Mn1.5Co1.5O4 spinel conducting coatings on AL453 ferritic steel with regard to their application as interconnects in IT-SOFC

Abstract

The ferritic AL453 steel is one of potential metallic interconnect materials for intermediate-temperature solid oxide fuel cells. However, the evaporation of chromium from the chromia scale formed on this steel and the increasing thickness of this scale result in the slow deterioration in the electrical properties of the interconnect's elements. In order to improve fuel cell efficiency, the surface of the interconnect material was modified by applying a protective-conducting Mn1.5Co1.5O4 spinel coating. Thermal and electrical tests of the La0.8Sr 0.2FeO3 cathode - AL453/Mn1.5Co 1.5O4 interconnect system at 1073 K for 200 hrs in air confirmed the effectiveness of the spinel layers as a means of stopping chromium diffusion from the AL453 steel and inhibiting oxidation, while at the same time promoting electrical contact and minimizing cathode-interconnect interfacial resistance.