Sumitomo Electric Industries, Limited

Ube Industries, Inc.

International Superconductivity Technology Center

Matsushita Electrical Industrial Co., Ltd.

Tetsuyuki Kaneko

Shinichi Kobayashi

Naoki Ayai

Ryosuke Hata

Akira Mikumo

Munetsugu Ueyama

Shoji Tanaka

Kazuyuki Hamada

Jun Fujikami

Hisao Yamauchi

Seiji Adachi

Shin-ichi Kobayashi

Shin-ichi Kobayasi

Tetsuaki Sashida

The invention offers a superconducting coil that has the shape of a pancake formed by winding a superconducting conductor. The superconducting conductor is composed of a tape-shaped (Bi, Pb)2223-based superconducting wire and a tape-shaped thin-film RE123-based superconducting wire that are electrically connected in parallel with each other. The coil generates only a low voltage in the steady-operation state, limits the generated voltage to a low level even in a state where an external disturbance enters for some reason, and is therefore less susceptible to quenching. Consequently, the coil can be operated stably in both states. The invention also offers a superconducting conductor to be used to form the coil.

Superconducting coil and superconducting conductor for use therein

In order to provide a superconducting wire that has a high critical current value, has no defects such as bulges, and has high mechanical strength, an oxide superconducting material ( ) is covered, and ceramic particles or fibers ( ) are buried in the surface of a covering ( ) made of metal

Superconducting wire

The method of preparing an oxide superconducting wire comprises steps of preparing a wire by coating raw material powder for a Bi&mdash;Pb&mdash;Sr&mdash;Ca&mdash;Cu&mdash;O based oxide superconductor including a 2223 phase with a metal and heat treating the wire in a pressurized atmosphere containing oxygen in a prescribed partial pressure, and the total pressure of the pressurized atmosphere is at least 0.5 MPa. The pressure heat treatment apparatus comprises a pressure furnace storing and heat treating a target in a pressurized atmosphere, a pressure regulator for measuring the total pressure in the pressure furnace, an oxygen concentration meter for measuring the oxygen concentration in the pressure furnace and a controller for controlling the oxygen partial pressure in the pressure furnace in response to the total pressure measured by the pressure regulator and the oxygen concentration measured by the oxygen concentration meter.

Pressure heat treatment apparatus employed for preparing oxide superconducting wire

The present invention provides an oxide superconducting wire including a component provided in the form of a tape and a metal tape. The component in the form of a tape has an oxide superconducting member and a metal coating member formed mainly of silver and coating a surface of the oxide superconducting member. The metal tape, bonded in a heat treatment (e.g., fusion- or diffusion-bonded) to a surface of the component in the form of a tape, does not contain any superconducting material and it is formed mainly of silver and it also contains at least one component other than silver.

Method of manufacturing superconducting wire

Method of preparing oxide superconducting wire and pressure heat treatment apparatus employed for the method

The diameter of a first metal tube charged with raw material powder is reduced for obtaining an elementary wire. A plurality of such elementary wires are charged into a second metal tube, which in turn is reduced in diameter for obtaining a round first wire having a plurality of first filaments. The first wire is uniaxially compressed thereby obtaining a tape-like second wire having a plurality of second filaments. The second wire is heat treated thereby obtaining an oxide superconducting wire including a plurality of superconductor filaments. The maximum grain size of the raw material powder is smaller than the minor diameter of the first or second filaments.

Method of preparing oxide superconducting wire

Superconducting wire and method of manufacturing the same

A multifilamentary oxide superconducting wire having a low aspect ratio and a relatively high critical current density, and being suitable for a stranded wire. In order to produce such a wire, a tape-shaped, multifilamentary oxide superconducting wire prepared by the powder-in-tube process is cut along its length. The resulting multifilamentary oxide superconducting wires have a width smaller than that of the tape-shaped wire. The resulting wires typically have an aspect ratio of one to two. The filaments of the resulting wires are in the shape of a ribbon extending in the longitudinal direction, and arranged substantially parallel to each other and in layers. The filaments have an aspect ratio greater than two. The filaments inside include a filament having a portion substantially not covered with the stabilizer.

Multifilamentary oxide superconducting wire and method of producing the same, and stranded oxide superconducting wire and method of producing the same

Powder including at least a superconducting phase is degassed (step S ). After the powder is filled in a silver pipe (step S ), the silver pipe is degassed at a high temperature (step S ). After a plurality of single-core wires are inserted into another silver pipe to attain a multi-core structure, the silver pipe is degassed at a high temperature (step S ). The silver pipe is sealed under a reduced pressure (step S ). Therefore, even when a multi-core superconducting wire is manufactured, a manufacturing method of a superconducting wire capable of preventing swelling of the wire caused by a residual gaseous component can be obtained.

Manufacturing method of superconducting wire

Method and apparatus of measuring a critical current value of a superconducting wire formed by wire sections S(n), n being 1.ltoreq.n.ltoreq.N and initially set to 1, comprising a first step (a) of determining electric currents I(m), m being 1.ltoreq.m.ltoreq.M; a second step (b) of setting m to 1; a third step (c) of passing the electric current I(m) through the wire section S(n); a fourth step (d) of detecting a voltage generated in the wire section S(n) by the electric current I(m); a fifth step (e) of replacing m with m+1; a sixth step (f) of repeating the steps (c) to (e) until m is equal to M; a seventh step (g) of replacing n with n+1; an eighth step (h) of repeating the steps (b)-(g) until n is equal to N, thereby obtaining N.times.M voltages; a ninth step (i) of setting m to 1; a tenth step (j) of summing up the N voltages generated by the same electric current I(m) to obtain a summation voltage represented by Vsum(m); an eleventh step (k) of replacing m with m+1 after the step (j); a twelfth step (l) of repeating the steps (j) and (k) until m is equal to M, thereby obtaining M summation voltages Vsum(m); and a thirteenth step (m) of calculating the critical current value of the superconducting wire on the basis of a reference voltage and a relationship between the summation voltages Vsum(m) and the electric currents I(m), the reference voltage being predetermined depending upon the superconducting wire length.

Method and apparatus for measuring critical current value of

In order to provide a Tl--Ba--Ca--Cu--O superconductive material which can obtain a stable superconducting state and a method of preparing the same, the oxide superconductive material is expressed in the following composition formula:

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Osaka, Japan

Tetsuyuki Kaneko