Title :
Improvement of critical current density and microstructure of Tl-1223 tapes by a two-powder method
Author :
Shiming Wu ; Glowacki, B.A. ; Wei Yao Liang ; Xiao-Ming Yang ; Weber, H.W.
Author_Institution :
Interdisciplinary Res. Centre in Superconductivity, Cambridge Univ., UK
fDate :
6/1/1997 12:00:00 AM
Abstract :
Superconducting tapes of (Tl,R)(Ba,Sr)/sub 2/Ca/sub 2/Cu/sub 3/O/sub x/ (R=Bi or Pb) were prepared using a mixture of pre-reacted single phase powder and unreacted precursor of identical or different stoichiometry. The effects of mechanical densification and sintering conditions on critical current (I/sub c/) and microstructure of the tapes were investigated. Compared to the tapes made with entirety unreacted powder or pre-reacted powder, the tapes made with a mixture of the two showed a much improved microstructure, an improved self-field I/sub c/ at 77K, as well as a smaller dependence on sintering conditions and better reproducibility of I/sub c/.
Keywords :
barium compounds; bismuth compounds; calcium compounds; critical current density (superconductivity); crystal microstructure; densification; high-temperature superconductors; lead compounds; powder technology; sintering; strontium compounds; superconducting tapes; thallium compounds; (TlBi)(BaSr)/sub 2/Ca/sub 2/Cu/sub 3/O/sub 9+/spl delta//; (TlBi)(BaSr)/sub 2/Ca/sub 2/Cu/sub 3/O/sub 9/; (TlPb)(BaSr)/sub 2/Ca/sub 2/Cu/sub 3/O/sub 9+/spl delta//; (TlPb)(BaSr)/sub 2/Ca/sub 2/Cu/sub 3/O/sub 9/; 77 K; HTSC; Tl-1223 tapes; critical current; critical current density; mechanical densification; microstructure; pre-reacted single phase powder; self-field; sintering; stoichiometry; superconducting tapes; two-powder method; unreacted precursor; Bismuth; Critical current density; Heat treatment; Microstructure; Powders; Superconducting films; Superconducting transition temperature; Superconductivity; Temperature dependence; Wires;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
