Title :
The influence of heating temperature on the superconducting properties of silver-gold sheathed Bi-2223 tapes destined for power applications
Author :
Zhu, W. ; Willen, D. ; Watson, D.R. ; Cave, J.
Author_Institution :
IREQ, Varennes, Que., Canada
fDate :
6/1/1999 12:00:00 AM
Abstract :
For power engineering applications using HTS conductors, long-length Ag-Au sheathed Bi-2223 tapes are being developed. By a continuous fabrication process (rolling), tapes with J/sub c/ up to 20 000 A cm/sup -2/ (77 K, 0 T) have fabricated using the powder in tube method. The tapes were heat treated in the temperature range of 805-835/spl deg/C in an atmosphere of 8% oxygen in nitrogen. The influence of temperature and time on the evolution of the superconducting properties is investigated by means of electric transport current measurements (I/sub c/ and its distribution). Phase development at different processing stages is examined by XRD. The microstructure and phase assemblage at different heating temperatures are characterized with SEM/EDX. The critical current distribution in the tapes is studied by analyzing the second differential of the V-I curves and the effects of cracks and secondary phases are discussed.
Keywords :
X-ray chemical analysis; X-ray diffraction; bismuth compounds; calcium compounds; ceramics; composite superconductors; cracks; critical current density (superconductivity); gold alloys; heat treatment; high-temperature superconductors; materials preparation; rolling; scanning electron microscopy; silver alloys; strontium compounds; superconducting tapes; 0 T; 77 K; 805 to 835 C; Ag-Au sheathed Bi-2223 tapes; AgAu-Bi/sub 2/Sr/sub 2/Ca/sub 2/Cu/sub 3/O; SEM/EDX; V-I curves; XRD; cracks effect; critical current distribution; heating temperature influence; microstructure; phase assemblage; phase development; power applications; secondary phases effect; superconducting properties; Atmosphere; Conductors; Fabrication; Heating; High temperature superconductors; Nitrogen; Powders; Power engineering; Superconducting films; Temperature distribution;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
