Method for homogenizing and refining iron-based superconducting powder, iron-based superconducting fine powder and applications thereof

Abstract

The present application relates to the technical field of iron-based superconductor material, in particular to a uniform refinement method of iron-based superconducting powder, iron-based superconducting fine powder and application thereof. The present application refines the particle size of iron-based superconductor by wet ball milling, uses aromatic hydrocarbon solvent, alkane solvent, alcohol solvent, ether solvent, weak acid aqueous solution or weak base aqueous solution as wet medium, so that the material is fully dispersed, the grinding efficiency is improved, and free active impurities can be removed; by controlling the rotation speed (10-1200 r / min) and time (≥0.1 h) of wet ball milling, the iron-based superconducting fine powder with small particle size (≤12 μm), uniform and concentrated particle size distribution and high purity can be accurately obtained. Moreover, the refinement method of wet ball milling provided by the present application does not cause damage to the iron-based superconductor crystal, the wet medium is easy to remove and does not introduce impurities, and the superconducting critical transmission current of the iron-based superconductor tape made of the iron-based superconducting fine powder is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of iron-based superconductor materials technology, specifically to a method for uniformly refining iron-based superconducting powder, iron-based superconducting fine powder and its applications, and iron-based superconducting tape and its applications. Background Technology

[0002] Iron-based superconductors possess advantages such as low anisotropy and high upper critical field, making them a promising next-generation high-temperature superconductor. Currently, the main method for preparing iron-based superconducting wires and tapes is the powder-in-tube (PIT) method, the key step of which is obtaining high-performance, high-purity, high-stability, and highly uniform iron-based superconducting powder. The main method for obtaining iron-based superconducting powder involves obtaining a precursor through solid-state sintering, followed by manual grinding or mechanical crushing to obtain the iron-based superconducting powder. Manual grinding is extremely unstable, time-consuming, labor-intensive, and produces poor uniformity, resulting in large particle sizes and highly uneven distribution, making it unsuitable for large-scale applications. Mechanical crushing improves efficiency but is affected by equipment, can also lead to uneven distribution, and has a crushing limit; both manual grinding and mechanical crushing result in large particle sizes. Grain homogenization and refinement can significantly improve the purity and enhance the physical properties of the material. Therefore, providing a method to obtain finely refined ultrafine iron-based superconducting powder with small particle size and uniform distribution is of great significance. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide a method for uniformly refining iron-based superconducting powder, iron-based superconducting fine powder and its application. The iron-based superconducting powder obtained by the uniform refining method provided by the present invention has small particle size, uniform and concentrated particle size distribution and high purity.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0005] This invention provides a method for uniformly refining iron-based superconducting powder, comprising the following steps:

[0006] Iron-based superconducting coarse powder is mixed with a wet processing medium, wet ball milled, and then dried to obtain iron-based superconducting fine powder; the wet processing medium includes aromatic hydrocarbon solvents, alkane solvents, alcohol solvents, ether solvents, weak acid aqueous solutions, or weak alkali aqueous solutions; the wet ball milling speed is 10-1200 r / min, and the time is ≥0.1 h.

[0007] Preferably, the average particle size of the iron-based superconducting coarse powder is 12–5000 μm.

[0008] Preferably, the aromatic hydrocarbon solvent includes benzene and / or toluene;

[0009] The alkane solvents include hexane and / or heptane;

[0010] The alcohol solvents include one or more of methanol, ethanol, and propanol;

[0011] The ether solvent includes diethyl ether;

[0012] The pH value of the weak acid aqueous solution is 4 to 7;

[0013] The pH value of the weak alkaline aqueous solution is 7 to 10.

[0014] Preferably, the volume ratio of the iron-based superconducting coarse powder to the wet medium is 1:0.5 to 4.

[0015] Preferably, the rotation speed of the wet ball mill is 50 to 500 rpm, and the wet ball milling time is 0.5 to 24 hours.

[0016] Preferably, the chemical composition of the iron-based superconducting coarse powder includes one or more of the following: type 1111 iron-based superconductor, type 122 iron-based superconductor, type 11 iron-based superconductor, type 11111 iron-based superconductor, type 42622 iron-based superconductor, and type 32522 iron-based superconductor.

[0017] Preferably, after wet ball milling, the process further includes ultrasonic treatment of the resulting wet milled slurry followed by centrifugation, and subsequent drying of the resulting solid components.

[0018] The present invention provides an iron-based superconducting fine powder prepared by the preparation method described above, wherein the average particle size of the iron-based superconducting fine powder is ≤12μm.

