Abstract: A superconductive element containing Nb3Sn, in particular a multifilament wire, comprising at least one superconductive filament (8) which is obtained by a solid state diffusion reaction from a preliminary filament structure (1), said preliminary filament structure (1) containing an elongated hollow pipe (2) having an inner surface (3) and an outer surface (4), wherein said hollow pipe (2) consists of Nb or an Nb alloy, in particular NbTa, wherein the outer surface (4) is in close contact with a surrounding bronze matrix (5) containing Cu and Sn, and wherein the inner surface (3) is in close contact with an inner bronze matrix (5) also containing Cu and Sn, is characterized in that the inner bronze matrix (5) of the preliminary filament structure (1) encloses in its central region an elongated core (6) consisting of a metallic material, said metallic material having at room temperature (=RT) a thermal expansion coefficient ?core<17*10?6K?1, preferably ?core?8*10?6 K?1, said metallic material having at RT a

Abstract: The invention relates to a composite (1), comprising a Cu—Sn bronze matrix (2) and filaments (3) surrounded by the bronze matrix (2), wherein the filaments (3) contain niobium (?Nb) or a Nb alloy, characterized in that the filaments (3) contain between 0.3% and 20% of volume of copper (?Cu) substructures (4), which are distributed within the Nb or the Nb alloy. The composite can be used to produce a superconducting element with the bronze route which has an improved critical current density.

Abstract: The invention relates to a sheathing material for superconducting wires which are deformed during manufacture by drawing or a similar procedure. The superconducting material of the wires is composed of an oxide whose superconducting properties worsen during the deformation so that, in order to recover its original superconducting properties or to further improve them, the material must be subjected to a recovery heat treatment at temperatures above 940.degree. C.Customarily, silver is employed as the sheathing material for such wires. The recovery heat treatment is generally performed at temperatures around 900.degree. C. Experiments have shown that the optimum temperature range for a recovery heat treatment lies between about 940.degree. C. and 1030.degree. C. However, these temperatures were above the melting temperature of silver in an oxygen atmosphere.

Abstract: A process for the production of at least a one kilogram block of Chevrel-phase Pb.sub.x Mo.sub.y S.sub.z, wherein x=0.9 to 1.2, y=6.0 to 6.4, and z=7 to 8, includes mixing thoroughly stoichiometric quantities of starting materials in powdered form. The starting materials are selected from elemental Pb, Mo and S, sulfides of elemental Pb and Mo, and mixtures thereof. The starting mixture is introduced into a metallic container and evacuated to a pressure to 10.sup.4 Pa or less. The evacuated container is subjected to hot isostatic pressing at a constant pressure selected from a pressure ranging from 100 to 300 MPa, at a heating rate ranging from 10.degree. to 100.degree. C./hr., at a final pressing temperature ranging from 800.degree. to 1200.degree. C., and for a pressing period ranging from 10 to 100 hours, whereby the starting materials react to form the block of Chevrel-phase Pb.sub.x Mo.sub.y S.sub.z. The block is cooled at a cooling rate ranging from 50.degree. to 500.degree. C./hr.

Abstract: A multifilamentary, copper or copper alloy clad superconductive wire, comprising a superconductive, intermetallic compound Nb.sub.3 Sn or V.sub.3 Ga, having an A-15 crystal structure, and at least one additive metal from the group consisting of rare earth elements of atomic number 57 to 71, Th, U, Ti, Zr, Hf, V, Nb, Ta, Mo, Fe, Co, Ni, Pd, Cu, Ag, Al, and Pt. The additive is present in the wire within the A-15 phase in the form of uniformly and finely distributed, at least partially undissolved axially parallel inclusions at grain boundaries of the crystals and/or at an interface between the A-15 phase and the copper or copper alloy, or at an interface between the A-15 phase and a separate phase.

Abstract: The present invention relates to a method for producing multifilament superconductive wires of Nb.sub.3 Sn or V.sub.3 Ga filaments embedded in a Cu or Cu alloy matrix, with the wires containing metal additive elements from the group including Ti, Zr, Hf, V, Nb, Ta, Fe, Co, Ni in the filaments and/or in the matrix. The superconductive characteristics of the wires are predetermined for medium magnetic fields (below 12 T) as well as for high magnetic fields (12 T and above). The percentage of the additive (or additives) can be set to a predetermined value and thus the superconductive properties can be set as desired. This is accomplished by mixing metal additives in powder form with a powder of niobium or a niobium alloy, or of vanadium or a vanadium alloy, in a defined grain size and in a defined quantity. The resulting powder mixture is compacted in a container of copper or a copper alloy, the compacted container is shaped into a wire and, upon removal of the container layer, is processed further into wires.

Abstract: A method for producing a superconductive wire of multifilaments having components comprising niobium and aluminum encased in copper or a copper alloy, wherein the multifilament configuration and the formation of a superconductive Al5 phase are positively developed from the components disposed in a copper or copper alloy tube having an interior metallic coating serving as a diffusion barrier, by cold forming and subsequent heat treatment.