American Superconductor Corporation

Patrick John Walsh

Gilbert N Riley, Jr

Martin W Rupich

Alexander Otto

William L Carter

Qi Li

Eric R Podtburg

Elliott D Thompson

A method is described to prepare a highly textured oxide superconductor article in a single deformation-sinter process. A precursor article including a plurality of filaments comprising a precursor oxide having a dominant amount of a tetragonal BSCCO 2212 phase and a constraining member substantially surrounding each of the filaments is provided. Each of the filaments extends along the length of the article. The oxide article is subjected to a heat treatment at an oxygen partial pressure and temperature selected to convert a tetragonal BSCCO 2212 oxide into an orthorhombic BSCCO 2212 oxide and, thereafter, roll worked in a high reduction draft in a range of about 40% to 95% in thickness so that the filaments have a constraining dimension is substantially equivalent to a longest dimension of the oxide superconductor grains. The rolled article is sintered to obtain a BSCCO 2223 oxide superconductor.

Simplified deformation-sintering process for oxide superconducting articles

An aspected multifilamentary oxide article is provided having a plurality of aspected filaments including a metal oxide and extending continuously for the length of the article. A constraining member substantially surrounds each filament, wherein each of the filaments has an average transverse cross-sectional thickness less than about 35 &mgr;m and an average variation in cross-section along its length of less than about 10%. The article exhibits superior filament uniformity, hardness, and oxide density and texture.

High texture factor

A novel process of the production and processing of high quality, high T,(Bi,Pb)SCCO superconductors starts with fabrication of a precursor article including selected intermediate phases with desired chemical and structural properties. The precursor fabrication includes introducing the reacted mixture having a dominant amount of the tetragonal BSCCO phase into a metal sheath, and sealing the reacted mixture within said sheath, heating the mixture at a second selected processing temperature in an inert atmosphere with a second selected oxygen partial pressure for a second selected time period, the second processing temperature and the second oxygen partial pressure being cooperatively selected to form a dominant amount of an orthorhombic BSCCO phase in the reacted mixture. The sealed sheath is deformed to form an elongated precursor article of a desired texture; and thereafter heated at a third selected processing temperature in an inert atmosphere with a third selected oxygen partial pressure for a third selected time period. The third processing temperature and third oxygen partial pressure are cooperatively selected to convert at least a portion of the orthorhombic BSCCO phase to the final superconducting BSCCO material.

Processing of (Bi,Pb)SCCO superconductor in wires and tapes

A novel process of the production and processing of high quality, high T.sub.c (Bi,Pb)SCCO superconductors starts with fabrication of a precursor article including selected intermediate phases with desired chemical and structural properties. The precursor fabrication includes introducing the reacted mixture having a dominant amount of the tetragonal BSCCO phase into a metal sheath, and sealing the reacted mixture within said sheath, heating the mixture at a second selected processing temperature in an inert atmosphere with a second selected oxygen partial pressure for a second selected time period, the second processing temperature and the second oxygen partial pressure being cooperatively selected to form a dominant amount of an orthorhombic BSCCO phase in the reacted mixture. The sealed sheath is deformed to form an elongated precursor article of a desired texture; and thereafter heated at a third selected processing temperature in an inert atmosphere with a third selected oxygen partial pressure for a third selected time period. The third processing temperature and third oxygen partial pressure are cooperatively selected to convert at least a portion of the orthorhombic BSCCO phase to the final superconducting BSCCO material.

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Newton, MA, United States of America

Patrick John Walsh