Microstructural and electrical characterization of Cu1.2Mn1.8O4 coating for application in Solid Oxide Fuel Cells (SOFC) stacks

In this work, Cu1.2Mn1.8O4 was applied by means of magnetron sputtering on AISI 441 ferritic stainless steel as protective coating. Samples were aged for 250 hours at 800 degrees C in flowing air applying a DC electric load of 0.5 A.cm(-2) to reproduce the operating conditions of the cathode compartment of a Solid Oxide Fuel Cell (SOFC) stack. The coating resulted mechanically compatible with the steel and chemically stable exhibiting also good efficiency in limiting the chromium diffusion from the substrate. Additionally, the Area Specific Resistance (ASR) of the sample was measured during aging and cooling in order to evaluate its evolution over time and the temperature effects. The electrical conductivity resulted thermally activated, proportionally to the temperature. The ASR was stabilizing during aging to a value of 0.23 Omega.cm(2) after 250 hours.