Magnesium diffusion preparation method for magnesium diboride superconducting wire rod based on MgB<4> precursor powder

Abstract

Disclosed is a magnesium diffusion preparation method for a magnesium diboride superconducting wire rod based on MgB<4> precursor powder. The preparation method is based on a center magnesium diffusion technology; and MgB<4> is used as the precursor powder to replace the conventional boron precursor powder. The preparation method mainly comprises the steps of 1, performing ball milling and uniform mixing on original powder, then pressing the mixed powder into circular sheets by a powder compressing machine, and finally performing vacuum sintering and crushing on the circular sheets to obtain MgB<4> powder; and 2, fixing a magnesium rod in the center of a metal tube, filling the space between the magnesium rod and the metal tube with the MgB<4> powder, sealing the two ends of the tube, and then carrying out rotary calcining, pulling and drawing and vacuum thermal processing to obtain a MgB<2> wire rod. The MgB<2> wire rod superconducting core prepared by the preparation method is high in density; and meanwhile, the MgB<2> wire rod has high critical current density, superconducting phase filling rate and engineering critical current density, and excellent superconducting performance in medium and high magnetic fields.

Description

technical field [0001] The invention relates to a preparation method of a magnesium diboride superconducting wire. Background technique [0002] Since 2001 magnesium diboride (MgB 2 ) Since the discovery of superconductivity, this superconducting material has attracted scientists from all over the world to conduct in-depth research on it. MgB 2 Due to its simple structure, low cost, high critical transition temperature (39K), long coherence length, high upper critical field, and no weak connection at grain boundaries, superconducting materials are widely used in superconducting power, electronic devices and medical instruments. In particular, NMR imaging magnets have broad application prospects. At present, the international superconducting community has a great understanding of MgB 2 Consensus has been reached: Combined refrigeration cost and material cost, MgB 2 Superconducting materials are applied in the range of 20-25K, 1-3T magnetic field, and the advantages are v...

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Problems solved by technology

However, the disadvantage of this method is that after the central magnesium rod diffuses into the boron layer, a large area of ​​holes will be formed in the original center of the magnesium rod, and the filling rate of the superconducting phase is lower than 5%, which makes its engineering critical current density significantly larger. decline, and this process is in the preparation of MgB 2 Wire is still immature

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