A method for producing a bismuth-based high-temperature superconducting wire

Abstract

The application discloses a preparation method of a bismuth high-temperature superconducting wire, which comprises the following steps: 1, filling bismuth high-temperature superconducting precursor powder into a silver tube or a silver alloy tube, carrying out multi-pass drawing after tube end sealing and welding to obtain a bismuth wire; 2, connecting both ends of the bismuth wire into a clamp of an electric pulse assisted annealing device to carry out electric pulse assisted annealing; and 3, taking out the bismuth wire and continuing to carry out multi-pass drawing to obtain a single-core or multi-core structure bismuth high-temperature superconducting wire. The electric pulse assisted annealing process is introduced to replace conventional heat annealing, rapid heating of the bismuth wire sheath material is realized, residual stress is effectively removed, the bismuth high-temperature superconducting wire sheath material grain refinement and grain size uniformity are maintained, the plasticity is enhanced, the mechanical property uniformity and the processing performance of the bismuth high-temperature superconducting wire are improved, the sheath oxidation, efficiency and size limitation and other restriction factors are reduced, and the efficient preparation of the bismuth superconducting wire is realized.

Description

Technical Field

[0001] This invention belongs to the field of superconducting wire technology, specifically relating to a method for preparing bismuth-based high-temperature superconducting wire. Background Technology

[0002] Bismuth-based high-temperature superconducting materials include Bi₂Sr₂CaCu₂O₈ (Bi-2212) and Bi₂Sr₂Ca₂Cu₃O₄. 10 (Bi-2223) is prepared by a powder-packing method, in which the precursor superconducting ceramic powder is packed into a silver or silver alloy sheath and encapsulated, and then a multi-core wire structure is prepared by multiple cold drawing and bundle assembly.

[0003] Due to the large processing volume of bismuth-based high-temperature superconducting materials, the cladding material undergoes severe work hardening, necessitating the elimination of residual stress generated during drawing passes. Currently, the common practice is hot annealing, which involves heating the cladding material in the superconducting wire to above its recrystallization temperature through intermediate heat treatment to eliminate residual stress. However, due to equipment limitations, the heating and cooling stages of the intermediate heat treatment process cannot be shortened, especially for long superconducting wires, where the heat treatment time is long and the cost is high. Furthermore, grain growth caused by intermediate heat treatment can reduce the processing performance of the superconducting wire. Therefore, a method is needed to rapidly heat the wire to remove residual stress while maintaining grain refinement, thereby improving production efficiency. Summary of the Invention

[0004] The technical problem to be solved by this invention is to provide a method for preparing bismuth-based high-temperature superconducting wires, addressing the shortcomings of the prior art. This invention introduces an electric pulse-assisted annealing process into the preparation of bismuth-based high-temperature superconducting wires, achieving rapid heating of the bismuth-based wire cladding material, effectively removing residual stress, maintaining grain refinement and uniformity of grain size in the bismuth-based high-temperature superconducting wire cladding material, enhancing its plasticity, and improving the uniformity of mechanical properties, processing performance, and preparation efficiency of the bismuth-based high-temperature superconducting wires. This solves the problem of long-term heat treatment reducing the processing performance of superconducting wires.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for preparing bismuth-based high-temperature superconducting wires, characterized in that the method includes the following steps:

[0006] Step 1: Fill bismuth-based high-temperature superconducting precursor powder into a silver tube or silver alloy tube, and weld silver plugs at both ends of the tube to obtain a bismuth-based billet rod. Then, the bismuth-based billet rod is drawn into shape through multiple passes to obtain bismuth-based wire.

[0007] Step 2: Turn on the electric pulse assisted annealing equipment, set the electric pulse frequency, current peak value, average current density, and energizing time, and then connect both ends of the bismuth-based wire obtained in Step 1 into the fixture of the electric pulse assisted annealing equipment and fix them for electric pulse assisted annealing.

