A high temperature superconducting tape with a non-uniform distribution of critical current density and a method of making the same

Abstract

The application discloses a high-temperature superconducting tape with non-uniform distribution of critical current density and a preparation method thereof, and belongs to the technical field of high-temperature superconducting materials. The critical current density of the high-temperature superconducting tape is non-uniformly distributed in the width direction, and the current distribution can be regulated according to requirements. The high-temperature superconducting tape comprises a high-temperature superconducting layer, and the chemical formula of the high-temperature superconducting layer is Re 1+a Ba 2+b Cu 3+c O 7‑d +x% (mol) BaMO3, wherein Re is selected from Y, Gd, Eu and Sm; M is selected from Hf, Zr and Sn; the preparation method comprises the following steps: depositing the high-temperature superconducting layer on a tape substrate; depositing a silver layer on the deposited tape; and performing heat treatment on the deposited tape in an oxygen environment, and further comprising the step of performing laser heat treatment after slitting and / or copper plating. The critical current density of the high-temperature superconducting tape of the application is non-uniformly distributed in the width direction and controllable, the failure risk of the tape is effectively reduced, and the service performance of the tape is improved.

Description

Technical Field

[0001] This invention belongs to the field of high-temperature superconducting materials technology, specifically relating to a high-temperature superconducting tape with a non-uniform critical current density distribution and its preparation method. Background Technology

[0002] Rare-earth barium copper oxide (REBCO) high-temperature superconducting (HTS) tapes are ideal for strong magnetic field applications due to their high transition temperature (above liquid nitrogen temperature, 77K), high transport current, and high irreversible field. Compared with traditional low-temperature superconducting materials, HTS tapes have significant advantages in the field of magnets and are widely used in nuclear magnetic resonance (NMR), particle accelerators, controlled nuclear fusion devices such as tokamaks, and high-field scientific research magnets, enabling compact and efficient designs. In recent years, with the improvement of the mechanical properties and critical current density of the tapes, the commercial application of HTS magnets in energy, medical, and scientific research fields is accelerating, becoming one of the core directions of strong magnetic field technology development.

[0003] However, in practical applications with strong magnetic fields, HTS tapes still face many challenges. For example, the complex stress conditions of HTS tapes under magnetic field environments are one of the causes of their failure. When HTS tapes carry large currents and are in a high magnetic field environment, the interaction between the current and the magnetic field generates a huge Lorentz force (F=J × B), which is perpendicular to the plane formed by the current and the magnetic field. This periodic or continuous mechanical stress may cause microcracks, delamination, or even plastic deformation in the superconducting layer or substrate, thereby reducing the critical current (Ic). Especially in high-field magnets such as nuclear fusion devices or high-energy physics experimental magnets, alternating or pulsed magnetic fields can further exacerbate the effects of dynamic Lorentz forces, leading to fatigue failure.

[0004] In strong magnetic fields, the shielding current (or induced current) in HTS tapes induces significant electromagnetic stress, becoming another key factor in material failure. When the external magnetic field changes, a shielding current is generated inside the superconductor to maintain magnetic flux repulsion (Meissner effect). These currents interact with the magnetic field to produce localized Lorentz forces, leading to stress accumulation within the material. For anisotropic superconducting tapes such as REBCO, this stress distribution is uneven, especially at edges or defects, where stress concentration is likely to occur, potentially causing superconducting layer delamination, baseband deformation, or microcrack propagation.

[0005] In alternating magnetic fields or pulsed magnets, repeated magnetic flux penetration and withdrawal induce dynamic shielding currents, generating cyclic mechanical stress and accelerating material fatigue. Studies have shown that shielding current stress is closely related to the magnetic field change rate (dB / dt) and the critical current density (Jc) of the HTS tape, with its influence even exceeding that of the static Lorentz force. Therefore, optimizing the microstructure of the HTS tape (such as introducing nano-pinning centers to enhance magnetic flux pinning capability), improving the interfacial bonding strength of multilayer composite materials, and employing low AC loss magnet designs are effective ways to alleviate shielding current stress.

