A method of improving the performance of copper-based superconducting tapes by ion irradiation

Abstract

The application provides an ion irradiation method for improving the performance of copper-based superconducting tapes, and belongs to the technical field of ion irradiation.The ion irradiation method comprises the following steps: under vacuum conditions, ion irradiation is performed on a copper-based superconducting tape by using an ion beam; the ion beam comprises a light ion beam or a heavy ion beam.The application realizes effective modification of the copper-based superconducting tape by precisely controlling the energy, dose and flow intensity of the ion beam, significantly improves the current-carrying performance of the 2G- HTS tape under high temperature and high field, and increases the critical current density Jc by 2.1-5 times.In addition, the application can modify the copper-based superconducting tape according to specific requirements, thereby improving the consistency and stability of the modification effect.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of ion irradiation technology, and particularly relates to an ion irradiation method for improving the performance of copper-based superconducting tapes. BACKGROUND

[0002] With the rapid development of superconducting technology, the second-generation high-temperature superconducting tapes (2G-HTS) have shown great application potential in the fields of power, transportation, medical treatment and the like due to their unique performance, such as high critical transition temperature (T c ), upper critical field (H c2 ), critical current density (J c ), low AC loss, good thermodynamic and magnetic stability.

[0003] However, in extreme environments, the performance stability and reliability thereof become a bottleneck restricting further development. Although the traditional material modification method (such as introducing secondary phase doping) has a certain effect, it is difficult to meet the current-carrying performance (heavy ion critical current density J c of 2G-HTS tapes under high temperature (> 30K) and high field (> 3T) environments, which is increased by 1.1-1.5 times or 1.1-1.2 times for light ions. SUMMARY

[0004] Therefore, the purpose of the present application is to provide an ion irradiation method for improving the performance of copper-based superconducting tapes. The ion irradiation method provided by the present application can significantly improve the current-carrying performance of 2G-HTS tapes under high temperature and high field.

[0005] In order to achieve the above purpose, the present application provides the following solutions:

[0006] The present application provides an ion irradiation method for improving the performance of copper-based superconducting tapes, comprising the following steps:

[0007] Under vacuum conditions, ion beams are used to irradiate copper-based superconducting tapes; the ion beams comprise light ion beams or heavy ion beams; the flow intensity of the ion irradiation is 1-10 mu A;

[0008] The energy of the light ion beams is 270 keV, and the dose is 0.1*10 16 -1*10 16 ions / cm 2 ;

[0009] The energy of the heavy ion beams is 45-200 MeV, and the dose is 0.01*10 12 -1*10 12 ions / cm 2 .

[0010] Preferably, the light ion beam comprises a proton beam; and the heavy ion beam comprises a Xe ion beam.

[0011] Preferably, the vacuum degree of the vacuum condition is 1×10 -3 Torr.

[0012] Preferably, the irradiation fluence rate of the ion irradiation is 5×10 9 ions / (cm 2 ·s).

[0013] Preferably, the energy of the heavy ion beam is 45 MeV, 65 MeV, 85 MeV, 100 MeV, 150 MeV or 200 MeV, and the dose is 2×10 10 , 5×10 10 , 2×10 11 , 4×10 11 , 5×10 11 or 1×10 12 ions / cm 2 .

[0014] Preferably, the copper-based superconducting tape is located at the center of the ion irradiation spot; and the size of the ion irradiation spot is 2 cm×2 cm.

[0015] Preferably, when multiple copper-based superconducting tapes are irradiated simultaneously, the distance between adjacent copper-based superconducting tapes is 1 mm; and the width of a single copper-based superconducting tape is 4 mm.

[0016] Preferably, the copper-based superconducting tape comprises a 2G-HTS tape.

[0017] Preferably, the superconducting layer of the 2G-HTS tape is a doped or undoped EuBa2Cu3O7 layer; when the superconducting layer is a doped EuBa2Cu3O7 layer, the secondary phase dopant comprises BaHfO3.