[0008] Step 3: After removing the bismuth-based wires that have undergone electrical pulse-assisted annealing in Step 2, continue to perform multiple drawing passes to obtain a single-core bismuth-based high-temperature superconducting wire. Alternatively, after removing the bismuth-based wires that have undergone electrical pulse-assisted annealing, continue to perform multiple drawing passes, and then bundle and assemble them for multiple drawing passes until a multi-core bismuth-based high-temperature superconducting wire is obtained. During each of the multiple drawing passes, the drawn object is subjected to electrical pulse-assisted annealing in accordance with the electrical pulse-assisted annealing process in Step 2.

[0009] The above-mentioned method for preparing a bismuth-based high-temperature superconducting wire is characterized in that the bismuth-based high-temperature superconducting precursor powder in step one is a multi-metal oxide powder of bismuth, strontium, calcium, copper and oxygen.

[0010] The above-mentioned method for preparing a bismuth-based high-temperature superconducting wire is characterized in that the frequency of the electrical pulse in step two is 100Hz to 200Hz.

[0011] The above-mentioned method for preparing a bismuth-based high-temperature superconducting wire is characterized in that the peak current in step two is 500A to 2000A.

[0012] The above-mentioned method for preparing a bismuth-based high-temperature superconducting wire is characterized in that the average current density in step two is 10 A / mm². 2 ~60A / mm 2 .

[0013] The above-mentioned method for preparing a bismuth-based high-temperature superconducting wire is characterized in that the energizing time in step two is 3s to 40s.

[0014] This invention sets the electric pulse frequency, peak current, average current density, and energizing time for electric pulse assisted annealing based on the characteristics of the sheath material in bismuth-based wires. While ensuring the effect of electric pulse assisted annealing, it avoids local overheating and burnout, thus enabling the electric pulse assisted annealing process to proceed smoothly.

[0015] Compared with the prior art, the present invention has the following advantages:

[0016] 1. This invention employs an electric pulse-assisted annealing process to heat-treat bismuth-based wires after processing. The Joule heat generated by the pulse current rapidly heats the cladding material of the long bismuth-based wires, thereby removing residual stress from the processed superconducting wires and improving the preparation efficiency of bismuth-based high-temperature superconducting wires.

[0017] 2. This invention utilizes the rapid heating and cooling characteristics of the electric pulse assisted annealing process to avoid grain growth caused by conventional long-term annealing heat treatment and oxidation of alloy elements in the cladding material when in contact with air at high temperatures due to long-term cooling. This maintains the grain refinement and uniformity of the cladding material of bismuth-based high-temperature superconducting wires, and improves the uniformity of the mechanical properties of bismuth-based high-temperature superconducting wires and the machinability of the wires.

[0018] 3. This invention utilizes the electroplastic effect brought about by the pulse current in the electric pulse assisted annealing process, which enhances the plasticity of bismuth-based high-temperature superconducting wires after electric pulse assisted annealing and improves their processing performance.

[0019] 4. The electric pulse-assisted annealing process of the present invention effectively reduces the constraints such as oxidation inside the cladding, efficiency and size limitations caused by conventional long-term thermal annealing, and realizes the efficient preparation of bismuth-based superconducting wires.

[0020] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the electrical pulse-assisted annealing equipment used in this invention.

[0022] Figure 2a This is an assembly design diagram of the Bi-2212 billet prepared in Example 1 of the present invention.

[0023] Figure 2b Metallographic micrograph of the single-core Bi-2212 high-temperature superconducting wire prepared in Example 1 of this invention.

[0024] Figure 3a This is an assembly design diagram of the Bi-2212 high-temperature superconducting wire assembly prepared in Example 2 of the present invention.

[0025] Figure 3b Metallographic micrograph of the 55-core hexagonal Bi-2212 high-temperature superconducting wire with a side width of 1.9 mm prepared in Example 2 of this invention.

