A method of repairing a high temperature superconducting tape

Abstract

The application discloses a high-temperature superconducting tape repairing method, which comprises the following steps: S1, placing a to-be-repaired area of a high-temperature superconducting tape in a reaction container; S2, maintaining a certain oxygen partial pressure of the reaction container and performing annealing treatment on the to-be-repaired area; and S3, after the annealing treatment is completed, taking out the high-temperature superconducting tape after the reaction container is cooled; wherein the to-be-repaired area is a bad point area in the high-temperature superconducting tape and a certain length area on both sides of the bad point area in the length direction of the tape. The repairing method of the application does not need to be cut off, that is, the original tape is basically not damaged, and only proper heat treatment is needed on the bad point area to repair the bad point area.

Description

Technical Field

[0001] This invention relates to the field of materials technology, and in particular to a method for repairing high-temperature superconducting tapes. Background Technology

[0002] REBCO-coated conductors, based on thin-film epitaxial growth and biaxial texturing technology, are known as second-generation high-temperature superconducting tapes. RE stands for rare earth elements, B for Ba, C for Cu, and O for oxygen. The critical temperature of REBCO-coated conductors is significantly higher than that of traditional low-temperature superconducting materials, reaching over 90K, exceeding the temperature of liquid nitrogen (77K). This allows liquid nitrogen to be used as a coolant, thus reducing cooling costs. Second-generation high-temperature superconducting tapes possess extremely high upper critical fields, extremely high current-carrying capacity, and high mechanical strength, making them more suitable for large-scale applications. Currently, the manufacturing technology for second-generation high-temperature superconducting tapes is relatively mature and has been industrialized.

[0003] REBCO-coated conductors mainly consist of a metal substrate, multiple buffer layers, a superconducting layer, and a protective layer. The metal substrate is typically Ni or a Ni alloy (such as Hastelloy), or even stainless steel, with a thickness of 50-100 μm, serving to support the superconducting layer and provide mechanical properties. The multiple buffer layers are generally obtained using magnetron sputtering or pulsed laser deposition; besides blocking atomic diffusion, they also transfer texture to the superconducting layer. The superconducting layer, a biaxially textured REBCO grown epitaxially, is the core of the tape, providing the required superconductivity; its thickness is typically 1-6 μm. Finally, the tape is wrapped with silver and copper layers to protect the entire structure. At high temperatures, oxygen atoms can permeate through the silver layer and react with the superconducting layer, allowing for the control of oxygen content.

[0004] In mass-produced REBCO-coated conductors, deviations in process stability can lead to performance degradation in certain areas of the tape, reducing the texture and connectivity of the superconducting layer and weakening superconductivity properties such as the superconducting transition temperature and critical current density. These localized defects impede superconducting current, severely reducing the current-carrying capacity of the entire long tape. Therefore, it is necessary to cut the entire long tape from both sides of the defect, significantly reducing the product length and yield. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a method for repairing high-temperature superconducting tapes. This method only requires appropriate heat treatment of the defective area and can repair the defective area without damaging the original tape.

[0006] The present invention adopts the following technical solution:

[0007] A method for repairing high-temperature superconducting tapes includes the following steps:

[0008] S1: Place the area of ​​the high-temperature superconducting tape to be repaired in the reaction vessel;

[0009] S2: Maintain a certain oxygen partial pressure in the reaction vessel and perform annealing treatment on the area to be repaired;

[0010] S3: After the annealing process is completed, wait for the reaction vessel to cool down and then take out the high-temperature superconducting tape.

[0011] The areas to be repaired are the defective areas in the high-temperature superconducting tape and the areas of a certain length on both sides of the defective areas along the length of the tape.

[0012] Wherein, the certain length is 5% to 15% of the length of the defective area.

[0013] The repair method does not cut off the defective areas of the high-temperature strip.

[0014] The high-temperature superconducting tape is a REBCO coated conductor, where RE represents rare earth elements, B represents Ba, C represents Cu, and O represents oxygen.

[0015] The oxygen partial pressure is 0.5 bar to 100 bar, the annealing temperature is 200℃ to 800℃, and the holding time is 10 to 1500 min.