[0018] Preferably, the EuBa2Cu3O7 layer is a single-layer, double-layer or triple-layer structure, the thickness of the single layer is 1 μm, the thickness of the double layer is 2 μm, and the thickness of the triple layer is 3 μm.

[0019] The present application provides an ion irradiation method for improving the performance of a copper-based superconducting tape, comprising the following steps: irradiating a copper-based superconducting tape with an ion beam; the ion beam comprises a light ion beam or a heavy ion beam; the flow intensity of the ion irradiation is 1-10 μA; the energy of the light ion beam is 270 keV, and the dose is 0.1×10 16 -1×10 16 ions / cm 2 ; the energy of the heavy ion beam is 45-200 MeV, and the dose is 0.01×1012 ~1x10 12 ions / cm 2 .

[0020] The present application realizes effective modification of copper-based superconducting tapes by precisely controlling the energy, dose and flow intensity of the ion beam, significantly improving the current-carrying performance of 2G-HTS tapes under high temperature and high field. The results of the embodiments show that the critical current density J c is increased by 2.1-5 times.

[0021] The present application ensures the stability and consistency of the modification effect (J c value) by real-time monitoring of ion beam parameters and tape response and timely adjustment of irradiation parameters.

[0022] The present application can avoid burning out the copper-based superconducting tapes due to high flow intensity by controlling the flow intensity as low as possible (1-10 μA).

[0023] In addition, due to the complex composition and large surface area of 2G-HTS tapes, the loss of irradiation ions in the tapes is large, resulting in uneven distribution of defect density introduced by the ion beam, which affects the current-carrying performance. The present application can avoid the unevenness problem caused by ion irradiation by controlling the spot size to 2 cm x 2 cm, which can cover at least one cut sample (maximum 4 mm x 4 mm) while meeting the uniformity (uniform distribution of ion beam on the surface of the tape), thereby avoiding affecting the current-carrying performance of 2G-HTS tapes. The present application ensures the uniform distribution and efficient irradiation of the ion beam on the surface of the tape by optimizing the fixed position of the tape and the distance between the tapes (tape width 4 mm, in the center of the spot; distance between the tapes 1 mm) and the flow intensity of the ion beam.

[0024] The ion irradiation method provided by the present application is not only suitable for the modification of 2G-HTS tapes, but also can be extended to the modification of other types of superconducting materials and complex structure superconducting tapes, thus having strong adaptability and flexibility.

[0025] The ion irradiation method provided by the present application not only brings technical advantages in material modification, but also provides favorable support for the wide application of high-temperature superconducting tapes, and promotes the further development of superconducting technology. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0027] Figure 1 The tape (double layer + 6% BHO doping, superconducting layer film thickness about 2 μm) before and after Xe ion irradiation of Example 1 c Data at different irradiation energies and doses under external magnetic field H at 77 K;

[0028] Figure 2 The tape (three layers + 10% BHO doping, superconducting layer film thickness about 3 μm) before and after Xe ion irradiation of Example 2 c Data at different irradiation energies and doses under external magnetic field H at 77 K;

[0029] Figure 3 The tape (three layers + 10% BHO doping, film thickness about 3 μm) before and after 270 keV proton [dose 1×10 15 ions / cm 2 ] irradiation of Example 3 c Variation results of external magnetic field H at different temperatures. DETAILED DESCRIPTION

[0030] The application provides an ion irradiation method for improving the performance of copper-based superconducting tape, comprising the following steps:

[0031] Under vacuum condition, ion beam is used to irradiate the copper-based superconducting tape; the ion beam comprises light ion beam or heavy ion beam.

[0032] Unless otherwise specified, the materials and equipment used in the application are commercially available.

[0033] In the application, the vacuum degree of the vacuum condition is preferably 1×10 -3 Torr. In the application, the light ion beam preferably comprises proton beam; and the heavy ion beam preferably comprises Xe ion beam.

