Graphene/metal/mgb2 composite material with high intercrystalline connectivity and preparation method

A composite material and connectivity technology, applied in the field of superconductivity, to achieve the effects of fine grain size, improved connectivity, and good connectivity between grains

Inactive Publication Date: 2018-11-30
TIANJIN UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

So, how to satisfy the condition (1) while ensuring the conditions (2) and (3)? In other words, how to effectively increase the MgB while providing more flux pinning centers 2 What about inter-die connectivity? So far there is no effective method to solve it, in view of this difficult problem, the present invention is proposed

Method used

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  • Graphene/metal/mgb2 composite material with high intercrystalline connectivity and preparation method
  • Graphene/metal/mgb2 composite material with high intercrystalline connectivity and preparation method
  • Graphene/metal/mgb2 composite material with high intercrystalline connectivity and preparation method

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Experimental program
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Effect test

Embodiment 1

[0042] The method provided by the present invention utilizes metal powder and graphene co-doping to improve MgB 2 A method for grain-to-grain connectivity, the steps of which are:

[0043] 1) raw materials are commercially available magnesium powder (average diameter is 100 microns, purity 99.5%), amorphous boron powder (average diameter is 25 microns, purity 99%), graphene (single-layer graphene, purity 99%), metal Ni powder (average diameter 40 nm, purity 99.5%). The four are uniformly mixed at a molar ratio of Mg:B:C:Ni=0.94:1.9:0.1:0.06 to form a mixed raw material.

[0044] 2) Put 4g of the mixed raw material into the ball mill tank, the ratio of the balls to the mixed raw material is 30:1, the milling time is 8 hours, and the ball milling speed is 300rpm. During the ball milling process, in order to prevent the temperature in the tank from being too high, the milling is stopped every 55 minutes After 5 minutes, the Mg-B-C-Ni composite powder was obtained after ball mil...

Embodiment 2

[0050] The method provided by the present invention utilizes metal powder and graphene co-doping to improve MgB 2 A method for grain-to-grain connectivity, the steps of which are:

[0051] 1) raw materials are commercially available magnesium powder (average diameter is 100 microns, purity 99.5%), amorphous boron powder (average diameter is 25 microns, purity 99%), graphene (single-layer graphene, purity 99%), metal Cu powder (average diameter 100 nm, purity 99.5%). The four are uniformly mixed at a molar ratio of Mg:B:C:Cu=0.94:1.9:0.1:0.06 to form a mixed raw material.

[0052] 2) Put 4g of the mixed raw material into the ball mill tank, the ratio of the balls to the mixed raw material is 30:1, the milling time is 8 hours, and the ball milling speed is 300rpm. During the ball milling process, in order to prevent the temperature in the tank from being too high, the milling is stopped every 55 minutes After 5 minutes, the Mg-B-C-Cu composite powder was obtained after ball mi...

Embodiment 3

[0056] The method provided by the present invention utilizes metal powder and graphene co-doping to improve MgB 2 A method for grain-to-grain connectivity, the steps of which are:

[0057] 1) raw materials are commercially available magnesium powder (average diameter is 100 microns, purity 99.5%), amorphous boron powder (average diameter is 25 microns, purity 99%), graphene (single-layer graphene, purity 99%), metal Ag powder (average diameter 60 nm, purity 99.9%). The four are uniformly mixed at a molar ratio of Mg:B:C:Ag=0.92:1.8:0.2:0.08 to form a mixed raw material.

[0058] 2) Put 4g of the mixed raw material into the ball mill tank, the ratio of the balls to the mixed raw material is 35:1, the milling time is 8 hours, the milling speed is 300rpm, and the ball milling process is to prevent the temperature in the tank from being too high, and the milling is stopped every 55 minutes After 5 minutes, the Mg-B-C-Ag composite powder was obtained after ball milling,

[0059]...

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Abstract

The invention relates to a graphene / metal / MgB2 composite material with high intergranular connectivity and a preparation method thereof. Mg, B and a certain proportion of graphene and metal are jointly subjected to ball milling, and finally, an MgB2 superconducting block body is obtained through high-temperature sintering. The MgB2 superconducting block body prepared through the method is good in intergranular connectivity, thin and small in grain and even in distribution, and forms an eutectic liquid phase with the Mg at the low temperature through doping of Cu or Ni, favorable conditions are provided for diffusion and reaction between Mg and B particles, the reaction free energy is reduced, and the formation temperature of MgB2 is decreased to 500 DEG C. A reaction site is further provided for the particles through adding of the graphene, and thus MgB2 particles are subjected to nucleation and growth on a graphene carrier, so that the MgB2 forms a network structure, and the intergranular connectivity is improved. The used raw materials are easy to obtain, the material preparation method is mature in development, operation is convenient, and the process is controllable; and according to the method, the MgB2 reaction temperature is effectively decreased, and the intergranular connectivity of the MgB2 is improved.

Description

technical field [0001] The invention belongs to the technical field of superconductivity, and relates to a graphene / metal / MgB with high intercrystalline connectivity 2 Composite materials and methods for their preparation. Background technique [0002] In 2001, Professor Akimitsu Jun, a Japanese scientist, announced the discovery of MgB 2 High-temperature superconducting properties, its critical temperature is as high as 39K. Although with cuprate high-temperature superconducting materials (the highest T c =164K) and the newly discovered iron-based superconducting material in 2008 (the highest T c =55K) is not very high, but MgB 2 It is a simple and stable metal compound superconducting material with the highest critical temperature found so far. Scientists are working on MgB 2 In the study of the relationship between the critical current density and the magnetic field of the powder, it was found that MgB 2 The critical current density decreases sharply with the incre...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C29/14C22C1/05B22F9/04
CPCB22F9/04B22F2009/043B22F2998/10C22C1/058C22C29/14B22F3/02
Inventor 赵倩矫春健
Owner TIANJIN UNIV OF SCI & TECH
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