Processing Issues of Bi-2212 Wires

T. Haugan；S. Patel；D. T. Shaw

Chinese Journal of Physics

34卷2S期（1996 / 04 / 01）

215 - 221

英文

Long length (＞ 100 meters) Ag-sheathed high temperature superconducting (HTS) Bi2Sr2CaCu2O8 (Bi-2212) oxide conductors have been processed using conventional powder-in-tube (PIT) and partial-melt-growth (PMG) techniques. Results show that the critical current density (Jc) of long length tapes is significantly lower when compared with Jcs of shorter length conductors (＜ 1 meter). This decrease in Jc is attributed to: (a) processing temperature non-uniformities along the conductor length, and (b) Jc sensitivity to temperature variations. The non-uniformity and sensitivity issues are being addressed by new furnace designs and annealing methods (such as the isothermal melt process method which has the potential to reduce the Jc temperature sensitivity), respectively. Simultaneously, other defects that are incorporated into the conductor during processing, with detrimental effect to the Jc, need to be addressed. The issues relevant to processing of long length HTS Bi-2212 conductors with uniformly high Jc are discussed.