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  • Novel coatings for protecti...
    Tomas, M.; Visibile, A.; Svensson, J.-E.; Froitzheim, J.

    International journal of hydrogen energy, 06/2023, Volume: 48, Issue: 48
    Journal Article

    A key component of a Solid Oxide Fuel Cell (SOFC) is the interconnect, which connects individual fuel cells in series to form a fuel cell stack to reach a desired electrical potential. The interconnect is exposed to air and fuel in parallel, these so-called dual-atmosphere conditions give rise to especially severe corrosion on the air-side. This work investigates coatings to mitigate this effect. Physical Vapour Deposition (PVD) CeCo-coated AISI 441 samples on the air-side and PVD metallic Al- and Al2O3-coated AISI 441 samples on the fuel-side were exposed under dual-atmosphere conditions for up to 7000 h. The evolution of the corrosion products was followed every 1000 h with an optical microscope. Scanning electron microscopy and energy-dispersive x-ray spectroscopy were performed on cross-sections of the samples after 3000 h of exposure. The SEM analysis showed that coating on the air-side improved the sample's life-time by reducing the level of Cr evaporation even in a dual-atmosphere. The use of fuel-side coatings suppressed the dual-atmosphere effect since the coatings formed a barrier to hydrogen permeation. The best results were observed with metallic Al and Al2O3 coating on the fuel-side, which drastically reduced the dual-atmosphere effect. However, the poor conductivity of Al2O3 makes its use as a coating challenging. •Coatings against hydrogen permeation are investigated for up to 7000 h.•Al-based coatings effectively reduce the dual-atmosphere effect.•A combined Al2O3//Ce/Co-coating reduces Cr evaporation and the dual-atmosphere effect.•Al2O3 coatings exhibit high ASR values.