[0034] In the application, the copper-based superconducting tape preferably comprises 2G-HTS tape; the 2G-HTS tape preferably comprises Hastelloy, buffer layer, superconducting layer and protective layer which are stacked in sequence; the superconducting layer of the 2G-HTS tape preferably comprises doped or undoped EuBa2Cu3O7 layer, the EuBa2Cu3O7 layer preferably has single layer, double layer or triple layer structure, the single layer preferably has a thickness of 1 μm, the double layer preferably has a thickness of 2 μm, and the triple layer preferably has a thickness of 3 μm; when the superconducting layer is doped EuBa2Cu3O7 layer, the secondary phase dopant preferably comprises BaHfO3.

[0035] In the present application, the superconducting layer preferably comprises a doped BaHfO3 superconducting layer or an undoped BaHfO3 superconducting layer. In the present application, the molar concentration of BaHfO3 in the doped BaHfO3 superconducting layer is preferably > 0% and ≤ 10%, and in the embodiments of the present application, it can be specifically 3.5%, 4.5%, 5%, 6% or 10%.

[0036] In the present application, the protective layer is preferably an Ag layer, and the thickness of the Ag layer is preferably 0.38 μm.

[0037] In the present application, when multiple copper-based superconducting tapes are subjected to ion irradiation at the same time, the distance between adjacent copper-based superconducting tapes is preferably 1 mm, and the width of a single copper-based superconducting tape is preferably 4 mm.

[0038] In the present application, the ion irradiation has a current intensity of 1-10 μA, and in the embodiments of the present application, it can be specifically 1 μA, 4 μA, 6 μA, 8 μA or 10 μA. The present application can avoid burning out the copper-based superconducting tape due to high current intensity by controlling the current intensity as low as possible (1-10 μA).

[0039] In the present application, the spot size of the ion irradiation is preferably 2 cm x 2 cm. The temperature of the ion irradiation is preferably room temperature. In the present application, the copper-based superconducting tape is preferably at the center of the spot of the ion irradiation; the distance between the copper-based superconducting tapes is 1 mm.

[0040] By controlling the spot size to be 2 cm x 2 cm, the present application can cover at least one cut sample (maximum 4 mm x 4 mm) with the spot while meeting the uniformity (uniform distribution of the ion beam on the surface of the tape), and can avoid the non-uniformity problem caused by ion irradiation, thereby avoiding affecting the current-carrying performance of the 2G-HTS tape. By optimizing the fixing position of the tape and the distance between the tapes (the width of the tape is 4 mm, at the center of the spot; the distance between the tapes is 1 mm) and the current intensity of the ion beam, the present application ensures the uniform distribution of the ion beam on the surface of the tape and efficient irradiation.

[0041] In the present application, the dose of the light ion beam is 0.1 x 10 16 - 1 x 10 16 ions / cm 2 , and in the embodiments of the present application, it can be specifically 1 x 10 16 ions / cm 2 or 1 x 10 15 ions / cm 2 .

[0042] In the present application, the energy of the heavy ion beam is 45-200 MeV, and in the embodiments of the present application, it can be specifically 45 MeV, 65 MeV, 85 MeV, 100 MeV, 150 MeV or 200 MeV.

[0043] In the present application, the dose of the heavy ion beam is 0.01x10 12 ions / cm 12 . 2 In the embodiments of the present application, it can be specifically 2x10 10 , 5x10 10 , 2x10 11 , 4x10 11 , 5x10 11 or 1x10 12 ions / cm 2 .

[0044] In the present application, the irradiation fluence rate of the ion irradiation is preferably 5x10 9 ions / (cm 2 ·s). The time of the ion irradiation in the present application can be calculated according to the dose of the ion irradiation divided by the irradiation fluence rate.

[0045] The present application realizes effective modification of the copper-based superconducting tape by precisely controlling the energy, dose and flow intensity of the ion beam, significantly improves the current-carrying performance of the 2G-HTS tape under high temperature and high field, i.e. the critical current density J c is increased by 2.1-5 times.

