Effect of twisting on the filaments of multifilamentary BSCC0(2223)/Ag and /AgMg tapes

Author

Goldacker, W. ; Eckelmann, H. ; Quilitz, M. ; Ullmann, B.

Author_Institution

Inst. fur Tech. Phys., Forschungszentrum Karlsruhe, Germany

Volume

7

Issue

2

fYear

1997

fDate

6/1/1997 12:00:00 AM

Firstpage

1670

Lastpage

1673

Abstract

For reduced AC losses of multifilamentary BSCC0(2223) tapes, it is necessary to apply a twist to the filaments along the tape direction reducing the filament coupling losses. Twists with different twist pitches (10-80 mm) were realized in either Ag sheathed and mechanically reinforced AgMg sheathed 37 filament tapes. Possible reasons for the observed degradations of the transport critical current densities of 22000 Acm/sup -2/ (Ag sheath) and 19000 Acm/sup -2/ (AgMg sheath) down to 50% in the worst case (10 mm twist pitch) for twisted tapes, were investigated analyzing the influence of twisting on the conductor geometry and deformation via quantitative image processing of micrographs. The critical current I/sub C/ of differently twisted tapes was measured in a magnetic field for various tape orientations. From the J/sub C/(B) anisotropy the misalignment angle of the Bi(2223) phase texture was analyzed, and a comparison with rocking angles from X-ray experiments was performed.

Keywords

bismuth compounds; calcium compounds; critical current density (superconductivity); high-temperature superconductors; losses; magnesium alloys; magnetic field effects; multifilamentary superconductors; silver; silver alloys; strontium compounds; superconducting tapes; 10 to 80 mm; AC losses; Bi/sub 2/Sr/sub 2/Ca/sub 2/Cu/sub 3/O-Ag; Bi/sub 2/Sr/sub 2/Ca/sub 2/Cu/sub 3/O-AgMg; Bi/sub 2/Sr/sub 2/Ca/sub 2/Cu/sub 3/O/sub x//Ag; Bi/sub 2/Sr/sub 2/Ca/sub 2/Cu/sub 3/O/sub x//AgMg; X-ray experiments; conductor geometry; critical current densities; deformation; filament coupling losses; filament twisting; image processing; magnetic field; misalignment angle; multifilamentary tapes; phase texture; tape orientation; twist pitch; Conductors; Critical current; Critical current density; Current measurement; Degradation; Geometry; Image analysis; Image processing; Magnetic analysis; Magnetic field measurement;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/77.620899

Filename

620899