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Effect of Extrusion on the Critical Current Density of Bi 1.4 Pb 0.6 Sr 2 Ca 2 Cu 3 O x Superconducting Wires
Author(s) -
Suzuki Suguru,
Asada Shinji,
Takahashi Minoru,
Hikichi Yasuo
Publication year - 1991
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1991.tb06913.x
Subject(s) - extrusion , materials science , calcination , critical current , superconductivity , analytical chemistry (journal) , viscosity , current density , metallurgy , composite material , high density polyethylene , current (fluid) , polyethylene , chemistry , condensed matter physics , electrical engineering , biochemistry , physics , engineering , chromatography , quantum mechanics , catalysis
The effect of extrusion on improving the critical current density ( J c ) of Bi 1.4 Pb 0.6 Sr 2 Ca 2 Cu 3 O x superconducting wires is investigated. Calcined powders (Bi 1.4 Pb 0.6 Sr 2 Ca 2 Cu 3 O x ) are first mixed with a forming aid—a thermoplastic polymer (polyethylene)—for workability, and then extruded, using a capillary rheometer, to form wires 2 mm in diameter. The J c value, measured by the four‐probe method in liquid nitrogen at 77 K, is improved substantially by the following process: (1) the superconducting precursors are extruded at high viscosity with a forming aid, to align the platelike particles unidirectionally; (2) the forming aid alone is carefully burned out, without destroying the extruded configuration; and (3) the extruded wires are annealed at 850°C in air for more than 96 h.