Method for preparing iron-based superconducting wire strip

Abstract

The invention belongs to the field of superconducting materials, and particularly relates to a method for preparing an iron-based superconducting wire strip, which comprises the following steps of: a) filling precursor powder of an iron-based superconductor into a first metal sheath to prepare a superconducting wire, and cutting to obtain a superconducting section material; b) preparing a metal raw material consistent with the material of the first metal sheath, preparing a metal wire, and cutting to obtain a metal section material; c) loading the superconducting section materials and the metal section materials into a second metal sheath, wherein the superconducting section materials and the metal section materials are alternately arranged in the second metal sheath; d) performing length extension on the material prepared in the step c) to obtain a wire strip; e) the wire strip is cut, the cutting position is the area, filled with the metal section material, of the wire strip, and wire strip sections are obtained; and f) welding and sealing the end surfaces of the wire strip sections, and then carrying out heat treatment to obtain the iron-based superconducting wire strip. According to the method, a segmented tubing mode is adopted, so that the error-tolerant rate of product preparation can be greatly improved, and meanwhile, various wire strip products can be efficiently prepared.

Description

Technical Field

[0001] This invention belongs to the field of superconducting materials, and particularly relates to a method for preparing iron-based superconducting wires and tapes. Background Technology

[0002] Iron-based superconductors, a novel type of superconductor discovered in 2008, have quickly become a focus of research both domestically and internationally due to their advantages such as high transition temperature, extremely high upper critical field, and extremely low anisotropy. Compared with other superconductor systems, iron-based superconductors also exhibit high critical current densities under high magnetic fields of 4.2K and in the liquid hydrogen temperature range of 20K, showing great promise for applications in strong magnetic fields.

[0003] For the fabrication of superconducting wires and strips, powder packing is a method suitable for large-scale production and is widely used in many superconducting materials (such as MgB2, Bi-based superconductors, and iron-based superconductors). Wires and strips prepared by powder packing have poor internal connectivity and require further heat treatment. Hot isostatic pressing (HIP) is an effective method for this. Applying high-pressure gas during heat treatment can effectively improve the performance of the superconducting strip. However, during HIP, gas can enter the wire interior, leading to performance degradation. Therefore, end-capping techniques must be considered. Commonly used methods include argon arc welding, Ag-dipping sealing, electron beam welding, and ultrasonic spot welding.

[0004] Compared to other end-capping methods, ultrasonic spot welding offers better results, but it requires sealing the entire wire strip before hot isostatic pressing (HIP). This leads to the following problems: 1. During HIP, high-pressure gas cannot enter the conductor due to any holes or gaps, requiring high precision in the process to prevent damage; 2. Preparing the entire wire strip makes modifying the manufacturing process cumbersome and costly in terms of manpower and resources; 3. The limited variety of samples prepared results in long performance feedback cycles and slow process optimization, thus affecting the efficiency of performance improvement. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a method for preparing iron-based superconducting wires and strips. This method adopts a segmented tube packaging method, which can greatly improve the fault tolerance rate of product preparation and at the same time efficiently prepare various wire and strip products.

[0006] This invention provides a method for preparing iron-based superconducting wire strips, comprising the following steps:

[0007] a) The precursor powder of the iron-based superconductor is packed into a first metal sheath and extended in length by cold working to obtain a superconducting wire; the superconducting wire is cut to obtain a superconducting segment.

[0008] b) Prepare a metal raw material that is the same material as the first metal sheath, and extend its length by cold working to obtain a metal wire; cut the metal wire to obtain metal segments;

[0009] Steps a) and b) are not in any particular order;

[0010] c) The superconducting segment and the metal segment are loaded into a second metal sheath, wherein the superconducting segment and the metal segment are arranged alternately along the length of the second metal sheath, and both ends of the alternating arrangement are metal segments.

