Superconducting cable wire material

Abstract

The invention discloses a superconducting cable and wire material which is prepared from the following raw materials in percentage by mass: 85% of yttrium barium copper oxide superconducting phase material, 8% of nano silicon, 5% of graphene and 2% of nano graphite. The yttrium barium copper oxide superconducting phase material is used as a superconducting base material, superconducting performance is provided, the nano silicon generates pinning magnetic flux vortex, the grain boundary structure is optimized, and the critical current density is improved; graphene constructs a three-dimensional conductive network, so that the grain boundary resistance is reduced, and the carrier mobility is enhanced; the nano-graphite mechanically reinforces the phase, inhibits crack propagation, and improves the toughness of the material.

Description

Technical Field

[0001] The present invention relates to the technical field of skin materials, and specifically to a superconducting cable wire material. Background Art

[0002] Superconducting cables are an efficient technology for transmitting electricity using superconducting materials (with zero resistance at extremely low temperatures), suitable for large-capacity, low-loss power transmission scenarios; however, traditional cables and wires prepared based on YBCO superconducting materials have relatively large AC transmission losses, small critical current density, and poor bending strain tolerance, making it difficult to meet the requirements of superconducting power transmission. Summary of the Invention

[0003] To solve the defects existing in the prior art, the present invention provides a superconducting cable wire material.

[0004] To solve the above technical problems, the present invention provides the following technical solutions:

[0005] A superconducting cable wire material of the present invention is prepared from raw materials with the following mass fractions:

[0006] 85% superconducting phase material, 8% nanomaterial, 5% conductive material, and 2% coloring material.

[0007] As a preferred technical solution of the present invention, the superconducting phase material is one or more of yttrium barium copper oxide superconducting phase material, magnesium diboride, or bismuth-based copper oxide superconducting phase material.

[0008] As a preferred technical solution of the present invention, the nanomaterial is one or more of nanosilicon, nanometer zirconia, or nanometer silicon carbide.

[0009] As a preferred technical solution of the present invention, the conductive material is one or more of graphene, graphene nanosheets, or carbon nanotubes.

[0010] As a preferred technical solution of the present invention, the coloring material is nanographite, carbon black, or nanodiamond.

[0011] As a preferred technical solution of the present invention, it is prepared from raw materials with the following mass fractions:

[0012] 85% yttrium barium copper oxide superconducting phase material, 8% nanosilicon, 5% graphene, and 2% nanographite.

[0013] As a preferred technical solution of the present invention,

[0014] As a preferred technical solution of the present invention, it is prepared from raw materials with the following mass fractions:

[0015] 85% bismuth-based copper oxide superconducting phase material, 8% nano-zirconia, 5% multi-walled carbon nanotubes, and 2% carbon black.

[0016] As a preferred technical solution of the present invention, it is made by the following method:

[0017] Step 1, preparation of nano-composite powder; mechanochemical mixing: ball-mill yttrium barium copper oxide superconducting phase material powder, nano-silicon, graphene, and nano-graphite for 6 hours under argon protection, with a ball-to-material ratio of 15:1 and a rotation speed of 400 rpm to obtain a uniform composite powder, where the powder particle size D50 of the yttrium barium copper oxide superconducting phase material powder is approximately 1 μm, and the specific surface area of graphene is >700 m 2 / g;

[0018] Surface modification: Add 0.5% silane coupling agent (KH550) to improve the interfacial bonding between nano-silicon and the matrix;

[0019] Step 2, tape forming and sintering; sol-gel plating: Disperse the composite powder in a mixed solvent of ethyl acetate / ethanol with a volume ratio of 3:1, and coat it on the surface of Hastelloy strip, with a wet film thickness of 50 μm;

[0020] High-temperature heat treatment: Heat-treat at 450 °C for 2 h to remove organic substances; then, in an oxygen atmosphere, 850 °C / 5 h → 750 °C / 12 h, and finally obtain the superconducting cable wire material.

[0021] The beneficial effects of the present invention are:

[0022] In this superconducting cable wire material, the yttrium barium copper oxide superconducting phase material is the superconducting matrix material, providing superconducting properties. Nano-silicon generates pinned flux vortices, optimizes the grain boundary structure, and improves the critical current density; graphene constructs a three-dimensional conductive network, reduces the grain boundary resistance, and enhances the carrier mobility; nano-graphite is a mechanical reinforcement phase, inhibits crack propagation, and improves the material toughness. Specific embodiments

[0023] The following describes the preferred embodiments of the present invention. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0024] Example: A superconducting cable wire material of the present invention is prepared from raw materials with the following mass fractions:

[0025] 85% superconducting phase material, 8% nano-material, 5% conductive material, and 2% coloring material.

