Method of preparing MgB2/Nb/Cu multi-core composite superconducting wire

Abstract

The invention discloses a method of preparing an MgB2 / Nb / Cu multi-core composite superconducting wire. Firstly, MgB4 powder is prepared according to an atomic ratio of Mg to B which equals to 1 to 4, then, Mg powder is added according to the atomic ratio of Mg to B which equals to 1 to 2 to obtain tubulating precursor powder. And then, the prepared powder is filled in a pure Nb metal tube to obtain a tubulating composite body. The circumflex section drawing is carried out on the tutulating composite body to be processed into a single-core wire; the secondary assembly is carried out on the single-core wire according to the conducting structure of a 7-37 core, the single-core wire is canned for the second time into an oxygen-free copper tube, and the rotary swaging and the drawing are carried out on the oxygen-free copper tube; the processed wire is arranged in a vacuum annealing furnace the vacuum pumping is carried out under the room temperature, mixed gas of pure argon or argon and hydrogen is pumped into the furnace, and then the wire is heated, insulated and cooled to the room temperature. The multi-core composite superconducting wire with free length, good compactness and highcritical current density is prepared by the phase composition control of the precursor powder and the optimizing of the corresponding drawing process.

Description

Technical field [0001] The invention relates to a method for preparing a composite superconducting wire, in particular to a MgB 2 / Nb / Cu multi-core composite superconducting wire. Background technique [0002] 2001 MgB 2 The discovery of superconductivity caused a sensation in the entire condensed matter physics world. It created a new record for intermetallic superconducting materials. The superconducting transition temperature was as high as 39K, which filled the gap of medium temperature superconductors. Internal (10-30K) new superconducting material with great application potential. Compared with oxide high-temperature superconducting materials, MgB 2 The crystal structure of MgB is simpler, the coherence length is larger, there is no weak connection between grain boundaries, and it can carry high current density. Therefore, MgB 2 The preparation of wire and strip has received extensive international attention. [0003] Current MgB 2 There are two main methods for wire prepara...

AI Technical Summary

Problems solved by technology

The process of preposition method is simple, but in the process of drawing, MgB 2 The core wire is prone to microcracks, and it is difficult to bridge them by heat treatment, so it is difficult to prepare MgB with high critical current density with application value 2 superconducting wire

MgB prepared by in situ method 2 MgB in superconducting wire 2 The grains are well connected and can carry higher current density, but due to avoid MgB during processing 2 intermediate annealing is not possible, and the fluidity of Mg powder and B powder is very different, so the wire is easily broken during processing, so it is difficult to process into a long wire with engineering application value