P. E. Gannnon, M. C. Deibert, C. V. Ramana, A. Kayani, R. J. Smith, Montana State University, Bozeman, MT; V. I. Gorokhovsky, Arcomac Surface Engineering, LLC., Bozeman, MT; V. Shutthanandan, D. Gelles, Pacific Northwest National Laboratory, Richland, WA
Abstract: Reduction of SOFC operation temperature may enable the use of inexpensive interconnect metallic alloys. Crofer 22 APU, an Fe-Cr based alloy available from ThyssenKrupp VDM GmbH, was specifically designed to meet the demanding performance criteria of intermediate temperature (600 – 800°C) SOFC’s. SOFC interconnect performance of Crofer 22 APU with and without protective filtered arc coatings from the Cr-Al-O-N elemental system has been investigated as a function of exposure to simulated SOFC cathode-gas phase conditions. The coatings were deposited using large area filtered arc deposition (LAFAD) technology 1, and subsequently annealed in air up to 800°C for varying times. Area Specific Resistance (ASR) of coated and uncoated Crofer 22 APU samples has been measured using a 4-point probe method with Pt paste as electrical contact. Sample surface morphology, chemical and phase composition were determined using SEM, EDS and XRD techniques. The surface stability and ASR of Crofer 22 APU have been improved by varying the coating composition and/or architecture. The efficacy of further investigation into variations of the basic Cr-Al-O-N elemental coating system is discussed.
1Vladimir I. Gorokhovsky, Rabi Bhattacharya and Deepak G. Bhat, Surface and Coating Technology, 140 (2) 2001, pp. 82-92.
Intermediate tempearture (600 - 800C) Solid Oxide Fuel Cells may enable the use of inexpensive metallic alloys as interconnect components. Recently, attention has been drawn to the use of protective, conductive coatings on metallic alloys to reduce SOFC stack performance degradation. Filtered arc coatings from the Cr-Al-O-N elemental system have been invesigated on specifically designed SOFC metallic interconnects. Simulated SOFC performance of these coatings as well as morphologies, chemical and phase compositions of these materials are discussed.
