Calcination and solid state reaction of ceramic-forming components to provide single-phase superconducting materials having fine particle sizesize
This patent describes an improved method of preparing copper oxide superconducting materials having one of the following formulas, YBa[sub 2]CU[sub 3]O[sub x], YBa[sub 2]Cu[sub 4]O[sub 8], Bi[sub 2]Sr[sub 2]CaCu[sub 3]O[sub x] and Bi[sub 1.6]Pb[sub 0.4]Sr[sub 2]Ca[sub 2]Cu[sub 3]O[sub x], wherein the material is prepared by the calcination and reaction of a precursor powder mixture containing at least one alkali earth carbonate. It comprises: preparing a stoichiometric precursor mixture containing at least one alkali earth carbonate, calcining and reacting the mixture by the following steps: heating the mixture in a furnace to a first temperature, simultaneously establishing a partial vacuum in the furnace of from about 213 to 2 [times] 10[sup 4] Pa, simultaneously providing flowing oxygen at a pressure from about 266 to 1300 Pa to the furnace, heating the mixture to at least 750[degrees]C, simultaneously controlling the rate of evolution of CO[sub 2] from the mixture as the mixture is heated, maintaining the mixture at 750[degrees]C for a period of time sufficient for CO[sub 2] evolution to cease and for the reaction of the mixture to go to completion forming a ceramic material, cooling the ceramic material to a third temperature, and increasing the pressure of the oxygen in the furnace to about ambient and soaking the ceramic in the oxygen for a period of time sufficient for the superconducting material to form.
- Assignee:
- Dept. of Energy, Washington, DC (United States)
- Patent Number(s):
- US 5086034; A
- Application Number:
- PPN: US 7-589562
- OSTI ID:
- 6901811
- Resource Relation:
- Patent File Date: 28 Sep 1990
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BISMUTH COMPOUNDS
SUPERCONDUCTIVITY
CUPRATES
SUPERCONDUCTING DEVICES
MATERIALS TESTING
YTTRIUM COMPOUNDS
CALCINATION
CHEMICAL REACTION KINETICS
FABRICATION
PARTICLE SIZE
PRECURSOR
SOLID-STATE PLASMA
CHEMICAL REACTIONS
COPPER COMPOUNDS
DECOMPOSITION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
KINETICS
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
PLASMA
PYROLYSIS
REACTION KINETICS
SIZE
TESTING
THERMOCHEMICAL PROCESSES
TRANSITION ELEMENT COMPOUNDS
360201* - Ceramics
Cermets
& Refractories- Preparation & Fabrication