[0026] Figure 4a This is an assembly design diagram of the Bi-2212 high-temperature superconducting wire assembly prepared in Example 3 of the present invention.

[0027] Figure 4b Metallographic micrograph of a 990-core Bi-2212 high-temperature superconducting wire with a diameter of Ф1mm prepared in Example 3 of the present invention.

[0028] Figure 5a This is an assembly design diagram of the Bi-2223 billet prepared in Example 4 of the present invention.

[0029] Figure 5b Metallographic micrograph of the single-core Bi-2223 high-temperature superconducting wire prepared in Example 4 of this invention.

[0030] Figure 6a This is an assembly design diagram of the Bi-2223 high-temperature superconducting wire assembly prepared in Example 5 of the present invention.

[0031] Figure 6b Metallographic micrograph of a 37-core Bi-2223 high-temperature superconducting wire with a diameter of Ф1.51 mm prepared in Example 5 of this invention.

[0032] Figure 6c Metallographic micrograph of a 37-core Bi-2223 high-temperature superconducting tape with a width of 4.3 mm and a thickness of 0.3 mm prepared in Example 5 of this invention.

[0033] Figure 7a This is an assembly design diagram of the Bi-2223 high-temperature superconducting wire assembly prepared in Example 6 of the present invention.

[0034] Figure 7b Metallographic micrograph of the 121-core Bi-2223 high-temperature superconducting wire with a diameter of Ф1.51 mm prepared in Example 6 of this invention.

[0035] Figure 7c Metallographic micrograph of the 121-core Bi-2223 high-temperature superconducting tape with a width of 4.3 mm and a thickness of 0.3 mm prepared in Example 6 of this invention.

[0036] Explanation of reference numerals in the attached figures:

[0037] 1—Pulse power supply; 2—Reference resistor; 3—Voltmeter;

[0038] 4—Clamp; 5—Bismuth-based wire. Detailed Implementation

[0039] like Figure 1 As shown, the electric pulse assisted annealing equipment used in this invention includes a pulse power supply 1. The pulse power supply 1 is connected to a clamp 4 for fixing bismuth-based wires 5 via a wire. The size of the clamp 4 is adjustable. A reference resistor 2 is connected in series in the connecting wire between the pulse power supply 1 and the clamp 4. A voltmeter 3 for measuring the voltage at the reference resistor 2 is connected in parallel on the reference resistor 2.

[0040] The working process of the electrical pulse-assisted annealing equipment used in this invention is as follows: bismuth-based wire 5 is fixed in the clamp 4 and the two are in full contact, forming a series circuit with the pulse power supply 1; the pulse power supply 1 is then turned on. Figure 1The voltage V at the reference resistor 2 is detected and recorded by voltmeter 3. The pulse current is calculated by combining the known resistance value R of the reference resistor 2. After the electric pulse assisted annealing process of the bismuth wire 5 is completed, it is taken out and separated from the fixture 4.

[0041] Example 1

[0042] This embodiment includes the following steps:

[0043] Step 1: Fill a silver tube with an outer diameter of Ф31mm and a wall thickness of 2.5mm into a Bi2Sr2CaCu2O8 (Bi-2212) high-temperature superconducting precursor powder, and weld silver plugs to both ends of the silver tube to obtain a Bi-2212 billet rod. Figure 2a As shown, the Bi-2212 billet bar is then drawn in multiple passes to obtain a single-core Bi-2212 wire with a diameter of Ф4mm.

[0044] Step 2: Turn on the electrical pulse-assisted annealing equipment, and set the electrical pulse frequency to 100Hz, the peak current to 500A, and the average current density to 10A / mm². 2 The power-on time is 40s. Then, the two ends of the Bi-2212 wire with a diameter of Ф4mm obtained in step one are connected to the fixture of the electric pulse assisted annealing equipment and fixed for electric pulse assisted annealing.

