severe oxidation and phase destabilization. Precalcined ZrO₂ nonstick coarse powder at 1600 °C for 2 h was used during sintering to prevent contamination from Al₂O₃. A well-developed lamellar microstructure and peculiar interconnected porosity were observed in the sintered PMS, both of which are fundamental for ensuring gas permeability in MS-SOFC applications. The permeability of the PMS was tested for H₂, obtaining a result of 5.85 to 8.36 × 10^-12 m². Additionally, the PMSs showed an average resistivity of 2.45 ± 0.28 Ω·cm. This process addresses several obstacles in PMS fabrication pathway for integrating PMSs into next-generation SOFC architectures.