Development of a High Current Density Distributed Tin Method Nb3Sn Wire

We have developed a high-performance (high J(C)) Nb3Sn wire via a distributed tin (DT) method. Non-Cu J(C) of 1100 A/mm(2) at 16 T, 4.2 K has been achieved by improving the Sn diffusion and optimizing the Ti content. With the future circular collider magnet planned by European Organization for Nuclear Research (CERN), the target of non-Cu J(C) is set to 1500 A/mm(2) at 4.2 K, 16 T. For this target, we have chosen the DT method, which is a type of internal Sn method, and because it has no limitation of Sn solubility, higher J(C) can be expected. This paper finds that further improvement of J(C) can be realized by controlling the Sn diffusion condition and the ternary additive elements. By setting the Sn diffusion distance to lower than 48 mu m, the Nb3Sn composition in multi-Nb modules becomes uniform and fine. In addition, by controlling the ternary element content (Ti) for improving the characteristics of the middle magnetic field, it is possible to achieve high J(C) at 16 T.