[0006] Recent studies have shown that in uninsulated coil magnets, problems in the fabrication process of HTS tape may lead to an uncontrolled non-uniform distribution of critical current density in the width direction. In this case, the shielding current stress on the HTS tape may be reduced, thereby reducing the risk of tape failure. This provides a new approach to improving the service performance of the tape, namely, how to create HTS tape with a non-uniform distribution of critical current density in the width direction. Summary of the Invention

[0007] To overcome the above-mentioned shortcomings of the prior art, the main objective of this invention is to provide a high-temperature superconducting tape with a non-uniform distribution of critical current density, wherein the critical current density is not uniformly distributed in the width direction, which effectively reduces the shielding current stress on the high-temperature superconducting tape and thus reduces the risk of tape failure.

[0008] Another objective of this invention is to provide a method for preparing a high-temperature superconducting tape with a non-uniform distribution of critical current density. It is the first to propose a method for actively controlling the distribution of critical current density in the width direction of the high-temperature superconducting tape. Combined with the specific distribution requirements of magnet applications, this method prepares a high-temperature superconducting tape with a controllable distribution of critical current density in the width direction, thereby improving the service performance of the tape.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] In a first aspect, the present invention provides a high-temperature superconducting tape with a non-uniform distribution of critical current density, wherein the critical current density is non-uniformly distributed in the width direction and the current distribution can be adjusted according to requirements.

[0011] It includes a high-temperature superconducting layer, the chemical formula of which is Re. 1+a Ba 2+b Cu 3+c O 7-d +x% (mol) BaMO3, where:

[0012] Re is selected from one or more elements from Y, Gd, Eu, and Sm;

[0013] M is selected from one or more elements of Hf, Zr, and Sn;

[0014] The value range of 'a' is -0.5 to 0.5;

[0015] The value of b ranges from -0.3 to 0.3;

[0016] The value range of c is -0.5 to 0.5;

[0017] The value of d ranges from 0 to 1;

[0018] The value of x ranges from 0 to 15.

[0019] Preferably, the critical current density of the high-temperature superconducting tape is adjustable within the range of 10% to 90% of the maximum value in the width direction.

[0020] Preferably, the thickness of the high-temperature superconducting layer is 0.5~4 µm.

[0021] Preferably, the thickness fluctuation of the high-temperature superconducting layer is less than 5%.

[0022] Preferably, the width of the high-temperature superconducting tape is 2~10 mm.

[0023] A second aspect of the present invention provides a method for preparing the high-temperature superconducting tape, comprising the following steps:

[0024] (1) A high-temperature superconducting layer is deposited on a strip substrate using pulsed laser deposition or metal-organic chemical vapor deposition.

[0025] (2) A metallic silver layer is deposited on the strip after the high-temperature superconducting layer is deposited in step (1) by evaporation or sputtering deposition process;

[0026] (3) In an oxygen environment, the strip after the deposition of the metallic silver layer in step (2) is subjected to heat treatment at a temperature of 200~600 ℃ and a time of 0.5~50 hours.

[0027] (4) The high-temperature superconducting tape obtained in step (3) is slit along the width direction and / or plated with copper;

[0028] (5) The critical current density distribution of the high-temperature superconducting tape after step (4) is controlled by laser heat treatment. The critical current density at the corresponding position is adjusted to obtain a non-uniformly distributed critical current density in the width direction.

[0029] Preferably, in step (4), the slitting method is mechanical cutting or laser cutting, and the width of the slitting high-temperature superconducting tape is 2~10 mm.

[0030] Preferably, in step (4), the copper plating method is selected from one or more of vacuum physical copper plating, vacuum chemical copper plating, and electroplating.

[0031] Preferably, in step (5), the critical current density of the high-temperature superconducting layer decreases in the width direction due to the increase in temperature and the decrease in oxygen content.

[0032] Preferably, in step (5), the critical current density at the corresponding position is adjusted by adjusting the processing power and / or processing time of the laser at different width positions, thereby obtaining a critical current density that is non-uniformly distributed in the width direction.

[0033] Preferably, in step (5), the laser beam is a flat-top beam with a spot diameter of not less than 1 mm.

