Mitsubishi Denki Kabushiki Kaisha

Kunihiko Egawa

Takayuki Nagai

Yoshio Kubo

Fusaoki Uchikawa

Hiroko Higuma

Shinichi Kinouchi

Shoji Miyashita

Osamu Taguchi

Takanori Sone

Toshio Umemura

Ayumi Nozaki

Shin Utsunomiya

Masayoshi Wake

Mitsunobu Wakata

Kiyoshi Hiramoto

A method of producing NbSn superconducting wire, including the steps of: preparing a plurality of Sn modules obtained by burying Sn-based metal cores in a Cu-based metal matrix and a plurality of Nb modules obtained by burying Nb-based metal filaments in a Cu-based metal matrix; bundling the Nb modules and the Sn modules such that the Nb modules surround the Sn modules and obtaining an assembly; inserting the assembly in a tubular member of Cu-based metal which internally comprises tube-like shaped Ta-based metal or Nb-based metal which serves as a diffusion barrier and obtaining a composite; drawing the composite; and heat-treating the composite.

Method of producing superconducting wire

A method for manufacturing a Sn-based alloy containing a finely dispersed Sn&mdash;Ti compound includes melting Sn by heating to a temperature in a range from 1300 to 1500&deg; C. in vacuum or an inert gas atmosphere, adding 0.1 to 5% by weight of Ti followed by melting by heating, and casting the molten alloy into a copper mold directly or through a pouring cup. The Sn-based alloy obtained by this method contains the Sn&mdash;Ti compound having a maximum particle diameter of 30 &mgr;m and a mean particle diameter of 5 to 20 &mgr;m. A precursor of a Nb Sn wire is also obtained by an inner diffusion method using this Sn-based alloy. The Nb Sn wire manufactured by using the Sn-based alloy of the present invention exhibits excellent superconductive characteristics. The method of the present invention enables the ingot to be free from a shrinkage cavity appearing during prior art manufacturing processes.

Sn based alloy containing Sn&mdash;Ti compound, and precursor of Nb3SN superconducting wire

A compound superconducting wire comprising a matrix of CuX alloy and a multiplicity of Z.sub.3 X filaments embedded in the matrix in a spaced relationship so as not to come into contact with each other wherein X is Sn or Ga and Z.sub.3 X is Nb.sub.3 Sn or V.sub.3 Ga. In a precursor, therefore, a multiplicity of filaments of a base metal material Z such as Nb are arranged in a Cu base metal matrix concentrically in layers around a center core of a base metal material X such as Sn, in which the spacing between any adjacent filaments arranged in a former boundary region of an .epsilon.-phase bronze layer having a certain radius from the center produced when the precursor is preheat-treated at a temperature of 300.degree. to 600.degree. C. is made larger than the spacing between any adjacent filaments arranged in the other matrix regions. Also disclosed is a precursor wire wherein a composite of a Cu base metal material and a base metal material X capable of forming an alloy with the Cu base metal material is used as a matrix without arranging a core of the base metal material X at the center, and a multiplicity of filaments of a base metal material Z are embedded in the composite in a spaced relationship.

Method for manufacturing superconducting wire

A compound superconducting wire comprising a matrix of CuX alloy and a multiplicity of Z.sub.3 X filaments embedded in the matrix in a spaced relationship so as not to come into contact with each other wherein X is Sn or Ga and Z.sub.3 X is Nb.sub.3 Sn or V.sub.3 Ga. In a precursor, therefore, a multiplicity of filaments of a base metal material Z such as Nb are arranged in a Cu base metal metrix concentrically in layers around a center core of a base metal material X such as Sn, in which the spacing between any adjacent filaments arranged in a former boundary region of an .epsilon.-phase bronze layer having a certain radius from the center produced when the precursor is preheat-treated at a temperature of 300.degree. to 600.degree. C. is made larger than the spacing between any adjacent filaments arranged in the other matrix regions. Also disclosed is a precursor wire wherein a composite of a Cu base metal material and a base metal material X capable of forming an alloy with the Cu base metal material is used as a matrix without arranging a core of the base metal material X at the center, and a multiplicity of filaments of a base metal material Z are embedded in the composite in a spaced relationship.

Compound superconducting wire and method for manufacturing the same

A process for preparing a superconducting wire having improved superconducting characteristics in shortened period of time at a reduced cost, which comprises the steps of forming a plurality of holes in each of Cu base metal plates, stuffing the plates in a supporting container to form a stacked body of the plates with their holes aligned with each other, stuffing a superconductor or a material convertible into a superconductor by a heat treatment into the resulting through-holes of the stacked body, evacuating and sealing the supporting container to form a composite billet, and processing the composite billet in a usual manner to give a superconducting wire.

Process for preparing superconducting wire

A method for manufacturing the oxide superconductor according to the present invention comprises the steps of: mixing a starting material including Bi, Sr, Ca and Cu such that a mole ratio of Bi, Sr, Ca and Cu is 2:2+a:1+b:2+c, wherein a.gtoreq.0, b.gtoreq.0, c.gtoreq.0, and 0&lt;a+b+c&lt;3; melting the mixed material at a temperature of 900.degree. C.-1500.degree. C.; quenching rapidly the molten material; and annealing the quenched material at a partial molten temperature of 800.degree. C.-1000.degree. C. This method gives product wherein a precipitate of at least one compound in the group SrO, CuO and (Ca.sub.1-x Sr.sub.x).sub.2 CuO.sub.3 (wherein 0.gtoreq.x&lt;1) is finely dispersed in the superconducting crystal of Bi.sub.2 Sr.sub.2 Ca.sub.1 Cu.sub.2 O.sub.y (wherein y is about 8). The precipitates act as flux pinning centers. Further, an oxide superconductor according to the present invention comprises superconducting crystal consisting of Bi, Sr, Ca and Cu oxides and separate oxide phases including Pt as a principal component being finely dispersed in the superconducting crystal. These finely dispersed oxides including Pt act as flux pinning centers.

Growing community of inventors

Amagasaki, Japan

Kunihiko Egawa