Degradation of properties of YBa₂Cu₃O_x superconductors sintered in CO₂-containing atmosphere

Conference · Sat Sep 01 00:00:00 EDT 1990

OSTI ID:6334745

Balachandran, U; Zhang, C; Xu, D; Gao, Y; Merkle, K L; Mundy, J N; Veal, B W; Poeppel, R B ^[1]; Selvaduray, G ^[2]; Mason, T O ^[3]

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1. Argonne National Lab., IL (USA)
2. San Jose State Univ., CA (USA). Dept. of Materials Engineering
3. Northwestern Univ., Evanston, IL (USA). Dept. of Materials Science and Engineering

Stability of the YBa{sub 2}Cu{sub 3}O{sub x} (YBCO) superconductor toward reacting with CO{sub 2} in CO{sub 2}/O{sub 2} gas mixtures during sintering was investigated as a function of the partial pressure of CO{sub 2} and temperature. The transport critical current density, J{sub c}, of the superconductor decreased drastically with increasing partial pressure of CO{sub 2} was increased, J{sub c} became zero (at 77 K) even though the major phase of the sample was still a superconductor as determined by magnetic susceptibility measurements. Microstructures and compositions of the samples were investigated by transmission electron microscopy in conjunction with energy-dispersive x-ray spectroscopy. Two types of grain boundaries were observed: {approximately}10% of the grain boundaries contained a second phase; the regions near the remaining grain boundaries were tetragonal. At high partial pressures of CO{sub 2}, the YBCO completely decomposed to BaCO{sub 3}, Y{sub 2}BaCuO{sub 5}, and CuO. 11 refs., 3 figs.

• Research Organization: Argonne National Lab., IL (USA)
• Sponsoring Organization: DOE/CE; DOE/ER; NSF
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 6334745
• Report Number(s): CONF-900990-2; ON: DE91006569; CNN: DMR88-09854
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202 -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
656100 -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
CRITICAL CURRENT
CRYSTAL STRUCTURE
CURRENTS
ELECTRIC CURRENTS
FABRICATION
GRAIN BOUNDARIES
HIGH-TC SUPERCONDUCTORS
MICROSTRUCTURE
OXIDES
OXYGEN COMPOUNDS
PARTIAL PRESSURE
SINTERING
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES