La0.7Sr0.3MnO3−δ barrier for Cr2O3-forming SOFC interconnect alloy coated by electrostatic spray deposition

In this work, electrostatic spray deposition (ESD) technology was used to deposit dense, free-cracks and thin La0.7Sr0.3MnO3−δ (LSM) layers on SS446 alloy interconnect to be used in solid oxide fuel cell (SOFC) after subsequent annealing at 800°C in air for 2h. The corrosion resistance of uncoated and LSM-coated steels has been studied by electrical and thermogravimetric measurements. The oxidation rate was strongly reduced for LSM-coated steel in ambient air and pure oxygen at 800°C for 250h. It was found for the first time that a dense LSM coating as thin as 300nm efficiently reduces the oxidation rate by limiting outward Cr3+ diffusion. A protective chromia scale was detected by SEM and EDS at the interfacial layer. The area specific resistance (ASR) of LSM-coated SS446 was found very low (30mΩ·cm2) and stable in comparison with the uncoated one (80mΩ·cm2) after 200h oxidation in air at 800°C. The results of this work demonstrate the possibility of automated production of dense conductive interconnect LSM-coated materials and give a standard thickness to obtain stable long-term operation. •Dense, free-cracks and thin La0.7Sr0.3MnO3-δ (LSM) layers films.•The oxidation rate was strongly reduced for LSM-coated steel in ambient air and pure oxygen at 800°C for 250h.•The LSM coating as thin dense as 300nm efficiently reduces the corrosion rate by limiting outward Cr3+ diffusion.•ASR values of LSM-coated SS446 was found very low (30mΩ.cm2) and stable after 200h oxidation in air at 800°C.