Abstract We are developing Bi-2223/Ag tapes with a high engineering critical current density by optimizing the powder-in-tube process and are studying its application to coil and current leads. We have fabricated 250 m-long tape and investigated optimized processing conditions to enhance engineering critical current density. More bubbling was found when the tape was heat-treated with a higher heating rate. Different kinds of superconducting joints were fabricated with multi-filamentary Bi-2223/Ag tapes, and 58% of retained I c was achieved using the insertion of Bi-2223 core between two exposed tapes. Current decay property of the persistent mode HTS coil was investigated. Rapid current decay was observed when the operating current is in a flux-flow range. We could successfully fabricate a low heat leak type HTS current lead with Bi-2223/Ag–Au tapes by employing a stepped geometry. Using this lead, safe operation of 2 kA current transport was confirmed.
[1]
E. Hellstrom,et al.
Effects of overpressure processing on porosity in Ag-sheathed Bi-2212 multifilamentary tapes with various geometries
,
1999,
IEEE Transactions on Applied Superconductivity.
[2]
Hae-Jong Kim,et al.
1.5 kA Bi-2223 HTS current leads for SMES magnets
,
2001
.
[3]
D. Parker,et al.
HTS wire at commercial performance levels
,
1999,
IEEE Transactions on Applied Superconductivity.
[4]
R. H. Arendt,et al.
Superconducting joints formed between powder-in-tube Bi/sub 2/Sr/sub 2/Ca/sub 2/Cu/sub 3/O/sub z//Ag tapes
,
1993,
IEEE Transactions on Applied Superconductivity.
[5]
General design formula for tapered, conduction-cooled current lead utilizing high temperature superconducting tapes
,
1999
.