阅读说明：本技术 一种MgB2超导材料的制备方法 (Preparation method of MgB2 superconducting material ) 是由 杜永明 于 2019-11-01 设计创作，主要内容包括：本发明公开了一种MgB2超导材料的制备方法,具体按照以下步骤实施：将有机酸或有机酸盐潜于丙酣或乙醇中,将所得的有机酸或有机酸盐、丙嗣或乙醇溶液与Mg粉和B粉混合后,球磨1-10小时；然后置于真空干燥箱中保温干燥,将粉末装入铁铜复合管中密封,密封后以5％的变形率依次进行旋锻、拉拔和轧制,得到MgB2超导线带材；将得到的MgB2超导线带材放在真空炉中,在真空或氧气保护下,热处理,最终制得MgB2超导材料,解决了现有技术中存在的高能球磨后细化粉末的氧化和自燃的问题。(The invention discloses a preparation method of an MgB2 superconducting material, which is implemented according to the following steps: submerging organic acid or organic acid salt in glycerin or ethanol, mixing the obtained organic acid or organic acid salt, glycerin or ethanol solution with Mg powder and B powder, and performing ball milling for 1-10 hours; then placing the powder into a vacuum drying oven for heat preservation and drying, filling the powder into an iron-copper composite pipe for sealing, and carrying out rotary swaging, drawing and rolling in sequence at a deformation rate of 5% after sealing to obtain an MgB2 superconducting wire strip; the obtained MgB2 superconducting wire strip is put in a vacuum furnace and is subjected to heat treatment under the protection of vacuum or oxygen to finally prepare the MgB2 superconducting material, thereby solving the problems of oxidation and spontaneous combustion of the refined powder after high-energy ball milling in the prior art.)

1. A preparation method of MgB2 superconducting material is characterized by comprising the following steps:

step 1, submerging organic acid or organic acid salt in propane or ethanol, mixing the obtained organic acid or organic acid salt, propane or ethanol solution with Mg powder and B powder, and performing ball milling for 1-10 hours;

step 2, placing the solution obtained in the step 1 in a vacuum drying oven for heat preservation and drying, placing the powder into an iron-copper composite pipe for sealing, and performing rotary swaging, drawing and rolling in sequence at a deformation rate of 8% after sealing to obtain an MgB2 superconducting wire strip;

and 3, putting the obtained MgB2 superconducting wire strip in a vacuum furnace, and carrying out heat treatment under the protection of vacuum or oxygen to finally obtain the MgB2 superconducting material.

2. The method of claim 1, wherein the molar ratio of Mg powder to B powder in step 1 is 0.5-1: 1-2.2.

3. The method of claim 1, wherein the purity of the Mg powder is 94% -98%, and the particle size of the Mg powder is 1-80 μm.

4. The method for preparing MgB2 superconductive material according to claim 1, wherein the purity of B powder is 85-92%, and the particle size of B powder is 1-5 μm.

5. The method of claim 1, wherein the drying temperature of the vacuum drying oven in step 2 is 40-70 ℃ and the drying time is 1-6 hours.

6. The method as claimed in claim 1, wherein the heat treatment temperature in step 3 is 600-900 ℃.

7. The method for preparing the MgB2 superconducting material according to claim 1, wherein the MgB2 superconducting material is obtained after heat treatment in the step 3 and heat preservation for 1-3 hours.

Technical Field

The invention belongs to the technical field of MgB2 superconducting materials, and relates to a preparation method of a MgB2 superconducting material.

Background

Since the discovery of a novel superconductor double-shed mirror (MgB2) in 2001, scientists of various countries have conducted a great deal of intensive research, and at present, in the method for preparing the off-performance MgB2 wire strip, the in-situ powder sleeve technology is the most convenient and practical one, but the critical current density (Jc) is still low, and research shows that the particle size of the original powder plays an important role in the critical current density of the MgB2 superconducting material.