[0046] The present application realizes real-time monitoring of the ion beam parameters and the tape response, timely adjustment of the irradiation parameters, and ensures the stability and consistency of the modification effect (J c numerical value). For example, if the tape is found to be bright during irradiation, it means that the irradiation overheats the tape and may damage the tape, at which time the irradiation energy needs to be reduced or the irradiation needs to be stopped.

[0047] In order to further illustrate the present application, a method for improving the performance of a copper-based superconducting tape by ion irradiation provided by the present application is described in detail below in combination with the drawings and examples, but they should not be understood as limiting the scope of protection of the present application.

[0048] Example 1

[0049] The method for ion irradiation of the copper-based superconducting tape by the heavy ion beam Xe ions is as follows:

[0050] 1. Preparation stage: select 2G-HTS tapes meeting the experimental requirements, and pre-appoint ion irradiation equipment in good condition.

[0051] Material and equipment preparation: First, select the 2G-HTS tape to be irradiated: double-layer + 6% BaHfO3 (abbreviated as BHO) doped, superconducting layer film thickness about 2 μm, ensure that its superconducting performance meets the experimental requirements. At the same time, make an appointment for the corresponding ion irradiation equipment, and make sure the equipment is running, so that it can run stably during the experiment. Among them, proton and Xe ion irradiation requires a tandem accelerator with different energies, and the specific irradiation energy is determined by the demand.

[0052] Xe ion irradiation uses the medium-energy irradiation terminal (No. 128) equipment in the Heavy Ion Accelerator Device of the Institute of Modern Physics [can provide the required irradiation energy 50 MeV ~ 200 MeV].

[0053] Environmental preparation: Ensure that the experimental environment meets the temperature, vacuum degree and other requirements, and take appropriate isolation measures to avoid external interference.

[0054] Specifically, the experimental environment temperature is room temperature; the sample cavity is maintained by a mechanical pump, and is pumped to 10 -3 Torr;

[0055] Isolation measures are to wear protective clothing, and to avoid entering the separate room containing the irradiation equipment as much as possible during irradiation operation.

[0056] The environment has a non-negligible impact on the experiment. If the vacuum degree cannot be reduced, the ion beam will be difficult to uniformly irradiate the sample surface, and the energy of the ion beam (irradiation energy) will be greatly lost. In addition, heavy ion Xe ion irradiation may also irradiate other particles (such as gamma rays), which may affect the human body, so isolation measures are necessary.

[0057] Safety preparation: Wear protective equipment and check the safety performance of the equipment to ensure the safe operation of the experiment.

[0058] 2, Parameter setting: Parameter setting is one of the key steps of ion irradiation modification experiment.

[0059] Ion beam type and energy selection: Select the appropriate ion beam type (Xe ion) and its energy according to the requirements of the tape, specifically, the energy is 100 MeV, 150 MeV or 200 MeV.

[0060] Flow intensity and irradiation fluence setting: Considering the ion beam energy, type and tape characteristics, set a reasonable flow intensity and irradiation fluence. By adjusting the flow intensity and irradiation fluence, the uniformity and consistency of the ion beam on the tape surface can be controlled, and the specific flow intensity is 10 μA, and the irradiation fluence (dose) rate is 5 × 10 9 ions / (cm 2 ·s)

[0061] Temperature setting: room temperature (kept constant by water cooling);

[0062] Spot size setting: 2 cm x 2 cm.

[0063] 3. Irradiation treatment: Irradiation treatment is the core step of irradiation modification experiment.

[0064] Tape placement: The prepared 2G-HTS tapes are placed in the irradiation chamber of the ion irradiation equipment, ensuring that the relative position between the tapes and the ion beam is fixed (the width of the tape is 4 mm, in the center of the spot; the distance between the tapes is 1 mm). At the same time, check the fixation of the tapes to avoid movement or deformation during irradiation.

