National Research Institute for Metals

Other

Sumitomo Heavy Industries, Ltd.

National Institute for Materials Science

Mituba Electric Mfg. Co., Ltd.

Toshihisa Asano

Yoshiaki Tanaka

Hiroshi Maeda

Masao Fukutomi

Kazunori Komori

Fumiaki Matsumoto

Tomoyuki Yanagiya

Kyoji Tachikawa

Takao Takeuchi

Nobuya Banno

Hitoshi Wada

Yuji Yoshida

Shigeki Aoki

The present invention provides a high-temperature oxide superconductors, which comprises an oxide expressed as (BiA)&#x2014;B&#x2014;C&#x2014;Cu oxide (where, A is Sb and/or AS; B and C are elements different from each other, each being one or more elements selected from the group consisting of Be, Mg, Ca, Sr and Ba; and x is characterized by 0&#x2266;x&#x2266;1). According to the present invention, it is possible to manufacture a high-temperature oxide superconductor having a transition temperature of over 100 K and not containg a rare-earth element at all, and to manufacture an excellent superconductor in reliability and stability easilier than doing conventional superconductors such as Y&#x2014;Ba type ones.

High-temperature oxide superconductor

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.

Production method of Nb3Al superconducting multifilamentary wire

A clad superconductive wire or tape of an oxide superconductive material and a silver-copper alloy base containing 0.05-90 atomic % a copper or a silver alloy. The silver-copper alloy base contains one or more elements selected from the group of Zr, Hf, Al, V, Nb and Ta in amounts of from 0.01-3 atomic %, or contains Au in amount of 0.01-10 atomic %. The silver alloy contains one or more elements selected from the group of Ti, Zr, Hf, V, Nb, Ta, Mg, Ca, Sr and Ba in amounts of from 0.01 to 3 atomic %, or one or more elements selected from the group of Au, Al, Ga, In and Sn in amounts of 0.05 to atomic %. The base material is filled with a Bi-containing oxide of Bi,Pb,Sr,Ca,Cu,O,wherein u&equals;0-0.3, X&equals;0.8-1.2, y&equals;0.2-1.2, and z&equals;0.8-2.0, and processed to obtain a superconductive wire or tape having enhanced mechanical strength, superconductivity and plastic workability.

Oxide superconductive wire and process for manufacturing the same

A clad superconductive wire or tape of an oxide superconductive material and a silver-copper alloy base containing 0.05-90 atomic % copper or a silver alloy. The silver-copper alloy base contains one or more elements selected from the group of Zr, Hf, Al, V, Nb and Ta in amounts of from 0.01-3 atomic %, or contains Au in amount of 0.01-10 atomic %. The silver alloy contains one or more elements selected from the group of Ti, Zr, Hf, V, Nb, Ta, Mg, Ca, Sr and Ba in amounts of from 0.01 to 3 atomic %, or one or more elements selected from the group of Au, Al, Ga, In and Sn in amounts of 0.05 to atomic %. The base material is filled with a Bi-containing oxide of Bi,Pb,Sr,Ca,Cu,O,wherein u&equals;0-0.3, X&equals;0.8-1.2, y&equals;0.2-1.2, and z&equals;0.8-2.0, and processed to obtain a superconductive wire or tape having enhanced mechanical strength, superconductivity and plastic workability.

A clad superconductive wire or tape of an oxide superconductive material and a silver-copper alloy base containing 0.05-90 atomic % copper or a silver alloy. The silver-copper alloy base contains one or more elements selected from the group of Zr, Hf, Al, V, Nb and Ta in amounts of from 0.01-3 atomic %, or contains Au in amount of 0.01-10 atomic %. The silver alloy contains one or more elements selected from the group of Ti, Zr, Hf, V, Nb, Ta, Mg, Ca, Sr and Ba in amounts of from 0.01 to 3 atomic %, or one or more elements selected from the group of Au, Al, Ga, In and Sn in amounts of 0.05 to atomic %. The base material is filled with a Bi-containing oxide of Bi.sub.1 Pb.sub.u Sr.sub.x Ca.sub.y Cu.sub.z O.sub.w wherein u=0-0.3, x=0.8-1.2, y=0.2-1.2, and z=0.8-2.0, and processed to obtain a superconductive wire or tape having enhanced mechanical strength, superconductivity and plastic workability.

