Protective Coatings of Metallic Interconnects for IT-SOFC Application

The development of high-performing planar solid oxide fuel cell (SOFC) stacks operating at intermediate temperature (700–850°C) is based on thin-electrolyte anode supported cells (ASCs) and interconnects made by ferritic stainless steels. These metallic materials match very well the thermal expansion behavior of the ASCs and can be manufactured and formed using cheaper and easier processes than ceramics or chromium alloys. Nevertheless, some problems remain to be solved with these components as the performance degradation due to the oxide scale growth at the cathodic contact surface and the evaporation of volatile Cr-containing species, which poisons the cathodic materials. Both effects strongly limit the stack performance compared to single cells and increase the degradation rate with time. Providing the steel composition is carefully controlled, the above problems can be limited and some special ferritic stainless steels have been developed in the past years for SOFC application. Unfortunately, no commercial alloy is still able to satisfy the limit in degradation rate required for stationary applications (SECA target is