Magnesium Manganese Spinel Coatings for Solid Oxide Fuel Cell Interconnects

Magnesium and manganese were electrodeposited on stainless steel 430 and oxidized in air at 800°C to form a spinel coating. Electrical conductivity of MgMn2O4 spinel was determined to be ~2 S/cm at 800°C. An under layer of copper aided uniform manganese deposition and uniform spinel formation. Copper in the spinel also increased conductivity (Cu0.7Mg0.3Mn2O4 ~60 S/cm at 800°C). The ternary Cu-Mg-Mn system has a wide spinel stability region compared to binary systems. CuMn2O4 spinel without magnesium has higher conductivity (~100 S/cm at 800°C) but this coating tended to bubble and detach from the substrate. The bubbling effect was reduced when magnesium was co-deposited.