Stability of chromite interconnections in dual environments

Technical Report · Tue Nov 01 00:00:00 EST 1994

DOI:https://doi.org/10.2172/28236· OSTI ID:28236

Armstrong, T R; Stevenson, J W; Raney, P; Pederson, L R

One of the most critical technical concerns in high-temperature SOFCs is the physical, chemical, and electrical stability of the interconnect (typically a doped lanthanum chromite) in the dual (oxidizing and reducing atmosphere) SOFC environment. The reducing or fuel side may experience oxygen partial pressures (P(O{sub 2})) from 10{sup {minus}18} to 10{sup {minus}6} atmospheres, while the oxidizing side may have P(O{sub 2}) from 10{sup {minus}6} to greater than 1 atm. These conditions limit the possible candidate materials to lanthanum or yttrium chromites. In the past decade, much work has centered on development of air-sinterable chromites and understanding their physical properties; little work, however, has focused on the stability of these chromites in dual environments. Chromite powders were synthesized using the glycine-nitrate process. The powders were calcined at 1,000 C for 1 hour and then uniaxially pressed into bars (46mm x 16mm x 3mm) at 55 MPa and isostatically pressed at 138 MPa. Samples were sintered in air. The dependence of the physical properties of sintered lanthanum chromites upon ambient P(O{sub 2}) and temperature (using dilatometry, thermogravimetric analysis, and oxygen permeation measurements) were studied. La{sub 1{minus}x}A{sub x}CrO{sub 3} and Y{sub 1{minus}x}Ca{sub x}CrO{sub 3}, where A is Ca or Sr and x was varied from 0.1 to 0.4 were evaluated in this study. The P(O{sub 2}) was varied using a buffered CO{sub 2}/Ar-4%H{sub 2} gas system, enabling expansion measurements to be made over a partial pressure range from 10{sup {minus}5} to 10{sup {minus}18} atmosphere at 800, 900, and 1,000 C.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE Assistant Secretary for Fossil Energy, Washington, DC (United States)
• DOE Contract Number: AC06-76RL01830
• OSTI ID: 28236
• Report Number(s): PNL-SA-25014; CONF-941109-1; ON: DE95007755; TRN: AHC29510%%41
• Resource Relation: Conference: Fuel cell seminar, San Diego, CA (United States), 28 Nov - 1 Dec 1994; Other Information: PBD: Nov 1994
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
36 MATERIALS SCIENCE
SOLID ELECTROLYTE FUEL CELLS
BATTERY SEPARATORS
PERFORMANCE
LANTHANUM OXIDES
THERMODYNAMIC PROPERTIES
PHASE STUDIES
CHROMIUM OXIDES
YTTRIUM OXIDES
CALCIUM OXIDES
STRONTIUM OXIDES
CORROSION RESISTANCE
FABRICATION
THERMAL EXPANSION
MICROSTRUCTURE
OXIDATION
FRACTURE PROPERTIES
EXPERIMENTAL DATA