A Method to Increase Current Density in a Mono Element Internal Tin Process Superconductor Utilizing ZrO2 to Refine the Grain Size

65026 Magnets for the next generation of high energy physics accelerators require higher superconductor performance to enable magnetic fields up to 15T. The superconductors must also be cost effective so that the magnets, and hence the accelerators, will be economically viable. This project will use zirconium oxide, ZrO2, to increase the inherent current density of Nb3Sn superconductor material. The Nb3Sn superconductor will be produced initially in small-scale billets and then in larger scale billets, incorporating niobium alloyed with zirconium and the appropriate amount of oxygen. The resulting ZrO2 will be used to refine the grains of Nb3Sn, thereby increasing the current density toward the goal of 3000 Amps/mm2 . In Phase I, an alloy of niobium zirconium, with an appropriate amount of oxygen, will be prepared and used in a multiple extrusion billet designed to produce approximately 1500 filaments in an Nb3Sn internal tin superconductor. The conductor will be processed and heat treated in order to optimize the grain refining properties of the ZrO2. The critical current density will be measured to determine effectiveness and aid in design of Phase II conductors. Commercial Applications and Other Benefits as described by awardee: Lower cost superconductors should reduce the cost of MRI machines and expand the range of applications for MRI, a billion dollar industry. Their use at higher temperatures would allow the use of helium-free devices, making MRI technology more available to the Third World and remotes sites. Other applications should exist in the utility sector.