Title :
Fabrication and characterization of (Bi,Pb)-Sr-Ca-Cu-O (2223) bars
Author :
Chudzik, M.P. ; Polzin, J. ; Thayer, R. ; Picciolo, J.J. ; Fisher, B.L. ; Lanagan, M.T.
Author_Institution :
Div. of Energy Technol., Argonne Nat. Lab., IL, USA
fDate :
6/1/1997 12:00:00 AM
Abstract :
Bulk bars for current lead applications were fabricated from (Bi,Pb)-Sr-Ca-Cu-O (Bi-2223) for low thermal conductivity and high critical current. Bars measuring 17.8 cm in length were made by uniaxially pressing Bi-2223 powder of controlled (1.7/0.34)223 and (1,8/0.4)223 phase composition. The bulk bars were densified by subjecting them to a schedule of alternate liquid-phase sintering and cold isostatic pressing. Liquid-phase sintering temperatures were optimized from differential thermal analysis and microstructure morphology. Phase purity and microstructure were evaluated by X-ray diffraction and scanning electron microscopy. Low-resistance silver contacts were applied to the bars by hot-pressing at 820/spl deg/C and 3 MPa. Critical current densities /spl ap/1000 A/cm/sup 2/ (critical currents of 750 A at 77 K in self-field conditions) were achieved.
Keywords :
X-ray diffraction; bismuth compounds; calcium compounds; critical current density (superconductivity); crystal microstructure; densification; high-temperature superconductors; hot pressing; lead compounds; powder technology; scanning electron microscopy; sintering; strontium compounds; thermal analysis; thermal conductivity; (Bi,Pb)-Sr-Ca-Cu-O (2223) bars; 3 MPa; 750 A; 77 K; 820 degC; Ag; BiPbSrCaCuO; HTSC; X-ray diffraction; characterization; cold isostatic pressing; critical current densities; current lead applications; densification; fabrication; high critical current; hot-pressing; liquid-phase sintering; low thermal conductivity; low-resistance silver contacts; microstructure; microstructure morphology; phase purity; scanning electron microscopy; self-field conditions; thermal analysis; uniaxially pressing Bi-2223 powder; Bars; Critical current; Fabrication; Length measurement; Microstructure; Phase measurement; Powders; Pressing; Temperature; Thermal conductivity;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
