Effect of Mn–Co spinel coating for Fe–Cr ferritic alloys ZMG232L and 232J3 for solid oxide fuel cell interconnects on oxidation behavior and Cr-evaporation

Abstract

Metallic materials, especially Fe–Cr ferritic alloys, are promising as interconnect materials of solid oxide fuel cells (SOFCs) operated at around medium temperatures. ZMG232L is one of the developed Fe–Cr ferritic alloys for SOFC metallic interconnects. These metallic materials are usually machined or pressed into various shapes of interconnect parts, and thickness of these parts is often thin. However, the oxidation rate of thin sheet was much higher than that of thick one because Cr content decreased under oxide layer of edge part of thin sheet. Such accelerated oxidation behavior could be improved by reducing Mn, increasing Cr, and adding W in ZMG232L. It is also very important to reduce Cr-evaporation from the oxidized surface of ferritic alloys in cathode side. The aim of this study is to reduce the Cr-evaporation from oxidized alloy surface in air by coating with Mn–Co spinel oxide. In this study, oxidation behavior and Cr-evaporation of ZMG232L and improved Fe–Cr alloy, 232J3, coated with Mn–Co spinel oxide were investigated at elevated temperature in air. MnCo 2O 4 spinel coating on the pre-oxidized Fe–Cr ferritic alloy surface improved oxidation resistance and Cr-evaporation.