| 摘要 |
A superconducting copper oxide based wire exhibiting improved critical current density and method. A superconductor powder and a binder melt are mixed at a solids loading of at least 90% by weight. The binder is an ester wax with no more than about 0.25 weight percent extrusion-aiding additives. The ester wax has the general formula RCOOR' with R and R' being hydrocarbon chains of at least 6 carbons. The ester wax melting point is 40 degrees-100 degrees C.; its melt viscosity is 94-2000 centipoise. The mixture is shaped and heated in an oxidizing atmosphere at up to 120 degrees C./hr to 500 degrees-600 degrees C., and held at that temperature for a time sufficient to remove the binder and achieve a wire density of at least 50% of theoretical. The green wire is heated at 50 degrees-130 degrees C./hr to at least 920 degrees C., and held at 920 degrees-990 degrees C. to achieve 90% of theoretical density, then annealed in oxygen. The wire may be textured during the heating process or by seeding. About 3-12 w/o silver may be included in a superconducting rare earth barium copper oxide based wire. The superconducting copper oxide based wire exhibits a density of at least about 99% of theoretical density, a critical temperature at dc zero resistance of at least about 90 K, and a critical current density of at least about 1000 A/cm2.
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