[0016] Step S0 is included before step S1;

[0017] S0: The step of analyzing whether the outer layer of the area to be repaired contains an oxygen-impermeable material; wherein the oxygen-impermeable material includes copper, stainless steel, nickel-based alloys and aluminum;

[0018] If it does not contain oxygen-impermeable materials, proceed directly to step S1;

[0019] If it contains materials that are not oxygen-permeable, proceed to step S01, and then proceed to step S1.

[0020] Step S01: Remove the oxygen-impermeable material from the area to be repaired.

[0021] Furthermore, if the material contains an oxygen-impermeable material, then step S03 is included after step S3;

[0022] S03: Restore the oxygen-impermeable material to the area to be repaired.

[0023] The reaction vessel is made of stainless steel or quartz.

[0024] The beneficial effects of this invention are as follows:

[0025] (1) The repair method of the present invention does not require cutting, that is, it basically does not require damage to the original strip. Only appropriate heat treatment of the defective area is needed to repair the defective area. The repair result is as follows: Figure 2 As shown, the superconducting transition temperature of the defect fully recovers to 93K.

[0026] (2) The repair method of the present invention can improve the microstructure of high temperature superconducting tape through a simple process, increase the critical current of the bad point, and restore its current carrying capacity to 95%-110% of the normal value.

[0027] (3) The repair method of the present invention uses simple equipment and has extremely low repair cost, thereby greatly improving the yield of strip and reducing the preparation cost. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the area to be repaired according to the present invention.

[0029] Figure 2 The image shows the MT changes of the high-temperature superconducting tape in Example 3 after repair. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0031] A method for repairing high-temperature superconducting tapes includes the following steps:

[0032] S1: Place the area to be repaired of the high-temperature superconducting tape in the reaction vessel; it should be noted that only the area to be repaired is placed in the reaction vessel, while other areas are located outside the reaction vessel; the reaction vessel can be sealed or not, as long as the oxygen partial pressure is maintained;

[0033] S2: Maintain a certain oxygen partial pressure in the reaction vessel and perform annealing treatment on the area to be repaired;

[0034] S3: After the annealing process is completed, wait for the reaction vessel to cool down and then take out the high-temperature superconducting tape.

[0035] The area to be repaired includes the defective area in the high-temperature superconducting tape and a certain length of area on both sides of the defective area along the length of the tape. In other words, the area to be repaired is not only the defective area, but also includes a certain area on both sides of the defective area (the defect-free area), but the length of the defect-free area should be appropriate.

[0036] See Figure 1 If the length of the defective area along the strip length is d, then the length of the area to be repaired (along the strip length) = ;in It is the length of the defect-free area on one side (along the strip length direction) of the defect area. The length of the defect-free area on the other side of the defect area (along the strip length direction); and The lengths can be the same or different.

[0037] Preferably, the specified length is 5% to 15% of the length of the defective area. This setting takes into account the workload of subsequent processing, so 5% to 15% is more appropriate.

[0038] It should be noted that the repair method of the present invention does not cut off the defective area of ​​the high-temperature strip.

[0039] The high-temperature superconducting tape is a REBCO coated conductor, where RE represents rare earth elements, B represents Ba, C represents Cu, and O represents oxygen.

[0040] Preferably, the oxygen partial pressure is 0.5 bar to 100 bar, the annealing temperature is 200°C to 500°C, and the holding time is 10 to 1000 min.

[0041] Preferably, step S0 is included before step S1;

[0042] S0: The step of analyzing whether the outer layer of the area to be repaired contains an oxygen-impermeable material; wherein the oxygen-impermeable material includes copper, stainless steel, nickel-based alloys and aluminum;

[0043] If the material does not contain oxygen-impermeable materials, proceed directly to step S1.

[0044] If it contains oxygen-impermeable materials, proceed to step S01, then to step S1; the details are as follows:

[0045] Step S01: Remove the oxygen-impermeable material from the area to be repaired; this can be done by corrosion; one method is to use an acidic solution (such as dilute hydrochloric acid) for anodic corrosion; another method is to use hydrogen peroxide and sulfuric acid solution as the corrosive agent for chemical corrosion removal.

[0046] S1: Place the area of ​​the high-temperature superconducting tape to be repaired in the reaction vessel;

[0047] S2: Maintain a certain oxygen partial pressure in the reaction vessel and perform annealing treatment on the area to be repaired;

[0048] S3: After the annealing process is completed, wait for the reaction vessel to cool down and then take out the high-temperature superconducting tape.

