Abstract: A composite member is prepared which comprises a core which will have a compound superconducting layer when heat-treated, and a stock for forming a stabilizing member made of copper and surrounding the core. The composite member is heat-treated in an oxidizing atmosphere, thus forming a copper-oxide thin layer on the surface of the stock. Thereafter, the composite member is heat-treated in a non-oxidizing atmosphere or in an atmosphere having an oxygen partial pressure which is too low to allow the forming of copper oxide. As a result, a compound superconducting wire is made which comprises a member including a compound superconductor, a diffusion-preventing layer made of oxide and surrounding the member, and a stabilizing member made of copper and surrounding the layer.

Abstract: A composite member is prepared which comprises a core which will have a compound superconducting layer when heat-treated, and a stock for forming a stabilizing member made of copper and surrounding the core. The composite member is heat-treated in an oxidizing atmosphere, thus forming a copper-oxide thin layer on the surface of the stock. Thereafter, the composite member is heat-treated in a non-oxidizing atmosphere or in an atmosphere having an oxygen partial pressure which is too low to allow the forming of copper oxide. As a result, a compound superconducting wire is made which comprises a member including a compound superconductor, a diffusion-preventing layer made of oxide and surrounding the member, and a stabilizing member made of copper and surrounding the layer.

Abstract: An improved multifilament superconductor is fabricated by the method in which a tin rod or tin based alloy rod is clad with a copper based alloy tube, the thus obtained copper-clad rod is further clad with a niobium based alloy tube, and a copper material is applied as a stabilizer on an outer peripheral surface of the niobium based alloy tube to form a composite. This composite is then reduced and thermally treated at a temperature ranging from 640.degree. to 770.degree. C. to thereby form an Nb.sub.3 Sn superconductor composite with a filament tube therein. At least one of the copper based alloy tube and the niobium based alloy tube contains 0.1-5.0 at. % titanium, and in addition, the tin based alloy rod may contain 0.1-3.5 at. % titanium. The tin is contained in the copper-clad rod at weight % of about 25-85, preferably 30-80 weight %.

Abstract: A compound-superconducting coil of the type including a plurality of superconducting wires in a tube and forcing a coolant through the tube. The subject compound-superconducting coil comprises a plurality of compound-superconducting wires and a tube for receiving the plural wires. Void spaces are provided in the interior of the tube to allow for the passage of a coolant. The void fraction is 45% to 70% of the tube interior. The subject compound-superconducting coil, when brought to a superconducting condition, allows for the passage of a current whose magnitude accounts for at least 80% of a critical current observed when the wire is strain-free state.

Abstract: A method of making stabilized superconductors of a composition such as Nb.sub.3 Sn is disclosed. The method includes forming a stock product comprising a tin base alloy as a core with a copper jacket and having a niobium tube clad thereon. The stock product is then embedded in a good thermally and electrically conducting matrix which is then coreduced until the desired size is obtained. This cold worked product is then submitted to a heat treatment to form superconductors of Nb.sub.3 Sn.