Patents
The invention provides a process for preparing high-temperature superconducting (HTS) bulk current leads capable of supplying a continuous current of more than 200A at 77K, at least for 2 to 4 hours without any substantial heat load to cryogen-free cryocooler and other superconducting magnet systems. The superconducting bulk current leads with improved properties are prepared from an improved high temperature superconducting (HTS) bismuth-based cuperate [(Bi, Pb)2 Sr2Ca2Cu3O10+x ] material in tube and rod shape with both ends metallic contacts. To produce such a lead, the process included modification of the superconducting material with homogeneous silver addition, a step of initial sintering in a large size tube followed by crushing into powder, a step of shaping the said initially sintered tube powder into tubes and rods of different size, a step of formation of metallic contacts by a perforated silver foil sandwiched between two metal spray deposited silver at both end parts of the said tubes and rods followed by a final step of co-sintering. In the current leads obtained according to these aspects, it is possible to stably carry a current of more than 200A required for energizing superconducting magnet systems.