TY - GEN
T1 - Fabrication of pancake coil magnets from one to ten meter length powder-in-tube Bi2Sr2CaCu2O8+x/Ag tapes
AU - Haugan, T.
AU - Pitsakis, M.
AU - Li, S. S.
AU - Patel, S.
AU - Shaw, D. T.
PY - 1994
Y1 - 1994
N2 - Results of processing one to ten meter length Bi2Sr2Ca1Cu2O8+x/Ag cold-rolled powder-in-tube tapes with uniform properties and high critical current densities are presented. Tape sections were processed by partial-melting and slow cooling and were free of bubble defects. Pancake coil magnets (ID = 1.25 cm) were fabricated with one to ten meter length tape sections by a wind-react-wind (WRW) method using different configurations, including single layer, multiple layer, single and double pancakes and different initial and final winding dimensions. The central magnetic fields of coil magnets were measured with a Hall sensor at 4.2 K and varied from 0.07-0.45 T, in excellent agreement with theoretical values calculated for coil dimensions such as OD, ID and Ic. Critical current densities (Jc's) of one to ten meter length tape sections measured resistively after winding to magnet form were in the range of 32,000 A/cm2-54,000 A/cm2 at 4.2 K. The bending strains exerted on coil segments from winding were calculated as approximately 0.10-0.25% for the range of initial and final coiling dimensions tested. By measuring the Jc vs bending strain properties of short length tapes, the drop in Jc expected from winding strains was estimated as approximately 65-75%. Combined with a measured approximately 3-14% drop in Jc's from magnetic self field effects, transport Jc's of one to ten meter tape sections prior to winding were estimated as approximately 55,000-80,000 A/cm2 at 4.2 K, approximately 60-85% of Jc's of short length tapes processed under similar conditions. The possible operation of Bi-2212 coils at 20 K are discussed and the temperature dependence of Jc for several processing conditions are presented.
AB - Results of processing one to ten meter length Bi2Sr2Ca1Cu2O8+x/Ag cold-rolled powder-in-tube tapes with uniform properties and high critical current densities are presented. Tape sections were processed by partial-melting and slow cooling and were free of bubble defects. Pancake coil magnets (ID = 1.25 cm) were fabricated with one to ten meter length tape sections by a wind-react-wind (WRW) method using different configurations, including single layer, multiple layer, single and double pancakes and different initial and final winding dimensions. The central magnetic fields of coil magnets were measured with a Hall sensor at 4.2 K and varied from 0.07-0.45 T, in excellent agreement with theoretical values calculated for coil dimensions such as OD, ID and Ic. Critical current densities (Jc's) of one to ten meter length tape sections measured resistively after winding to magnet form were in the range of 32,000 A/cm2-54,000 A/cm2 at 4.2 K. The bending strains exerted on coil segments from winding were calculated as approximately 0.10-0.25% for the range of initial and final coiling dimensions tested. By measuring the Jc vs bending strain properties of short length tapes, the drop in Jc expected from winding strains was estimated as approximately 65-75%. Combined with a measured approximately 3-14% drop in Jc's from magnetic self field effects, transport Jc's of one to ten meter tape sections prior to winding were estimated as approximately 55,000-80,000 A/cm2 at 4.2 K, approximately 60-85% of Jc's of short length tapes processed under similar conditions. The possible operation of Bi-2212 coils at 20 K are discussed and the temperature dependence of Jc for several processing conditions are presented.
UR - https://www.scopus.com/pages/publications/0028056462
M3 - Conference contribution
AN - SCOPUS:0028056462
SN - 087339271X
T3 - Proceedings of the Symposium on Processing of Long Lengths of Superconductors
SP - 91
EP - 100
BT - Proceedings of the Symposium on Processing of Long Lengths of Superconductors
A2 - Balachandran, U.
A2 - Collings, E.W.
A2 - Goyal, A.
PB - Publ by Minerals, Metals & Materials Soc (TMS)
T2 - Proceedings of the Symposium on Processing of Long Lengths of Superconductors
Y2 - 17 October 1993 through 21 October 1993
ER -