Production of a superconductor powder having a narrow melting transition width using a controlled oxygen atmosphere
This patent describes a process for producing a superconductor powder, it comprises: providing a mixture of finely divided R[sub 2]O[sub 3], BaCO[sub 3] and CuO in stoichiometric proportions; heating the mixture to a preheat temperature in oxygen at an initial oxygen partial pressure between about 1 and 40 torr; heating the mixture from the preheat temperature to a plateau temperature greater than the preheat temperature; maintaining the mixture at the plateau temperature and the initial oxygen partial pressure for a time sufficient to calcine the mixture to a superconductor powder; increasing oxygen partial pressure to between about 200 and about 800 torr above the initial oxygen partial pressure; heating the superconductor powder to an increased temperature between about 880[degrees]C and 925[degrees]C at the increased oxygen partial pressure; and maintaining the superconductor powder at the increased temperature and the increased oxygen partial pressure for a time sufficient to reduce the melting transition width of the superconductor powder.
- Assignee:
- General Atomics, San Diego, CA (United States)
- Patent Number(s):
- US 5149684; A
- Application Number:
- PPN: US 7-682552
- OSTI ID:
- 7011502
- Country of Publication:
- United States
- Language:
- English
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75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
CHEMICAL COMPOSITION
CHEMICAL PREPARATION
CONTROL
COPPER COMPOUNDS
CUPRATES
DISPERSIONS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
MIXTURES
NONMETALS
OXYGEN
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
POWDERS
PROCESS CONTROL
STOICHIOMETRY
SUPERCONDUCTIVITY
SUPERCONDUCTORS
SYNTHESIS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
YTTRIUM COMPOUNDS