Cost-effective methods of fabricating thin rare-earth element layers on SOC interconnects based on low-chromium ferritic stainless steel and exposed to air, humidified air or humidified hydrogen atmospheres.

Most oxidation studies involving interconnects are conducted in air under isothermal conditions, but during real-life solid oxide cell (SOC) operation, cells are also exposed a mixture of hydrogen and water vapor. For this study, an Fe–16Cr low-chromium ferritic stainless steel was coated with different reactive element oxides – Gd 2 O 3 , CeO 2 , Ce 0.9 Y 0.1 O 2 – using an array of methods: dip coating, electrodeposition and spray pyrolysis. The samples underwent oxidation experiments carried out over 100 h in three different atmospheres at 800 °C: air, an air/H 2 O mixture, and an Ar/H 2 /H 2 O mixture. The influence of different atmospheres on the corrosion of the Fe–16Cr steel was determined via oxidation kinetics studies; the corrosion product was evaluated using X-ray diffraction, scanning electron microscopy and area-specific resistance (ASR) measurements. All coated samples exhibited lower parabolic oxidation rate constants than bare steel and most also had lower ASR. The applied modifications were found to be sufficiently effective to allow the investigated low-chromium steel to be considered for application as an interconnect material for SOCs. [Display omitted] • Gd 2 O 3 -based thin layers improved corrosion resistance for all oxidation atmospheres. • Under some conditions RE perovskite phases were formed. • The thinnest scale was observed after oxidation in H 2 –H 2 O atmosphere. • Gd 2 O 3 -based thin layers significantly reduced ASR for all oxidation atmospheres. • Addition of Y to CeO 2 improves its electrical conductivity. [ABSTRACT FROM AUTHOR]