[0049] If the material contains an oxygen-impermeable material, then step S03 is included after step S3.

[0050] S03: Restore the oxygen-impermeable material in the area to be repaired. The preferred restoration methods are physical vapor deposition, chemical vapor deposition, electroplating, ion-assisted deposition, and magnetron sputtering. Repair complete.

[0051] Preferably, the reaction vessel is made of stainless steel or quartz.

[0052] Example 1

[0053] A method for repairing high-temperature superconducting tapes includes the following steps:

[0054] S0: Analysis shows that the outer layer of the area to be repaired contains only Ag;

[0055] S1: Place the area to be repaired into the annealing furnace. The annealing furnace used is a stainless steel tube furnace; the length of the defective area d=3mm, and the length of the area to be repaired is 3.3mm.

[0056] S2: Introduce high-purity oxygen into the annealing furnace, seal it and maintain the pressure at 1.5 bar, raise the temperature to the annealing temperature of 350°C, and keep the annealing temperature constant for 120 minutes.

[0057] S3: After annealing is completed and the temperature of the annealing furnace drops below 80°C, the seal of the annealing furnace is removed and the strip is taken out.

[0058] Testing revealed that the current-carrying capacity at the faulty point had recovered to 98% of its normal value.

[0059] Example 2

[0060] A method for repairing high-temperature superconducting tapes includes the following steps:

[0061] S0: Analysis revealed that the protective layer of the superconducting tape to be repaired includes an inner Ag layer and an outer Cu layer;

[0062] S01: The Cu layer in the area to be repaired is removed by chemical etching using hydrogen peroxide and dilute sulfuric acid solution as etchants. The length of the bad spot area is d=4mm, and the length of the area to be repaired is 5.2mm.

[0063] S1: Place the area to be repaired into the annealing furnace;

[0064] S2: High-purity oxygen is introduced into the annealing furnace, sealed and the pressure is maintained at 10 bar. The temperature is raised to the annealing temperature of 350°C and kept constant for 120 minutes.

[0065] S3: After annealing, once the temperature of the annealing furnace drops below 80°C, remove the seal from the area to be repaired and take out the strip.

[0066] S03: A Cu layer is deposited on the repaired defective area using magnetron sputtering, and the repair is complete.

[0067] Testing revealed that the current-carrying capacity at the faulty point had recovered to 99% of its normal value.

[0068] Example 3

[0069] A method for repairing high-temperature superconducting tapes includes the following steps:

[0070] S0: Analysis shows that the protective layer of the superconducting tape to be repaired is only Ag, where the length of the bad spot region is d=4mm and the length of the region to be repaired is 5mm;

[0071] S1: Place the area to be repaired directly into the annealing furnace;

[0072] S2: High-purity oxygen is introduced into the annealing furnace to maintain a flowing oxygen atmosphere and a pressure (oxygen partial pressure) of 1 bar. The temperature is raised to the annealing temperature of 350°C and maintained at the annealing temperature for 300 min.

[0073] S3: After annealing is completed and the temperature of the annealing furnace drops below 80°C, the strip is removed.

[0074] Testing revealed that the current-carrying capacity at the faulty point had recovered to 96% of its normal value.

[0075] Example 4

[0076] This embodiment is basically the same as Embodiment 1, including the following steps:

[0077] A method for repairing high-temperature superconducting tapes includes the following steps:

[0078] S0: Analysis revealed that the protective layer of the superconducting tape to be repaired only contains Ag;

[0079] S1: Place the area to be repaired directly into the annealing furnace, where the length of the defective area d=5mm and the length of the area to be repaired is 6mm; the annealing furnace used is a laser heating furnace.

[0080] S2: Introduce a nitrogen-oxygen mixture in a 1:1 ratio into the annealing furnace, seal it and maintain a pressure of 2 bar, raise the temperature to the annealing temperature of 400℃, and keep the annealing temperature constant for 120 min.

[0081] S3: After annealing, once the temperature of the annealing furnace drops below 80°C, unseal the annealing furnace and remove the strip.

[0082] Testing revealed that the current-carrying capacity at the faulty point had recovered to 105% of its normal value.

