Processing Yttrium Barium Copper Oxide Superconductor in Near-Zero Gravity
The effects of processing YBa2Cu3Ox (Y123) superconductor in the near-zero gravity (0g) environment provided by the NASA KC-135 airplane flying on parabolic trajectories were studied. A new sheet float zone furnace, designed for this study, enabled fast temperature ramps. Up to an 18 g sample was processed with each parabola. Samples of Y123 were processed as bulk sheets and composites containing Ag and Pd. The 0g processed samples were multi-phase yet retained a localized Y123 stoichiometry where a single ground-based (1g) oxygen anneal at temperatures of 800°C recovered nearly 100 vol% superconducting Y123. The 1g processed control samples remained multi-phase after the same ground-based anneal with less than 45 vol% as superconducting Y123. The superconducting transition temperature was 91 K for both 0g and 1g processed samples. Melt texturing of bulk Y123 in 0g produced aligned grains about a factor of three larger than in analogous 1g samples. Transport-critical current densities were at or below 18 A/cm2, due to the formation of cracks caused by the rapid heating rates required by the short time at 0g.
D. R. Pettit et al., "Processing Yttrium Barium Copper Oxide Superconductor in Near-Zero Gravity," Journal of Crystal Growth, vol. 139, no. 3-4, pp. 302-308, Elsevier, May 1994.
The definitive version is available at http://dx.doi.org/10.1016/0022-0248(94)90179-1
Materials Science and Engineering
Keywords and Phrases
Annealing; Copper oxides; Cracks; Grain boundaries; Grain size and shape; Microgravity processing; Microstructure; Superconducting transition temperature; Textures; Yttrium compounds; Near zero gravity processing; Sheet float zone furnace; High temperature superconductors
International Standard Serial Number (ISSN)
Article - Journal
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