[0065] Ion beam start: Start the ion source according to the preset parameters.

[0066] Irradiation process monitoring: During the irradiation process, the parameters of the ion beam and the response of the tapes need to be monitored in real time.

[0067] Post-irradiation inspection: After the irradiation treatment is completed, the integrity and surface condition of the tapes need to be checked.

[0068] Performance test comparison before and after irradiation: Compare the performance data before and after irradiation to evaluate the modification effect.

[0069] Example 2

[0070] The method for irradiating copper-based superconducting tapes with heavy ion beam Xe ions is as follows:

[0071] The steps are the same as those of Example 1, except that the instrument is the medium-energy irradiation terminal (name: leaf terminal) device in the near object heavy ion accelerator device [can provide the required irradiation energy 45 MeV-90 MeV].

[0072] 2G-HTS tapes: The superconducting layer is three layers (superconducting layer film thickness about 3 μm) + 10% BHO doping.

[0073] The parameter settings are as follows: 45 MeV-85 MeV Xe ions, dose 2 x 10 10 -4 x 10 11 ions / cm 2 ; spot size 2 cm x 2 cm; temperature setting during ion irradiation: room temperature (kept constant by water cooling).

[0074] Example 3

[0075] The method for irradiating copper-based superconducting tapes with single light ion beam protons is as follows:

[0076] The steps are the same as in Example 1, except that the proton irradiation utilizes a 320keV low-energy ion device in the heavy ion accelerator facility of the Institute of Modern Physics, Chinese Academy of Sciences (IMPH).

[0077] 2G-HTS tape: The superconducting layer is EuBa2Cu3O7, which is a three-layer superconducting layer with 10% BHO doping, and the superconducting layer film thickness is about 3μm.

[0078] The parameter settings are as follows: 270keV protons, dose 1×10⁻⁶. 15 ions / cm 2 The flux intensity was 10 μA; the spot size was 2 cm × 2 cm; the temperature during ion irradiation was set to room temperature (maintained at a constant temperature by water cooling).

[0079] Performance testing

[0080] The performance of the 2G-HTS tapes from Examples 1-3 after ion irradiation was tested using a PPMS instrument.

[0081] Figure 1 Example 1: Xe ion irradiation before and after tape (double layer + 6% BHO doping) J c Data on external magnetic field H at 77K (liquid nitrogen temperature) and different irradiation energies. Pristine represents unirradiated areas.

[0082] from Figure 1 As can be seen from this, Xe ion irradiation [dose including 5 × 10⁻⁶ BHO doped tape] on a double-layer +6% BHO doped tape 10 and 2×10 11 ions / cm 2 [Two doses], under low field [here referring to an external magnetic field H < 2T], such as 150MeV irradiation at H = 0T, can reduce the J of an unirradiated sample (pristine). c Increased by 4.7 times, while J under high field conditions c The increase is even more significant. This is a very high value among other heavy ion irradiation effects.

[0083] Figure 2 Example 2: Xe ion irradiation before and after tape (three layers + 10% BHO doping) J c Data from external fields at 77K and different irradiation energies, including J c The change factors at H=5T are shown in Table 1.

[0084] Table 1J c Change factor at H=5T

[0085] Energy-Dose After irradiation J c Lift at H = 5T 65 MeV - 2e10 2.1 65 MeV - 5e10 2.6 65 MeV - 2el 1 3.2 65 MeV - 4el 1 3.9 85 MeV - 5e10 1.9 85 MeV - 2el 1 2.1

[0086] From Table 1, it can be seen that for the change of J c before and after irradiation, the 65 MeV irradiation energy [dose of 4 x 10 11 ions / cm 2 ] provides a relatively optimal reference value. The corresponding J c is increased by nearly four times at an external field H = 5 T, and is still significantly greater than the average value of the irradiation effect of other heavy ions.

