Pre-treatment and oxidation behavior of sol-gel Co coating on 430 steel in 750 °C air with thermal cycling

Research and development efforts continue to improve oxidation resistance and electrical conductivity of solid oxide fuel cell (SOFC) interconnects. This research evaluates the performance of a ferritic stainless steel (AISI 430 - a candidate SOFC interconnect material) with and without a Co coating (via sol-gel dip coating technique) with various pre-treatments, during cyclic oxidation exposures up to 750 degrees C in laboratory air. A pre-treatment exposure of Co coated samples to a 750 degrees C reducing atmosphere (prior to oxidation exposures) led to the formation of an effective Co-based spinet oxide coating that lowers oxidation rates by more than 40 times, and substantially lowers area specific resistance (ASR) in comparison to uncoated specimens. The development of effective sol-gel Co coatings with reducing pre-treatments, and their evolution within simulated SOFC interconnect environments is presented and discussed. (C) 2012 Elsevier B.V. All rights reserved.