Method for preparing iron/copper compound coated magnesium diborate superconductive long wire

A technology of magnesium diboride and superconducting wire, which is applied in the field of preparation of MgB2 superconducting long wire, can solve the problems of affecting the condition of Fe/Cu composite interface, affecting the low temperature thermal stability of superconducting wire, uneven filling density in the tube, etc. It is convenient for industrial continuous operation, convenient for industrial application, and the effect of superconductivity is full and uniform.

Inactive Publication Date: 2007-04-11
INST OF ELECTRICAL ENG CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In particular, the processing specifications of Fe and Cu tubes not only affect the elongation of the superconducting wire, but also affect the composite interface between Fe / Cu, thereby affecting the thermal stability of the superconducting wire at low temperature; in order to improve the uniformity of the long wire, the particle size of the core material must be reduced. To improve the uniformity of filling materials, at present, the ball milling process under the protection of Ar atmosphere is mostly used (see: B Lorenz et al., Superconducting properties of nanocrystalline MgB2, Supercond.Sci.Technol.19(2006) 912-915), the method equipment The process is complicated, and the temperature of the material will rise after ball milling, which will easily cause the secondary oxidation of Mg powder
Chinese patent 1190802C proposes a method of filling superconducting powder: continuous feeding, filling, and compact filling in stages. Due to uneven pressure during filling, it is easy to cause uneven filling density in the tube, especially for long tubes.
This method will eventually affect the uniformity of each segment of the superconducting wire

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] The preparation steps of the iron / copper composite sheathed magnesium diboride superconducting long wire are as follows:

[0017] (1) The inner and outer surfaces of an oxygen-free copper pipe with an outer diameter of 20.00mm, an inner diameter of 18.45mm, and a length of 200mm, and a low-carbon iron pipe with an outer diameter of 18.40mm, an inner diameter of 14.10mm, and a length of 200mm are machined, and the surface roughness after processing is small. The arithmetic average deviation (Ra) of its profile: 6.3μm. After processing, the copper tube can be tightly sleeved on the outside of the iron tube. The inner diameter of the copper tube is 50 μm different from the outer diameter of the iron tube. After cleaning the surface with acetone, put the iron tube into the copper tube Internal reserve;

[0018] (2) Weigh metal magnesium powder and amorphous boron powder in a molar ratio of 1:2, add nano-SiC as a doping material, and put the mixed material into a ball mill j...

Embodiment 2

[0025] (1) Machine the inner and outer surfaces of an oxygen-free copper pipe with an outer diameter of 18.00mm, an inner diameter of 15.01mm, and a length of 250mm, and a low-carbon iron pipe with an outer diameter of 15.00mm, an inner diameter of 11.20mm, and a length of 250mm. After processing, the surface roughness is small, The arithmetic average deviation (Ra) of its profile: 0.4μm. After processing, the copper tube can be tightly placed on the outside of the iron tube. The inner diameter of the copper tube is 10 μm different from the outer diameter of the iron tube. After cleaning the surface with acetone, put the iron tube into the copper tube Internal reserve;

[0026] (2) Weigh MgB2 powder and nano-C doping; put the mixed material into a ball mill jar, and then add grinding balls in a ratio of 1 / 5 material / ball by mass ratio.

[0027] (3) add carbon tetrachloride solvent in the ball mill jar, the carbon tetrachloride add-on is advisable with just submerging the mixtu...

Embodiment 3

[0033](1) The inner and outer surfaces of the oxygen-free copper pipe with an outer diameter of 20.00mm, an inner diameter of 18.42mm, and a length of 350mm, and a low-carbon iron pipe with an outer diameter of 18.40mm, an inner diameter of 14.10mm, and a length of 350mm are machined, and the surface roughness after processing is small. The arithmetic mean deviation (Ra) of its profile: 0.8μm. After processing, the copper tube can be tightly sleeved on the outside of the iron tube. The inner diameter of the copper tube is 20 μm different from the outer diameter of the iron tube. After cleaning the surface with acetone, put the iron tube into the copper tube Internal reserve;

[0034] (2) Weigh metal magnesium powder and amorphous boron powder in a molar ratio of 1:2, add nano-SiC, put the mixed material into a ball mill jar, and then add it for grinding at a mass ratio of 1 / 2.5 material / ball ball.

[0035] (3) Add toluene solvent in the ball mill jar, the amount of toluene ad...

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Abstract

This invention relates to a preparation method for an iron/copper compound packet wrapping MgB2 super-conduction long wires including: processing an iron tube and a copper tube of a certain specification, jacketing the iron tube into the copper tube, putting Mg powder, B powder and doped materials into a ball mill tank, then adding acetone reagent to dip the materials and mill the balls, vacuum-drying the ball-mill sample under ordinary temperature to get the material powder to be pressed to a cylinder with 10-600 MPa pressure and put into an iron tube, then to be pressed tightly and seal the port to get a compound packet wire in a certain diameter and length after swaging, rolling the hole and drawing, which is processed under 650-950deg.C for 0.5-5h to get a MgB2 super conduction wire with compound iron/copper.

Description

technical field [0001] The present invention relates to a kind of MgB 2 The invention relates to a method for preparing a long superconducting wire, in particular to a method for preparing a magnesium diboride superconducting wire with excellent performance and covered with Fe / Cu compound. Background technique [0002] In January 2001, J. Akimitsu, a professor at Aoyama College in Japan, announced the discovery of magnesium diboride (MgB 2 ) At 39K, it has superconducting properties. It is the binary intermetallic compound superconductor with the highest critical temperature found so far. The binary compound with the highest Tc found in the past is niobium trigermanium (Nb 3 Ge), its transition temperature is only 23.2K, an increase of nearly 16K. And the magnesium diboride material is a binary compound of A15 structure, which has the characteristics of simple synthesis process, low cost, no weak connection of grain boundary and low normal resistivity. In addition, MgB ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01B13/00H01B12/00
CPCY02E40/64Y02E40/60
Inventor 禹争光马衍伟王栋梁张现平高召顺
Owner INST OF ELECTRICAL ENG CHINESE ACAD OF SCI
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