Method for producing carbon doped MgB2 cryogenic conductor by step-by-step sintering reaction

A step-by-step sintering and superconductor technology, applied in the usage of superconductor elements, etc., can solve the problems of unusable and high cost, and achieve the effect of improving density, improving magnetic flux pinning force, and strengthening grain connection

Active Publication Date: 2009-08-19
NORTHWEST INSTITUTE FOR NON-FERROUS METAL RESEARCH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the high-pressure method has high cost and cannot be used in

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0015] Example 1

[0016] The dried magnesium (99%), boron (99%), and nano-C powder were thoroughly mixed in the ratio of atomic ratio Mg:B:C=1:3.9:0.1 for 1 hour. The mixed powder is pressed into a sheet with a diameter of Φ20mm with a hydraulic press, and the pressure is 30MPa, and then placed in a vacuum annealing furnace, evacuated at room temperature, until the vacuum degree reaches 10 -3 After Pa was filled with pure argon gas, the flakes or blocks were heated at a heating rate of 60°C / min, kept at a temperature of 900°C for 2 hours, and finally the flakes were cooled to room temperature at a cooling rate of 25°C / min. Then the flakes are crushed into micron-sized powder, and an appropriate amount of metal magnesium powder is added to it to obtain a mixed powder with an atomic ratio of magnesium and (boron + C) of 1:2. The mixed powder is pressed into a sheet with a diameter of Φ20mm with a hydraulic press, and the pressure is 30MPa, and then it is placed in a vacuum annealin...

Example Embodiment

[0017] Example 2

[0018] The dried magnesium (99%), boron (99%), and nano-C powder were thoroughly mixed in the ratio of atomic ratio Mg:B:C=1:3.9:0.1 for 1 hour. The mixed powder is pressed into a sheet with a diameter of Φ20mm with a hydraulic press, and the pressure is 30MPa, and then placed in a vacuum annealing furnace, evacuated at room temperature, until the vacuum degree reaches 10 -3 After Pa was filled with pure argon gas, the flakes or blocks were heated at a heating rate of 60°C / min, kept at a temperature of 900°C for 2 hours, and finally the flakes were cooled to room temperature at a cooling rate of 25°C / min. Then the flakes are crushed into micron-sized powder, and an appropriate amount of metal magnesium powder is added to it to obtain a mixed powder with an atomic ratio of magnesium and (boron + C) of 1:2. The mixed powder is pressed into a sheet with a diameter of Φ20mm with a hydraulic press, and the pressure is 30MPa, and then it is placed in a vacuum annealin...

Example Embodiment

[0019] Example 3

[0020] The dried magnesium (99%), boron (99%), and nano-C powder were thoroughly mixed in the ratio of atomic ratio Mg:B:C=1:3.9:0.1 for 1 hour. The mixed powder is pressed into a sheet with a diameter of Φ20mm with a hydraulic press, and the pressure is 30MPa, and then placed in a vacuum annealing furnace, evacuated at room temperature, until the vacuum degree reaches 10 -3 After Pa was filled with pure argon gas, the flakes or blocks were heated at a heating rate of 60°C / min, kept at a temperature of 900°C for 2 hours, and finally the flakes were cooled to room temperature at a cooling rate of 25°C / min. Then the flakes are crushed into micron-sized powder, and an appropriate amount of metal magnesium powder is added to it to obtain a mixed powder with an atomic ratio of magnesium and (boron + C) of 1:2. The mixed powder is pressed into a sheet with a diameter of Φ20mm with a hydraulic press, and the pressure is 30MPa, and then it is placed in a vacuum annealin...

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PUM

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Abstract

The invention discloses a method for preparing carbon doping MgB2 superconductor by fractional sintering reaction. The method has the following steps: a first sintering is carried out on mixed powder of magnesium, boron and C with an atomicity ratio of 1:(4-x):x (x is between 0.05-0.3); then a moderate amount of magnesium metal powder is added to the sintering product for a second sintering; finally MgB2 superconductor with C element as doping is obtained. In the invention, the fractional sintering reaction is adopted to prepare the carbon doping MgB2 superconductor, the doping elements can enter crystal lattices at low temperature, MgB2 crystal grains are effectively thinned, connection of MgB2 crystal grains is strengthened, pinning force of flux nails is improved, meanwhile the number of hollow holes caused by gasification of magnesium in the process of reaction between magnesium and boron is reduced and density of the MgB2 superconductor is effectively improved; moreover, in the invention, low-cost and large-scale preparation of MgB2 basic superconducting materials are realized.

Description

technical field [0001] The present invention relates to a kind of MgB 2 Preparation method of superconductor, especially involving a step-by-step sintering reaction to prepare carbon-doped MgB 2 approach to superconductors. Background technique [0002] New superconductor MgB 2 The discovery has set off a research boom all over the world. MgB 2 The transition temperature of the superconductor is 39K, which can be cooled by a refrigerator; compared with the oxide superconductor, MgB 2 The critical current density is high, and the grain boundary is "transparent" to the superconducting current, that is, the superconducting current is not limited by the connectivity of the grain boundary. The study found that MgB 2 The coherence length of the oxide is larger than that of the perovskite structure, which means that the MgB 2 It is easier to introduce effective flux pinning centers in . But since MgB 2 The irreversible magnetic field of a superconductor (H irr ) and the up...

Claims

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Application Information

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IPC IPC(8): C04B35/58C04B35/622C04B35/64
CPCY02E40/64Y02E40/60
Inventor 焦高峰闫果刘国庆王庆阳熊晓梅李成山
Owner NORTHWEST INSTITUTE FOR NON-FERROUS METAL RESEARCH
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