[0019] This invention provides the application of the iron-based superconducting fine powder described above in the preparation of iron-based superconducting wires and strips, iron-based superconducting bulk materials, or iron-based superconducting single crystals.

[0020] This invention provides a method for uniformly refining iron-based superconducting powder, comprising the following steps: mixing coarse iron-based superconducting powder with a wet medium, performing wet ball milling, and then drying to obtain fine iron-based superconducting powder; the wet medium includes alkane solvents, alcohol solvents, ether solvents, aromatic hydrocarbon solvents, weak acid aqueous solutions, or weak alkali aqueous solutions; the wet ball milling speed is 10–1200 r / min, and the time is ≥0.1 h. This invention uses wet ball milling to refine the particle size of reactive iron-based superconductors, using one or more of alkane solvents, alcohol solvents, and ether solvents as the wet medium, which allows for thorough dispersion of the coarse iron-based superconducting powder, improving grinding efficiency and refining efficiency; simultaneously, the wet grinding process can remove free reactive impurities; and by controlling the speed and time of the wet ball milling, fine iron-based superconducting powder with small particle size (average particle size ≤16 μm, minimum particle size in the nanometer range), uniform particle size distribution, and high purity can be precisely obtained. Moreover, the wet ball milling refinement method provided by the present invention does not damage the iron-based superconductor crystal, the wet medium is easy to remove and does not introduce impurities, which greatly improves the superconducting critical transport current of iron-based superconductor tapes made of iron-based superconducting fine powder.

[0021] The iron-based superconducting fine powder prepared by this invention has small particle size, good particle size uniformity, and high purity. Iron-based superconducting tapes made from this iron-based superconducting fine powder have excellent transmission performance and have good application prospects in the preparation of iron-based superconducting tapes, iron-based superconducting bulk materials, and iron-based superconducting single crystals. Attached Figure Description

[0022] Figure 1 Ba prepared in Example 1 0.6 K 0.5 10 μm fine powder of Fe2As2 and Ba prepared in Comparative Example 1 0.6 K 0.5 SEM image of 12μm fine powder of Fe2As2;

[0023] Figure 2 Ba prepared in Examples 3-4 and Comparative Example 1 0.6 K 0.5 Particle size distribution diagram of Fe2As2 powder;

[0024] Figure 3 Ba prepared in Examples 1-3 and Comparative Example 1 0.6 K 0.5 The Jc-B test results of iron-based superconducting tapes prepared from Fe2As2 powder at 4.2K and 6–14T are shown in the figure. Detailed Implementation

[0025] This invention provides a method for uniformly refining iron-based superconducting powder, comprising the following steps:

[0026] Iron-based superconducting coarse powder is mixed with a wet processing medium, wet ball milled, and then dried to obtain iron-based superconducting fine powder; the wet processing medium includes aromatic hydrocarbon solvents, alkane solvents, alcohol solvents, ether solvents, weak acid aqueous solutions, or weak alkali aqueous solutions; the wet ball milling speed is 10-1200 r / min, and the time is ≥0.1 h.

[0027] Unless otherwise specified, all raw materials used in this invention are commercially available products.

[0028] In this invention, the chemical composition of the iron-based superconducting coarse powder is preferably one or more of type 1111 iron-based superconductors, type 122 iron-based superconductors, type 11 iron-based superconductors, type 11111 iron-based superconductors, type 42622 iron-based superconductors, and type 32522 iron-based superconductors, more preferably including FeSexTe1-x and Ba a K b Fe2As c Ba d Na 1-d 122, Sr e K 1-e Fe2As2 or CaKFe4As4; wherein, the value of x is preferably in the range of 0.3 to 0.7, the value of a is preferably in the range of 0.3 to 0.8, more preferably in the range of 0.5 to 0.7, the value of b is preferably in the range of 0.3 to 0.7, more preferably in the range of 0.4 to 0.6, the value of c is preferably in the range of 1.9 to 2.2, more preferably in the range of 2 to 2.1, the value of d is preferably in the range of 0.4 to 0.7, more preferably in the range of 0.5 to 0.6, and the value of e is preferably in the range of 0.3 to 0.8, more preferably in the range of 0.5 to 0.7.

