Method for preparing naphthalene-doped MgB2 superconductive single-core wire

Abstract

The invention discloses a method for preparing a naphthalene-doped MgB2 superconductive single-core wire, which comprises the following: 1, a step of making a holding pipe, in which dried magnesium powder and high-purity crystalline boron powder are fully and uniformly mixed in an atomic ratio of 1:2, 2 to 15 mass percent of crystalline naphthalene is added, the mixture is fully mixed and uniformly ground, and the obtained composite material is filled into a Nb / Cu composite metal pipe to make a holding pipe composite body; 2, a step of holding pipe composite body rotary swaging and drawing for making a primary product of the MgB2 superconductive single-core wire; and 3, a step of high temperature sintering, in which the primary product of the MgB2 superconductive single-core wire is subjected to high-temperature sintering in a protective atmosphere in a vacuum annealing furnace. The method of the invention adopts simple steps, requires low preparation cost and short preparation flow, and makes operation and control convenient. The prepared naphthalene-doped MgB2 superconductive single-core wire has excellent properties such as small hole size, high crystal connectivity, high compactness and high critical current density.

Description

technical field [0001] The present invention relates to a kind of MgB 2 The preparation method of superconducting wire rod, especially relates to a kind of naphthalene-doped MgB 2 A method for preparing a superconducting single-core wire. Background technique [0002] New superconducting material MgB 2 It has the advantages of high transition temperature (39K), large coherence length, and easy introduction of magnetic flux pinning. At the same time, MgB 2 Superconductors can work in the temperature range of GM refrigerators, so MgB 2 Superconductors have broad potential applications in superconducting power, electronic devices, and national defense. High J c , Highly stable long wire strip is MgB 2 basis for superconductor applications, so MgB 2 The research on the preparation technology of superconducting wire strips is of great significance. The in-situ powder-in-tube technique (in-situ PIT) is the preparation of MgB 2 One of the main technologies of wire, its pre...

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Problems solved by technology

[0003] Currently, C element substitution at the B site is to increase the MgB 2 One of the effective methods for the performance of superconducting wires, the doping source generally uses nanometer or micron C powder, the large particle size of micron C powder leads to low reactivity, and only a small amount of carbon atoms enter MgB 2 The crystal lattice, and the remaining carbon is all accumulated at the grain boundary, which reduces the connectivity between the grains, so the critical current density and irreversible field of the wire are limited; while the nano-C powder is easy to agglomerate, resulting in uneven distribution of doping sources. This also affects the performance of the wire to a certain extent.

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