[0011] d) The material obtained in step c) is extended in length using a cold working method to obtain wire and strip material;

[0012] e) Cut the wire strip material into sections, where the cutting position is the area in the wire strip material filled with metal segments, to obtain wire strip material segments;

[0013] f) Weld the exposed metal sections at both ends of the wire strip segment, and then perform heat treatment to obtain iron-based superconducting wire strip.

[0014] Preferably, the iron-based superconductor is a Ba-122 iron-based superconductor, a CaK-1144 iron-based superconductor, a Sr-122 iron-based superconductor, or a FeSe.

[0015] Preferably, the precursor powder is prepared according to the following steps: mixing the raw materials of the iron-based superconductor, sintering in an oxygen-free environment, and pulverizing to obtain the precursor powder of the iron-based superconductor.

[0016] Preferably, the temperature of the oxygen-free sintering is 600~1000℃.

[0017] Preferably, the material of the first metal sheath is Ag, Cu, Ni, Fe, Ta or Monel alloy; the material of the second metal sheath is Ag, Cu, Ni, Fe, Ta or Monel alloy.

[0018] Preferably, the length of the superconducting segment is 0.5~3cm.

[0019] Preferably, within the second metal sheath, the length of the metal segment located between the superconducting segments is 0.2~1cm, and the length of the metal segment located at both ends is 4~6cm.

[0020] Preferably, the welding method is ultrasonic spot welding or fusion welding.

[0021] Preferably, the heat treatment method is one or more of hot pressing, hot isostatic pressing, atmospheric pressure sintering, vacuum sintering, or Joule heating rapid sintering.

[0022] Preferably, the heat treatment temperature is 600~1000℃; the hot pressing pressure is 10~50MPa and the time is 0.5~10h; the hot isostatic pressing pressure is 100~150MPa and the time is 0.5~2h.

[0023] Compared with the prior art, the present invention provides a method for preparing iron-based superconducting wires and strips, comprising the following steps: a) loading the precursor powder of an iron-based superconductor into a first metal sheath, and extending its length by cold working to obtain a superconducting wire; cutting the superconducting wire to obtain a superconducting segment; b) preparing a metal raw material of the same material as the first metal sheath, and extending its length by cold working to obtain a metal wire; cutting the metal wire to obtain a metal segment; steps a) and b) are not sequential; c) ... The superconducting segments and metal segments are loaded into a second metal sheath. The superconducting segments and metal segments are arranged alternately along the length of the second metal sheath, with both ends of the alternation being metal segments; d) The material obtained in step c) is extended in length by cold working to obtain a wire strip; e) The wire strip is cut at the area where the metal segments are filled, to obtain wire strip segments; f) The exposed metal segments at both ends of the wire strip segments are welded and then heat-treated to obtain iron-based superconducting wire strips. To solve the problems of slow efficiency, long cycle time, and complex preparation in existing technologies, this invention, for the first time, adopts a segmented tube loading method for the preparation of superconducting wire strips, which has at least the following advantages:

[0024] (1) It increases the success rate of the processing. During the cold processing, the product is very easy to break due to human and equipment factors, which will cause the product preparation to fail. However, after adopting the process of this invention, the fault tolerance rate of product preparation can be greatly improved. The damage in a local area will not affect the rest of the product.

[0025] (2) The products prepared by the process of the present invention can be well end capped and have a short product length, which can significantly reduce the preparation cost; with the same raw material consumption, the process of the present invention can prepare more different kinds of sample products;

[0026] (3) Multiple products can be obtained in one process and they do not interfere with each other, thus greatly improving the preparation efficiency. In addition, different products prepared using the process of this invention can ensure that the processing parameters are completely consistent, greatly reducing the error caused by the processing. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0028] Figure 1 This is the MT curve of the Ag-Ag iron-based superconducting tape product provided in Embodiment 1 of the present invention;

[0029] Figure 2 This is a curve showing the change of critical current density of the Ag-Ag iron-based superconducting tape product with hot-pressing pressure provided in Embodiment 2 of the present invention;

