Foil samples of Haynes 230 and 430 stainless steel were coated with thin layers of Mn and La metal, oxidized in air and humidified hydrogen atmospheres at 800°C for various periods of time, and evaluated for use as metallic interconnects in planar SOFC. A Mn-coating on the interconnects promoted the formation of the spinel phase (Mn, Cr)3O4 while suppressing the formation of Cr2O3 during oxidation. The area specific resistance (ASR) of the oxide layer on the Mn-coated Haynes 230 samples (-0.24

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... cm2 at 800°C) was significantly less than that formed on the uncoated sample (~1.2 ftcm2 at 800°C). The oxide layer formed on the La-coated Haynes 230 consisted primarily of the perovskite phase La(Cr, Mn)03. The ASR of the perovskite oxide layer formed on the La-coated Haynes 230 was an order of magnitude lower than the oxide layer, primarily CfoCb, formed on uncoated Haynes 230. Planar SOFC stacks operated with coated interconnects delivered double the maximum power and exhibited half the total stack resistance as compared to stacks operated with uncoated Haynes 230 interconnects.