[0045] Step 3: After removing the Ф4mm diameter single-core Bi-2212 wire that has undergone electrical pulse assisted annealing in Step 2, continue to perform multiple drawing passes to obtain a hexagonal single-core Bi-2212 high-temperature superconducting wire with a side width of 2.1mm.

[0046] Figure 2b Metallographic micrograph of the single-core Bi-2212 high-temperature superconducting wire prepared in this embodiment, from... Figure 2b It can be seen that the Bi-2212 high-temperature superconducting wire with this single-core structure has a complete and uniform superconducting structure, a smooth interface, and a silver-to-superconducting ratio s = 0.84.

[0047] Example 2

[0048] This embodiment includes the following steps:

[0049] Step 1: Cut the hexagonal Bi-2212 high-temperature superconducting wire with a side width of 2.1 mm and a single core structure prepared in Example 1 into 55 components with a length of 1.2 m. Then, arrange the 55 components in a hexagonal close-packed arrangement and bundle them into a silver tube with an outer diameter of Ф21 mm and a wall thickness of 1.5 mm as Bi-2212 superconducting core wire. Seal the two ends of the silver tube with silver plugs to obtain the Bi-2212 high-temperature superconducting wire assembly. Figure 3aAs shown, a 55-core Bi-2212 high-temperature superconducting wire with a diameter of Ф6.6mm was obtained by multiple drawing processes.

[0050] Step 2: Turn on the electrical pulse-assisted annealing equipment, and set the electrical pulse frequency to 100Hz, the peak current to 1000A, and the average current density to 20A / mm². 2 The power-on time is 20s. Then, the two ends of the 55-core Bi-2212 high-temperature superconducting wire with a diameter of Ф6.6mm obtained in step one are connected to the fixture of the electric pulse assisted annealing equipment and fixed for electric pulse assisted annealing.

[0051] Step 3: After removing the 55-core Bi-2212 high-temperature superconducting wire with a diameter of Ф6.6mm that has undergone electrical pulse assisted annealing in Step 2, continue to perform multiple drawing passes to obtain a 55-core Bi-2212 high-temperature superconducting wire with a diameter of Ф3mm.

[0052] Step 4: Turn on the electrical pulse-assisted annealing equipment, and set the electrical pulse frequency to 150Hz, the peak current to 1000A, and the average current density to 25A / mm². 2 The power-on time is 10s. Then, the two ends of the 55-core Bi-2212 high-temperature superconducting wire with a diameter of Ф3mm obtained in step three are connected to the fixture of the electric pulse assisted annealing equipment and fixed for electric pulse assisted annealing.

[0053] Step 5: After removing the 55-core Bi-2212 high-temperature superconducting wire with a diameter of Ф3mm that has undergone electrical pulse assisted annealing in Step 4, continue to perform multiple drawing passes to obtain a 55-core Bi-2212 high-temperature superconducting wire with a hexagonal side width of 1.9mm.

[0054] Figure 3b Metallographic micrograph of the 55-core Bi-2212 high-temperature superconducting wire with a hexagonal side width of 1.9 mm prepared in this embodiment. Figure 3b It can be seen that the superconducting core and outer sheath structure of the 55-core Bi-2212 high-temperature superconducting wire are intact, with no internal cracks or broken cores, and the silver-to-superconducting ratio s = 1.76.

[0055] Example 3

[0056] This embodiment includes the following steps:

[0057] Step 1: Cut the 55-core Bi-2212 high-temperature superconducting wire with a hexagonal side width of 1.9 mm prepared in Step 2 into 18 components, each 1 m long. Take another 1-meter-long silver wire with a hexagonal side width of 1.9 mm as the central reinforcing component. Then, bundle the 18 components and the central reinforcing component together in a hexagonal close-packed arrangement and fill them into a silver alloy tube with an outer diameter of Ф11.2 mm and a wall thickness of 0.6 mm as the Bi-2212 superconducting core wire. Weld silver plugs to both ends of the silver alloy tube to obtain the Bi-2212 high-temperature superconducting wire assembly. Figure 4a As shown, a 990-core Bi-2212 high-temperature superconducting wire with a diameter of Ф8mm was obtained by multiple drawing processes.

