Processing chemically prepared Tl-Ca-Ba-Cu oxide superconductors
The recently discovered Tl-Ca-Ba-Cu oxide high temperature superconductors have proven difficult to synthesize in phase pure form. Thallium volatility has been difficult to control, and the resulting materials can contain a large number of thallium-containing phases having different compositions and superconducting properties. We have developed a chemical synthesis technique for Tl-based superconductors specifically to prepare materials with enhanced phase purity. The Tl-based powders were made by precipitation from aqueous solution. The desired cation stoichiometry of the precipitate was controlled via the solution compositions. The powders were calcined and sintered into superconducting ceramics with critical current densities of 1570 A/cm/sup 2/ at 76 K. Investigation of the calcination step has shown the chem-prep powders to be more reactive with respect to the formation of desired superconducting phases than conventionally prepared mixed-oxide precursor powders. Also, the evolution of phases during calcination is dependent on the powder synthesis method. 25 refs., 7 figs., 1 tab.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (USA)
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 6049705
- Report Number(s):
- SAND-88-2296C; CONF-8902100-1; ON: DE89011535
- Resource Relation:
- Conference: TMS symposium on high temperature superconductors, Las Vegas, NV, USA, 27 Feb 1989; Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BARIUM COMPOUNDS
SYNTHESIS
CALCIUM COMPOUNDS
COPPER OXIDES
THALLIUM OXIDES
CALCINATION
CRITICAL CURRENT
ELECTRIC CONDUCTIVITY
POWDERS
SINTERING
STOICHIOMETRY
SUPERCONDUCTORS
VOLATILITY
ALKALINE EARTH METAL COMPOUNDS
CHALCOGENIDES
CHEMICAL REACTIONS
COPPER COMPOUNDS
CURRENTS
DECOMPOSITION
ELECTRIC CURRENTS
ELECTRICAL PROPERTIES
FABRICATION
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
PYROLYSIS
THALLIUM COMPOUNDS
THERMOCHEMICAL PROCESSES
TRANSITION ELEMENT COMPOUNDS
360201* - Ceramics
Cermets
& Refractories- Preparation & Fabrication
360204 - Ceramics
Cermets
& Refractories- Physical Properties
360202 - Ceramics
Cermets
& Refractories- Structure & Phase Studies
360203 - Ceramics
Cermets
& Refractories- Mechanical Properties