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in creator/contributor: "Hoehn, J.G. Jr."

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Processing and Transport Properties of High J[sub c] Silver Clad Bi-2223 Tapes and Coils

The powder-in-tube process has been used to fabricate long lengths of flexible, high J[sub c], silver clad Bi-2223 HTS conductors. By improving thermo-mechanical processing and precursor powder preparationwe have succeeded in achieving J[sub c]'s exceeding 4 [times] 10[sup 4] A/cm[sup 2] at liquid nitrogen (77K) and > 10[sup 5] A/cm[sup 2] at liquid helium (4.2K) and liquid neon (27K) temperatures for short tapesamples. Detailed measurements with high applied magnetic fields are reported. Sever… more

Date: February 1, 1993

Creator: Haldar, P.; Hoehn, J. G., Jr.; Balachandran, U. & Motowidlo, L. R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

High-temperature superconducting magnets and coils from silver- sheathed Bi-2223 tapes

Long lengths (30 to 100 m) of silver-sheathed Bi-2223 tapes with high current densities were fabricated by the conventional powder-in-tube technique and used to make compact and robust coils by the wind-and-react approach. The tapes were insulated co-wound in parallel, and heat treated to produce a fused conductor of larger cross section in the form of pancake coils. The coils were stacked in series to make test magnets. The coils and test magnets were characterized at liquid nitrogen (77 K) an… more

Date: October 1, 1993

Creator: Haldar, P.; Hoehn, J. G. Jr.; Motowidlo, L. R. & Balachandran, U.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Fabrication and properties of Ag-clad Bi-2223 conductors and magnets

Significant progress has been made in fabricating Ag-clad Bi-2223 tapes that are suitable for practical applications. Long lengths ({approx}100 m) of tapes with high transport critical current density (J{sub c}) were fabricated by the powder-in-tube technique, starting with partially reacted precursor powders. The tapes were given appropriate heat treatment, and growth of the 2223 phase at each step of the heat treatment was studied. At 77 K, J{sub c} values of >4 x 10{sup 4} A/cm{sup 2} and {a… more

Date: April 1, 1994

Creator: Balachandran, U.; Iyer, A. N.; Haldar, P.; Hoehn, J. G. Jr. & Motowidlo, L. R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Recent developments in fabrication of Bi-2223 conductors and magnets

Significant progress has been made in the fabrication of Bi-2223 high-{Tc}, high-critical-current-density (J{sub c}) superconductor tapes that are attractive for electrical power and high-field magnet applications. Long lengths ({approx}100 m) of Ag-clad Bi-2223 tapes with high J{sub c} were fabricated by powder-in-tube technique and used to make compact and robust pancake coils by wind-and-react method. Three to five layers of tapes were co-wound with an insulation and heat treated to produce … more

Date: December 1, 1993

Creator: Balachandran, U.; Iyer, A. N.; Haldar, P.; Hoehn, J. G. Jr. & Motowidlo, L. R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Powder synthesis, fabrication, and transport properties of long-length Ag clad Bi-2223 conductors

Prereacted, polyphase powders of Pb-doped Bi-Sr-Ca-Cu-O (2223) were prepared by the solid-state reaction of appropriate amounts of Bi{sub 2}O{sub 3}, PbO, SrCO{sub 3}, CaCO{sub 3}, and CuO. The calcined powders were characterized by thermal analysis, x-ray diffraction and scanning electron microscopy. The powders were then used to fabricate long lengths of flexible Ag-clad 2223 superconductor tapes, via the powder-in-tube technique. Growth of the 2223 phase in the tapes at each heat-treatment s… more

Date: October 1, 1993

Creator: Iyer, A. N.; Balachandran, U.; Haldar, P.; Hoehn, J. G. Jr. & Motowidlo, L. R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Fabrication and characterization of high-{Tc} tapes and coils made from Ag-clad Bi-2223 superconductors

Prereacted Pb-doped Bi-Sr-Ca-Cu-0 powders were packed into Ag tubes, drawn, rolled, and given intermediate heat treatment to prepare long lengths of Ag-clad Bi-2223 superconductor tapes. With the use of improved process conditions, transport critical current density (J{sub c}) values exceeding 10{sup 5} A/cm{sup 2} at 4.2 K and 27 K, and greater than 4 {times} 10{sup 4} A/cm{sup 2} at 77 K, were obtained in zero applied field with short tape samples. Detailed microstructural analysis and J{sub … more

Date: July 1, 1993

Creator: Balachandran, U.; Iyer, A. N.; Youngdahl, C. A.; Motowidlo, L. R.; Hoehn, J. G. Jr. & Haldar, P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Fabrication and characteristics of a test magnet from HTS Bi-2223 silver-clad tapes

Critical currents of powder-in-tube processed silver-clad Bi-2223 short tape samples and coils have been measured at liquid nitrogen (77 K), liquid neon (27 K) and liquid helium (4.2 K) temperatures. The short samples have been characterized in fields up to 20 T and indicate a large anisotropy at 27 K with resistive behavior above 15 T in the worst field direction. A test magnet consisting of pancake coils generated magnetic fields greater than 1.0, 0.7 and 0.11 T at 4.2 K, 27 K and 77 K respec… more

Date: July 1, 1993

Creator: Haldar, P.; Hoehn, J. G. Jr.; Motowidlo, L. R.; Balachandran, U. & Iwasa, Y.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Recent developments in processing HTS silver-clad Bi-2223 tapes, coils and test magnets

Considerable progress has been made in fabricating Bi-2223 high temperature superconductor (HTS) wires and tapes with high critical current densities that are attractive for electric power and high-field magnet applications. Powder-in-tube processed silver-clad Bi-2223 short tape samples, small coils and test magnets have been fabricated and measured at liquid nitrogen (77K), pumped liquid nitrogen (64 K), liquid neon (27K) and liquid helium (4.2K) temperatures. Optimization of thermo-mechanica… more

Date: October 1, 1993

Creator: Haldar, P.; Hoehn, J. G. Jr.; Motowidlo, L. R.; Balachandran, U.; Iwasa, Y. & Yunus, M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Performance of pancake coils of parallel co-wound Ag/BSCCO tape conductors in static and ramped magnetic fields

Critical Currents are reported for several Ag/BSCCO single-pancake coils in static magnetic fields ranging from 0 to 5 T and temperatures from 4.2 K to 105 K. The sample coils were co-wound of one to six tape conductors in parallel. Since the closed loops formed in such an arrangement could lead to eddy current heating or instability in changing fields, one of the coils was also tested in helium gas, in fields ramped at rates of up to 1.5 T/s. For these quasi-adiabatic tests, at each temperatur… more

Date: December 31, 1994

Creator: Schwenterly, S. W.; Lue, J. W.; Lubell, M. S.; Walker, M. S.; Hazelton, D. W.; Haldar, P. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department