[0030] Figure 3 This is the MT curve of the Cu-Ag iron-based superconducting tape product provided in Embodiment 3 of the present invention;

[0031] Figure 4 J is the Cu-Ag iron-based superconducting tape product provided in Embodiment 3 of the present invention. c Curve showing the change with magnetic field. Detailed Implementation

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] This invention provides a method for preparing iron-based superconducting wire strips, comprising the following steps:

[0034] a) The precursor powder of the iron-based superconductor is packed into a first metal sheath and extended in length by cold working to obtain a superconducting wire; the superconducting wire is cut to obtain a superconducting segment.

[0035] b) Prepare a metal raw material that is the same material as the first metal sheath, and extend its length by cold working to obtain a metal wire; cut the metal wire to obtain metal segments;

[0036] Steps a) and b) are not in any particular order;

[0037] c) The superconducting segment and the metal segment are loaded into a second metal sheath, wherein the superconducting segment and the metal segment are arranged alternately along the length of the second metal sheath, and both ends of the alternating arrangement are metal segments.

[0038] The second metal sheath is made of a different metal material than the first metal sheath;

[0039] d) The material obtained in step c) is extended in length using a cold working method to obtain wire and strip material;

[0040] e) Cut the wire strip material into sections, where the cutting position is the area in the wire strip material filled with metal segments, to obtain wire strip material segments;

[0041] f) Weld the exposed metal sections at both ends of the wire strip segment, and then perform heat treatment to obtain iron-based superconducting wire strip.

[0042] In the method provided by the present invention, in step a), the iron-based superconductor includes, but is not limited to, Ba-122 iron-based superconductor, CaK-1144 iron-based superconductor or Sr-122 iron-based superconductor.

[0043] In the method provided by the present invention, in step a), the precursor powder is preferably prepared according to the following steps: mixing the raw materials of the iron-based superconductor, sintering in an oxygen-free environment, and pulverizing to obtain the precursor powder of the iron-based superconductor. The raw materials for Ba-122 iron-based superconductors include Ba, K, Fe, and As; the raw materials for CaK-1144 iron-based superconductors include Ca, K, Fe, and As; the raw materials for Sr-122 iron-based superconductors include Sr, K, Fe, and As; and the raw materials for FeSe include Fe and Se. The oxygen-free sintering is preferably carried out under an inert gas atmosphere, which includes, but is not limited to, Ar gas. The oxygen-free sintering temperature is preferably 600~1000℃, specifically 600℃, 700℃, 800℃, 900℃, or 1000℃. The oxygen-free sintering time is preferably 30~40h, specifically 30h, 31h, 32h, 33h, 34h, 35h, 36h, 37h, 38h, 39h, or 40h.

[0044] In the method provided by the present invention, in step a), the material of the first metal sheath is preferably Ag, Cu, Ni, Fe, Ta or Monel alloy.

[0045] In the method provided by the present invention, in step a), the shape of the first metal sheath is preferably a circular tube; the inner diameter of the first metal sheath is preferably 4~8mm, specifically 4mm, 5mm, 6mm, 7mm or 8mm; the wall thickness of the first metal sheath is preferably 0.5~2mm, specifically 0.5mm, 0.7mm, 1mm, 1.2mm, 1.5mm, 1.7mm or 2mm.

[0046] In the method provided by the present invention, in step a), the cold working method includes, but is not limited to, one or more of rotary forging, drawing and extrusion.

[0047] In the method provided by this invention, in step a), the radial cross-section of the superconducting wire is preferably circular or square; wherein, the diameter of the circular cross-section superconducting wire is preferably 1~5mm, specifically 1mm, 1.5mm, 1.9mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 4.8mm or 5mm; the radial cross-section side length of the square cross-section superconducting wire is preferably 1~5mm, specifically 1mm, 1.5mm, 1.9mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 4.8mm or 5mm; the diameter or radial cross-section side length of the superconducting segment is the same as that of the superconducting wire; the length of the superconducting segment is preferably 0.5~3cm, specifically 0.5cm, 1cm, 1.5cm, 2cm, 2.5cm or 3cm.

