Hitachi, Ltd.

The University of Tokyo

Junichi Shimoyama

Motomune Kodama

Hideki Tanaka

Takaaki Suzuki

Kazuhide Tanaka

Akiyasu Yamamoto

The following two problems arise when carbon is added to a starting material powder in the process of production of an MgBsuperconductor: (1) an impurity phase increases; and (2) the degree of substitution of carbon at boron sites is spatially non-uniform. This superconductor production method comprises: a mixing step of mixing a starting material powder and an additive; and a heat treatment step of heat-treating the mixture prepared in the mixing step. The starting material powder is MgBpowder or a mixed powder of magnesium and boron, and the additive is an Mg&#x2014;B&#x2014;C compound containing three elements of magnesium, boron and carbon.

Method of producing superconductor

An MgBsuperconducting wire excellent in critical current density property is supplied by using a crystalline boron powder which is low in costs and easy to obtain. For the wire, a precursor of the MgBsuperconducting wire is used, the precursor having a linear structure including a core region containing a magnesium powder and a boron powder, and a sheath region formed of a metal covering an outer circumferential portion of the core region. The boron powder is crystalline, and has a volume-mean particle size of 2 &#x3bc;m or less.

Precursor of MgB2 superconducting wire, and method for producing the same

Growing community of inventors

Sagamihara, Japan

Junichi Shimoyama