Oxide superconductive wire and process for manufacutring the same

A clad superconductive wire or tape of an oxide superconductive material and a silver-copper alloy base containing 0.05-90 atomic % copper or a silver alloy. The silver-copper alloy base contains one or more elements selected from the group of Zr, Hf, Al, V, Nb and Ta in amounts of from 0.01-3 atomic %, or contains Au in amounts of 0.01-10 atomic %. The silver alloy contains one or more elements selected from the group of Ti, Zr, Hf, V, Nb, Ta, Mg, Ca, Sr and Ba in amounts of from 0.01 to 3 atomic %, or one or more elements selected from the group of Au, Al, Ga, In and Sn in amounts of 0.05 to 5 atomic %. The base material is filled with a Bi-containing oxide of Bi.sub.1 Pb.sub.u Sr.sub.x Ca.sub.y Cu.sub.z O.sub.w wherein u=0-0.3, X=0.8-1.2, y=0.2-1.2, and z=0.8-2.0, and processed to obtain a superconductive wire or tape having enhanced mechanical strength, superconductivity and plastic workability.

A substrate electrode having a plurality of substrate holders capable of causing a substrate to tilt by an arbitrary angle .theta. relative to the horizontal plane is provided. A plurality of auxiliary electrodes are arranged substantially vertically below the substrate electrode and between the substrate electrode and a target. The substrate electrode and the auxiliary electrodes are electrically insulated from the target. Bias voltage applied to the substrate electrode and the auxiliary electrodes causes the plasma boundary between the cathode dark space and the negative glow to form a cathodic plasma space having a parabolic section, thus forming a crystal-oriented thin film on the substrate surface.

Crystal-oriented thin film manufacturing apparatus

A compacted and highly oriented microstructure of the bulk-shaped Bi-Sr-Ca-Cu-O system oxide superconductor is obtained by the intermediate pressing method of the present invention. The growth rate of the high critical temperature phase in the bulk of Pb-doped Bi-Sr-Ca-Cu-O system oxide superconductor is also much improved and the sintering duration for obtaining a single phase having a high critical temperature is shorteneed by this method. Additionally, a higher critcal current density of Bi-Sr-Ca-Cu-O system oxide superconductor is obtained by the working under pressure process after cooling between a first and a second sintering step. Furthermore, the magnetic field dependence of the critical current density of Bi-Sr-Ca-Cu-O system oxide superconductor is also improved by the method of the present invention. The thus intermediate pressing process between the first and second sintering step of the present invention may be applied so easily as to facilitate the manufacture of tapes, wires, discs or the like of the Bi-Sr-Ca-Cu-O system oxide superconductor.

Method for manufacturing oxide high-temperature superconductor

In a method for producing an Nb.sub.3 Sn superconductor which comprises elongating a composite composed of a core portion of an alloy containing niobium and a matrix portion of a copper-tin alloy, a copper-tin-aluminum alloy or a copper-tin-gallium alloy and heat-treating the elongated composite to form an Nb.sub.3 Sn layer between the core portion and the matrix portion; the improvement wherein the core portion of the composite is made of a niobium-titanium alloy containing 0.1 to 10 atomic percent of titanium.

Method for producing Nb.sub.3 Sn superconductors

In a method for producing V.sub.3 Ga superconductors which comprises forming a composite of a core portion and a sheath portion surrounding said core portion, said sheath portion being composed of a gallium-containing alloy selected from the group consisting of copper-gallium and copper-silver-gallium alloys, and said core portion being composed of a vanadium metal, elongating said composite, and heat-treating the resulting elongated composite to form a V.sub.3 Ga layer between said sheath and core portions; the improvement wherein the gallium-containing alloy has a gallium content of 0.1 to 30 atomic percent and additionally contains at least one metal selected from the group consisting of 0.05 to 5 atomic percent of magnesium, 0.5 to 10 atomic percent of aluminum, 0.1 to 10 atomic percent of cerium and 0.05 to 10 atomic percent of sodium, and the vanadium metal is a vanadium alloy containing 0.1 to 15 atomic percent of gallium.

Growing community of inventors

Tsukuba, Japan

Toshihisa Asano