[0034] Preferably, in step (5), the wavelength of the laser applied to the high-temperature superconducting tape is greater than 178 nm.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows: It is the first to propose a method for actively controlling the critical current density distribution of high-temperature superconducting tape in the width direction. Combined with the application requirements of magnets, a high-temperature superconducting tape is prepared in which the critical current density in the width direction is non-uniformly distributed and controllable. This can effectively reduce the shielding current stress on the high-temperature superconducting tape, thereby reducing the risk of tape failure and improving the service performance of the tape. Attached Figure Description

[0036] Figure 1 The results are the performance test results of the high-temperature superconducting tape in Example 1.

[0037] Figure 2 The results are the performance test results of the high-temperature superconducting tape in Example 2.

[0038] Figure 3 The results are the performance test results of the high-temperature superconducting tape in Example 3. Detailed Implementation

[0039] To more fully understand and demonstrate the technical solutions, objectives, and advantages of the present invention, the technical effects produced by the present invention will be further described in detail and completely below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. It should be noted that other embodiments obtained by those skilled in the art without departing from the concept of the present invention are all within the protection scope of the present invention.

[0040] The following embodiments propose a high-temperature superconducting tape with a non-uniform critical current density distribution. The critical current density is non-uniformly distributed in the width direction and its current distribution can be adjusted according to requirements.

[0041] It includes a high-temperature superconducting layer with the chemical formula Re. 1+a Ba 2+b Cu 3+c O 7-d +x% (mol) BaMO3, where:

[0042] Re is selected from one or more elements from Y, Gd, Eu, and Sm;

[0043] M is selected from one or more elements of Hf, Zr, and Sn;

[0044] The value range of 'a' is -0.5 to 0.5;

[0045] The value of b ranges from -0.3 to 0.3;

[0046] The value range of c is -0.5 to 0.5;

[0047] The value of d ranges from 0 to 1;

[0048] The value of x ranges from 0 to 15.

[0049] In some embodiments, the critical current density of the high-temperature superconducting tape is adjustable within a range of 10% to 90% of the maximum value in the width direction.

[0050] In some embodiments, the thickness of the high-temperature superconducting layer is 0.5 to 4 µm.

[0051] In some embodiments, the thickness variation of the high-temperature superconducting layer is less than 5%.

[0052] In some embodiments, the width of the high-temperature superconducting tape is 2 to 10 mm.

[0053] The following embodiments present a method for preparing the above-mentioned high-temperature superconducting tape, including the following steps:

[0054] (1) A high-temperature superconducting layer is deposited on a strip substrate using pulsed laser deposition or metal-organic chemical vapor deposition.

[0055] (2) A metallic silver layer is deposited on the strip after the high-temperature superconducting layer is deposited in step (1) by evaporation or sputtering deposition process;

[0056] (3) In an oxygen environment, the strip after the deposition of the metallic silver layer in step (2) is subjected to heat treatment at a temperature of 200~600 ℃ and a time of 0.5~50 hours.

[0057] (4) The step of slitting and / or copper plating the high-temperature superconducting tape obtained in step (3) along the width direction; wherein, the width of the slitting high-temperature superconducting tape is 2~10 mm, and the slitting method is mechanical cutting or laser cutting; the copper plating method is selected from one or more of vacuum physical copper plating, vacuum chemical copper plating, and electroplating copper.

[0058] (5) Use laser heat treatment to control the critical current density distribution of slit high-temperature superconducting tape or copper-plated high-temperature superconducting tape.

[0059] In some embodiments, by adjusting the processing power and / or processing time of the laser at different width positions, where the critical current density at the corresponding position decreases due to the increase in temperature and the decrease in oxygen content of the high-temperature superconducting layer, a non-uniformly distributed critical current density in the width direction is obtained.

[0060] In some embodiments, the laser beam is a flat-top beam with a spot diameter of no more than 1 mm.

[0061] In some embodiments, the wavelength of the laser applied to the high-temperature superconducting tape is greater than 178 nm.

