Preparation method of high density MgB2 superconduction block material

A superconducting block and high-density technology, which is applied in the field of MgB2 superconducting material preparation, can solve the problems of limited superconducting current carrying capacity, will not reach 100%, complicated equipment and process, etc., and can increase the critical current density and refine the Crystal grains, the effect of high purity

Inactive Publication Date: 2006-06-28
SHANGHAI UNIV
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Problems solved by technology

[0003] However, in MgB 2 In the preparation process of superconducting materials, especially bulk materials, wires and strips, since Mg and B are raw materials with low density, the density of Mg is 1.74g/cm 3 , the density of B is 2.34g/cm 3 , even after pressing to achieve 100% compactness, its volume will shrink to 76% of its original volume during sintering, and the obtained MgB 2 There are a lot of shrinkage cavities in the sample, and the density is far lower than its theoretical value of 2.62g/cm 3 , and the pressing will not reach 100%, so after sintering, generally only 1.1~1.5g/cm 3 The loose structure of the material is the main reason that limits the increase of the critical current density of the material, and the MgB 2 It has great

Method used

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Experimental program
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Effect test

Example Embodiment

[0014] Example one:

[0015] MgB of this example 2 The preparation steps of superconducting materials are as follows:

[0016] (1) Mg powder with a purity of 99% and passing through a 325-mesh sieve and B powder with a purity of 99% are placed in a vacuum drying oven at a constant temperature of 120°C for 24 hours, and then the Mg and B powders are weighed separately , According to the stoichiometric ratio Mg:B=1:2, the batching is carried out. After the batching is uniformly ground, it is sealed in tantalum foil;

[0017] (2) Place the above-mentioned tantalum foil containing the Mg and B mixture in the heating tube, use a diffusion vacuum pump to remove the air in the heating tube to make a vacuum, then fill it with high-purity argon for scrubbing, and then vacuum. After repeating this three times, continue to slowly fill the high-purity argon gas to ensure the inert atmosphere in the tube;

[0018] (3) Put the above heating tube in a tube furnace to heat at a rate of 100°C / h; h...

Example Embodiment

[0024] Embodiment 2: The preparation steps in this embodiment are exactly the same as those in the first embodiment. The difference is: ①Mg powder and B powder are weighed according to Mg:B=0.7:2; ②MgB obtained by ball milling 2 When mixed with Mg powder and B powder with a stoichiometric ratio of Mg:B=0.7:2, the ratio of the added amount of Mg powder and B powder to the primary sintered sample powder is 0.02:1; ③The reaction temperature of the material is controlled at At 750°C, the holding time is 0.5 hours.

Example Embodiment

[0025] Embodiment 3: The preparation steps in this embodiment are exactly the same as those in the first embodiment. The difference is: ①Mg powder and B powder are weighed according to Mg:B=0.8:2; ②MgB obtained by ball milling 2 When mixed with Mg powder and B powder with a stoichiometric ratio of Mg:B=0.8:2, the ratio of the added amount of Mg powder and B powder to the primary sintered sample powder is 0.05:1; ③The reaction temperature of the material is controlled at 800°C, the holding time is 2 hours.

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Abstract

This invention relates to a preparation method for a high density MgB2 super-conduction block including: grinding powders of Mg and B and sealing them in a Ta foil to be put in a heating tube to rise the temperature to 650-950deg.C for 0.5-10 hours to be sintered for the first time to produce MgB2 super-conduction material to be ground to powders of 2-3mum then to be mixed and sintered for the second time to get the high density MgB2 super conduction material with fine particles, large grain boundary area and ideal connection without micro-crack.

Description

technical field [0001] The present invention relates to a kind of MgB 2 Preparation method of superconducting material, especially a kind of high-density MgB 2 Preparation method of superconducting bulk material. Background technique [0002] In 2001, the intermetallic compound MgB was discovered 2 The result of superconductivity has caused a great sensation in the field of condensed matter physics and materials science. Because many of its unique properties have not been fully recognized and understood by people, it has attracted widespread attention in many disciplines such as materials, physics, and chemistry. MgB 2 The superconducting critical transition temperature of the superconductor is 39K, and its superconducting temperature is second only to oxide superconductors, doped C 60 Solid material superconductor is a simple and stable intermetallic compound superconducting material with the highest superconducting temperature found so far. MgB 2 The structure is a ...

Claims

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Application Information

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IPC IPC(8): H01B12/00H01B13/00H01L39/24
CPCY02E40/60
Inventor 李文献朱明原李瑛金红明陈荣华
Owner SHANGHAI UNIV
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