Preparation of MgB_2 superconducting wires by the rapid heating and quenching method

摘要

In order to reduce the long-term annealing process and prevent excessive grain growth, we attempted to fabricate MgB2 superconducting wires by the rapid heating and quenching (RHQ) method. In this paper, we have successfully prepared MgB2 superconductive wires with self-made RHQ equipment, and the effect of various Joule heating currents on the properties of MgB2 was investigated. The XRD results showed that the sample had relatively strongest diffraction peaks and least heterogenous peaks when the loading heating current was 350 A, so the superconducting transition temperature (T-c) could reach 38.5 K. Because the MgB2 phase particles were small and uniformly distributed, there was a good critical current density (J(c)). That is, in the self-field, the J(c) value of the 350 A sample reached up to 1.39 x 10(5) A/cm(2), and the downward trend was the flattest. When the magnetic field was 7 T, the critical current density was still as high as 300 A/cm(2). (C) 2019 Elsevier B.V. All rights reserved.