Title :
Overpressure processing Bi2223/Ag tapes
Author :
Rikel, M.O. ; Williams, R.K. ; Cai, X.Y. ; Polyanskii, A.A. ; Jiang, J. ; Wesolowski, D. ; Hellstrom, E.E. ; Larbalestier, D.C. ; DeMoranville, K. ; Riley, G.N., Jr.
Author_Institution :
Appl. Supercond. Center, Wisconsin Univ., Madison, WI, USA
fDate :
3/1/2001 12:00:00 AM
Abstract :
We report on the effect of overpressure processing on the electromagnetic properties and microstructure of monocore and multifilamentary Bi2223/Ag tapes. Samples at various stages of the usual thermo-mechanical processing for Bi2223/Ag tapes (from as-rolled to fully processed) were subjected to annealing at 815-820°C for 18-108 h in a static Ar+O2 atmosphere at the overall pressure 17.5±0.5 MPa (pO2= 0.003-0.02 MPa). Density measurements, microhardness tests, and SEM examination of polished sections reveal a notable densification of overpressure-processed samples. For partly reacted (so called HT1) samples, we found that overpressure processing for 36 h is sufficient to densify the Bi2223 core from 70±5 to 87±4% theoretical density and increase self-field Jc(77 K) from 8±1 to 30±5 kA/cm2 The results show that one-step processing of Bi2223/Ag tapes is possible
Keywords :
annealing; bismuth compounds; calcium compounds; critical current density (superconductivity); crystal microstructure; densification; density; hardness testing; high-pressure effects; high-temperature superconductors; lead compounds; microhardness; multifilamentary superconductors; scanning electron microscopy; silver; strontium compounds; superconducting tapes; thermomechanical treatment; (BiPb)2Sr2Ca2Cu3O 10-Ag; 17.5 MPa; 18 to 108 h; 815 to 820 C; Bi2223 core; Bi2223/Ag tapes; SEM; annealing; densification; density; electromagnetic properties; microhardness tests; microstructure; monocore; multifilamentary Bi2223/Ag tapes; one-step processing; overpressure processing; partly reacted samples; self-field Jc; static Ar+O2 atmosphere; thermo-mechanical processing; Annealing; Argon; Atmosphere; Conductors; Density measurement; High temperature superconductors; Hip; Microstructure; Testing; Thermomechanical processes;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