[0058] Step 2: Turn on the electrical pulse-assisted annealing equipment and set the electrical pulse frequency to 200Hz, the peak current to 2000A, and the average current density to 50A / mm². 2 The power-on time is 5 seconds. Then, the two ends of the 990 core Bi-2212 high-temperature superconducting wire with a diameter of Ф8mm obtained in step one are connected to the fixture of the electric pulse assisted annealing equipment and fixed for electric pulse assisted annealing.

[0059] Step 3: After removing the 990-core Bi-2212 high-temperature superconducting wire with a diameter of Ф8mm that has undergone electrical pulse assisted annealing in Step 2, continue to perform multiple drawing passes to obtain a 990-core Bi-2212 high-temperature superconducting wire with a diameter of Ф4mm.

[0060] Step 4: Turn on the electrical pulse-assisted annealing equipment, and set the electrical pulse frequency to 200Hz, the peak current to 2000A, and the average current density to 60A / mm². 2 The power-on time is 3 seconds. Then, the two ends of the 990 core Bi-2212 high-temperature superconducting wire with a diameter of Ф4mm obtained in step three are connected to the fixture of the electric pulse assisted annealing equipment and fixed for electric pulse assisted annealing.

[0061] Step 5: After removing the 990-core Bi-2212 high-temperature superconducting wire with a diameter of Ф4mm that has undergone electrical pulse assisted annealing in Step 4, continue to perform multiple drawing passes to obtain a 990-core Bi-2212 high-temperature superconducting wire with a diameter of Ф2mm.

[0062] Step 6: Turn on the electrical pulse-assisted annealing equipment, and set the electrical pulse frequency to 200Hz, the peak current to 1000A, and the average current density to 20A / mm². 2 The power-on time is 5 seconds. Then, the two ends of the 990 core Bi-2212 high-temperature superconducting wire with a diameter of Ф2mm obtained in step five are connected to the fixture of the electric pulse assisted annealing equipment and fixed for electric pulse assisted annealing.

[0063] Step 7: After removing the 990-core Bi-2212 high-temperature superconducting wire with a diameter of Ф2mm that has undergone electrical pulse assisted annealing in Step 6, continue to perform multiple drawing passes to obtain a 990-core Bi-2212 high-temperature superconducting wire with a diameter of Ф1mm.

[0064] Figure 4b Metallographic micrograph of a 990-core Bi-2212 high-temperature superconducting wire with a diameter of Ф1 mm prepared in this embodiment. Figure 4b It can be seen that the 990-core Bi-2212 high-temperature superconducting wire has a complete structure, without cracks or broken cores, and the core wires are deformed evenly and fully, with a silver-to-superconducting ratio of s = 3.13.

[0065] Example 4

[0066] This embodiment includes the following steps:

[0067] Step 1: Prepare Bi₂Sr₂Ca₂Cu₃O₃ 10 (Bi-2223) high-temperature superconducting precursor powder was filled into a silver tube with an outer diameter of Ф31mm and a wall thickness of 1.5mm, and silver plugs were welded to both ends of the silver tube to obtain a Bi-2223 billet rod. Figure 5a As shown, the Bi-2223 billet bar is then drawn in multiple passes to obtain a single-core Bi-2223 wire with a diameter of Ф3mm.

[0068] Step 2: Turn on the electrical pulse-assisted annealing equipment, and set the electrical pulse frequency to 150Hz, the peak current to 1000A, and the average current density to 25A / mm². 2 The power-on time is 15s. Then, the two ends of the Bi-2223 wire with a diameter of Ф3mm obtained in step one are connected to the fixture of the electric pulse assisted annealing equipment and fixed for electric pulse assisted annealing.