[0048] In the method provided by the present invention, in step b), the cold working method includes, but is not limited to, one or more of rotary forging, drawing and extrusion.

[0049] In the method provided by this invention, in step b), the radial cross-section of the metal wire is preferably circular or square; wherein, the diameter of the circular cross-section metal wire is preferably 1~5mm, specifically 1mm, 1.5mm, 1.9mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 4.8mm or 5mm; the radial cross-section side length of the square cross-section metal wire is preferably 1~5mm, specifically 1mm, 1.5mm, 1.9mm, 2mm, 2.5mm, 3mm, 3.5mm, 4 ... The diameter or radial cross-sectional side length of the metal segment is 0.8mm or 5mm; the diameter or radial cross-sectional side length of the metal segment is the same as that of the metal wire; the length of the metal segment is divided into two specifications, wherein the length of the metal segment used to fill between the superconducting segments is preferably 0.2~1cm, specifically 0.2cm, 0.3cm, 0.4cm, 0.5cm, 0.6cm, 0.7cm, 0.8cm, 0.9cm or 1cm, and the length of the metal segment used to fill at both ends of the inner cavity of the second metal sheath is preferably 4~6cm, specifically 4cm, 4.5cm, 5cm, 5.5cm or 6cm.

[0050] In the method provided by the present invention, in step b), the obtained metal segment is preferably annealed; the annealing temperature is preferably 250~350℃, specifically 250℃, 260℃, 270℃, 280℃, 290℃, 300℃, 310℃, 320℃, 330℃, 340℃ or 350℃; the annealing time is preferably 3~8h, specifically 3h, 4h, 5h, 6h, 7h or 8h.

[0051] In the method provided by the present invention, in step c), the radial cross-sectional diameter or radial cross-sectional side length of the superconducting segment and the metal segment are preferably the same.

[0052] In the method provided by the present invention, in step c), the material of the second metal sheath is preferably Ag, Cu, Ni, Fe, Ta or Monel alloy; the material of the second metal sheath may be the same as or different from that of the first metal sheath.

[0053] In the method provided by this invention, in step c), the shape of the second metal sheath is preferably a circular tube or a square tube; wherein, the inner diameter of the circular tube is preferably 0.05~0.3 mm larger than the maximum value of the diameter of the circular cross-section superconducting segment and the diameter of the metal segment, specifically 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm or 0.3 mm larger; the radial inner side length of the square tube is preferably 0.05~0.3 mm larger than the maximum value of the radial cross-sectional side length of the square cross-section superconducting segment and the radial cross-sectional side length of the metal segment, specifically 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm or 0.3 mm larger; the wall thickness of the second metal sheath is preferably 0.5~2 mm, specifically 0.5 mm, 0.7 mm, 1 mm, 1.2 mm, 1.5 mm, 1.7 mm or 2 mm.

[0054] In the method provided by the present invention, in step c), it is preferable to fix the metal segments filled at both ends of the inner cavity of the second metal sheath, and the tool used for fixing is preferably a hydraulic clamp.

[0055] In the method provided by the present invention, in step d), the cold working method includes, but is not limited to, one or more of rotary forging, drawing, extrusion and rolling.

[0056] In the method provided by the present invention, in step d), when the wire strip is a strip, its thickness is preferably 0.1~0.5mm, specifically 0.1mm, 0.2mm, 0.3mm, 0.4mm or 0.5mm; when the wire strip is a wire, its diameter is preferably 1~1.5mm, specifically 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm or 1.5mm.

[0057] In the method provided by the present invention, in step f), the welding method is preferably ultrasonic spot welding or fusion welding.

