Fabrication and Properties of Superconducting Wire Formed by Extruding Method

Abstract

The critical current density (J_c) of superconductor with high-T_c depends on the orientation of grains highly. In order to investigate the effect of orientation, the superconducting wires were fabricated by an extrusion method and examined on superconducting properties. The Bi-based superconducting powders were mixed with the wax binder after calcining at 1113K for 200h in air, and extruded to form wires 1mm in diameter at 403K. The samples, after burned wax binder out in air, showed the poor superconductivity due to a deficiency of oxygen confirmed by an X-ray diffraction analysis. On the other hand, the good superconducting property was obtained with the samples burned wax binder out in flowing oxygen gas. It is found from magnetic susceptibility data that particles oriented approximately parallel to the extrusion direction.