Effects of atmosphere and heating rate during processing of a ceramic superconductor

Conference · Tue Jan 01 04:00:00 EST 1991

OSTI ID:6237449

Balachandran, U; Xu, D; Zhang, C; Dorris, S E; Russell, R A; Dusek, J T; Picciolo, J J; Poeppel, R B ^[1]; Gao, Y; Merkle, K L ^[2]; Selvaduray, G ^[3]

---

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

Properties of ceramic superconductors depend strongly on the temperature, heating rate, pressure, and atmosphere used during synthesis and fabrication. We have developed a process for synthesizing orthorhombic YBa{sub 2}Cu{sub 3}O{sub x} (123) superconducting powders by calcining the precursor powders under reduced total oxygen pressure. The resultant 123 powders are mixed with organics, and wires and coils are fabricated by extrusion. The wires and coils are fired at a reduced total pressure in flowing O{sub 2} to reduce the concentrations of CO{sub 2}, CO, and H{sub 2}O and thus prevent decomposition of the 123. Transport critical current density of the superconductor decreases drastically with increasing concentrations of CO{sub 2} in the gas mixture. Transmission electron microscopy of materials sintered in O{sub 2} atmospheres containing various levels of CO{sub 2} clearly shows the extent of grain boundary degradation. 29 refs., 9 figs., 2 tabs.

• Research Organization: Argonne National Lab., IL (USA)
• Sponsoring Organization: DOE/CE; DOE/ER; NSF
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 6237449
• Report Number(s): CONF-910212-1; ON: DE91007761; CNN: DMR88-09854
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360201* -- Ceramics
Cermets
& Refractories-- Preparation & Fabrication
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
CURRENTS
ELECTRIC CURRENTS
ELEMENTS
FABRICATION
HEATING RATE
HIGH-TC SUPERCONDUCTORS
NONMETALS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SINTERING
SUPERCONDUCTORS
SYNTHESIS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
YTTRIUM COMPOUNDS
YTTRIUM OXIDES