Abstract: A precursor for manufacturing a Nb3Sn superconducting wire according to the present invention includes a mono-element wire including a Sn or Sn-based alloy core disposed at the, a Cu or Cu-based alloy matrix and a plurality of Nb or Nb-based alloy filaments surrounding the Sn or Sn-based alloy core, and a diffusion barrier layer and a stabilizing copper layer surrounding the Cu or Cu-based alloy matrix. In a final shape after a reduction process, the average diameter of the Nb or Nb-based alloy filaments is set to 5 ?m to 30 ?m, and the average distance between the Sn or Sn-based alloy core and the Nb or Nb-based alloy filaments nearest the Sn or Sn-based alloy core is set to 100 ?m or less.

Abstract: A method for manufacturing a powder-metallurgy processed Nb3Sn superconducting wire is provided. In the method, a sheath made of Nb or a Nb alloy is filled with a raw material powder containing Sn. The sheath filled with the raw material powder is subjected to diameter reduction to form a wire. The wire is heat-treated to form a superconducting phase at the internal surface of the sheath. The raw material powder is prepared by adding a Sn powder to a Cu—Sn alloy powder or a Cu—Sn intermetallic compound powder, and is compacted under isotropic pressure.

Abstract: An internal diffusion process Nb3Sn superconducting wire is produced by drawing a composite wire including a composite material containing a plurality of Nb or Nb based alloy cores embedded in a Cu or Cu based alloy matrix and a Sn or Sn based alloy core disposed in the center portion, a diffusion barrier layer composed of Nb or Ta and disposed on the outer perimeter of the composite material, and stabilizing Cu disposed on the outside of the diffusion barrier layer and heat-treating the resulting composite wire so as to diffuse Sn and react Sn with the Nb or Nb based alloy cores, wherein the area percentage of the stabilizing Cu in a cross section in a direction perpendicular to the axis center of the composite wire is 10% to 35% and the area percentage of the diffusion barrier layer is 10% to 25%.

Abstract: A precursor for manufacturing a Nb3Sn superconducting wire according to the present invention includes a mono-element wire including a Sn or Sn-based alloy core disposed at the, a Cu or Cu-based alloy matrix and a plurality of Nb or Nb-based alloy filaments surrounding the Sn or Sn-based alloy core, and a diffusion barrier layer and a stabilizing copper layer surrounding the Cu or Cu-based alloy matrix. In a final shape after a reduction process, the average diameter of the Nb or Nb-based alloy filaments is set to 5 ?m to 30 ?m, and the average distance between the Sn or Sn-based alloy core and the Nb or Nb-based alloy filaments nearest the Sn or Sn-based alloy core is set to 100 ?m or less.

Abstract: A bobbin for a superconducting coil includes a cylindrical drum, and a tapered portion extending from each end of the drum. A superconducting wire or a precursor of the superconducting wire shaped like a tape is helically wound around the drum in multiple layers. The tapered portion has a tapered surface that is inclined at an arbitrary angle.

Abstract: A method for manufacturing a powder-metallurgy processed Nb3Sn superconducting wire is provided. In the method, a sheath made of Nb or a Nb alloy is filled with a raw material powder containing Sn. The sheath filled with the raw material powder is subjected to diameter reduction to form a wire. The wire is heat-treated to form a superconducting phase at the internal surface of the sheath. The raw material powder is prepared by adding a Sn powder to a Cu—Sn alloy powder or a Cu—Sn intermetallic compound powder, and is compacted under isotropic pressure.

Abstract: A method for fabricating a Nb3Sn superconducting wire includes the steps of loading or inserting a core material containing at least Sn into a pipe member made of Nb or a Nb alloy, inserting the pipe member into a Cu billet to form a composite member, subjecting the composite member to diameter reduction, and then heat-treating the composite member to form a Nb3Sn superconducting layer from the inner surface of the pipe member, wherein, in the pipe member made of Nb or the Nb alloy after the diameter reduction, the average crystal grain size is 0.1 to 2 ?m, and preferably, the total concentration of oxygen, nitrogen, and carbon is 120 ppm or less.

Abstract: Disclosed herein are high-temperature oxide superconductors of RBa.sub.2 Cu.sub.4 O.sub.8 type, with Ba partly replaced by Sr or Ca, or with R and Ba partly replaced by Ca and Sr, respectively, as represented by the chemical composition formula of R(Ba.sub.1-y Sr.sub.y).sub.2 Cu.sub.4 O.sub.8 or R(Ba.sub.1-z Ca.sub.z).sub.2 Cu.sub.4 O.sub.8 or (R.sub.1-x Ca.sub.x) (Ba.sub.1-y Sr.sub.y).sub.2 Cu.sub.4 O.sub.8. They exhibit superconductivity at high temperatures. Especially, the last one exhibits superconductivity at a higher temperature than the former two. All of them can be made with a less amount of Ba as a deleterious substance, and the first two have improved sinterability. The best results are obtained when they are produced by the process involving the hot hydrostatic pressure treatment of the mixture of raw materials at 850.degree.-1100.degree. C. in an atmosphere composed of an inert gas and oxygen. The process permits a wider selection of Ba raw materials.

Abstract: A superconductive material is disclosed which has the following composition:(R.sub.1-x Ca.sub.x)(Ba.sub.1-y La.sub.y).sub.2 Cu.sub.4 O.sub.8wherein R is at least one element selected from Y, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb and Lu, x is a number in the range of 0-0.3 and y is a number in the range of 0.001-0.3 with the proviso that y is not greater than 0.2 when x is not 0.