| 摘要 |
1521346 Super-conductors BBC BROWN BOVERI & CO Ltd 24 March 1976 [26 March 1975] 11902/76 Heading C7D [Also in Divisions B3 and H1] A method of making a stabilized super-conductor containing filaments of super-conductive material in which a composite slug is mechanically deformed followed by the formation of superconductive filaments by the diffusion of at least one material in the matrix into a second material in filament form in the conductor, in which the middle region of the slug is provided with rods or wires 2 of the second material which are surrounded by a material 3 containing the diffusible material, and in the outer region wires or rods 4 of good electric conductivity which are surrounded individually or in groups with a diffusion-blocking barrier material 6 and a high resistance layer 5. Material 2 is of niobium, material 3 of bronze, material 4 is copper, material 5 of a copper-nickel alloy, and material 6 is tantalum. The diffusible material is tin. The conductor is surrounded with a tube 1 of copper-nickel alloy, brass or copperaluminium alloy. The slug is hot and/or cold worked into a wire with niobium filaments, with intermediate anneals if necessary for softening the bronze. The super-conductive compound Nb3Sn is formed by annealing the wire at between 500 and 900‹C to cause diffusion of the tin from bronze block 3 into the surface of the niobium filaments. Cylinder 1 may be removed by pickling in acid. In a second embodiment, Fig. 2 (not shown), niobium rods are in bronze tubes packed together, and are surrounded by copper rods in highresistance copper-nickel alloy and diffusionblocking tantalum layers, the whole being inserted into a brass cylinder and processed as above. Super-conductors V 3 Ga and V 3 Si may be made in a similar way. In place of niobium rods 2 or bronze tubes (7, Fig. 2), niobium rods in a copper or bronze matrix may be used and may be surrounded by a high-resistance layer 8 or (8'). Copper rods 4 may be surrounded by a material both diffusion-blocking and of high-resistance e.g. TaV alloy or TaNb alloy. Rods 4 may be further sub-divided by high-resistance layers. In Fig. 3 (not shown) the diffusion-material containing matrix 10 also extends between and outside the rods 4 so that the principal part of the matrix is on the outside of the slug and removed after the super-conductive material is formed, e.g. by pickling in acid. |