[0029] In this invention, the preferred method for preparing the iron-based superconducting coarse powder includes the following steps: mechanically pulverizing the iron-based superconducting solid-state sintering precursor to obtain the iron-based superconducting coarse powder. This invention does not impose any particular limitation on the preparation method of the iron-based superconducting solid-state sintering precursor; any preparation method well-known to those skilled in the art can be used. Specifically, refer to: Supercond.Sci.Technol.31(2018)015017, Supercond.Sci.Technol.32(2019)015008, Physica C 516(2015)17-26, Sci China Mater 2021,64(10):2530-2540, or Supercond.Sci.Technol.31(2018)015017. This invention does not impose any particular limitation on the pulverization; any iron-based superconducting coarse powder with an average particle size of 12–5000 μm can be obtained, specifically through mechanical pulverization. In this invention, the particle size of the iron-based superconducting coarse powder is more preferably 13-100 μm, and even more preferably 14-50 μm.

[0030] In this invention, the aromatic hydrocarbon solvent preferably includes benzene and / or toluene. In this invention, the alkane solvent preferably includes hexane and / or heptane, wherein hexane preferably includes n-hexane and / or its isomers; heptane preferably includes n-heptane and / or its isomers; pentane's boiling point (36°C) is too low, making the refining process too dangerous, and octane's boiling point (125°C) is too high, making removal difficult. In this invention, the alcohol solvent preferably includes one or more of methanol, ethanol, and propanol; butanol's boiling point is too high, making removal difficult. In this invention, the ether solvent preferably includes diethyl ether. In this invention, the pH value of the weak acid aqueous solution is preferably 4-7, more preferably 5-6; the weak acid in the weak acid aqueous solution preferably includes an aqueous acetic acid solution. In this invention, the pH value of the weak base aqueous solution is preferably 7-10, more preferably 8-9; the weak base in the weak base aqueous solution preferably includes ammonia.

[0031] In this invention, the ratio of the loose volume of the iron-based superconducting coarse powder to the volume of the wet medium is preferably 1:0.5 to 4, more preferably 1:0.5 to 2, and even more preferably 1:0.5 to 1.

[0032] In this invention, the rotational speed of the wet ball mill is 10–1200 r / min, preferably 50–500 r / min, more preferably 150–400 r / min; the wet ball milling time is ≥0.1 h, preferably 0.5–24 h, more preferably 0.5–10 h, further preferably 1–5 h, and most preferably 1.5–3 h; the grinding media used in the wet ball milling preferably include stainless steel grinding balls; the ball-to-material ratio of the wet ball milling is preferably 5–22, more preferably 6–20. In this invention, the volume ratio of the grinding jar to the mass of the iron-based superconducting coarse powder used in the wet ball milling is preferably 150 mL: 4–16 g, more preferably 150 mL: 6–14 g, and more preferably 150 mL: 8–12 g.

[0033] Following the wet ball milling, the present invention preferably further includes ultrasonic treatment of the resulting wet milled slurry, followed by centrifugation, and then subsequent drying of the resulting solid components. In the present invention, the ultrasonic treatment temperature is preferably 25–45°C, more preferably 30–35°C; the ultrasonic treatment time is preferably 10–30 min, more preferably 15–20 min. In the present invention, the centrifugation speed is preferably 8000–12000 r / min, more preferably 10000 r / min; the centrifugation time is preferably 3–10 min, more preferably 5 min. In the present invention, the drying temperature is preferably 70–120°C, more preferably 70–90°C; the drying preferably includes freeze drying, vacuum heating drying, and flowing atmosphere drying; the present invention does not have a specific limitation on the drying time, drying to constant weight is sufficient, specifically, 60 min.

[0034] This invention provides iron-based superconducting fine powder prepared by the method described in the above technical solution. In this invention, the average particle size (median particle size) of the iron-based superconducting fine powder is ≤12μm, preferably 0.01~12μm, more preferably 0.1~10μm, further preferably 1~10μm, and most preferably 3~10μm.

[0035] This invention provides the application of the iron-based superconducting fine powder described above in the preparation of iron-based superconducting tapes, iron-based superconducting bulk materials, or iron-based superconducting single crystals. The iron-based superconducting fine powder provided by this invention has small particle size, good particle size uniformity, and high purity. Iron-based superconducting tapes made from this fine powder exhibit excellent transmission performance, iron-based superconducting bulk materials prepared with this powder exhibit excellent magnetization performance, and iron-based superconducting single crystals prepared with this powder exhibit excellent magnetization performance. It has excellent application prospects in the preparation of iron-based superconducting tapes, iron-based superconducting bulk materials, and iron-based superconducting single crystals.