The grain sizes of the commercial mould powder prepared from the superconducting material are all larger and the grain size distribution is also very uneven, so that the superconducting performance of the MgB2 superconducting material is greatly influenced. For this reason, chinese patent CN 1439601a proposes a way to effectively improve superconducting properties of MgB2 by directly ball-milling commercial powder to reduce the particle size of the powder. It is noted, however, that during the ball milling process, the oxide layer on the surface is easily peeled off, resulting in a sharp increase of specific surface area and a sharp increase of activity, and is easily oxidized or even spontaneously ignited upon contact with oxygen or water vapor in the air, and the fine shed powder is also very easily oxidized and adsorbed, which undoubtedly seriously affects the performance of the superconducting material, and also brings a considerable risk to the preparation process.

Disclosure of Invention

The invention aims to provide a preparation method of an MgB2 superconducting material, which solves the problems of oxidation and spontaneous combustion of refined powder after high-energy ball milling in the prior art.

The technical scheme adopted by the invention is that the preparation method of the MgB2 superconducting material is implemented according to the following steps:

step 1, submerging organic acid or organic acid salt in propane or ethanol, mixing the obtained organic acid or organic acid salt, propane or ethanol solution with Mg powder and B powder, and performing ball milling for 1-10 hours;

step 2, placing the solution obtained in the step 1 in a vacuum drying oven for heat preservation and drying, placing the powder into an iron-copper composite pipe for sealing, and performing rotary swaging, drawing and rolling in sequence at a deformation rate of 8% after sealing to obtain an MgB2 superconducting wire strip;

and 3, putting the obtained MgB2 superconducting wire strip in a vacuum furnace, and carrying out heat treatment under the protection of vacuum or oxygen to finally obtain the MgB2 superconducting material.

The invention is also characterized in that:

in the step 1, the molar ratio of the Mg powder to the B powder is 0.5-1: 1-2.2.

The purity range of the Mg powder is 94% -98%, and the particle size range of the Mg powder is 1-80 microns.

The purity range of the powder B is 85-92%, and the particle size range of the powder B is 1-5 microns.

In the step 2, the drying temperature of the vacuum drying oven is 40-70 ℃, and the drying time is 1-6 hours.

The heat treatment temperature in step 3 is 600-.

And (3) after the heat treatment in the step (3), preserving the heat for 1-3 hours to obtain the MgB2 superconducting material.

The invention has the beneficial effects that: the preparation method of the MgB2 superconducting material solves the problems of oxidation and spontaneous combustion of the refined powder after high-energy ball milling in the prior art, remarkably improves the superconducting performance of the MgB2 superconducting material, and has the advantages of low cost, simple operation and high preparation safety.

Detailed Description

The present invention will be described in detail with reference to the following embodiments.

The invention relates to a preparation method of an MgB2 superconducting material, which is implemented according to the following steps:

step 1, submerging organic acid or organic acid salt in propane or ethanol, mixing the obtained organic acid or organic acid salt, propane or ethanol solution with Mg powder and B powder, and performing ball milling for 1-10 hours;

in the step 1, the molar ratio of the Mg powder to the B powder is 0.5-1:1-2.2, the purity range of the Mg powder is 94% -98%, the granularity range of the Mg powder is 1-80 microns, the purity range of the B powder is 85% -92%, the granularity range of the B powder is 1-5 microns,

step 2, placing the solution obtained in the step 1 in a vacuum drying oven for heat preservation and drying, placing the powder into an iron-copper composite pipe for sealing, and performing rotary swaging, drawing and rolling in sequence at a deformation rate of 8% after sealing to obtain an MgB2 superconducting wire strip;

in the step 2, the drying temperature of the vacuum drying oven is 40-70 ℃, and the drying time is 1-6 hours.

And 3, putting the obtained MgB2 superconducting wire strip in a vacuum furnace, and carrying out heat treatment under the protection of vacuum or oxygen to finally obtain the MgB2 superconducting material.

The heat treatment temperature in the step 3 is 600-.