[0058] In the method provided by this invention, in step f), the heat treatment method is preferably one or more of hot pressing, hot isostatic pressing, atmospheric pressure sintering, vacuum sintering, and Joule heating rapid sintering. Specifically, it can be: first hot pressing, then hot isostatic pressing; wherein, the temperature of the heat treatment is preferably 600~1000℃, specifically 600℃, 650℃, 700℃, 750℃, 800℃, 850℃, 900℃, 950℃, or 1000℃; the pressure of the hot pressing is preferably 10~50MPa, specifically 10MPa, 15MPa, 20MPa, 25MPa, 30MPa, 35MPa, or 40MPa. The pressure is preferably 0 MPa, 41 MPa, 45 MPa, or 50 MPa; the hot pressing time is preferably 0.5 to 10 hours, specifically 0.5 hours, 1 hour, 1.5 hours, 2 hours, 5 hours, 7 hours, or 10 hours; the hot isostatic pressing pressure is preferably 100 to 150 MPa, specifically 100 MPa, 105 MPa, 110 MPa, 115 MPa, 120 MPa, 125 MPa, 130 MPa, 135 MPa, 140 MPa, 145 MPa, or 150 MPa; the hot isostatic pressing treatment time is preferably 0.5 to 2 hours, specifically 0.5 hours, 1 hour, 1.5 hours, or 2 hours.

[0059] For clarity, the following examples will be used to provide a detailed description.

[0060] Example 1

[0061] In an argon-filled glove box, 20g of Ba, K, Fe, and As raw material powders were weighed out in an atomic ratio of 0.6:0.5:2:2 and mixed by ball milling. The uniformly mixed raw material powder was then sealed and sintered in a flowing Ar atmosphere (800℃, 30h) to obtain the precursor powder for the iron-based superconductor. The precursor powder was pulverized and packed into a circular Ag tube with an outer diameter of 8mm and an inner diameter of 6mm. It was then drawn to a diameter of 4.8mm and cut into superconducting segments with a length of 1cm. In addition, Ag rods with a diameter of 6mm were drawn to a diameter of 4.8mm and then cut into several Ag segments with a length of 0.5cm and two Ag segments with a length of 5cm. Prepare a circular Ag tube with an outer diameter of 8mm and an inner diameter of 5mm. First, insert a 5cm Ag segment into the bottom end of the circular Ag tube, and fix the inner and outer materials at this end with hydraulic clamps. Then, using a segmented tube-loading method, alternately insert 1cm superconducting segments and 0.5cm Ag segments into the circular Ag tube. Finally, insert another 5cm Ag segment into the top of the circular Ag tube, and fix the inner and outer materials at this end with hydraulic clamps. After the segment loading is completed, draw the material to a diameter of 1.9mm, and further roll it into a strip with a thickness of 0.3mm. Cut the strip at the area filled with Ag segments, resulting in several strip segments, each segment sealed at both ends with Ag segments. The exposed Ag segments at both ends of the strip were sealed using ultrasonic spot welding equipment, and then placed in a hot isostatic pressing furnace for high-pressure sintering at a temperature of 800℃, a pressure of 100MPa, and a time of 1 hour, ultimately yielding Ag-Ag iron-based superconducting strip products.

[0062] The magnetization (M) versus temperature (T) curve of the Ag-Ag iron-based superconducting tape product prepared in this embodiment was detected, and the results are as follows: Figure 1 As shown. Figure 1 This is the MT curve of the Ag-Ag iron-based superconducting tape product provided in Embodiment 1 of the present invention. (Through...) Figure 1 It can be seen that the Ag-Ag iron-based superconducting tape product prepared in this embodiment has an initial transition temperature of over 36K, indicating that the product exhibits excellent superconductivity and a pure superconducting phase.