[0062] Example 1

[0063] This embodiment proposes a high-temperature superconducting tape with a non-uniform critical current density distribution. The tape has a width of 10 mm, and the minimum critical current density along its width is 71% of the maximum. It includes a high-temperature superconducting layer with the chemical formula Y. 1.5 Ba 2.3 Cu 3.5 The O7+0%BaHfO3 has a thickness of 0.5 μm and a thickness fluctuation of 1%.

[0064] The preparation method of the above-mentioned high-temperature superconducting tape includes the following steps:

[0065] (1) A high-temperature superconducting layer is deposited on a strip substrate using pulsed laser deposition process;

[0066] (2) A metallic silver layer is deposited on the strip after the high-temperature superconducting layer is deposited in step (1) using an evaporation deposition process;

[0067] (3) In an oxygen environment, the strip after the deposition of the metallic silver layer in step (2) is subjected to heat treatment at a temperature of 600 ℃ for 50 hours.

[0068] (4) The high-temperature superconducting tape obtained in step (3) is cut and copper plated along the width direction; wherein, the width of the cut high-temperature superconducting tape is 6 mm, the cutting method is mechanical cutting, and the copper plating method is vacuum physical copper plating.

[0069] (5) The critical current density distribution of the high-temperature superconducting tape after step (3) is controlled by laser heat treatment. The specific parameters are: the laser beam is a flat-top light, the laser processing position is 0~2 mm; the laser spot diameter is 1 mm, the laser wavelength is 632.8 nm, and the critical current density decrease ratio of the processing position is adjusted to obtain a non-uniformly distributed critical current density in the width direction.

[0070] The performance testing of the high-temperature superconducting tape prepared in this embodiment is as follows: Figure 1 As shown, the critical current density at the 0-2 mm position decreases by 25%, while there is no significant change at other positions.

[0071] Example 2

[0072] This embodiment proposes a high-temperature superconducting tape with a non-uniform critical current density distribution. The tape has a width of 10 mm, and the lowest critical current density along its width is 39% of the highest. It includes a high-temperature superconducting layer with the chemical formula Y. 1.0 Ba 2.0 Cu 3.0 O 6.5 +8% BaZrO3, with a thickness of 2.4 μm and a thickness fluctuation of 3%.

[0073] The preparation method of the above-mentioned high-temperature superconducting tape includes the following steps:

[0074] (1) A high-temperature superconducting layer is deposited on a strip substrate using a metal-organic chemical vapor deposition process;

[0075] (2) A sputtering process is used to deposit a metallic silver layer on the strip after the high-temperature superconducting layer is deposited in step (1);

[0076] (3) In an oxygen environment, the strip after the deposition of the metallic silver layer in step (2) is subjected to heat treatment at a temperature of 400 °C for 25 hours.

[0077] (4) Vacuum physical copper plating is performed on the high-temperature superconducting tape obtained in step (3) along the width direction;

[0078] (5) The critical current density distribution of copper-plated high-temperature superconducting tape was controlled by laser heat treatment. The specific parameters were: laser processing position: 0~2 mm, 8~10 mm; laser spot diameter: 0.7 mm; laser wavelength: 441.6 nm. The critical current density decrease ratio of the processing position was adjusted to obtain a non-uniformly distributed critical current density in the width direction.

[0079] The performance testing of the high-temperature superconducting tape prepared in this embodiment is as follows: Figure 2As shown, the critical current density at the 0-2 mm position decreases by 50%, the critical current density at the 8-10 mm position decreases by 60%, and there is no significant change at other positions.

[0080] Example 3

[0081] This embodiment proposes a high-temperature superconducting tape with a non-uniform critical current density distribution. The tape has a width of 10 mm, and the minimum critical current density along its width is 11% of the maximum. It includes a high-temperature superconducting layer with the chemical formula Y. 0.5 Ba 1.7 Cu 2.5 O6+15%BaSnO3, with a thickness of 4 μm and a thickness fluctuation of 5%.

