Process for making 90 K superconductors using a spray dried oxalate precursor

Patent · Tue Feb 06 00:00:00 EST 1990

OSTI ID:7009942

Michel, J B

This patent describes an improved process for preparing a superconducting composition. It has the formula MBa{sub 2}O{sub {ital x}} wherein M is selected from the group consisting of Y, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb and Lu; x is from about 6.5 to about 7.0. The composition having a superconducting transition temperature of about 90 K. The process consists essentially of heating a precursor powder in an oxygen-containing atmosphere at a temperature from about 875{degrees}C to about 950{degrees}C for a time sufficient to form MBa{sub 2}Cu{sub 3}O{sub {ital y}}, where y is from about 6.0 to about 6.4; and maintaining the MBa{sub 2}Cu{sub 3}O{sub {ital y}} in an oxygen-containing atmosphere while cooling for a time sufficient to obtain the desired product. The precursor powder is prepared by forming an aqueous solution of M(NO{sub 3}){sub 3}, Ba(NO{sub 3}){sub 2} and Cu(No{sub 3}){sub 2} in an atomic ratio of M:Ba:Cu of about 1:2:3, adding the resulting solution to sufficient oxalic acid to precipitate the metals present as salts, and spray drying the resulting slurry to obtain the precursor powder.

• Assignee: E.I. DuPont de Nemours and Co., Wilmington, DE
• Patent Number(s): US 4898851; A
• Application Number: PPN: US 7-064951A; TRN: 90-013010
• OSTI ID: 7009942
• Resource Relation: Patent File Date: 22 Jun 1987
• Country of Publication: United States
• Language: English

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SUPERCONDUCTORS
SYNTHESIS
BARIUM OXIDES
COPPER OXIDES
DYSPROSIUM OXIDES
ERBIUM OXIDES
EUROPIUM OXIDES
GADOLINIUM OXIDES
HOLMIUM OXIDES
LOW TEMPERATURE
LUTETIUM OXIDES
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SAMARIUM OXIDES
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BARIUM COMPOUNDS
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COPPER COMPOUNDS
DYSPROSIUM COMPOUNDS
ERBIUM COMPOUNDS
EUROPIUM COMPOUNDS
GADOLINIUM COMPOUNDS
HOLMIUM COMPOUNDS
LUTETIUM COMPOUNDS
NEODYMIUM COMPOUNDS
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THULIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
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