Making large, single crystal, 123 YBCO superconductors

US6046139A · kind A · utility

Assignee

• The Boeing Company · US

Inventors

• Kay Y. Blohowiak · Issaquah, US
• Darryl F. Garrigus · Issaquah, US
• Thomas S. Luhman · Westhampton Beach, US
• Kevin E. McCrary · Port Orchard, US
• Michael Strasik · Renton, US
• Ilhan A. Aksay · Princeton, US
• Fatih Dogan · Rolla, US
• William C. Hicks · Olympia, US
• Corrie B. Martin · Seattle, US

Key dates

• Filing date: Aug 7, 1998
• Grant date: Apr 4, 2000
• Expiry date: Aug 7, 2018

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S505/729
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

We make large (in excess of 2 cm in diameter), single crystal YBa.sub.2 Cu.sub.3 O.sub.7-x [123 YBCO] crystals, where x.ltoreq.0.6, in a seventeen step process or some variant thereof from finely ground and well mixed 123 YBCO and 211 YBCO powders with a small amount of Pt by controlling the rate of cooling from within a compact of the powders using a temperature gradient in the radial and axial planes (independently) of about 1-1.degree. C./inch diameter of compact to nucleate the crystal growth. We promote crystal growth as well using a samarium oxide seed crystal, preferably SmBa.sub.2 Cu.sub.3 O.sub.(7-y), where y.ltoreq.1.6. After nucleation we cool the compact slowly at a rate from about 0.1-1.degree. C./hr to promote the single crystal development.