[0082] The preparation method of the above-mentioned high-temperature superconducting tape includes the following steps:

[0083] (1) A high-temperature superconducting layer is deposited on a strip substrate using pulsed laser deposition process;

[0084] (2) A metallic silver layer is deposited on the strip after the high-temperature superconducting layer is deposited in step (1) using an evaporation deposition process;

[0085] (3) In an oxygen environment, the strip after the deposition of the metallic silver layer in step (2) is subjected to heat treatment at a temperature of 200 °C for 10 hours.

[0086] (4) Electroplating copper along the width direction of the high-temperature superconducting tape obtained in step (3);

[0087] (5) The critical current density distribution of copper-plated high-temperature superconducting tape was controlled by laser heat treatment. The specific parameters were: laser processing position: 0~1 mm, 5~7 mm, 9~10 mm; laser spot diameter: 0.5 mm; laser wavelength: 325 nm. The critical current density decrease ratio of the processing position was adjusted to obtain a non-uniformly distributed critical current density in the width direction.

[0088] The performance testing of the high-temperature superconducting tape prepared in this embodiment is as follows: Figure 3 As shown, the critical current density at the 0-1 mm position decreases by 50%, at the 5-7 mm position by 88%, and at the 9-10 mm position by 12%, while there is no significant change at other positions.

[0089] The above are merely preferred embodiments of the present invention and are not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-temperature superconducting tape with a non-uniform critical current density distribution, characterized in that, Its critical current density is non-uniformly distributed in the width direction and its current distribution can be adjusted according to demand. The high-temperature superconducting tape includes a high-temperature superconducting layer; The chemical formula of the high-temperature superconducting layer is Re. 1+a Ba 2+b Cu 3+c O 7-d +x% (mol) BaMO3, where: Re is selected from one or more elements from Y, Gd, Eu, and Sm; M is selected from one or more elements of Hf, Zr, and Sn; The value range of 'a' is -0.5 to 0.5; The value of b ranges from -0.3 to 0.3; The value range of c is -0.5 to 0.5; The value of d ranges from 0 to 1; The value of x ranges from 0 to 15; The preparation method of the high-temperature superconducting tape includes the following steps: (1) A high-temperature superconducting layer is deposited on a strip substrate using pulsed laser deposition or metal-organic chemical vapor deposition. (2) A metallic silver layer is deposited on the strip after the high-temperature superconducting layer is deposited in step (1) by evaporation or sputtering deposition process; (3) In an oxygen environment, the strip after the deposition of the metallic silver layer in step (2) is heat-treated at a temperature of 200~600 ℃ for 0.5~50 hours to obtain the product. (4) The high-temperature superconducting tape obtained in step (3) is slit and / or plated with copper along its width; wherein: The slitting method is mechanical cutting, and the width of the slitting high-temperature superconducting tape is 2~10 mm. The copper plating method is selected from vacuum physical copper plating or electroplating copper. (5) The critical current density distribution of the slit high-temperature superconducting strip or the copper-plated high-temperature superconducting strip is controlled by laser heat treatment; wherein, the critical current density of the high-temperature superconducting layer decreases in the width direction due to the increase in temperature and the decrease in oxygen content; by adjusting the processing power and / or processing time of the laser at different width positions, the critical current density at the corresponding position is adjusted to obtain a non-uniformly distributed critical current density in the width direction.

2. The high-temperature superconducting tape with non-uniform critical current density distribution according to claim 1, characterized in that, The critical current density of the high-temperature superconducting tape is adjustable within the range of 10% to 90% of the maximum value in the width direction.

3. The high-temperature superconducting tape with non-uniform critical current density distribution according to claim 1, characterized in that, The thickness of the high-temperature superconducting layer is 0.5~4 µm.

4. The high-temperature superconducting tape with non-uniform critical current density distribution according to claim 1, characterized in that, The thickness fluctuation of the high-temperature superconducting layer is less than 5%.

5. The high-temperature superconducting tape with non-uniform critical current density distribution according to claim 1, characterized in that, The width of the high-temperature superconducting tape is 2~10 mm.

6. The high-temperature superconducting tape with non-uniform critical current density distribution according to claim 1, characterized in that, The laser beam is a flat-top beam with a spot diameter of less than 1 mm; And / or the wavelength of the laser applied to the high-temperature superconducting tape is greater than 178 nm.

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