Method for preparing magnesium diboride superconducting wire rod by using graphite-like phase carbon nitride in-situ coating boron powder

A graphite phase carbon nitride, in-situ coating technology, applied in the usage of superconducting elements, superconducting devices, superconducting/high-conducting conductors, etc., can solve the problem of uneven distribution of doping sources, and achieve low prices. , The coating layer is thin and uniform, and the effect of increasing the connectivity between grains

Inactive Publication Date: 2018-07-24
SHANGHAI UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] In order to solve the problems of the prior art, the object of the present invention is to overcome the deficiencies in the prior art, and provide a method for preparing magnesium diboride superconducting wires by in-situ coating of boron powder with graphite-like phase carbon nitride. Carbon nitride has a lamellar structure. By using the graphite-like carbon nitride precursor as the raw material, after heat treatment, the graphite-like carbon nitride can be tightly and uniformly coated on the boron particles, avoiding the uneven distribution of doping sources in the traditional method. uniform defect; the prepared graphite-like phase carbon nitride in-situ coated boron powder ensures the activity of boron powder and prevents the oxidation of boron powder, and then adopts the powder-in-tube method to prepare magnesium diboride super wire rod

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  • Method for preparing magnesium diboride superconducting wire rod by using graphite-like phase carbon nitride in-situ coating boron powder
  • Method for preparing magnesium diboride superconducting wire rod by using graphite-like phase carbon nitride in-situ coating boron powder
  • Method for preparing magnesium diboride superconducting wire rod by using graphite-like phase carbon nitride in-situ coating boron powder

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Embodiment 1

[0029] In this example, see Figure 1~3 , a method for preparing a magnesium diboride superconducting wire by using graphite-like carbon nitride in situ to coat boron powder, comprising the steps of:

[0030] (1) Urea is used as the graphite-like phase carbon nitride precursor material, and the urea and boron powder are ground and mixed for 30 minutes to obtain a mixed powder according to the mass of urea being 1 times the mass of boron powder;

[0031] (2) placing the mixed powder prepared in the step (1) in a crucible, placing the open but not closed crucible into a muffle furnace to be heated evenly, and heat-treating the mixed powder in an air state, and then After cooling down to room temperature in the furnace, uniformly coat graphite-like carbon nitride with controllable thickness on the surface of boron particles in situ to obtain boron powder coated with graphite-like carbon nitride in situ; control the thermal system of heat treatment as follows: heat treatment tempe...

Embodiment 2

[0039] This embodiment is basically the same as Embodiment 1, especially in that:

[0040] In this embodiment, a method for preparing a magnesium diboride superconducting wire by in-situ coating boron powder with graphite-like carbon nitride comprises the following steps:

[0041] (1) Dicyandiamide is used as the graphite-like carbon nitride precursor material, and the mass of dicyandiamide is 3 times that of boron powder, and the dicyandiamide and boron powder are ground and mixed for 40 minutes to obtain a mixed powder ;

[0042] (2) placing the mixed powder prepared in the step (1) in a crucible, putting the open and unclosed crucible into a muffle furnace to be heated evenly, and heat-treating the mixed powder in an air state, and then Cool down to room temperature with the furnace, uniformly coat graphite-like carbon nitride with controllable thickness on the surface of boron particles in situ, and obtain boron powder coated with graphite-like carbon nitride in situ; con...

Embodiment 3

[0050] This embodiment is basically the same as the previous embodiment, and the special features are:

[0051] In this embodiment, a method for preparing a magnesium diboride superconducting wire by in-situ coating boron powder with graphite-like carbon nitride comprises the following steps:

[0052] (1) Using melamine as the graphite-like carbon nitride precursor material, according to the mass of melamine being 6 times the mass of boron powder, the melamine and boron powder were ground and mixed for 50 minutes to obtain a mixed powder;

[0053] (2) placing the mixed powder prepared in the step (1) in a crucible, putting the open and unclosed crucible into a muffle furnace to be heated evenly, and heat-treating the mixed powder in an air state, and then Cool down to room temperature with the furnace, uniformly coat graphite-like carbon nitride with controllable thickness on the surface of boron particles in situ, and obtain boron powder coated with graphite-like carbon nitri...

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Abstract

The invention discloses a method for preparing a magnesium diboride superconducting wire rod by using a graphite-like phase carbon nitride in-situ coating boron powder. The method comprises the following steps of fully mixing a graphite-like phase carbon nitride precursor and the boron powder so as to obtain a mixed powder; through heat treatment, acquiring a granular carbon-nitride in-situ coating boron powder; uniformly mixing the graphite-like phase carbon nitride in-situ coating boron powder and a magnesium powder and putting into a metal pipe, and using a wire drawing machine to carry outdrawing and acquiring the wire rod; and carrying out heat treatment on a composite wire rod and acquiring a magnesium diboride superconducting wire. In the invention, the graphite-like phase carbon nitride precursor and a nanometer boron powder are mixed and then the heat treatment is performed on the mixture so as to realize in-situ uniform coating of the graphite-like phase carbon nitride to the boron powder. During a subsequent heat treatment process, the lamellar carbon nitride achieves uniform doping to magnesium diboride grains so as to avoid a nonuniform phenomenon caused by doping themagnesium diboride with other carbon sources; and simultaneously, a MgB2 wire rod with good grain connectivity and uniform graphite-like carbon nitride doping can be prepared through a carbon-nitridein-situ coating boron particle technology.

Description

technical field [0001] The invention relates to a preparation method of a magnesium diboride superconducting wire, in particular to a preparation method of a second-phase carbon element-doped magnesium diboride superconducting wire, which is applied in the technical field of superconducting material preparation. Background technique [0002] 2001MgB 2 The superconductivity was reported by a Japanese research group, and quickly attracted the attention of scientific researchers all over the world. Its superconducting transition temperature is 39K, which is close to the limit value of BCS theory. MgB 2 It has excellent characteristics such as simple structure, large coherence length and no weak connection at grain boundaries. In addition, MgB 2 Superconductivity can be realized in the working temperature range (>10K) of the ultra-low temperature refrigerator. Since superconducting materials have zero resistance and Meissner effect in the superconducting state, MgB 2 Wir...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01B12/04H01B13/00
CPCH01B12/04H01B13/00Y02E40/60
Inventor 李文献王岩闫佳何小芳于上家胡业旻朱明原李瑛
Owner SHANGHAI UNIV
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