[0063] Example 2

[0064] In an argon-filled glove box, 20g of Ba, K, Fe, and As raw material powders were weighed out in an atomic ratio of 0.6:0.5:2:2 and mixed by ball milling. The uniformly mixed raw material powder was then sealed and sintered in a flowing Ar atmosphere (800℃, 30h) to obtain the precursor powder for the iron-based superconductor. The precursor powder was pulverized and packed into a circular Ag tube with an outer diameter of 8mm and an inner diameter of 6mm. It was then drawn using a square die to a radial cross-sectional side length of 1.9mm and cut into superconducting segments 1cm in length. Additionally, Ag rods with a diameter of 4mm were drawn using a square die to a radial cross-sectional side length of 1.9mm, then cut into several Ag segments 0.5cm in length and two Ag segments 5cm in length, and annealed at 300℃ for 5h. Prepare a square Ag tube with an outer side length of 4mm and an inner side length of 2mm. First, insert a 5cm Ag segment into the bottom end of the square Ag tube, and fix the inner and outer materials at this end with hydraulic clamps. Then, by segmenting the tube, alternately insert 1cm superconducting segments and 0.5cm Ag segments into the square Ag tube. Finally, insert another 5cm Ag segment into the top of the square Ag tube, and fix the inner and outer materials at this end with hydraulic clamps. After the segments are filled, draw the material to a diameter of 1.9mm, and further roll it into a strip with a thickness of 0.3mm. Cut the strip at the area filled with Ag segments, resulting in several strip segments, each segment sealed at both ends with Ag segments. The exposed Ag segments at both ends of the strip were welded using ultrasonic spot welding equipment. Then, the material was pre-sintered by hot pressing (600℃, 30~45MPa, 1h). After that, it was placed in a hot isostatic pressing furnace for high-pressure sintering at a temperature of 700℃, a pressure of 150MPa, and a time of 1h, finally obtaining the Ag-Ag iron-based superconducting strip product.

[0065] The magnetization (M) of the Ag-Ag iron-based superconducting tape product prepared in this embodiment was measured as a function of hot-pressing pressure (test temperature: 4.2K). The results are as follows: Figure 2 As shown. Figure 2 The critical current density (J / L) of the Ag-Ag iron-based superconducting tape product provided in Embodiment 2 of this invention is... c A graph showing the change in pressure with hot pressing. Figure 2 It can be seen that the optimal hot-pressing pressure is 41 MPa.

[0066] Example 3

[0067] In an argon-filled glove box, 20g of Ba, K, Fe, and As raw material powders were weighed out in an atomic ratio of 0.6:0.5:2:2 and mixed by ball milling. The uniformly mixed raw material powder was then sealed and sintered in a flowing Ar atmosphere (800℃, 30h) to obtain the precursor powder for the iron-based superconductor. The precursor powder was pulverized and packed into a circular Ag tube with an outer diameter of 8mm and an inner diameter of 6mm. It was then drawn to a diameter of 1.9mm and cut into superconducting segments with a length of 1.5cm. In addition, Ag rods with a diameter of 4mm were drawn to a diameter of 1.9mm, then cut into several Ag segments with a length of 0.5cm and two Ag segments with a length of 5cm, and annealed at 300℃ for 5h. Prepare a circular Cu tube with an outer diameter of 4mm and an inner diameter of 2mm. First, insert a 5cm Ag segment into the bottom end of the circular Cu tube, and fix the inner and outer materials at this end with hydraulic clamps. Then, using a segmented tube-loading method, alternately insert 1.5cm superconducting segments and 0.5cm Ag segments into the circular Cu tube. Finally, insert another 5cm Ag segment into the top of the circular Cu tube, and fix the inner and outer materials at this end with hydraulic clamps. After completing the segment loading, draw the material to a wire with a diameter of 1.2mm. Cut the wire at the area where the Ag segments are filled, resulting in several wire segments. Each wire segment is sealed at both ends with Ag segments. The exposed Ag segments at both ends of the wire section were sealed using a welding equipment, and then placed in a hot isostatic pressing furnace for high-pressure sintering at a temperature of 700℃, a pressure of 150MPa, and a time of 1 hour, ultimately yielding Cu-Ag iron-based superconducting tape products.

