Title :
Reduction in secondary phases and increased transport Ic of (Bi,Pb)2223/Ag tapes sintered with rapid heating rates
Author :
Young, E.A. ; Yang, Y. ; Lehmann, M. ; Riddle, R. ; Beduz, C.
Author_Institution :
Sch. of Eng. Sci., Univ. of Southampton, UK
fDate :
6/1/2003 12:00:00 AM
Abstract :
In a two-step heat treatment with one intermediate rolling the final transport critical current, (Ic at 77 K, self field, 1ı`V/cm), of 37 filament (Bi,Pb)2223/Ag tapes increases linearly with the heating ramp rate: 20 A to 40 A, (∼20,000 Acm-2), for 20°C/hour to 400°C/hour. The principle benefit of the rapid ramp rate is likely to come from ramping fast though 800°C to 832°C in the 1st heat treatment. SEM and XRD analysis on the superconductor-Ag interface show a decrease in the amount of secondary phases, Cu2O, Bi2(Sr,Ca)2Cu1Ox, Bi(Sr,Ca)Ox, with increasing ramp rate and critical current.
Keywords :
X-ray diffraction; bismuth compounds; calcium compounds; critical current density (superconductivity); high-temperature superconductors; lead compounds; phase diagrams; scanning electron microscopy; silver; strontium compounds; superconducting tapes; (Bi,Pb)2223/Ag tapes; (BiPb)2Sr2Ca2Cu3O10-Ag; 20 to 40 A; 77 K; 800 to 832 degC; SEM; XRD; critical current; high temperature superconductor; rapid ramp rate; secondary phases; Bismuth; Critical current; Current measurement; Heat treatment; Heating; High temperature superconductors; Manufacturing; Microstructure; Powders; Superconducting films;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
DOI :
10.1109/TASC.2003.812062