[0069] Step 3: After removing the Ф3mm diameter single-core Bi-2223 wire that has undergone electrical pulse assisted annealing in Step 2, continue to perform multiple drawing passes to obtain a hexagonal Bi-2223 high-temperature superconducting wire with a single-core structure and a side width of 1.36mm.

[0070] Figure 5b Metallographic micrograph of the single-core Bi-2223 high-temperature superconducting wire prepared in this embodiment, from... Figure 5b It can be seen that the Bi-2223 high-temperature superconducting wire with this single-core structure has an intact and unbroken wire structure, a smooth silver-superconducting interface, and a silver-superconducting ratio s = 0.69.

[0071] Example 5

[0072] Step 1: Cut the hexagonal Bi-2223 high-temperature superconducting wire with a side width of 1.36 mm and a single core structure prepared in Example 4 into 37 components with a length of 0.5 m. Then, arrange the 37 components in a hexagonal close-packed arrangement and bundle them into a silver alloy tube with an outer diameter of Ф12 mm and a wall thickness of 1 mm as Bi-2223 superconducting core wires. Seal the two ends of the silver tube with silver plugs to obtain the Bi-2223 high-temperature superconducting wire assembly. Figure 6a As shown, a 37-core Bi-2223 high-temperature superconducting wire with a diameter of Ф4mm was obtained by multiple drawing processes.

[0073] Step 2: Turn on the electrical pulse-assisted annealing equipment and set the electrical pulse frequency to 180Hz, the peak current to 1600A, and the average current density to 30A / mm². 2 The power-on time is 10s. Then, the two ends of the 37-core Bi-2223 high-temperature superconducting wire with a diameter of Ф4mm obtained in step one are connected to the fixture of the electric pulse assisted annealing equipment and fixed for electric pulse assisted annealing.

[0074] Step 3: After removing the 37-core Bi-2223 high-temperature superconducting wire with a diameter of Ф4mm that has undergone electrical pulse assisted annealing in Step 2, continue to perform multiple drawing passes to obtain a 37-core Bi-2223 high-temperature superconducting wire with a diameter of Ф1.51mm. Then continue rolling to obtain a 37-core Bi-2223 high-temperature superconducting tape with a width of 4.3mm and a thickness of 0.3mm.

[0075] Figure 6b Metallographic micrograph of a 37-core Bi-2223 high-temperature superconducting wire with a diameter of Ф1.51 mm prepared in this embodiment. Figure 6b It can be seen that the 37-core Bi-2223 high-temperature superconducting wire has a complete wire structure, uniform and sufficient core wire deformation, no local core breakage, and a silver-to-superconducting ratio s = 1.72.

[0076] Figure 6c Metallographic micrograph of the 37-core Bi-2223 high-temperature superconducting tape, 4.3 mm wide and 0.3 mm thick, prepared in this embodiment, is shown below. Figure 6c It can be seen that the 37-core Bi-2223 high-temperature superconducting tape obtained after rolling has a complete structure, the core wires are fully expanded, there are no broken cores, no core wire adhesion, and the silver-to-superconducting ratio s = 1.51.

[0077] Example 6

[0078] Step 1: Cut the 37-core Bi-2223 high-temperature superconducting wire with a diameter of Ф1.51mm prepared in Example 4 into 121 components with a length of 1m. Then, arrange the 121 components in a hexagonal close-packed arrangement and bundle them into a silver alloy tube with an outer diameter of Ф21mm and a wall thickness of 2mm as Bi-2223 superconducting core wires. Seal the two ends of the silver tube with silver plugs to obtain the Bi-2223 high-temperature superconducting wire assembly. Figure 7a As shown, a 121-core Bi-2223 high-temperature superconducting wire with a diameter of Ф4mm was obtained by multiple drawing processes.

[0079] Step 2: Turn on the electrical pulse-assisted annealing equipment and set the electrical pulse frequency to 200Hz, the peak current to 2000A, and the average current density to 40A / mm². 2 The power-on time is 10s. Then, the two ends of the 121-core Bi-2223 high-temperature superconducting wire with a diameter of Ф4mm obtained in step one are connected to the fixture of the electric pulse assisted annealing equipment and fixed for electric pulse assisted annealing.

