Process for making 90 degree K. superconductors by impregnating cellulosic article with precursor solution

Patent · Tue Jan 08 00:00:00 EST 1991

OSTI ID:5776894

Bolt, J D; Subramanian, M A

This patent describes an improved process for preparing a shaped article of a superconducting composition having the formula MBa{sub 2}Cu{sub 3}O{sub 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. It comprises: forming in acetic acid a mixture of M(C{sub 2}H{sub 3}O{sub 2}){sub 3}, barium acetate and copper acetate in an atomic ratio of M:Ba:Cu of about 1:2:3; heating the resulting mixture to boiling, and adding sufficient formic acid to dissolve any undissolved starting material while continuing to boil the solution; contacting an article of cellulose material with the solution thereby impregnating the article with the solution, the article having the shape desired; removing excess solution from the resulting impregnated article of cellulose material and drying the impregnated article; heating the impregnated article of cellulose material to a temperature from about 850{degree}C to about 925{degree}C in an oxygen-containing atmosphere for a time sufficient to form MBa{sub 2}Cu{sub 3}O{sub y}, where y is from about 6.0 to about 6.5, the heating effecting carbonization of the cellulose material and oxidization of carbon without ignition; and maintaining the resulting article in an oxygen-containing atmosphere while cooling for a time sufficient to obtained the desired product.

• Assignee: E.I. Du Pont de Nemours and Co., Wilmington, DC (USA)
• Patent Number(s): US 4983573; A
• Application Number: PPN: US 7-323366
• OSTI ID: 5776894
• Resource Relation: Patent File Date: 12 Mar 1989
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BARIUM OXIDES
SYNTHESIS
COPPER OXIDES
SUPERCONDUCTORS
CHEMICAL COMPOSITION
CELLULOSE
LOW TEMPERATURE
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
CARBOHYDRATES
CHALCOGENIDES
COPPER COMPOUNDS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
POLYSACCHARIDES
SACCHARIDES
TRANSITION ELEMENT COMPOUNDS
360201* - Ceramics
Cermets
& Refractories- Preparation & Fabrication
360204 - Ceramics
Cermets
& Refractories- Physical Properties