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Microstructure and Associated Properties of YBa[sub 2]Cu[sub 3]O[sub x] Superconductors Prepared by Melt-Processing Techniques

Description: From the standpoint of applications, melt-processed bulk YBa[sub 2]Cu[sub 3]O[sub x] (YBCO) superconductors are of considerable interest. We have studied the microstructure and levitation force of melt-processed YBCO, YBCO plus Y[sub 2]BaCuO[sub 5], and YBCO plus Pt samples. Large single crystalline samples, grown using a seeding technique, were also studied. The levitation force is highest in melt-processed samples made by the seeding technique. 6 figs, 24 refs.
Date: March 1, 1993
Creator: Balachandran, U.; Zhong, W.; Youngdahl, C. A. & Poeppel, R. B.
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Partner: UNT Libraries Government Documents Department
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Processing and Microstructural Development of Ag-clad Bi-Sr-Ca-Cu-O Tapes

Description: Ag-clad Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub x} (2212) and (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} (2223) tapes were fabricated by drawing and rolling. Highly textured microstructures and high critical current density values were obtained for each system. However, the heat treatments and phase evolutions for 2212 and 2223 were different. For 2212, nearly phase-pure powder was used, and the heat treatments consisted of partial melting followed by solid-state sintering. For 2223, several … more
Date: October 1, 1992
Creator: Poeppel, R. B.; Goretta, K. C.; Balachandran, U.; Biondo, A. C.; Dorris, S. E.; Hathcox, S. C. et al.
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Partner: UNT Libraries Government Documents Department
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Microstructural characterization of Ag-sheathed Tl-Ba-Ca-Cu-O and Bi-Sr-Ca-Cu-O superconducting tapes by analytical electron microscopy

Description: The microstructures of Tl(1223) and Pb-doped Bi(2223) silver tapes produced by the powder-in-tube (PM) method have been examined by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive spectrometry (EDS). The Tl tapes annealed below the melting point exhibited fine grains and a high density of pores while tapes subjected to partial melting prior to solid state annealing were fully dense with large grains. However, these tapes also showed an increase i… more
Date: September 1, 1992
Creator: Hu, J. G.; Miller, D. J.; Goretta, K. C. & Poeppel, R. B.
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Partner: UNT Libraries Government Documents Department
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The effect of processing parameters during heat treatment of bulk high-{Tc} superconductors

Description: Plastic extrusion is a promising method for producing the long lengths of high-{Tc} superconductor that will be necessary to meet many potential applications. A crucial phase of the extrusion method is removal of organic constituents. Incomplete removal can leave residual carbon at grain boundaries, which can adversely affect the superconducting properties, whereas excessively rapid removal of the organics can cause the extruded superconductor to disintegrate completely. In this paper, we analy… more
Date: April 1, 1991
Creator: Cha, Y. S.; Dorris, S. E.; Hull, J. R. & Poeppel, R. B.
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Partner: UNT Libraries Government Documents Department
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Reaction of iron and steel slags with refractories

Description: Slag corrosion and erosion has been a major wear factor for refractories wear in contact with molten iron and steel. In blast furnace ironmaking, the slag/iron interface plays a more important role than does the slag/refractory interface. On the other hand in steelmaking, the slag in the ladles and tundish predominantly affect refractory wear. This paper presents the results of a detailed microstructural evaluation of (a) slag and slag/iron interactions with A1{sub 2}O{sub 3}-SiC-C refractories… more
Date: April 1, 1993
Creator: Banerjee, S.; Anderson, M. W.; Singh, J. P. & Poeppel, R. B.
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Partner: UNT Libraries Government Documents Department
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Microstructural characterization of Ag-sheathed Tl-Ba-Ca-Cu-O and Bi-Sr-Ca-Cu-O superconducting tapes by analytical electron microscopy

Description: The microstructures of Tl(1223) and Pb-doped Bi(2223) silver tapes produced by the powder-in-tube (PM) method have been examined by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive spectrometry (EDS). The Tl tapes annealed below the melting point exhibited fine grains and a high density of pores while tapes subjected to partial melting prior to solid state annealing were fully dense with large grains. However, these tapes also showed an increase i… more
Date: September 1, 1992
Creator: Hu, J. G.; Miller, D. J.; Goretta, K. C. & Poeppel, R. B.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Thermomechanical processing of Ag-clad Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub x} superconductors

