Superconductivity and mechanical property of Bi-2223/Ni meshes composite bulk

Abstract

In order to improve superconductivity and mechanical property of Bi-2223 sintered bulk, nickel (Ni) meshes were composed in the bulk. Ni wires of 0.15 and 0.25 mm in diameters were plated with silver of 0.03 mm in thickness. The samples were sintered at 840 °C for 50 h, intermediate pressed and then, re-sintered at 840 °C for 50 h. The mechanical property was estimated by a three point bending test. The bending stress of ca. 85 MPa was obtained in the bulk without Ni meshes, which was ruptured separately. The composite did not rapture but fine cracks were induced after the maximum bending stress, which was 100 MPa in the composite with one layer of the meshes and ca. 50 MPa in the composite with two or more layers of the meshes. When one layer of the meshes was composed, the J c at 77 K increased to 600 from 200 A/cm 2 of the sample without the meshes. SEM observation results showed that high alignment and dense structure of Bi-2223 plate-like grains was formed around the interfacial region between the superconducting oxide and the Ni wires.