Journal article
Observation of the Bi,Pb(2223) reaction mechanism and alternative ways of producing tapes with new filament configurations
Investigations on the Bi,Pb(2223) phase formation confirm a mechanism based on nucleation and growth. The same mechanism was found to hold under various external conditions: a) in pressed samples, b) in Ag sheathed tapes, c) in air or in reduced oxygen partial pressure and d) with or without the presence of Pb.
A high temperature neutron diffraction investigation on monofilamentary Bi,Pb(2223) tapes shows that this phase remains stable during the cooling process after reaction. On cooling, an enhancement of the Bi(2212) phase is observed, which occurs at the expense of the other phases, (Sr,Ca)/sub 14/Cu/sub 24/O/sub 41/ and Bi(2201).
New tape configurations are presented, in view of a) the reduction of anisotropy (on both, tapes or wires) and b) the reduction of AC losses. These configurations require the use of nonconventional techniques, e.g. two-axis rolling and/or periodic pressing. Using periodic pressing, j/sub c/(77K,0T) values of 35,000 A/cm/sup 2/ have been obtained in Bi,Pb(2223) multifilamentary tapes of lengths >2 m.
Language: | English |
---|---|
Publisher: | IEEE |
Year: | 1999 |
Pages: | 2430-2435 |
ISSN: | 10518223 , 15582515 and 23787074 |
Types: | Journal article |
DOI: | 10.1109/77.784965 |
(BiPb)/sub 2/Sr/sub 2/Ca/sub 2/Cu/sub 3/O/sub 10/ AC losses Ag sheathed tapes Anisotropic magnetoresistance Bi,Pb(2223) reaction mechanism Cooling Diffraction High temperature superconductors Lead Neutrons Powders Pressing Temperature control Wires bismuth compounds calcium compounds cooling process growth high temperature neutron diffraction high temperature superconductor high-temperature superconductors lead compounds monofilamentary Bi,Pb(2223) tapes multifilamentary superconductors multifilamentary tapes neutron diffraction new filament configurations nucleation periodic pressing pressed samples strontium compounds superconducting tapes tapes two-axis rolling