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.


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

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Article - Journal

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