Airco, Inc.

Oxford Superconducting Technology

Oxford Instruments, Inc.

William G Marancik

Seung Hong

Jeff Parrell

Seungok Hong

Frederick T Ormand

Seung-Ok Hong

Michael Field

Youzhu Zhang

Morris S Young

Robert William Hentges

Rouyi Zhou

Eric Gregory

Kenneth Marken

Glenn W Grabinsky

A method for fabrication of nanometer scale metal fibers, followed by optional further processing into cables, yarns and textiles composed of the primary nanofibers. A multicomponent composite is first formed by drilling a billet of matrix metal, and inserting rods of the metal desired as nanofibers. Hexed or round rods can also be inserted into a matrix metal can. The diameter of this composite is then reduced by mechanical deformation methods. This composite is then cut to shorter lengths and reinserted into another billet of matrix metal, and again the diameter is reduced by mechanical deformation. This process of large scale metal stacking followed by mechanical deformation is repeated until the desired fiber size scale is reached, the fibers being contained in the matrix metal. After size reduction, the composite metal wires may be further processed into built up configurations, depending on intended application, by stranding, cabling, braiding, weaving, knitting, felting, etc., to form yarns or textiles. After the built up configuration is formed, the matrix metal is removed by chemical etching, leaving a cable, yarn or textile composed of the primary nanofibers.

Method for producing metal nanofibers, yarns and textiles

A method for increasing the copper to superconductor ratio of a superconductor core wire by forming a copper-based strip about the core wire which at least partially encloses the core wire in contact therewith by deforming the strip longitudinally into a U shape nested about the wire; and soldering the wire and strip in the assembly of step (a) to form a strong mechanical, electrical and thermal bond therebetween.

Increasing the copper to superconductor ratio of a superconductor wire by cladding with copper-based strip

A method for producing a superconductor having a high copper to superconductor composition (Cu/SC) ratio by cross-sectional area. An assembly is prepared formed of one or more fine filaments of a superconductor composition or of a precursor component for a superconductor alloy composition, which filaments are embedded in a copper-based matrix. The assembly is electroplated with copper to increase the Cu/filament ratio in the resulting product, and thereby increase the said Cu/SC ratio to improve the stability of the final superconductor.

Method for increasing the copper to superconductor ratio in a superconductor wire

A method for producing a multifilamentary superconductor containing niobium-tin (Nb.sub.3 Sn). A fully bonded niobium/copper composite billet is formed having a plurality of longitudinally extending channels which are symmetrically distributed with reference to transverse cross-sections of the billet, each channel being filled with an inert removable filler material. The inert filler material is removed to open the longitudinally extending channels in the billet. Tin or a tin alloy is inserted into the channels, and the niobium/copper composite billet with the inserted tin or tin alloy is cold drawn to the desired final dimensions. The drawn composite is then heated to effect in situ formation of the niobium-tin.

Method for producing multifilamentary niobium-tin superconductor

The centers of a plurality of copper tubes are filled with an alloy of tin with a minor amount of aluminum and drawn to form Cu-Sn wires which are cabled around a core Nb wire; a plurality of these strands are provided in a copper tube, or a copper foil or finely wound copper wire and drawn to produce a multifilament wire; heat treatment is applied to cause the tin to diffuse and form the intermetalic Nb.sub.3 Sn at the surface of the Nb filaments to produce the ultimate superconducting wire product. The addition of a small quantity of Al to the Sn facilitates processing and improves the final product properties.

Fabrication of multifilament intermetallic superconductor using

A superconductor of the cable-in-conduit type which employs forced flow of liquid helium, comprises a flat-sided housing having an essentially rectangular cross-section, within the housing a metal support bar cabled with multifilamentary superconducting subcables alternated with stainless steel cables or wires. The superconductor provides a large heat transfer surface owing to the multifilamentary superconducting subcables which have a void volume in the range of about 30-35%, as well as mechanical support owing to the stainless steel cables or wires.

Forced flow superconducting cable and method of manufacture

The centers of a plurality of copper tubes are filled with tin and drawn to form Cu-Sn wires which are cabled around a core Nb wire; a plurality of these strands are provided in a copper tube, or a copper foil or finely wound copper wire; and a plurality of said tubes are packed into a copper can to form a billet which is drawn to produce a multifilament wire; and heat treatment is applied to cause the tin to diffuse and form the intermetallic Nb.sub.3 Sn at the surface of the Nb filaments to produce the ultimate superconducting wire product.

