GB1459716A - Method of producing a superconductor - Google Patents

Abstract

1459716 Nb-Cu composite for superconductors KABELUND METALLWERKE GUTEHOFFNUNGSHUTTE AG 13 Feb 1975 [19 Feb 1974] 6155/75 Heading H1A [Also in Division B3] In a method of producing a Nb-Cu superconductor, the Cu conductor is cast round a body of superconductive Nb, and cooled, so that the Nb is totally surrounded in cross-section. Preferably the composite body is continuously cast, the Nb strip or wire 2 being supplied from a reel, passing over roller 3 and is fed by rollers 4 into a continuous casting mould 5 of any desired shape. To ensure centralization of the Nb, the strip or wire 2, which is smaller than the material dimensions of mould 5, is fixed to the vertically movable ram 7 forming the base of mould 5 prior to casting. Liquid Cu 6 is poured into the mould, the resulting billet 8 being cast with the Nb centrally located. The composite NbCu body 8, in which the Nb and Cu are joined by a diffusion layer may be hot rolled, annealed, cold rolled to under 0À5 mm. and further annealed, the strip so formed being shaped into a tube, the edges of which 10, 11 may be welded 14. The resulting tube 17, may be corrugated at 15 and wound on to a drum 16. From the corrugated superconductor so formed, cables of great length may be produced. An example of a cable with a number of coaxial corrugated tubes, the innermost being the superconductor 17 is shown in Fig. 4, the spaces between the tubes being packed with "superinsulators" or evacuated. This type of cable has excellent heat insulation properties and is flexible and can accommodate thermal expansions and contractions due to the corrugations, and due to the diffusion layer between the Cu and Nb, is mechanically strong enough to withstand deformation.