GB1140696A - Superconducting magnets - Google Patents

Abstract

1,140,696. Superconductors; electromagnets. UNION CARBIDE CORP. 13 May, 1966 [14 May, 1965], No. 21272/66. Headings H1K and H1P. A superconducting magnet comprises superconducting layers alternating with layers of non-superconducting material. The superconducting layers, which are each constituted of particles bonded together at their interfaces and preferably form a helix, are mutually isolated except at their ends, through which they are interconnected. The superconducting layers are preferably deposited over a cylindrical substrate and then machined to helical form. The material of the layers or if it is a compound or alloy, its components, may be introduced in powdered form into a plasma jet produced by passing a gas stream through an electric arc. Layers of niobium-zirconium alloy, vanadium silicide, niobium aluminide, niobium stannide and niobium-tin-zirconium alloy may be formed by directing such a jet on a brass or aluminium substrate which may be cooled during the process. The plasma may in this case consist of argon or helium. On the other hand niobium oxynitride compounds may be deposited by detonating a fuel charge in a confined chamber and introducing niobium powder into the resulting plasma. In all cases the surfaces of the particles become molten so that they adhere when deposited. The superconducting properties are improved by subsequent heat treatment. In the preferred method the first superconductor layer is deposited on a cooled copper mandrel and layers of alumina and copper deposited over this after it has been machined to helical form. The process is then repeated to give the requisite number of layers. The resulting assembly, in which the superconducting helices may be connected in any series, parallel or series-parallel arrangement is shrink fitted into a cylindrical titanium or stainless steel casing.