R. J. Smith, A. Kayani, C. V. Ramana, P. E. Gannon, M. C. Deibert, Montana State University, Bozeman, MT; V. I. Gorokhovsky, Arcomac Surface Engineering, LLC., Bozeman, MT; V. Shutthanandan, D. Gelles, Pacific Northwest National Laboratory, Richland, WA
The requirements of low cost and high-temperature corrosion resistance for bipolar interconnect plates in solid oxide fuel cell stacks has directed attention to the use of metal plates with oxidation resistant coatings. We have investigated the performance of steel plates with superlattice coatings consisting of CrAlON (oxynitrides). The coatings were deposited using large area filtered arc deposition technology [1], with various O/N pressure ratios, and subsequently annealed in air for up to 25 hours at 800 C. The composition, structure and morphology of the coated plates were characterized using RBS, nuclear reaction analysis, XPS and AFM techniques. Area specific resistance was measured as a function of time and temperature. By altering the architecture and composition of the coatings, the rate of oxidation was reduced by more than an order of magnitude relative to the uncoated steel plates.
[1] Vladimir I. Gorokhovsky, Rabi Bhattacharya and Deepak G. Bhat, Surface and Coating Technology, 140 (2) 2001, pp. 82-92.
Work supported by DOI and DOE subcontract from PNNL, number 3917(413060-A). Work at PNNL (EMSL) supported through OBER (DOE).
The oxidation and electrical resistance of coated 440A disks were investigated for use as SOFC interconnects. CrAlON coatings, deposited using filtered arc deposition, were annealed in air at 800 oC, and characterized using RBS, NRA, XPS, AFM, TEM, and ASR. Significant reductions were observed for oxidation rates.
