Preparation and properties of hot-pressed YBa sub 2 Cu sub 3 O sub 7 minus x

Journal Article · Sun Apr 01 04:00:00 EDT 1990 · Journal of the American Ceramic Society; (USA)

OSTI ID:6068415

Loehman, R E; Hammetter, W F; Venturini, E L; Moore, R H; Gerstle, Jr, F P ^[1]

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1. Sandia National Lab., Albuquerque, NM (US)

The authors have hot-pressed dense, bulk specimens of the Yba{sub 2}Cu{sub 3}O{sub 7{minus}x} composition to near-theoretical density. Powders made by the mixed-oxide method were pressed at 6.9 MPa (1000 psi) in Al{sub 2}O{sub 3}-lined SiC dies at 950{degrees}C in air or oxygen for 30 min. Relative densities of 94% to 97% of theoretical were obtained for specimens as large as 200 g. In the aspressed condition the ceramic has an oxygen stoichiometry near YBa{sub 2}Cu{sub 3}O{sub 6.28}, as determined by thermogravimetric reduction in hydrogen and by wet chemical analysis. Scanning electron microscopy shows a microstructure of elongated grains that are partially oriented by the hot-pressing. Oxidation of bulk specimens of dense, as-hot-pressed material produced intergranular porosity, presumably from anisotropic contraction as individual grains are converted from the tetragonal to the orthorhombic structure.

• DOE Contract Number: AC04-76DP00789
• OSTI ID: 6068415
• Journal Information: Journal of the American Ceramic Society; (USA), Journal Name: Journal of the American Ceramic Society; (USA) Vol. 72:4; ISSN JACTA; ISSN 0002-7820
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360201 -- Ceramics
Cermets
& Refractories-- Preparation & Fabrication
360202 -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
360204 -- Ceramics
Cermets
& Refractories-- Physical Properties
426001* -- Engineering-- Superconducting Devices & Circuits-- (1990-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
CHEMICAL PREPARATION
COPPER COMPOUNDS
COPPER OXIDES
CRYSTAL LATTICES
CRYSTAL STRUCTURE
DENSITY
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTRON MICROSCOPY
ELECTRONIC EQUIPMENT
EQUIPMENT
EXPANSION
FABRICATION
FLUXMETERS
HOT PRESSING
MAGNETIC PROPERTIES
MAGNETIC SUSCEPTIBILITY
MATERIALS WORKING
MEASURING INSTRUMENTS
MICROSCOPY
MICROWAVE EQUIPMENT
ORTHORHOMBIC LATTICES
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
POROSITY
POWDERS
PRESSING
SCANNING ELECTRON MICROSCOPY
SQUID DEVICES
SUPERCONDUCTING DEVICES
SUPERCONDUCTIVITY
SYNTHESIS
TETRAGONAL LATTICES
THERMAL EXPANSION
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES