Effect of Extrusion on Critical Current of YBa₂Cu₃O_7-δ Superconducting Wires

Abstract

The effect of extrusion was investigated to obtain a high critical current density (J_c) of YBa₂Cu₃O_7-δ superconducting wires. A YBa₂Cu₃O_7-δ powder was prepared by calcining Y₂O₃ (99.99%), BaCO₃ (99.9%) and CuO (99.9%) at 1133 to 1173K for 36h in air and oxygen. The resultant powders were mixed with the thermoplastic polymer (polyethylene) and extruded with a capillary rheometer to form rods of 1, 2 and 3mm in diameter. After the thermoplastic polymer was burned out completely, the extruded materials were sintered between 1198 and 1273K to change the porosity. J_c was measured by the four-probe method in liquid nitrogen (77K). The high values of J_c were obtained for the rods extruded in the uniaxial orientation of YBa₂Cu₃O_7-δ particles and burned with the original shape preserved.