Recent Advances in Bi-2212 Round Wire Performance for High Field Applications

There has been sustained interest in the development of Bi-2212/Ag round wire because of its unique potential for application in ultra-high-field magnets (>; 25 T). Our development activity with this material has been focused on improving the engineering current density. Filament densification by swaging and isostatic pressing processes have been evaluated, as has further optimization of the melt heat treatment conditions. These improvements lead to an increased mass density of the filament in the final wire, and are essential to reduce filament porosity and obtain high performance over long wire length. Engineering current density values exceeding 480 A/mm² at 4.2 K, 15 T have been achieved on 1-m-long barrel samples.