Oxidation studies of CrAlON nanolayered coatings on steel plates

The requirements of low cost and high-temperature corrosion resistance for bipolar interconnect plates in solid oxide fuel cell stacks have directed attention to the use of metal plates with oxidation resistant coatings. We have investigated the performance of steel plates with nanolayered coatings consisting of [CrON/AlON]n. The coatings were deposited using large-area filtered arc deposition technology, with various O/N pressure ratios, and subsequently annealed in air for up to 25 h at 800 °C. The composition, structure and surface morphology of the coated plates were characterized using RBS, nuclear reaction analysis, and AFM techniques. By altering the architecture and composition of the coatings, the rate of oxidation was reduced relative to the uncoated steel plates, and Fe diffusion from the substrate to the surface through the coating was significantly reduced.