[0036] The following detailed description of the method for uniformly refining iron-based superconducting powder provided by the present invention, in conjunction with embodiments, should not be construed as limiting the scope of protection of the present invention.

[0037] The preparation methods for the iron-based superconducting tapes, bulk iron-based superconducting materials, and single iron-based superconducting crystals in the following examples and comparative examples are the same. Specifically, the preparation method for the iron-based superconducting tapes is CN108682509A (or https: / / iopscience.iop.org / article / 10.1088 / 0953-2048 / 28 / 1 / 012001 / meta). The preparation method for the bulk iron-based superconducting materials is https: / / doi.org / 10.1016 / j.cossms.2013.04.001. The preparation method for the single iron-based superconducting crystals is https: / / doi.org / 10.1143 / JPSJ.79.124713.

[0038] Example 1

[0039] Will 8g Ba 0.6 K 0.5 Fe2As2 precursor powder was mechanically pulverized to an average particle size of 14 μm to obtain Ba 0.6 K 0.5 Fe2As2 coarse powder; the Ba 0.6 K 0.5 The coarse Fe₂As₂ powder was placed in a clean 150 mL ball mill jar, and 20 mL of n-hexane was added. After sealing the jar, wet ball milling was performed using stainless steel grinding balls at a ball-to-powder ratio of 20:1. The milling speed was 185 r / min, and the milling time was 30 min. The powder was then centrifuged at 10000 rpm for 5 min. The resulting solid fraction was then vacuum dried at 70 °C for 60 min to obtain Ba. 0.6 K 0.5 Fine Fe2As2 powder. Ba 0.6 K 0.5 The median particle size of the Fe2As2 fine powder is 10 μm, and the particle size distribution width (maximum particle size minus minimum particle size) is 17 μm. This Ba... 0.6 K 0.5 The fineness of Fe2As2 powder is beyond the reach of mechanical crushing, and the collected Ba... 0.6 K 0.5 The Fe2As2 fine powder was almost unaffected, and its superconducting transition remained unaffected.

[0040] Ba 0.6 K 0.5 After preparing stainless steel strip from Fe2As2 fine powder, the superconducting critical transport current I c The value is 144A, and Jc reaches 1.3×10 at 4.2K and 10T. 5 A / cm 2 .

[0041] Example 2

[0042] Will 8g Ba 0.6 K 0.5 Fe2As2 precursor powder was mechanically pulverized to an average particle size of 14 μm to obtain Ba 0.6 K 0.5 Fe2As2 coarse powder; the Ba 0.6 K 0.5 The coarse Fe₂As₂ powder was placed in a clean 150 mL ball mill jar, and 20 mL of n-hexane was added. After sealing the jar, wet ball milling was performed using stainless steel grinding balls at a ball-to-powder ratio of 20:1. The milling speed was 185 r / min, and the milling time was 90 min. The powder was then centrifuged at 10000 rpm for 5 min, and the resulting solid fraction was vacuum dried at 70 °C for 15 min to obtain Ba. 0.6 K 0.5 Fine Fe2As2 powder. Ba 0.6 K 0.5 The median particle size of the Fe2As2 fine powder is 9 μm, and the particle size distribution width is 15 μm. This Ba... 0.6 K 0.5 The fineness of Fe2As2 powder is beyond the reach of mechanical crushing, and the collected Ba... 0.6 K 0.5 The Fe2As2 fine powder was almost unaffected, and its superconducting transition remained unaffected.

[0043] Will Ba 0.6 K 0.5 Iron-based superconducting bulk material was obtained by pressing and sintering fine Fe2As2 powder into sheets. The critical current density of this iron-based superconducting bulk material reached 1 MA / cm at 4.2 K and 0 T. 2 .

[0044] Example 3

[0045] Will 8g Ba 0.6 K 0.5 Fe2As2 precursor powder was mechanically pulverized to an average particle size of 14 μm to obtain Ba 0.6 K 0.5 Fe2As2 coarse powder; the Ba 0.6 K 0.5 The coarse Fe₂As₂ powder was placed in a clean 150 mL ball mill jar, and 20 mL of n-hexane was added. After sealing the jar, wet ball milling was performed using stainless steel grinding balls at a ball-to-powder ratio of 20:1. The milling speed was 185 r / min, and the milling time was 180 min. The powder was then centrifuged at 10000 rpm for 5 min, and the resulting solid fraction was vacuum dried at 70 °C for 15 min to obtain Ba. 0.6 K0.5 Fine Fe2As2 powder. Ba 0.6 K 0.5 The median particle size of the Fe2As2 fine powder is 7 μm, and the particle size distribution width is 12.5 μm. This Ba... 0.6 K 0.5 The fineness of Fe2As2 powder is beyond the reach of mechanical crushing, and the collected Ba... 0.6 K 0.5 The Fe2As2 fine powder was almost unaffected, and its superconducting transition remained unaffected.

