Patents

The invention provides a process for the preparation of High Temperature Superconducting (HTS) bulk current leads capable of supplying a continuous current of more than 200 A at 77 K, 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)2Sr2Ca2Cu3O10+x] material in tube and rod shape with both end 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 current more than 200 A required for energizing superconducting magnet systems.