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

Balachandran, U

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

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Abstract

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. 11 figs.

Inventors:: Balachandran, U

Issue Date:: 1996-06-04

Research Org.:: Univ. of Chicago, IL (United States)

OSTI Identifier:: 242595

Patent Number(s):: 5523285

Application Number:: PAN: 8-315,452

Assignee:: Dept. of Energy, Washington, DC (United States)

DOE Contract Number:: W-31109-ENG-38

Resource Type:: Patent

Resource Relation:: Other Information: PBD: 4 Jun 1996

Country of Publication:: United States

Language:: English

Subject:: 36 MATERIALS SCIENCE; LEAD OXIDES; SYNTHESIS; GRAIN BOUNDARIES; BISMUTH OXIDES; STRONTIUM OXIDES; CALCIUM OXIDES; COPPER OXIDES; PRECURSOR

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                    Balachandran, U. Rapid formation of phase-clean 110 K (Bi-2223) powders derived via freeze-drying process.  United States: N. p., 1996. 
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                    Balachandran, U. Rapid formation of phase-clean 110 K (Bi-2223) powders derived via freeze-drying process.  United States.

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                    Balachandran, U. Tue .  
        "Rapid formation of phase-clean 110 K (Bi-2223) powders derived via freeze-drying process".  United States.

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@article{osti_242595,

  title        = {Rapid formation of phase-clean 110 K (Bi-2223) powders derived via freeze-drying process},

  author       = {Balachandran, U},

  abstractNote = {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. 11 figs.},

  doi          = {},

  journal      = {},
number       = ,

  volume       = ,

  place        = {United States},

  year         = {1996},

  month        = {6}

}

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

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

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This invention relates to an improved process of preparing Bi-Sr-Ca-Cu-O (BSCCO) powders, and more particularly, to a process for preparing BSCCO powders that utilize freeze-drying. The process generally includes splat freezing a nitrate solution of Bi, Pb, Sr, Ca, and Cu to form flakes of the solution; grinding the flakes to form a powder; freeze-drying the frozen powder; heating the powder to form dry green precursor powders; denitrating the powders; and heating the powders to form phase-clean Bi-2223 powders.
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