Reducing the Effective Filament Diameter of Niobium-Tin Superconductors

Niobium tin superconductors have had large improvements in current density over the past few years. However, the effective filament diameters of these conductors are too large, which can limit their application in areas such as High Energy Physics Colliders, Fusion Devices, and laboratory electromagnets. The filament diameter limits have been shown to be caused by fundaments limits in the cold drawing process. An alternate technology, hydrostatic drawing, has been shown to remove these limits and will be capable of producing multi-filament superconductors with much smaller effective filament diameters. In this project, several billets, using two different conductor architectures, will be processed to produce short samples of conductors having filament sizes below 30µ. The samples will be tested to see if the reduction in filament diameters is affecting the critical current density. The most promising candidate design will be selected and long (>1,000 foot) lengths of the conductor will be produced in Phase II for testing in magnet systems. Commercial Applications and other Benefits as described by the awardee: Presently available superconductors are placing limits on the designs of systems. An improved niobium tin superconductor should displace the existing materials in many applications within a relatively short time frame. The present commercial market for niobium tin superconductors is approximately $20,000,000 per year.