Method of fabricating multifilament intermetallic superconductor

Nb wire and Sn plated Cu wire and/or Sn plated Cu foil strip are fabricated into a composite that is mechanically worked to form a multifilament superconductor precursor that does not require intermediate anneals and that has required amounts of Sn distributed throughout its cross section for efficient reaction with the Nb filaments.

An improved method for manufacture of multifilamentary superconductors of the A.sub.3 B type having the A-15 crystal structure, such as Nb.sub.3 Sn, is disclosed in which rods or wires of the A material are disposed throughout a matrix consisting of Cu and the B material in substantially elemental form. The matrix is formed by compaction of powders of Cu; powders of the B may be mixed therewith or the B material may be infiltrated into pores between the individual Cu particles after compaction. The resultant composite has A, B and Cu distributed uniformly throughout its volume and can be worked to any desired final shape and size for heat treatment to form the A.sub.3 B material without intermediate annealing steps.

Method of manufacture of multifilamentary intermetallic superconductors

A method of making A-15 type intermetallic superconductors is disclosed which features elimination of numerous annealing steps. Nb or V filaments are embedded in Cu matrices; annular layers of Sn or Ga, respectively, separated from each other by Cu layers, provide the other component of the intermetallic superconductors Nb.sub.3 Sn and V.sub.3 Ga.

Method of production multifilamentary intermetallic superconductors

A composite multifilament superconducting structure is provided, which includes an elongated substrate-carrying, longitudinally-directed, sputtered discrete filament of an A-15 type intermetallic superconductor. In a preferable procedure, a plurality of spaced, generally longitudinal grooves are formed on the surface of an elongated filamentary substrate, preferably a metal wire. The walls of the grooves on the substrate surface are shaped to undercut the curvilinear surface of the substrate located between two adjacent grooves so that at least some of the wall portions of the grooves are geometrically shadowed during the subsequent sputtering step in which a superconductor is sputtered onto the substrate. In particular, a film of a suitable superconducting intermetallic compound having A-15 crystalline structure, such as Nb.sub.3 Ge, is thereupon sputtered onto the grooved substrate and deposits at the bottom of the grooves and at the surface portions of the substrate between grooves. The shadowed wall portions remain substantially deposit-free so that the resultant spaced deposits extend as distinct lines or bands along the substrate to thereby constitute the superconductive filaments. A plurality of such substrates may, if desired, be consolidated into a further composite structure, by bundling the substrates and passing same through a molten metal. The resultant structure may then be sized to yield as a final product a composite of the substrates bearing the superconducting filaments in a surrounding matrix of the metal.

Composite multifilament superconductors

A method and article produced thereby are disclosed wherein the method produces a multi-filament superconductor having an insulation capable of withstanding extended heat treatment. According to the invention, a plurality of superconductor forming rods and a plurality of rods of normally conductive material are packed into a can made of a ductile material such as copper and having its interior lined with a valve metal such as tantalum. This assembly is extruded and drawn to a desired size as is known in the art. The ductile metal exterior layer is then removed to expose the valve metal. The exposed valve metal is thereafter oxidized to form an insulating oxide.

Method for making an insulated superconductor and article produced

A method is described for joining first and second surfaces by depositing a layer of metal on the first surface, preparing the second surface to expose fresh metal, placing the deposited metal and the exposed metal in contact, and applying sufficient pressure to join the surfaces, all done in a protective environment, such as vacuum. Also described is a related apparatus comprising an evacuable chamber, an electron-beam heated vapor source, and a pair of rollers for contacting and applying pressure to join the surfaces.

Surface joining by bonding of metal and deposited metal

A superconducting compound of the A-15 crystal structure type is obtained in a composite by a high temperature diffusion between a first metallic component and a second metallic component contained in a bronze alloy. Stability is achieved by including in the composite a quantity of high-conductivity normal material. Diffusion of the second metallic component into the normal material with a resultant degradation of conductivity of the normal material is prevented by placing an impervious barrier layer between the bronze alloy and the normal material. In a specific embodiment, the barrier layer takes the form of an annular shell comprising at least two sectors of dissimilar metals, one of which reacts with a component of the bronze alloy to form a layer of said superconducting compound, and the other of which is substantially non-reactive. Thus, a discontinuous superconducting ring is formed on the barrier layer which prevents flux trapping.

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Basking Ridge, NJ, United States of America

William G Marancik