[0068] The magnetization (M) versus temperature (T) curve of the Cu-Ag iron-based superconducting tape product prepared in this embodiment was detected, and the results are as follows: Figure 3 As shown. Figure 3 This is the MT curve of the Cu-Ag iron-based superconducting tape product provided in Embodiment 3 of the present invention. (By...) Figure 3 It can be seen that the Cu-Ag iron-based superconducting tape product prepared in this embodiment has an initial transition temperature of over 36K, indicating that the product exhibits excellent superconductivity and a pure superconducting phase.

[0069] The critical current density (J) of the Cu-Ag iron-based superconducting tape product prepared in this embodiment was measured. c The curve of change with magnetic field was detected, and the results are as follows: Figure 4 As shown. Figure 4 J is the Cu-Ag iron-based superconducting tape product provided in Embodiment 3 of the present invention. c A graph showing the variation with magnetic field. Figure 4It can be seen that the product exhibits a fairly high critical current density at 4.2K, while its decay with magnetic field is very small, showing a very weak magnetic field dependence, indicating that the material exhibits excellent transport characteristics.

[0070] 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 preparing iron-based superconducting wire strips, characterized in that, Includes the following steps: a) The precursor powder of the iron-based superconductor is packed into a first metal sheath and extended in length by cold working to obtain a superconducting wire; the superconducting wire is cut to obtain a superconducting segment. b) Prepare a metal raw material that is the same material as the first metal sheath, and extend its length by cold working to obtain a metal wire; cut the metal wire to obtain metal segments; Steps a) and b) are not in any particular order; c) The superconducting segment and the metal segment are loaded into a second metal sheath, wherein the superconducting segment and the metal segment are arranged alternately along the length of the second metal sheath, and both ends of the alternating arrangement are metal segments. d) The material obtained in step c) is extended in length using a cold working method to obtain wire and strip material; e) Cut the wire strip material into sections, where the cutting position is the area in the wire strip material filled with metal segments, to obtain wire strip material segments; f) Weld the exposed metal sections at both ends of the wire strip segment, and then perform heat treatment to obtain iron-based superconducting wire strip.

2. The method according to claim 1, characterized in that, The iron-based superconductor is a Ba-122 iron-based superconductor, a CaK-1144 iron-based superconductor, a Sr-122 iron-based superconductor, or a FeSe.

3. The method according to claim 1, characterized in that, The precursor powder is prepared according to the following steps: The raw materials for iron-based superconductors are mixed, sintered in an oxygen-free environment, and pulverized to obtain precursor powders for iron-based superconductors.

4. The method according to claim 3, characterized in that, The temperature for oxygen-free sintering is 600~1000℃.

5. The method according to claim 1, characterized in that, The first metal sheath is made of Ag, Cu, Ni, Fe, Ta or Monel alloy; the second metal sheath is made of Ag, Cu, Ni, Fe, Ta or Monel alloy.

6. The method according to claim 1, characterized in that, The length of the superconducting segment is 0.5~3cm.

7. The method according to claim 1, characterized in that, Within the second metal sheath, the length of the metal segment located between the superconducting segments is 0.2~1cm, and the length of the metal segment located at both ends is 4~6cm.

8. The method according to claim 1, characterized in that, The sealing method is ultrasonic spot welding or fusion welding.

9. The method according to claim 1, characterized in that, The heat treatment method is one or more of the following: hot pressing, hot isostatic pressing, atmospheric pressure sintering, vacuum sintering, and Joule heating rapid sintering.

10. The method according to claim 9, characterized in that, The heat treatment temperature is 600~1000℃; the hot pressing pressure is 10~50MPa, and the time is 0.5~10h; the hot isostatic pressing pressure is 100~150MPa, and the time is 0.5~2h.

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