Type of Document	Thesis
Author	Myers, David Alan
Author's Email Address	myers@asc.magnet.fsu.edu
URN	etd-07312009-162815
Title	Characterization Of Bi2Sr2CaCu2Ox/Ag-Alloy Conductor Samples Extracted From Wind And React Solenoids
Degree	Master of Science
Department	Mechanical Engineering, Department of
Advisory Committee	Advisor Name Title David Larbalestier Committee Co-Chair Justin Schwartz Committee Co-Chair Eric Hellstrom Committee Member Ulf Trociewitz Committee Member Juan Ordonez University Representative
Keywords	Bi-2212 BSCCO
Date of Defense	2009-07-28
Availability	unrestricted
Abstract Wind-and-react coils using alumino-silicate insulated Bi2Sr2CaCu2Ox (Bi-2212) round wire consistently show reduced transport properties compared to short samples heat treated under identical conditions. To take full advantage of the Bi-2212 high field transport properties, in particular to maximize the performance of insert coils for high field magnets, this problem needs to be understood and solved. There are a number of potential reasons for degraded coil performance like inhomogeneous temperature distribution throughout the coil and insufficient oxygen penetration and diffusion into the coil during heat treatment. Each one of these or even a combination may result in a radial dependence of the superconducting properties within the coil. In this work, short conductor samples were systematically extracted from various locations of three heat treated Bi-2212 coils and the electromechanical properties of these samples are measured to create a position-sensitive map of the properties for each coil. Sample microstructures are also examined and correlated with the property measurements. Results show that there are radial variations within each coil, particularly of transport current properties. For two of the coils there was an improvement for the inner most layer compared to the remaining layers, which were fairly homogeneous. On the other hand, the third coil experienced a decrease in performance for the 5 inner most layers compared to the remaining layers. It was found that there was no variation in performance in the vertical direction of the coil. Additional properties measured included the transition temperature Tc, the Kramer field HK and remnant field analysis of the wire connectivity. The first two of these were found to be homogeneous throughout each of the coils, implying that the oxygen content and flux pinning of the conductor was independent of position in the coil. Remnant field measurements were conflicting; with the results for two coils supporting the trend seen in transport current properties, but not in the third case.
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