Rapid formation of phase-clean 110 K (Bi-2223) powders derived via freeze-drying process

Patent · Mon Jan 01 00:00:00 EST 1996

OSTI ID:870443

Balachandran, Uthamalingam ^[1]

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1. Hinsdale, IL

A process for the preparation of amorphous precursor powders for Pb-doped Bi.sub.2 Sr.sub.2 Ca.sub.2 Cu.sub.3 O.sub.x (2223) includes a freeze-drying process incorporating a splat-freezing step. The process generally includes splat freezing a nitrate solution of Bi, Pb, Sr, Ca, and Cu to form flakes of the solution without any phase separation; grinding the frozen flakes to form a powder; freeze-drying the frozen powder; heating the dried powder to form a dry green precursor powders; denitrating the green-powders; heating the denitrated powders to form phase-clean Bi-2223 powders. The grain boundaries of the 2223 grains appear to be clean, leading to good intergrain contact between 2223 grains.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States)
• DOE Contract Number: W-31109-ENG-38
• Assignee: United States of America as represented by United States (Washington, DC)
• Patent Number(s): US 5523285
• OSTI ID: 870443
• Country of Publication: United States
• Language: English

Related Subjects

rapid
formation
phase-clean
110
bi-2223
powders
derived
via
freeze-drying
process
preparation
amorphous
precursor
pb-doped
sr
cu
2223
incorporating
splat-freezing
step
splat
freezing
nitrate
solution
pb
form
flakes
phase
separation
grinding
frozen
powder
heating
dried
dry
green
denitrating
green-powders
denitrated
grain
boundaries
grains
appear
clean
leading
intergrain
contact
nitrate solution
phase separation
grain boundaries
precursor powder
precursor powders
drying process
dried powder
freeze-drying process
/505/252/