In various embodiments, superconducting wires incorporate diffusion barriers composed of Ta alloys that resist internal diffusion and provide superior mechanical strength to the wires.

In various embodiments, superconducting wires incorporate diffusion barriers composed of Ta alloys that resist internal diffusion and provide superior mechanical strength to the wires.

The method is for manufacturing a high temperature multi-filamentary superconducting tape wire having an oxide superconducting layer formed on a tape-shaped metal substrate with an intermediate layer therebetween and a metal stabilizing layer formed on the oxide superconducting layer, wherein one or more lengthwise slits are formed in the oxide superconducting layer and the intermediate layer and no slits are formed in the metal substrate and the stabilizing layer. The method includes: a step for preparing a high temperature superconducting wire material having an oxide superconducting layer formed on a tape-shape metal substrate with an intermediate layer therebetween and a stabilizing layer formed on the oxide superconducting layer; and a step for applying a load to the high temperature superconducting wire material to form slits. The method enables simple manufacturing of a high temperature superconducting wire material having a finer superconducting layer without sacrificing superconducting performance and mechanical strength.

The method is for manufacturing a high temperature multi-filamentary superconducting tape wire having an oxide superconducting layer formed on a tape-shaped metal substrate with an intermediate layer therebetween and a metal stabilizing layer formed on the oxide superconducting layer, wherein one or more lengthwise slits are formed in the oxide superconducting layer and the intermediate layer and no slits are formed in the metal substrate and the stabilizing layer. The method includes: a step for preparing a high temperature superconducting wire material having an oxide superconducting layer formed on a tape-shape metal substrate with an intermediate layer therebetween and a stabilizing layer formed on the oxide superconducting layer; and a step for applying a load to the high temperature superconducting wire material to form slits. The method enables simple manufacturing of a high temperature superconducting wire material having a finer superconducting layer without sacrificing superconducting performance and mechanical strength.

The present invention is intended to increase the critical current density of a wire rod having a shape with good symmetry such as a round wire or a square wire by making use of mechanical milling method. The production method of the present invention for the MgB.sub.2 superconducting wire rod comprises a mixing process of preparing a powder by adding a solid organic compound to a magnesium powder and a boron powder and then applying an impact to the powder to prepare a mixture of the powder in which boron particles are dispersed inside magnesium particles, a filling process of filling a metal tube with the mixture, an elongation process of elongating the metal tube filled with the mixture and a heat treatment process of heat-treating the metal tube to synthesize MgB.sub.2.

The present invention is intended to increase the critical current density of a wire rod having a shape with good symmetry such as a round wire or a square wire by making use of mechanical milling method. The production method of the present invention for the MgB.sub.2 superconducting wire rod comprises a mixing process of preparing a powder by adding a solid organic compound to a magnesium powder and a boron powder and then applying an impact to the powder to prepare a mixture of the powder in which boron particles are dispersed inside magnesium particles, a filling process of filling a metal tube with the mixture, an elongation process of elongating the metal tube filled with the mixture and a heat treatment process of heat-treating the metal tube to synthesize MgB.sub.2.

Methods for producing a multifilament Nb.sub.3Sn superconducting wire having a Jc value of at least 2000 A/mm.sup.2 at 4.2 K and 12 T by a) packing a plurality of Cu encased Nb rods within a first matrix which is surrounded by an intervening Nb diffusion barrier and a second matrix on the other side of the barrier remote from the rods thereby forming a packed subelement for the superconducting wire; b) providing a source of Sn within the subelement; c) assembling the metals within the subelement, the relative sizes and ratios of Nb, Cu and Sn being selected such that (i) the Nb fraction of the subelement cross section including and within the diffusion barrier is from 50 to 65% by area; (ii) the atomic ratio of the Nb to Sn including and within the diffusion barrier of the subelement is from 2.7 to 3.7; (iii) the ratio of the Sn to Cu within the diffusion barrier of the subelement is such that the Sn wt %/(Sn wt %+Cu wt %) is 45%-65%; (iv) the Cu to Nb local area ratio (LAR) of the Cu-encased Nb rods is from 0.10 to 0.30; (v) the Nb diffusion barrier being fully or partially converted to Nb.sub.3Sn by subsequent heat treatment; and (vi) the thickness of the Nb diffusion barrier is greater than the radius of the Nb portions of the Cu encased Nb rods; and d) assembling the subelements in a further matrix and reducing the assemblage to wire form such that (i) the multifilamentary Nb.sub.3Sn superconducting wire is formed of a plurality of the subelements, each having a Nb diffusion barrier to thereby form a wire having a distributed barrier design; (ii) the Nb portions of the copper encased Nb rods in the final wire are of diameter from 0.5 to 7 m before reaction, and (iii) the Nb diffusion barrier that is fully or partially converted to Nb.sub.3Sn by heat treatment is from 0.8 to 11 m thickness before reaction; and e) heat treating the final size wire from step d) to form the Nb.sub.3Sn superconducting phases, and multifilament Nb.sub.3Sn superconducting wires made thereby are described herein.

In various embodiments, superconducting wires incorporate diffusion barriers composed of Nb alloys or NbTa alloys that resist internal diffusion and provide superior mechanical strength to the wires.

In various embodiments, superconducting wires incorporate diffusion barriers composed of Nb alloys or NbTa alloys that resist internal diffusion and provide superior mechanical strength to the wires.

In the production of an internal-tin-processed Nb.sub.3Sn superconducting wire, the present invention provides a Nb.sub.3Sn superconducting wire that is abundant in functionality, such as, the promotion of formation of a Nb.sub.3Sn layer, the mechanical strength of the superconducting filament (and an increase in interface resistance), the higher critical temperature (magnetic field), and the grain size reduction, and a method for producing it. A method for producing a Nb.sub.3Sn superconducting wire according to an embodiment of the present invention includes a step of providing a bar 10 that has a Sn insertion hole 12 provided in a central portion of the bar 10 and a plurality of Nb insertion holes 14 provided discretely along an outer peripheral surface of the Sn insertion hole 12, and that has an alloy composition being Cu-xZn-yM (x: 0.1 to 40 mass %, M=Ge, Ga, Mg, or Al, provided that, for Mg, x: 0 to 40 mass %), a step of mounting an alloy bar with an alloy composition of Sn-zQ (Q=Ti, Zr, or Hf) into the Sn insertion hole 12 and inserting Nb cores into the Nb insertion holes 14, a step of subjecting the bar 10 to diameter reduction processing to fabricate a Cu-xZn-yM/Nb/Sn-zQ composite multicore wire with a prescribed outer diameter, and a step of subjecting the composite multicore wire to Nb.sub.3Sn phase generation heat treatment.