Process for producing a high-temperature superconductor and also shaped bodies composed thereof

US5047391A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Joachim Bock · Lechenich, DE
• Eberhard Preisler · Lechenich, DE

Key dates

• Filing date: Aug 18, 1989
• Grant date: Sep 10, 1991
• Expiry date: Aug 18, 2009

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S505/782
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

To produce a high-temperature superconductor of the composition Bi.sub.2 (Sr,Ca).sub.3 Cu.sub.2 O.sub.8+x having a strontium to calcium ratio of 5:1 to 2:1 and a value of x between 0 and 2, the oxides and/or carbonates of bismuth, strontium, calcium and copper are vigorously mixed in a stoichiometric ratio. The mixture is heated at temperatures of 870.degree. to 1100.degree. C. until a homogeneous melt is obtained. The melt is poured into molds and allowed to solidify in them. The cast bodies removed from the molds are annealed for 6 to 30 hours at 780.degree. to 850.degree. C. Finally, the annealed cast bodies are treated for at least 6 hours at temperatures of 600.degree. to 820.degree. C. in an oxygen atmosphere. The cast bodies can be converted into shaped bodies of the desired sizes by mechanical processes before they are annealed. The shape and size of the shaped bodies may also be determined by the shape and dimensioning of the molds used in producing the cast bodies.