National Institute for Materials Science

National Research Institute for Metals

Central Japan Railway Company

Kabushiki Kaisha Toshiba

Hitachi, Ltd.

Hiroaki Kumakura

Hitoshi Kitaguchi

Kazumasa Togano

Kyoji Tachikawa

Hideyuki Yamada

Akiyoshi Matsumoto

Shujun Ye

Yutaka Yamada

Michiya Okada

Mitsuo Sasaki

Hiroki Fujii

Kazuhide Tanaka

Akira Hasegawa

Satoru Murase

Masaya Takahashi

Eiki Yasukawa

Yoshihiko Takano

Susumu Tsukamoto

Yoshimi Kubo

Hirosada Irie

Ei Nakamura

Hanping Miao

Masazumi Hirakawa

Yoshikazu Mizuguchi

Takayuki Nakane

Nobuhito Uchiyama

Akihiro Nomura

Provided is a method for manufacturing a base material powder having a carbon nanocoating layer, the method including adding a polycyclic aromatic hydrocarbon to a base material powder, heating the mixture to a temperature that is higher than or equal to the boiling point of the polycyclic aromatic hydrocarbon and is lower than or equal to the relevant boiling point temperature+300&#xb0; C., and that is higher than or equal to the thermal decomposition temperature of the polycyclic aromatic hydrocarbon, and thereby coating the surface of the base material powder with a layer of carbon having a thickness of 0.1 nm to 10 nm. According to the method, when a source of carbon that covers a base material powder is appropriately selected, the base material powder having the carbon nanocoating layer can be provided, which does not have a possibility of causing inconveniences in the applications of a final manufactured product of the base material powder and exhibits satisfactory productivity of the base material powder, and from which a modified final manufactured product is obtained.

Method for manufacturing base material powder having carbon nano-coating layer, method for manufacturing MgB2 superconductor using the method, MgB2 superconductor, method for manufacturing positive electrode material for lithium ion battery, lithium ion battery, and method for manufacturing photocatalyst

Provided are a method for manufacturing MgBsuperconductor by pressure molding a mixture of Mg powder or MgHpowder and B powder and heat-treating the mixture, the method including (I) a step of adding a polycyclic aromatic hydrocarbon to the B powder, while heating the mixture to a temperature higher to or equal to the melting point of the polycyclic aromatic hydrocarbon at the time of this addition, and thereby covering the surface of the B powder with the polycyclic aromatic hydrocarbon; and (II) a step of mixing the B powder having the surface covered with the polycyclic aromatic hydrocarbon, with the Mg powder or the MgHpowder, or a step of combining the B powder having the surface covered with the polycyclic aromatic hydrocarbon, with an Mg rod; and an MgBsuperconducting wire which has high critical current density (Jc) characteristics and less fluctuation in the critical current density (Jc).

[object Object]

Disclosed is an iron-based superconducting wire comprising a tubular material formed mainly from iron, and an iron-based superconductor formed in the tubular material, wherein the iron-based superconductor contains the iron forming the tubular material as a chemical constituent element of the iron-based superconductor.

Iron-based superconducting wire and method for producing the same

In a fabrication method of a MgBsuperconducting tape and wire by filling a tube with a MgBsuperconducting powder and forming it into a tape or wire, a fabrication method of a MgBsuperconducting tape (and wire) which is characterized by using a MgBsuperconducting powder having a high critical current density (J) owing to its lowered crystallinity and having potential for excellent grain connectivity as the MgBsuperconducting powder. Provided are a fabrication method of a MgBsuperconducting tape and wire which can fabricate a MgBsuperconducting tape and wire having a level of Jsufficiently high for practical applications and homogeneous quality throughout its length by an ex-situ process employing a material of the composition suitable for its working environment as the sheath material, and a MgBsuperconducting tape and wire thereby fabricated.

The present invention provides a method for producing a MgBsuperconductor, comprising compacting and heating a mixture comprising Mg or MgHpowder and B powder, wherein said mixture comprises SiC powder and an aromatic hydrocarbon, and a MgBsuperconductor having a higher critical current density (J) than that of the known MgBsuperconductors added SiC only or added an aromatic hydrocarbon only such as benzene.

By adding an aromatic hydrocarbon such as benzene to the powder mixture of magnesium (Mg) or magnesium hydride (MgH) and boron (B) as raw materials of a superconductor MgB, high superconducting critical current density (Jc) is obtained.

MgB2 superconductor, its wire, and a manufacturing method thereof

In a metal sheath MgBsuperconducting wire, it is intended to achieve a wire having increased current density and a long length at the same time, by densitying superconducting core part. The superconducting wire is manufactured by forming diffusion hardened layer on the inner surface of the sheath such that the hardness of the inner surface becomes higher than that of the outer surface, filling MgBsuperconductor, and further if necessary, a critical current density increasing material such as indium, copper, and tin, in a metal sheath, to subject it to wire drawing. For the metal sheath, a material with toughness such as steel is used. Even if the sheath is made to a long wire, it does not break, thereby, enabling to density superconducting core part.

Metal sheath magnesium diboride superconducting wire and its manufacturing method

In a process in which a composite consisting of a metallic base and a superconductor mainly containing a Bi,Sr,CaCu,O,superconducting phase is formed into a composite wire or wire, the composite is subjected to calcination and cold working before heat treatment for crystallization from a partial molten state.

Making of bismuth 2212 superconducting wire or tape

A powder having a predetermined composition is filled in a tube. The tube is drawn to obtain a wire and the wire is rolled to obtain a tape-like starting body. Then, a laser beam is irradiated on the part of the tape to heat and melt the part of the tape. The starting body is rapidly heated and then cooled, thereby the part of the starting body is melted and solidified to form a compound superconductor layer.

Method of manufacturing compound superconductors

A process for producing a superconducting compound tape or wire material, which comprises irradiating electron beams at an acceleration voltage of 5 to 150 KV on a starting tape or wire material consisting essentially of constituent elements of a superconducting compound, a compound between the constituent elements, and/or an alloy between the constituent elements at a power density, determined on the starting tape or wire material, of 1.times.10.sup.3 to 1.times.10.sup.7 W/cm.sup.2 while the starting tape or wire material is moved at a rate of 1 cm to 10 m/sec relative to the electron beams.

Process for producing superconducting compound tape or wire material by

An A-15 type superconductor compound having the composition A.sub.3 B composed of niobium (element A) and at least one element (B) selected from gallium, aluminum and germanium is produced by coating at least one element B on a substrate of niobium, heat-treating the coated niobium substrate at a temperature of 500.degree. to 2,000.degree. C. for 1 second to 300 hours to form intermetallic compounds of niobium and the coated element which are richer in element B than A-15 A.sub.3 B compound, and thereafter subjecting the substrate to the irradiation of high density energy beams such as electron beams or laser beams to form the A-15 type superconductor compound having the composition A.sub.3 B.

Growing community of inventors

Ibaraki, Japan

Hiroaki Kumakura