[0080] Step 3: After removing the 121-core Bi-2223 high-temperature superconducting wire with a diameter of Ф4mm that has undergone electrical pulse assisted annealing in Step 2, continue to perform multiple drawing passes to obtain a 121-core Bi-2223 high-temperature superconducting wire with a diameter of Ф2mm.

[0081] Step 4: Turn on the electrical pulse-assisted annealing equipment, and set the electrical pulse frequency to 200Hz, the peak current to 1500A, and the average current density to 20A / mm². 2 The power-on time is 10s. Then, the two ends of the 121-core Bi-2223 high-temperature superconducting wire with a diameter of Ф2mm obtained in step three are connected to the fixture of the electric pulse assisted annealing equipment and fixed for electric pulse assisted annealing.

[0082] Step 5: After removing the 121-core Bi-2223 high-temperature superconducting wire with a diameter of Ф2mm that has undergone electrical pulse assisted annealing in Step 4, continue to perform multiple drawing passes to obtain a 121-core Bi-2223 high-temperature superconducting wire with a diameter of Ф1.51mm. Then continue rolling to obtain a 121-core Bi-2223 high-temperature superconducting tape with a width of 4.3mm and a thickness of 0.3mm.

[0083] Figure 7b Metallographic micrograph of a 121-core Bi-2223 high-temperature superconducting wire with a diameter of Ф1.51 mm prepared in this embodiment. Figure 7b It can be seen that the 121-core Bi-2223 high-temperature superconducting wire has a complete wire structure, uniform and sufficient core wire deformation, no local core breakage, and a silver-to-superconducting ratio s = 3.46.

[0084] Figure 7cMetallographic micrograph of the 121-core Bi-2223 high-temperature superconducting tape, 4.3 mm wide and 0.3 mm thick, prepared in this embodiment, is shown below. Figure 7c It can be seen that the 121-core Bi-2223 high-temperature superconducting tape obtained after rolling has a complete structure, the core wires are fully expanded, there are no broken cores, no core wire adhesion, and the silver-to-superconducting ratio s = 4.72.

[0085] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing a bismuth-based high-temperature superconducting wire, characterized in that, The method includes the following steps: Step 1: Fill bismuth-based high-temperature superconducting precursor powder into a silver tube or silver alloy tube, and weld silver plugs at both ends of the tube to obtain a bismuth-based billet rod. Then, the bismuth-based billet rod is drawn into shape through multiple passes to obtain a bismuth-based wire. The bismuth-based high-temperature superconducting precursor powder is a multi-metal oxide powder of bismuth, strontium, calcium, copper and oxygen. Step 2: Turn on the electrical pulse-assisted annealing equipment, set the electrical pulse frequency, peak current, average current density, and energizing time. Then, connect both ends of the bismuth-based wire obtained in Step 1 into the fixture of the electrical pulse-assisted annealing equipment and fix them for electrical pulse-assisted annealing. The electrical pulse frequency is 100Hz~200Hz, the peak current is 500A~2000A, and the average current density is 10A / mm². 2 ~60A / mm 2 The power-on time is 3s~40s; Step 3: After removing the bismuth-based wires that have undergone electrical pulse-assisted annealing in Step 2, continue to perform multiple drawing passes to obtain a single-core bismuth-based high-temperature superconducting wire. Alternatively, after removing the bismuth-based wires that have undergone electrical pulse-assisted annealing, continue to perform multiple drawing passes, and then bundle and assemble them for multiple drawing passes until a multi-core bismuth-based high-temperature superconducting wire is obtained. After each of the multiple drawing passes, the drawn object is subjected to electrical pulse-assisted annealing in accordance with the electrical pulse-assisted annealing process in Step 2.

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