Effects of Bi and Bi/sub 2/0/sub 3/ additions on the microstructure and superconducting properties of powder-in-tube BSCCO (2212) tapes

Author

Guo, J. ; Lewis, J.A. ; Goretta, K.C.

Author_Institution

Dept. of Mater. Sci. & Eng., Illinois Univ., Urbana, IL, USA

Volume

5

Issue

2

fYear

1995

fDate

6/1/1995 12:00:00 AM

Firstpage

1860

Lastpage

1863

Abstract

The microstructural development and superconducting properties of Bi/sub 2/Sr/sub 2/CaCu/sub 2/O/sub x/ (Bi-2212) Ag-clad powder-in-tube tapes with 2 vol% bismuth (Bi) added from either Bi (s) or Bi/sub 2/O/sub 3/ powders were investigated. Such additives reduce the peritectic decomposition temperature of pure Bi-2212 by approximately 15-20/spl deg/C. Scanning electron microscopy (SEM) and optical microscopy on polished top and cross-sections revealed that the volume fraction of Bi-free phases was lower in the Bi-added specimens relative to those based on pure Bi-2212. In addition, it appeared that the Bi-added samples had improved grain alignment, which was confirmed by X-ray diffraction analysis. Magnetic hysteresis (at 5 K between /spl plusmn/5.5 T) and transport measurements (at 4.2 K) were performed on each specimen. These results showed that Bi-additions yielded superior magnetization critical currents, which is attributed to improved grain alignment and reduced secondary phases.<>

Keywords

bismuth compounds; calcium compounds; critical currents; crystal microstructure; high-temperature superconductors; magnetic hysteresis; optical microscopy; powder technology; scanning electron microscopy; silver; strontium compounds; superconducting tapes; Ag-clad tapes; Bi additions; Bi/sub 2/0/sub 3/ additions; Bi/sub 2/Sr/sub 2/CaCu/sub 2/O-Ag; SEM; X-ray diffraction; grain alignment; high temperature superconductor; magnetic hysteresis; magnetization critical currents; microstructure; optical microscopy; peritectic decomposition temperature; powder-in-tube tapes; Bismuth; Electron optics; Optical diffraction; Optical microscopy; Powders; Scanning electron microscopy; Strontium; Superconducting films; Temperature; X-ray diffraction;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/77.402944

Filename

402944