[0083] Example 5

[0084] This embodiment is basically the same as Embodiment 1, including the following steps:

[0085] A method for repairing high-temperature superconducting tapes includes the following steps:

[0086] S0: Analysis revealed that the protective layer of the superconducting tape to be repaired only contains Ag;

[0087] S1: Place the area to be repaired directly into the annealing furnace; the annealing furnace used is a quartz glass box furnace.

[0088] S2: Introduce a nitrogen-oxygen mixture in a 1:1 ratio into the annealing furnace, maintain gas flow to keep the oxygen partial pressure at 1 bar, raise the temperature to the annealing temperature of 800℃, and keep the annealing temperature constant for 10 minutes.

[0089] S3: After annealing, once the temperature of the annealing furnace drops below 80°C, remove the strip.

[0090] Testing revealed that the current-carrying capacity at the faulty point had recovered to 96% of its normal value.

[0091] Example 6

[0092] This embodiment is basically the same as Embodiment 1, including the following steps:

[0093] A method for repairing high-temperature superconducting tapes includes the following steps:

[0094] S0: Analysis revealed that the protective layer of the superconducting tape to be repaired includes an inner Ag layer and an outer Cu and stainless steel layer;

[0095] S01: The Cu layer and stainless steel layer of the area to be repaired are removed by anodic corrosion with an acidic solution (such as dilute hydrochloric acid), wherein the length of the bad spot area d=4mm and the length of the area to be repaired is 5.2mm;

[0096] S1: Place the area to be repaired into the annealing furnace; the annealing furnace used is a fixture heating furnace.

[0097] S2: Introduce high-purity oxygen into the annealing furnace, seal it and maintain the pressure at 100 bar, raise the temperature to the annealing temperature of 200℃, and keep the annealing temperature constant for 1500 min.

[0098] S3: After annealing, once the temperature of the annealing furnace drops below 80°C, unseal the annealing furnace and remove the strip.

[0099] S03: A Cu layer and a stainless steel layer are deposited on the repaired defective area using physical vapor deposition, and the repair is complete.

[0100] After testing, the current carrying capacity at the faulty point has been restored to 100% of the normal value.

[0101] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0102] The parts of this invention not described in detail are well-known in the art. The above embodiments are provided merely for the purpose of describing the invention and are not intended to limit the scope of the invention. The scope of the invention is defined by the appended claims. Various equivalent substitutions and modifications made without departing from the spirit and principles of the invention should be covered within the scope of the invention.

Claims

1. A method for repairing high-temperature superconducting tapes, characterized in that, The repair method does not cut off the defective areas of the high-temperature superconducting tape; the repair method includes the following steps: S0: The step of analyzing whether the outer layer of the area to be repaired contains an oxygen-impermeable material; wherein the oxygen-impermeable material includes copper, stainless steel, nickel-based alloys and aluminum; If it does not contain oxygen-impermeable materials, proceed directly to step S1; If it contains materials that are not oxygen-permeable, proceed to step S01, and then proceed to step S1. Step S01: Remove the oxygen-impermeable material from the area to be repaired; S1: Place the area of ​​the high-temperature superconducting tape to be repaired in the reaction vessel; S2: Maintain a certain oxygen partial pressure in the reaction vessel and perform annealing treatment on the area to be repaired; S3: After the annealing process is completed, wait for the reaction vessel to cool down and then take out the high-temperature superconducting tape. The area to be repaired is the defective area in the high-temperature superconducting tape and a certain length of area on both sides of the defective area along the length of the tape.

2. The method for repairing high-temperature superconducting tapes according to claim 1, characterized in that, The specified length is 5% to 15% of the length of the defective area.

3. The method for repairing high-temperature superconducting tapes according to claim 1, characterized in that, The high-temperature superconducting tape is a REBCO coated conductor, where RE represents rare earth elements, B represents Ba, C represents Cu, and O represents oxygen.

4. The method for repairing high-temperature superconducting tapes according to claim 1, characterized in that, The oxygen partial pressure is 0.5 bar to 100 bar, the annealing temperature is 200℃ to 800℃, and the holding time is 10 to 1500 min.

5. The method for repairing high-temperature superconducting tapes according to claim 1, characterized in that, If the material contains an oxygen-impermeable material, then step S03 is included after step S3. S03: Restore the oxygen-impermeable material to the area to be repaired.

6. The method for repairing high-temperature superconducting tapes according to claim 1, characterized in that, The reaction vessel is made of stainless steel or quartz.

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