[0046] Will Ba 0.6 K 0.5 Iron-based superconducting single crystals were prepared by vacuum high-temperature heat treatment of Fe2As2 fine powder. The single-crystal critical current density of this iron-based superconducting single crystal reached 1 MA / cm at 4.2 K and 10 T. 2 .

[0047] Example 4

[0048] Will 8g Ba 0.6 K 0.5 Fe2As2 precursor powder was mechanically pulverized to an average particle size of 14 μm to obtain Ba 0.6 K 0.5 Fe2As2 coarse powder; the Ba 0.6 K 0.5 The coarse Fe₂As₂ powder was placed in a clean 150 mL ball mill jar, and 20 mL of n-hexane was added. After sealing the jar, wet ball milling was performed using stainless steel grinding balls at a ball-to-powder ratio of 20:1. The milling speed was 370 r / min, and the milling time was 300 min. The powder was then centrifuged at 10000 rpm for 5 min, and the resulting solid fraction was vacuum dried at 70 °C for 60 min to obtain Ba. 0.6 K 0.5 Fine Fe2As2 powder. Ba 0.6 K 0.5 The median particle size of the Fe2As2 fine powder is 1 μm, and the particle size distribution width is 4 μm. Some of its components have reached the nanoscale powder level, indicating that the method provided by this invention can obtain iron-based superconducting powder with extremely fine particle size.

[0049] Example 5

[0050] 8g FeSe 0.5 Te 0.5 The precursor powder was mechanically pulverized to an average particle size of 14 μm to obtain FeSe. 0.5 Te 0.5 Coarse powder; the FeSe 0.5 Te 0.5The coarse powder was placed in a clean 150 mL ball mill jar, and 20 mL of 5 wt% acetic acid aqueous solution was poured in. After sealing the jar, wet ball milling was performed using stainless steel grinding balls at a ball-to-powder ratio of 20:1. The milling speed was 185 r / min, and the milling time was 60 min. The powder was then centrifuged at 10000 rpm for 5 min, and the resulting solid fraction was vacuum dried at 80 °C for 60 min to obtain FeSe. 0.5 Te 0.5 Fine powder. This FeSe 0.5 Te 0.5 The median particle size of the fine powder is 8 μm, and its magnetization current density is measured at 4.2 K. (The last part, "FeSe," appears to be an unrelated fragment and is omitted from the translation.) 0.5 Te 0.5 Iron-based superconducting bulk material was obtained by pressing and sintering fine powder into sheets. The critical current density of this iron-based superconducting bulk material reached 1.2 MA / cm² at 4.2 K and 0 T. 2 .

[0051] Comparative Example 1

[0052] Dry ball milling, the specific steps are as follows: 8g Ba 0.6 K 0.5 Fe2As2 precursor powder was mechanically pulverized to an average particle size of 14 μm to obtain Ba 0.6 K 0.5 Fe2As2 coarse powder; the Ba 0.6 K 0.5 Coarse Fe₂As₂ powder was placed in a clean 150mL ball mill jar, sealed tightly, and then dry-milled using stainless steel grinding balls at a ball-to-powder ratio of 20:1. The milling speed was 185 r / min, and the milling time was 60 min to obtain Ba. 0.6 K 0.5 Fine Fe2As2 powder. Ba 0.6 K 0.5 The median particle size of Fe2As2 fine powder is 12μm. Although dry ball milling reduces the median particle size, the particle size distribution is not concentrated, the preparation time is long, the powder agglomerates and sticks to the wall, and the powder loss is high. After preparing stainless steel strip, the superconducting critical transport current is low and the performance is poor.