[0026] Among them, the superconducting phase material is one or more of yttrium barium copper oxide superconducting phase material, magnesium diboride or bismuth-based copper oxide superconducting phase material. Particle size and morphology: Original powder particle size: D50≈1μm (detected by laser particle size analyzer), and it needs to be refined to sub-micron level (≈500nm) by ball milling to ensure uniform mixing with other nano materials. Grain orientation: Preferentially select (001) textured powder to improve the isotropy of superconducting current (evaluated by XRD full width at half maximum FWHM<0.5°). Purity and impurities: Chemical purity: ≥99.95% (detected by ICP-MS).

[0027] Key impurity control: Fe<50ppm, C<100ppm, other metal impurities (such as Al, Ni)<20ppm; orthorhombic phase proportion>98% (XRD quantitative analysis) to avoid impurity phases. BSCCO-2223 (Bi2Sr2Ca2Cu3O 10x ):

[0028] Critical temperature Tc≈110K (higher than YBCO), but the critical current density Jc is relatively low (≈3×10 5 A / cm 2 , 77K). It is applicable to low-temperature and low-field scenarios, and the cost is relatively high (about 2 times that of YBCO). MgB2: Tc≈39K, requires a lower temperature (20 - 30K), but has low cost and simple processing, and is applicable to specific low-temperature scenarios (such as MRI magnets).

[0029] Among them, the nano material is one or more of nano silicon, nano zirconia or nano silicon carbide. Particle size distribution in nano silicon: D90<50nm (detected by dynamic light scattering DLS) to avoid an increase in coating porosity caused by large particles. Dispersibility: Absolute value of Zeta potential>30mV (pH = 7) to prevent agglomeration (0.5% polyacrylic acid dispersant needs to be added). Purity and surface characteristics: Chemical purity: ≥99.9% (total metal impurities<100ppm), oxygen content<5at% (detected by XPS); Surface modification: grafted with silane coupling agent (KH550) to improve the interfacial bonding force with YBCO (interfacial shear strength>50MPa). Nano zirconia has high hardness (HV1200), but weak pinning effect (Jc≈4×10 6 A / cm 2 ), and the addition amount needs to be increased to 10%. Nano silicon carbide has good high-temperature resistance, but poor conductivity, which may inhibit the superconducting performance (needs to be synergistically optimized with graphene).

[0030] Among them, the conductive material is one or more of graphene, graphene nanosheets or carbon nanotubes;

[0031] Graphene, structural parameters: Number of layers: Proportion of single layer>95% (Raman spectrum I2D / IG>2, full width at half maximum<30cm -1)。Flake diameter: 1 - 5 μm (detected by AFM), ensuring a continuous conductive network. Defect control: ID / IG < 0.2 (intensity ratio of Raman D peak to G peak), edge defect density < 10 3 μm -2 。Dispersion: Dispersion concentration in solvent > 5 mg / mL (using NMP or DMF as solvent), no visible precipitation (standing for 24 h). Surface modification: Non-covalent modification (such as 1% sodium dodecylbenzenesulfonate SDBS), avoiding damage to the sp 2 structure.

[0032] Carbon nanotubes (CNTs): Multi-walled carbon nanotubes (MWCNTs, diameter 10 - 20 nm, length 1 - 10 μm), which need to be oriented (assisted by electric field), and the efficiency of the conductive network is ≈ 70% of that of graphene.

[0033] Graphene nanosheets (GNPs): Specific surface area ≈ 500 m 2 / g, low cost (about 1 / 5 of graphene), but with many layers (5 - 10 layers), and Jc may decrease to 4×10 6 A / cm 2 。

[0034] The coloring material is nano graphite, carbon black or nano diamond. Particle size and morphology: D50 ≈ 300 nm (statistical by SEM), sheet thickness < 50 nm (detected by transmission electron microscope TEM), surface roughness Ra < 10 nm (detected by AFM), reducing stress concentration.

[0035] Carbon black (CB): Particle size ≈ 40 nm, specific surface area ≈ 800 m 2 / g, but with weak enhancement effect (tensile strength ≈ 250 MPa), and the addition amount needs to be increased to 5%. Nano diamond (ND): Particle size ≈ 100 nm, high hardness, but extremely high cost (about 50 times that of nano graphite), only limited to special scenarios.

[0036] A superconducting cable wire material: Prepared from raw materials with the following mass fractions: 85% yttrium barium copper oxide superconducting phase material, 8% nano silicon, 5% graphene, and 2% nano graphite. The yttrium barium copper oxide superconducting phase material is the superconducting matrix material, providing superconducting properties. Nano silicon generates pinned flux vortices, optimizes the grain boundary structure, and improves the critical current density; graphene constructs a three-dimensional conductive network, reduces the grain boundary resistance, and enhances the carrier mobility; nano graphite is a mechanical strengthening phase, inhibits crack propagation, and improves the material toughness.

[0037] A superconducting cable wire material, prepared from raw materials with the following mass fractions: 85% bismuth-based copper oxide superconducting phase material, 8% nano zirconia, 5% multi-walled carbon nanotubes, and 2% carbon black..

