National Institute for Materials Science

Nobuya Banno

Takao Takeuchi

Toshihisa Asano

Hitoshi Wada

Kyoji Tachikawa

A superconducting connection structure is provided with: a connection strip that comprises an Nb alloy strip to which an element M is added (wherein the element M is an element which increases the recovery temperature and the recrystallization temperature of Nb); an NbSn superconducting wire rod that comprises an NbSn superconducting core material; and an NbTi wire rod that comprises an NbTi core material. With respect to this superconducting connection structure, one end of the connection strip is connected to the NbSn superconducting wire rod by having the Nb alloy strip and the Nb3Sn superconducting core material in contact with each other by the intermediary of an Nb3Sn superconducting layer; and the other end of the connection strip is connected to the NbTi wire rod by having a newly formed surface of the Nb alloy strip and a newly formed surface of the NbTi core material in contact with each other.

Superconducting connection structure of Nb3Sn superconducting wire rod and NbTi wire rod, method for producing same, and nuclear magnetic resonance apparatus using same

In the production of an internal-tin-processed NbSn superconducting wire, the present invention provides a NbSn superconducting wire that is abundant in functionality, such as, the promotion of formation of a NbSn 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 NbSn superconducting wire according to an embodiment of the present invention includes a step of providing a barthat has a Sn insertion holeprovided in a central portion of the barand a plurality of Nb insertion holesprovided discretely along an outer peripheral surface of the Sn insertion hole, 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 holeand inserting Nb cores into the Nb insertion holes, a step of subjecting the barto 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 NbSn phase generation heat treatment.

Method for producing Nb3Sn superconducting wire, precursor for Nb3Sn superconducting wire, and Nb3Sn superconducting wire using same

A composite barrier-type NbAl superconducting multifilament wire material comprises Nb barrier filaments, Ta barrier filaments, Nb bulk dummy filaments, and a Nb or Ta covering. In the composite barrier-type NbAl superconducting multifilament wire material, the Nb barrier filaments and Ta barrier filaments are disposed in the wire material so that the Nb barrier filaments are concentrated in a filament region near a core formed from the Nb bulk dummy filaments and only the Ta barrier filaments are disposed or the Nb barrier filaments are dispersed in the Ta barrier filaments in an outer layer portion formed from a region outside the Nb barrier filaments, excluding the Nb or Ta covering.

Composite barrier-type Nb3AI superconducting multifilament wire material

A composite multi-core wire rod in which a plurality of Al alloy wires containing 15 at % to 40 at % of Ge are arranged in Nb matrix at a core diameter of 2 &#x3bc;m to 20 &#x3bc;m is subjected to heating for at least five hours at a temperature ranging from 1300&#xb0; C. to 1600&#xb0; C.; and additionally heating at a temperature ranging from 650&#xb0; C. to 900&#xb0; C.

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This invention provides a production method of Nb Al superconducting multifilamentary wire based on rapid-heating, quenching and transformation method, capable of producing a high-performance Nb Al superconducting multifilamentary wire by improving critical temperature thereof, upper critical field and critical current density. Upon a first stage heat treatment of beating a composite, in which bcc phase Nb&mdash;Al supersaturated solid solution is dispersed in Nb matrix, the bcc phase Nb&mdash;Al supersaturated solid solution ordered in temperature rise process is made disordered at an initial phase thereof and a non-reacting portion located adjacent is heated using a reaction heat generated when transforming this disordered bcc phase to A15 phase. Then, disordering of the bcc phase is promoted while propagating a high-temperature transformation region so as to automatically progress high-temperature beat treatment. As a result, a reaction-transformation is caused to block stacking fault from being generated in the A15 phase and crystal grain from being coarse and then, a second stage heat treatment for improving a long range ordering of the A15 phase is carried out.

Growing community of inventors

Ibaraki, Japan

Nobuya Banno