Superconductor technology: apparatus – material – process – High temperature – per se – Having tc greater than or equal to 150 k
Patent
1989-08-28
1991-04-09
Lowe, James
Superconductor technology: apparatus, material, process
High temperature , per se
Having tc greater than or equal to 150 k
264 63, 264 66, 505739, 505780, H01L 3912, C04B 3564
Patent
active
050065041
ABSTRACT:
A process for the preparation of superconducting ceramic materials by a solid state reaction technique. The process is especially suited for production of powders including .gtoreq.95% of Ba.sub.2 YCu.sub.3 O.sub.7 for use in producing sintered ceramic bodies including >99% Ba.sub.2 YCu.sub.3 O.sub.7. The process includes the steps of (a) wet milling raw powders of starting ingredients, including oxides and/or carbonates or the respective ions, to form a milled slurry, (b) separating particulate solids from the liquids of the slurry, the separating including continuously agitating the mixed slurry so as to avoid segregation of the milled ingredients and spray drying the milled slurry to produce spray dryed particles, (c) calcining the separated particles in oxygen to form calcined powder, (d) optionally remilling the calcined powder, (e) forming the calcined powder into a suitable form body and (f) sintering the formed body in oxygen; preferably said separating step including spray drying the agitated, milled slurry. The above process results in calcined material including .gtoreq.95% of a single phase material (Ba.sub.2 YCu.sub.3 O.sub.7) and a small amount e.g. 3%, of a single second phase material and leads to a sintered ceramic which is .gtoreq.99% single phase material.
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O'Bryan, Jr. Henry M.
Rhodes Warren W.
Thomson, Jr. John
Alber Oleg E.
AT&T Bell Laboratories
Fiorilla Christopher A.
Lowe James
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