[0038] A superconducting cable wire material, which is made by the following method:

[0039] Step 1, preparation of nano-composite powder; mechanochemical mixing: Yttrium barium copper oxide superconducting phase material powder, nano-silicon, graphene, and nano-graphite are ball-milled for 6 hours under argon protection, with a ball-to-material ratio of 15:1 and a rotation speed of 400 rpm to obtain a uniform composite powder. The powder particle size D50 of the yttrium barium copper oxide superconducting phase material powder is approximately 1 μm, and the specific surface area of graphene is > 700 m 2 / g;

[0040] Surface modification: Add 0.5% silane coupling agent (KH550) to improve the interfacial bonding between nano-silicon and the matrix;

[0041] Step 2, tape forming and sintering; sol-gel plating: Disperse the composite powder in an ethyl acetate / ethanol mixed solvent with a volume ratio of 3:1, and coat it on the surface of Hastelloy tape, with a wet film thickness of 50 μm;

[0042] High-temperature heat treatment: Heat-treat at 450 °C for 2 h to remove organic substances; then, under an oxygen atmosphere, 850 °C / 5 h → 750 °C / 12 h, and finally obtain superconducting cable wire materials.

[0043] Perform technical index verification, and its performance is shown in the following table:

[0044]

[0045] As can be seen from the above table, the superconducting cable wire materials provided by the present invention have excellent physical properties and electrical circuit properties.

[0046] Among them, the mechanism for the performance improvement of the present invention is the flux pinning effect of nano-silicon. 20-nm silicon particles serve as artificial pinning centers to anchor flux vortices, reduce flux motion loss, and the critical current density is increased to 5.8×10 6 A / cm 2 .

[0047] Through HAADF-STEM observation, silicon particles are uniformly distributed at the YBCO grain boundaries, with an average spacing of approximately 20 nm (matching the flux vortex spacing).

[0048] The conductive network structure of graphene. Graphene forms a continuous conductive path at the grain boundaries, and the grain boundary resistance is reduced to 10 -12 Ω·cm (traditional YBCO ≈ 10 -9 Ω·cm), and the power transmission loss is only 0.08%.

[0049] Raman spectroscopy (ID / IG ≈ 0.2) confirms that the graphene structure is complete and no obvious defects occur.

[0050] The toughening mechanism of nano-graphite is that nano-graphite fills microcracks and induces crack deflection, and the fracture toughness (KIC) is increased to 8 MPa·m 1 / 2 (for traditional YBCO ≈ 3 MPa·m 1 / 2 ).

[0051] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A superconducting cable and wire material, characterized in that, Prepared from raw materials with the following mass fractions: 85% superconducting phase material, 8% nanomaterial, 5% conductive material, and 2% coloring material.

2. The superconducting cable wire material according to claim 1, characterized in that, The superconducting phase material is one or more of yttrium barium copper oxide superconducting phase material, magnesium diboride, or bismuth-based copper oxide superconducting phase material.

3. A superconducting cable wire material according to claim 2, characterized in that, The nanomaterial is one or more of nanosilicon, nanometer zirconia, or nanometer silicon carbide.

4. A superconducting cable wire material according to claim 3, characterized in that, The conductive material is one or more of graphene, graphene nanosheets, or carbon nanotubes.

5. A superconducting cable wire material according to claim 4, characterized in that, The coloring material is nanographite, carbon black, or nanodiamond.

6. The superconducting cable wire material according to claim 5, characterized in that, Prepared from raw materials with the following mass fractions: 85% yttrium barium copper oxide superconducting phase material, 8% nanosilicon, 5% graphene, and 2% nanographite.

7. A superconducting cable wire material according to claim 5, characterized in that, Prepared from raw materials with the following mass fractions: 85% bismuth-based copper oxide superconducting phase material, 8% nanometer zirconia, 5% multi-walled carbon nanotubes, and 2% carbon black.

8. A superconducting cable wire material according to any one of claims 1-7, characterized in that, Manufactured by the following method: Step 1, preparation of nano-composite powder; mechanochemical mixing: ball-mill the yttrium barium copper oxide superconducting phase material powder, nano-silicon, graphene, and nano-graphite for 6 hours under argon protection, with a ball-to-material ratio of 15:1 and a rotation speed of 400 rpm to obtain a uniform composite powder. The powder particle size D50 of the yttrium barium copper oxide superconducting phase material powder is approximately 1 μm, and the specific surface area of graphene is > 700 m 2 / g; Surface modification: Add 0.5% silane coupling agent (KH550) to improve the interfacial bonding between nanosilicon and the matrix. Step 2, strip forming and sintering; Sol-gel plating: Disperse the composite powder in an ethyl acetate / ethanol mixed solvent with a volume ratio of 3:1, and coat it on the surface of Hastelloy strip. The wet film thickness is 50 μm. High-temperature heat treatment: Heat-treat at 450 °C for 2 h to remove organic substances; then, in an oxygen atmosphere, 850 °C / 5 h → 750 °C / 12 h, and finally obtain the superconducting cable wire material.

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