Development and evaluation of interconnect protective coatings based on commercial Mn_1.9CuFe_0.1O₄ spinel powder

The current coating materials for steel interconnects in SOCs (Solid Oxide Cells) typically rely on critical raw materials, specifically Co oxide spinels. A new approach is using copper-based spinel coatings, which are promising concerning price, conductivity, and sustainability. This investigation is dedicated to an evaluation of a commercially available powder provided by the Kceracell company with stoichiometric Mn_1.9CuFe_0.1O₄ as a protective material on the interconnects. The material was electrophoretically deposited onto a ferritic stainless-steel support and subsequently assessed. Prior to deposition, the powders underwent crystallographic phase analysis at high temperatures and electrical conductivity. The coated steel samples were oxidized in an air atmosphere at 750 °C for 5000 hours. The structure of the coating / steel system was evaluated before and after high temperature exposition by means of SEM-EDX, Raman spectroscopy, X-ray diffraction. The electrical properties of the steel-coating system were assessed through Area Specific Resistance measurements. The results indicate that the evaluated coatings react with Cr from the substrate during long-term oxidation and create a (Mn,Cu,Fe,Cr)₃O₄ spinel reaction layer, thus the whole system exhibits satisfactory resistance.