[0053] Figure 1 Ba prepared by wet milling in Example 1 0.6 K 0.5 Fine powder of Fe2As2 (median particle size 10 μm) and Ba prepared by dry milling in Comparative Example 1 0.6 K 0.5 SEM image of Fe2As2 fine powder (median particle size 12 μm), from Figure 1 It can be seen that Ba prepared by dry grinding and ball milling 0.6 K 0.5When Fe2As2 fine powder is left in air for a long time, impurities will appear on the surface of the grains, while Ba prepared by wet milling and ball milling... 0.6 K 0.5 The grain surface of the fine Fe2As2 powder remained smooth and clean. EDS analysis revealed that the surface impurities were potassium oxides. This indicates that the wet milling media removed free impurities. This contrasts with Ba2As2 powder prepared by dry ball milling. 0.6 K 0.5 Compared to Fe2As2 fine powder, Ba prepared by wet ball milling... 0.6 K 0.5 The residual potassium impurities in the Fe2As2 fine powder are significantly reduced.

[0054] Ba prepared in Examples 3 (median particle size 7 μm), 4 (median particle size 12 μm), and Comparative Example 1 0.6 K 0.5 The particle size distribution of Fe2As2 fine powder is as follows: Figure 2 As shown, by Figure 2 It can be seen that Ba obtained by dry ball milling 0.6 K 0.5 The particle size distribution of Fe2As2 fine powder is not concentrated. Although the median particle size is reduced, the particle size distribution width reaches 30 μm. Wet ball milling produces powder with smaller particle size and higher particle size distribution concentration. Increasing the wet milling time further reduces the median particle size and further improves the particle size concentration.

[0055] Transmission current test: Ba prepared in Examples 1-3 and Comparative Example 1 0.6 K 0.5 Superconducting tapes were obtained by sintering Fe2As2 fine powder at 880℃. The current obtained by testing the superconducting tapes on a magnet was divided by the cross-sectional area of ​​the superconducting core. Observation under an optical microscope showed that the cross-sectional area of ​​the superconducting core was 0.00118 cm². 2 The transmission current density was obtained. The Jc-B test data for the strip at 4.2K and 6–14T are as follows: Figure 3 As shown, the magnetization current density data for stainless steel strip at 4.2K and 10T can be found in the literature https: / / doi.org / 10.1038 / s41598-019-49363-y. The specific transmission current density results at 10T are shown in Table 1.

[0056] Table 1. Ba prepared in Examples 1-3 and Comparative Example 1 0.6 K 0.5 Test results of current transmission of superconducting tape made of Fe2As2 fine powder (4.2K, 10T)

[0057] Comparative Example 1 Dry ball milling 12μm 101000 Example 1 Wet ball milling for 30 min to 10 μm 122000 Example 2 Wet ball milling for 90 min to 9 μm 107000 Example 3 Wet ball milling 180 min 7 μm 81700

[0058] As shown in Table 1, compared with dry ball milling, the Ba obtained by wet ball milling in Examples 1-2...0.6 K 0.5 The superconducting tape prepared from Fe2As2 fine powder showed significantly improved transport performance, but the Ba2As2 prepared in Example 3 showed poor performance. 0.6 K 0.5 If the particle size of Fe2As2 powder is too fine, its transport performance will actually decrease.

[0059] In summary, compared with dry ball milling, the present invention employs a wet ball milling method for refining the iron-based superconducting powder. During the refining process, material agglomeration does not occur, resulting in a uniform and concentrated particle size distribution. Furthermore, the wet ball milling method significantly reduces free impurities on the surface of the obtained iron-based superconducting powder, greatly improving its purity and consequently significantly enhancing the transmission performance of the iron-based superconducting tape.

[0060] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for uniformly refining iron-based superconducting powder, comprising the following steps: Iron-based superconducting coarse powder was mixed with a wet medium, wet ball milled, and then dried to obtain iron-based superconducting fine powder. The wet process medium is an alkane solvent, which includes hexane and / or heptane; The iron-based superconducting coarse powder has a particle size of 12~50μm; the chemical composition of the iron-based superconducting coarse powder is Ba. 0.6 K 0.5 Fe2As2; The wet ball milling process is carried out at a speed of 50-500 r / min for a time of 0.5-10 h. The average particle size of the iron-based superconducting fine powder is ≤12μm.

2. The uniform refining method according to claim 1, characterized in that, The volume ratio of the iron-based superconducting coarse powder to the wet medium is 1:0.5~4.

3. The uniform refining method according to claim 1, characterized in that, The process after wet ball milling includes ultrasonic treatment of the resulting wet milled slurry followed by centrifugation, and subsequent drying of the resulting solid components.

4. Iron-based superconducting fine powder prepared by the method according to any one of claims 1 to 3.

5. The application of the iron-based superconducting fine powder according to claim 4 in the preparation of iron-based superconducting wires and strips, iron-based superconducting bulk materials or iron-based superconducting single crystals.

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