Use of SOFC Metallic Interconnect Coated with Spinel Protective Layers using the APS Technology

Abstract

The use of metallic interconnects for SOFC application leads to the degradation of the cell performance due to Cr migration. In order to avoid the cathode poisoning, spinel type coatings were developed and deposited on the cathode contact side of a ferritic interconnect, using Atmospheric Plasma Spraying. A porous contact layer was then deposited by Wet Powder Spraying on the top of the dense protective layer. This contact layer favours the adjustment between cathode and interconnect, reducing the possible stress caused by the difference in thermal expansion coefficients. This study shows the performance of a single repeating unit, i.e. cell and coated interconnect, tested at 800{degree sign}C during 600 h. After a decrease of the interconnect Area Specific Resistance during the first hours a low value, which remains stable until the end of the test, is reached. Post mortem analysis of both the cell and the interconnect confirmed the effectiveness of this coating against Cr poisoning.