METHOD OF AFTER TREATMENT OF A SUPER CONDUCTOR

摘要

1394297 Super-conductors SIEMENS AG 13 Nov 1973 [20 Nov 1972] 52725/73 Addition to 1245239 Headings H1A A5 and A4D A super-conductor comprising a support having a surface layer of Nb 3 Sn containing from 0À4 to 1À1 wt. per cent of C according to the main Specification 1245339 is annealed for a period of from more than 1 minute up to 100 minutes at 500-1000‹C in an inert gas or in vacuo. The annealing step increases the critical current density of the super-conductor particularly for transverse magnetic fields parallel to the larger surface of the flat strip structure of the preferred arrangement. In a specific embodiment a support strip of Ni-Mo alloy is coated with Nb3Sn containing 0À83 wt. per cent C by decomposition of NbCl 4 , SnCl 2 and CO as in the main patent. The strip is then heated for 30 minutes at 800‹C in an atmosphere of pure argon, and then allowed to cool rapidly. The strip is especially suitable for winding into coils.