American Superconductor Corporation

American Semiconductor Corporation

Eric R Podtburg

Alexander Otto

Lawrence J Masur

Gilbert N Riley, Jr

William L Carter

Qi Li

Martin W Rupich

Elliott D Thompson

Patrick John Walsh

Kenneth Henry Sandhage

Donald R Parker

Craig J Christopherson

Ronald D Parrella

Peter R Roberts

Christopher A Craven

Mark D Teplitsky

Steven Hancock

Jeffrey D Schreiber

William J Rosati

Michael A Tanner

Gregory L Snitchler

Peter D Antaya

Bruce R Bent

William J Michels

Derek Patrick Daly

Henry C Valcour, Iii

John Gannon

Sy-Jenq Loong

Subramaniam Anandakugan

Hong Cai

David Crotzer

Ronald D Parella

Dana Krause

Thomas De Santos

Deborah L Ouellette

David M Olen

Henry C Valcour Iii

A rotating machine includes a stator and a rotor configured to rotate within the stator. Rotor windings are supported in the rotor and are formed of a laminated electrical conductor in a single-layer saddle coil configuration. The conductor includes a first support lamina, a second support lamina, an insert including a high temperature superconductor disposed between the first and second support lamina, and a filler material surrounding the insert that bonds the insert to each of the first and second support lamina. At the location between the first support lamina and second support lamina corresponding to the location of the insert, the width dimension of the filler material on each side of the insert is at least 10 percent of a width of the conductor. The conductor is configured to carry at least 600 Amperes per turn and have a C-axis tensile strength of at least 21 MPa.

Wide electrical conductor having high C-axis strength

A method includes locating a defect in a first segment of high temperature superconducting wire. A second segment of high temperature superconducting wire is then positioned onto the first segment of high temperature superconducting wire such that the second segment of high temperature superconducting wire overlaps the defect. A path is then created such that current flows through the second segment of high temperature superconducting wire. The first segment of high temperature superconducting wire and second segment of high temperature superconducting wire are then laminated together.

Mitigating the effects of defects in high temperature semiconductor wires

Under one aspect, a laminated, spliced superconductor wire includes a superconductor joint, which includes (i) first and second superconductor wires, each wire including a substrate, a superconductor layer overlying the substrate, and a cap layer overlying the superconductor layer; and (ii) a conductive bridge, the conductive bridge including a substrate, a superconductor layer overlying the substrate, and a cap layer overlying the superconductor layer, wherein the cap layer of the conductive bridge is in electrically conductive contact with a portion of the cap layer of each of the first and second superconductor wires through an electrically conductive bonding material. The spliced wire also includes (b) a stabilizer structure surrounding at least a portion of the superconductor joint, wherein the superconductor joint is in electrical contact with the stabilizer structure; and (c) a substantially nonporous electrically conductive filler, wherein the filler substantially surrounds the superconductor joint.

Low resistance splice for high temperature superconductor wires

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

A novel process of the production and processing of high quality, high T BSCCO or (Bi,Pb)SCCO superconductors starts with fabrication of a forming a bundle including a plurality of billets, each billet containing at least one filament comprising a dominant amount of an tetragonal BSCCO phase with selected intermediate phases, and substantially surrounded by a constraining metal. The bundle is thermomechanically consolidated to form a multifilamentary precursor article by applying pressure and heat to the bundle under conditions cooperatively selected to cause interdiffusion of said constraining metal at the interfaces between said metal and said filaments and substantially complete elimination of voids in said bundle, and the consolidation step is completed before any high strain longitudinal deformation is performed on the bundle. The precursor article is then heated 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, the second time period and the second oxygen partial pressure being cooperatively selected to form a dominant amount of an orthorhombic BSCCO phase in the reacted mixture. It may then be 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, all cooperatively selected to convert at least a portion of the orthorhombic BSCCO phase to the final superconducting BSCCO material.

Method of forming superconducting composite article

The invention features high performing composite superconducting oxide articles that can be produced from OPIT precursors substantially without poisoning the superconductor. In general, the superconducting oxide is substantially surrounded by a matrix material. The matrix material contains a first constraining material including a noble metal and a second metal. The second metal is a relatively reducing metal which lowers the overall oxygen activity of the matrix material and the article at a precursor process point prior to oxidation of the second metal. The second metal is substantially converted to a metal oxide dispersed in the matrix during or prior to a first phase conversion heat treatment but after formation of the composite, creating an ODS matrix.

Performance of oxide dispersion strengthened superconductor composites

Methods of treating superconducting composites to enhance their wettability in solder, and composites having enhanced wettability. It has been found that wettability can be substantially enhanced by stripping a thin layer off the surface of the composite before incorporating it into a laminated component. This layer can be stripped, for example, by chemically etching the composite, for example in a solution of nitric acid and ammonium bifluoride.

Composites having high wettability

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 strongly-linked polycrystalline oxide superconductor article includes an oxide superconductor selected from the group consisting 124-type and 247-type oxide superconductors having fine, highly aligned oxide superconductor grains less than &mgr;m long a longest dimension. The oxide superconductor article has at least a 25% retention of critical current density in a 0.1 Tesla field. A method for preparing a strongly-linked oxide superconductor includes shaping a finely divided metallic precursor of an oxide superconductor; oxidizing the finely divided metallic precursor to produce a finely divided sub-oxide species while avoiding conversion of an appreciable amount of the sub-oxide species into the oxide superconductor, annealing and deforming the article, in either order, the annealing carried out at a temperature and for a time sufficient to convert some of the sub-oxide species into fine grains of the oxide superconductor thereby forming a mixture of sub-oxide species and oxide superconductor and the deformation carried out such that the fine grains of oxide superconductor are rotated into alignment parallel to an intended current carrying direction of the article without fracturing or pulverization of the oxide superconductor grains; alternating annealing and deformation of the article until no further improvement in alignment is observed; and subjecting the aligned grains to a final anneal in order to react any remaining sub-oxide species and maximize the growth and sintering of existing aligned grains.

Strongly-linked oxide superconductor and a method of its manufacture

A composite for preparation of an oxide superconductor includes a primary alloy phase of constituent elements of a desired oxide superconductor; and a secondary phase comprising copper, the secondary phase supported by the primary alloy phase. The composite may additionally include a matrix material for supporting the primary alloy phase and second phase disposed therein. The composite is oxidized to form an oxide superconductor composite.

Oxide superconductor precursors

The combination of one or more high reduction drafts with controlled, low back tensions increases the range of deformation conditions over which dimensional tolerances and J,may be optimized. The method comprises the steps of: first, providing a precursor article comprising a metal matrix surrounding a plurality of filaments extending along the length of the article and comprising precursors to a desired superconducting ceramic; next, roll working the precursor article during a breakdown stage at a back tension less than the elastic to plastic transition threshold of the composite during at least one high reduction roll working draft, and, then, sintering the rolled article to obtain the desired superconducting ceramic. In a preferred embodiment, the rolling step further comprises rolling the article at a front tension less than the elastic to plastic transition threshold of the rolled, unsintered article.

Tensioning process for manufacture of superconducting ceramic composite conductors

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Natick, MA, United States of America

Eric R Podtburg