Method for preparing single-core MgB2 superconducting line/strip

A superconducting wire and single-core technology, applied in cable/conductor manufacturing, electrical components, circuits, etc., can solve the problem that the critical current density of the wire/strip cannot be significantly improved, dopants are difficult to play a role, and equipment conditions are very demanding. Advanced problems, achieve good chemical inertness, increase critical current density, and increase surface activity

Active Publication Date: 2014-10-08
NORTHWEST INSTITUTE FOR NON-FERROUS METAL RESEARCH
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  • Abstract
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Problems solved by technology

However, when the heat treatment temperature is low, the dopant is difficult to play a role, and the critical current density of the wire / ribbon under high field cannot be significantly improved.
In addition, the synthetic element doped MgB under normal pressure 2 There are a lot of holes in the superconductor, and the use of hot pressing to increase the density is to improve the In-situ PIT MgB 2 Superconducting tape J c effective method, but the high-pressure synthesis requires high equipment conditions and can only be applied to MgB 2 The preparation of bulk materials and short wires is difficult in MgB 2 Application in In-situ PIT preparation of long strip

Method used

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  • Method for preparing single-core MgB2 superconducting line/strip
  • Method for preparing single-core MgB2 superconducting line/strip
  • Method for preparing single-core MgB2 superconducting line/strip

Examples

Experimental program
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Effect test

Embodiment 1

[0030] Single core MgB 2 Preparation of superconducting tape:

[0031] Step 1, mix magnesium powder, amorphous boron powder and micron-sized Ti powder according to the atomic ratio of Mg:Ti:B=0.8:0.2:4, mix them uniformly and press them into blocks, and place the blocks under argon gas Under the protection of the atmosphere, heat treatment at 900°C for 1.5h, after cooling, break the block, then add magnesium powder to the broken block according to the atomic ratio of Mg:Ti:B=0.9:0.1:2, and grind for 60min A mixed powder is obtained; the mass purity of the magnesium powder is not less than 99.8%, the particle size of the magnesium powder is -50 mesh, the mass purity of the amorphous boron powder is not less than 99%, and the mass purity of the micron Ti powder is not less than 99%, the particle size is -100 mesh;

[0032] Step 2. Place the mixed powder described in step 1 in a high-energy ball mill, and high-energy ball-mill the mixed powder for 10 hours at a rotational speed...

Embodiment 2

[0046] Single core MgB 2 Preparation of superconducting tape:

[0047] The preparation method of this embodiment is the same as that of Example 1, the difference being that step 5 is to roll the single-core wire described in step 4 into a single-core strip, and then seal both ends of the single-core strip Place in vacuum furnace and carry out vacuum sintering (vacuum sintering condition is the same as embodiment 1), obtains thickness and is 0.5mm, and width is 3.0mm single core MgB 2 Superconducting strip; the reduction ratios of the rolling passes are 20%, 20%, 15%, 10%, 10%, 10% and 10% in sequence.

[0048] In this embodiment, the supplemented magnesium powder in the step-by-step reaction process can bridge the microcracks formed in the processing process. In addition, due to the continuous fracture of powder particles during the high-energy ball milling process, a large number of fresh surfaces are produced, and the powder is milled to a certain extent by high-energy ball...

Embodiment 3

[0051] Single core MgB 2 Preparation of superconducting wires:

[0052] Step 1, mix magnesium powder, amorphous boron powder and micron-sized Ti powder according to the atomic ratio of Mg:Ti:B=0.98:0.02:4, mix them uniformly and press them into blocks, and place the blocks under argon gas Under the protection of the atmosphere, heat treatment at 800°C for 2 hours, after cooling, crush the block, then add magnesium powder to the crushed block according to the atomic ratio of Mg:Ti:B=0.99:0.01:2, and grind for 30 minutes to obtain Mixed powder; the mass purity of the magnesium powder is not less than 99.8%, the particle size of the magnesium powder is -50 mesh, the mass purity of the amorphous boron powder is not less than 99%, and the mass purity of the micron Ti powder is not less than 99% %, the particle size is -100 mesh;

[0053] Step 2. Place the mixed powder described in step 1 in a high-energy ball mill, and high-energy ball-mill the mixed powder for 20 hours at a spee...

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Abstract

The invention discloses a method for preparing a single-core MgB2 superconducting line/strip. The method comprises the steps that (1) mixed powder is prepared; (2) high-energy ball milling is conducted on the mixed powder, so that precursor powder is obtained; (3) the precursor powder is contained in a composite metal tube, so that a filled tube composite body is manufactured; (4) rotary forging and drawing are conducted, so that a single-core line is obtained; (5) vacuum sintering is conducted, so that the single-core MgB2 superconducting line is obtained or after the single-core line is rolled into a strip, vacuum sintering is conducted on the strip, so that the single-core MgB2 superconducting strip is obtained. According to method for preparing the single-core MgB2 superconducting line/strip, firstly, heat treatment with high temperature is conducted on powder raw materials, it can be guaranteed that TiB2 generated after a reaction is evenly distributed on a crystal boundary, and therefore the critical current density of the MgB2 superconducting line/strip can be increased easily; secondly, due to the fact that crystal grains are further refined through high-energy ball mining, the density of a superconducting core wire is increased easily and the connectivity of MgB2 crystal grains is improved easily; thirdly, more crystal boundaries formed by grain refinement can form a pinning center, and therefore the critical current density of the line/strip is increased further.

Description

technical field [0001] The invention belongs to the technical field of superconducting material processing engineering, in particular to a single-core MgB 2 Method for the preparation of superconducting wires / tapes. Background technique [0002] MgB 2 Since the superconductor was discovered in 2001, due to its critical temperature of 39K, its advantages such as large coherence length and no weak connection of grain boundaries, it has attracted the attention of scientists at home and abroad. Miscellaneous is to increase MgB 2 Wire under magnetic field J c The most performance-efficient method. When Ti is doped, Ti reacts with B to form nano-sized TiB 2 Distributed in MgB 2 The grain boundary becomes an effective pinning center, which can significantly refine the grain and improve the grain connectivity, thus increasing the MgB 2 Critical current density at high field. [0003] Currently using PIT technology to process MgB 2 There are two main technical routes for wir...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01B13/00
Inventor 杨芳李成山冯建情王庆阳熊晓梅刘国庆闫果冯勇
Owner NORTHWEST INSTITUTE FOR NON-FERROUS METAL RESEARCH
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