Description: Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub x} (2212) powders were synthesized by solid-state reaction, loaded into Ag tubes, and processed into tapes by various combinations of drawing, rolling, and heat treatment. Critical current densities at 4.2 K of greater than 10{sup 5} A/cm{sup 2} were achieved from microstructures consisting of large, highly textured 2212 grains. Optimal microstructures were produced by specific mechanical-working conditions and heat-treatment schedules that incorporated solid-… more
Date: October 1, 1993
Creator: Wu, C. T.; Goretta, K. C.; Lanagan, M. T.; Biondo, A. C. & Poeppel, R. B.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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TRIO-01 experiment: in-situ tritium-recovery results

Description: The TRIO-01 experiment is a test of in-situ tritium recovery from ..gamma..-LiAlO/sub 2/ with test conditions chosen to simulate those anticipated in fusion power reactors. A status report is presented which describes qualitatively the results observed during the irradiation phase of the experiment. Both the rate of tritium release and the chemical forms of tritium were measured using a helium sweep gas which flowed past the breeder material to a gas analysis system.
Date: August 1, 1983
Creator: Clemmer, R. G.; Finn, P. A.; Billone, M. C.; Misra, B.; Arons, R. M.; Poeppel, R. B. et al.
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Partner: UNT Libraries Government Documents Department
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TRIO-01 experiment: in-situ tritium recovery results

Description: The TRIO-01 experiment is a test of in-situ tritium recovery from ..gamma..-LiAlO/sub 2/ with test conditions chosen to simulate those anticipated in fusion power reactors. A status report is presented which describes qualitatively the results observed during the irradiation phase of the experiment. Both the rate of tritium release and the chemical forms of tritium were measured using a helium sweep gas which flowed past the breeder material to a gas analysis system.
Date: October 1, 1983
Creator: Clemmer, R. G.; Finn, P. A.; Billone, M. C.; Misra, B.; Arons, R. M.; Poeppel, R. B. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Superconducting wires

Description: The requirement of high critical current density has prompted extensive research on ceramic processing of high-T/sub c/ superconductors. An overview of wire fabrication techniques and the limitations they impose on component design will be presented. The effects of processing on microstructure and critical current density will also be discussed. Particle alignment has been observed in extruded samples which is attributed to high shear stresses during plastic forming. Composites of superconducto… more
Date: June 1, 1988
Creator: Lanagan, M. T.; Poeppel, R. B.; Singh, J. P.; Dos Santos, D. I.; Lumpp, J. K.; Dusek, J. T. et al.
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Partner: UNT Libraries Government Documents Department
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Evaluation of ceramic refractories for slagging gasifiers: summary of progress to date

Description: Commercial refractories were tested for up to 500 h in both basic and acidic slags. The slag compositions typify those expected in slagging coal gasifiers. The slag temperatures ranged up to 1600/sup 0/C. Compositions tested have included silicon carbides, chrome-alumina-magnesia spinels, and alumina and magnesia-based refractories with various amounts of chromia and silica. In some tests, the cold faces were water cooled. With water cooling, the silicon carbides showed virtually no attack afte… more
Date: September 1, 1978
Creator: Kennedy, C. R.; Swaroop, R.; Jones, D. J.; Fousek, R. J.; Poeppel, R. B. & Stahl, D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Ultrasonic determination of the elastic moduli and their pressure dependences in very dense YBa{sub 2}Cu{sub 3}O{sub 7{minus}x}

Description: The effects of hydrostatic pressure and temperature have been measured on the velocities of longitudinal and shear ultrasonic waves propagated in a very dense (96% of theoretical density) ceramic specimen of YBa{sub 2}Cu{sub 3}O{sub 7{minus}x}. In YBa{sub 2}Cu{sub 3}O{sub 7{minus}x} ceramics with such a high density the effects of porosity on the elastic properties should be much reduced. Nevertheless the bulk modulus of this dense material has the same small magnitude ({approximately} 55GPa) a… more
Date: December 1991
Creator: Cankurtaran, M.; Saunders, G. A.; Goretta, K. C. & Poeppel, R. B.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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