Formation of Intermediate Compounds During Reduced Pressure Calcination of Y-Ba-Cu-O Precursor

Conference · Mon Dec 31 23:00:00 EST 1990

OSTI ID:5941287

Balachandran, U. ^[1]; Morissette, S. L. ^[1]; Russell, R. A. ^[1]; Dorris, S. E. ^[1]; Poeppel, R. B. ^[1]

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1. Argonne National Laboratory (ANL), Argonne, IL (United States)

Reaction of Y₂O₃, BaCO₃, and CuO for 4 h at 800°C in flowing O₂ with a total pressure of about 2 mm Hg, followed by cooling in O₂ at ambient pressure, has produced phase-pure orthorhombic YBa₂Cu₃O_x (123). During calcination, BaCO₃ first decomposes and then reacts to form intermediate compounds. Reactions among the intermediate compounds result in formation of the 123 superconductor. Formation of intermediate compounds during calcination was monitored by X-ray diffraction, scanning electron microscopy, and thermal analyses of precursor powders heated to various temperatures up to 800°C. The reaction passes through the formation of BaCuO₂, BaCO₃, Y₂Cu₂O₅, and Y₂BaCuO₅. The 123 phase begins to form at temperatures as low as 725°C in a pressure of about 2 mm Hg of oxygen.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE); National Science Foundation (NSF)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 5941287
• Report Number(s): ANL/CP--71092; CONF-910202--12; ON: DE91011179
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
ALKALINE EARTH METAL COMPOUNDS
BARIUM CARBONATES
BARIUM COMPOUNDS
CALCINATION
CARBON COMPOUNDS
CARBONATES
CHALCOGENIDES
CHEMICAL REACTIONS
COHERENT SCATTERING
COPPER COMPOUNDS
COPPER OXIDES
DECOMPOSITION
DIFFRACTION
ELECTRON MICROSCOPY
HIGH TEMPERATURE
HIGH-TC SUPERCONDUCTORS
INTERMEDIATE STATE
MICROSCOPY
OXIDES
OXYGEN COMPOUNDS
PYROLYSIS
SCANNING ELECTRON MICROSCOPY
SCATTERING
SUPERCONDUCTORS
THERMAL ANALYSIS
THERMOCHEMICAL PROCESSES
TRANSITION ELEMENT COMPOUNDS
X-RAY DIFFRACTION
YTTRIUM COMPOUNDS
YTTRIUM OXIDES