Enabling Inexpensive Metallic Alloys as SOFC Interconnects: An Investigation into Hybrid Coating Technologies to Deposit Nanocomposite Functional Coatings on Ferritic Stainless Steel

Journal Article · Thu Nov 01 00:00:00 EDT 2007 · International Journal of Hydrogen Energy, 32(16):3672-3681

DOI:https://doi.org/10.1016/j.ijhydene.2006.08.012· OSTI ID:922169

Gannon, Paul; Gorokhovsky, Vladimir I; Deibert, Max; Smith, Richard J; Kayani, Asghar N; White, P T; Sofie, Stephen W; Yang, Z Gary; Mccready, David E; Visco, S; Jacobson, C; Kurokawa, H

Reduced operating temperatures (600-800°C) of Solid Oxide Fuel Cells (SOFCs) may enable the use of inexpensive ferritic steels as interconnects. Due to the demanding SOFC interconnect operating environment, protective coatings are required to increase long-term stability. In this study, large area filtered arc deposition (LAFAD) and hybrid filtered arc-assisted electron beam physical vapor deposition (FA-EBPVD) technologies were used to deposit two-segment coatings with Cr-Al-Y-O nanocomposite bottom segments and Mn-Co-O spinel-based top segments. Coatings were deposited on ferritic steels and subsequently annealed in air for various times. Surface oxidation was investigated using SEM/EDS, XRD and RBS analyses. Cr-volatilization was evaluated by transpiration and ICP-MS analysis of the resultant condensate. Time dependent Area Specific Resistance (ASR) was studied using the four-point technique. The oxidation behavior, Cr volatilization rate, and ASR of coated and uncoated samples are reported. Significant long-term (>1,000 hours) surface stability, low ASR, and dramatically reduced Cr-volatility were observed with the coated specimens. Improvement mechanisms, including the coating diffusion barrier properties and electrical conductivity are discussed.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 922169
• Report Number(s): PNNL-SA-50947; IJHEDX; AA2530000; TRN: US200803%%258
• Journal Information: International Journal of Hydrogen Energy, 32(16):3672-3681, Vol. 32, Issue 16; ISSN 0360-3199
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
30 DIRECT ENERGY CONVERSION
ALLOYS
COATINGS
DEPOSITION
DIFFUSION BARRIERS
ELECTRIC CONDUCTIVITY
ELECTRON BEAMS
EVAPORATION
FERRITIC STEELS
FUNCTIONALS
OXIDATION
PHYSICAL VAPOR DEPOSITION
PROTECTIVE COATINGS
RUTHERFORD BACKSCATTERING SPECTROSCOPY
SOLID OXIDE FUEL CELLS
STABILITY
STAINLESS STEELS
TRANSPIRATION
X-RAY DIFFRACTION
metallic alloys
SOFCs
hybrid coating technology
nanocomposite functional coatings