William L Hicks

US Patent:

6046139, Apr 4, 2000

Filed:

Aug 7, 1998

Appl. No.:

9/130780

Inventors:

Kay Y. Blohowiak - Issaquah WA
Darryl F. Garrigus - Issaquah WA
Thomas S. Luhman - Bellevue WA
Kevin E. McCrary - Port Orchard WA
Michael Strasik - Issaquah WA
Ilhan Aksay - Princeton NJ
Fatih Dogan - Seattle WA
William C. Hicks - Olympia WA
Corrie B. Martin - Seattle WA

Assignee:

The Boeing Company - Seattle WA

International Classification:

C04B 35653

US Classification:

505450

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. 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.