React-Wind-Sinter Technology for Bi2Sr2CaCu2Ox

Bi2212, which has the highest Jc of any practical superconductor at fields greater than 15 T, is currently being considered for high-field particle accelerator magnets. In particular, it is attractive for high field magnets that are needed to improve the performance of machines such as the Large Hadron Collider and Muon Collider. However, the processing requirements for Bi2212 are extremely stringent ¿ so much so that it is very difficult to produce a reliable magnet of the size need for these applications. Bi2212 is a brittle, strain sensitive material that can not tolerate substantial deformation after heat treatment. To overcome this difficulty, this project will develop an alternate fabrication process involving react-wind-sinter (RWS), which breaks the heat treatment cycle into two independent segments. The temperature-critical reaction step is done on the bare wire before magnet winding. The reacted wire then is wound and the magnet is sintered to fully develop superconducting properties. Temperature control during sintering is not nearly as stringent as for the reaction step. Thus large magnets can be fabricated without concern for temperature variations and gradients in the magnet windings, which lead to poor properties and magnet performance. Commercial Applications and other Benefits as described by the awardee: The RWS technology should reduce the risk in fabricating large Bi2212 magnets. Because these high field accelerator magnets are very expensive, the RWS technology should have a significant financial impact on accelerator programs.