[0087] In summary, Xe ion irradiation effectively improves the current carrying performance of the tape, especially at high temperature and high field, which is of great significance to practical engineering applications.

[0088] Figure 3 For Example 3, 270 keV protons [dose of 1 x 10 15 ions / cm 2 ] were irradiated before and after the irradiation of the tape (three layers + 10% BHO doping) J c changes with the external magnetic field H at different temperatures. Among them, pristine represents no irradiation; irradiation represents irradiation.

[0089] As can be seen from Table 2, the irradiation effect of protons at low temperature is more significant than that at high temperature, for example, J c is increased by about 1.2 times before and after irradiation at 4.2 K self-field (H = 0), and the difference between before and after irradiation gradually disappears as the temperature rises. This is because the point defects or clusters produced by collision cascade introduced by proton irradiation have a size close to the coherence length of the superconductor at low temperature, which can effectively pin the magnetic flux, so that J c is slightly improved. As the temperature rises, the coherence length becomes larger, and the pinning ability of the point defects becomes weaker, so the proton irradiation has little effect on J c .

[0090] In contrast, Xe ion irradiation introduces columnar defects, which can effectively pin the magnetic flux lines along the columnar defect direction. In addition, entanglement occurs between adjacent magnetic flux lines, which makes the improvement of J c more significant than that of proton irradiation. In the present application, Xe ions improve J c of all samples with different film thicknesses and doping to varying degrees, while proton irradiation only has a certain effect on J of some samples at low temperature, which is closely related to the intrinsic pinning mode.

[0091] Although the above examples make a detailed description of the present application, it is only a part of the examples of the present application, not all examples, and other examples can be obtained according to the present examples without creativity, which are within the protection scope of the present application.

Claims

1. A method of improving the performance of a copper-based superconducting tape by ion irradiation, characterized by, The method comprises the following steps: The copper-based superconducting tape is irradiated by ion beam under vacuum condition; the ion beam comprises light ion beam or heavy ion beam; the light ion beam is proton beam; the heavy ion beam is Xe ion beam; the flow intensity of the ion irradiation is 1-10 μA; The light ion beam has an energy of 270 keV and a dose of 0.1 x 10 16 ~ 1 x 10 16 ions / cm 2 ; The heavy ion beam has an energy of 100-200 MeV and a dose of 2x10 10 -5x10 10 ions / cm 2 . The copper-based superconducting tape is located at the center of the light spot of the ion irradiation.

2. The ion irradiation method according to claim 1, wherein The vacuum degree of the vacuum condition is 1 x 10 - 3 Torr.

3. The ion irradiation method according to claim 1, wherein The ion irradiation has a fluence rate of 5 x 10 9 ions / (cm 2 ·s).

4. The ion irradiation method according to claim 1, wherein The energy of the heavy ion beam is 100 MeV, 150 MeV or 200 MeV, and the dose is 2 x 10 10 or 5 x 10 10 ions / cm 2 .

5. The ion irradiation method according to claim 1, wherein The size of the light spot of the ion irradiation is 2 cm×2 cm.

6. The ion irradiation method according to claim 1, wherein When multiple copper-based superconducting tapes are irradiated by ion beam simultaneously, the distance between the adjacent copper-based superconducting tapes is 1 mm; the width of a single copper-based superconducting tape is 4 mm.

7. The ion irradiation method according to claim 1, wherein The copper-based superconducting tape comprises 2G-HTS tape.

8. The ion irradiation method according to claim 7, wherein The superconducting layer of the 2G-HTS tape is doped or undoped EuBa2Cu3O7 layer; when the superconducting layer is doped EuBa2Cu3O7 layer, the secondary phase dopant comprises BaHfO3.

9. The ion irradiation method according to claim 8, wherein, The EuBa2Cu3O7 layer is single-layer, double-layer or triple-layer structure; the thickness of the single-layer is 1 μm, the thickness of the double-layer is 2 μm, and the thickness of the triple-layer is 3 μm.

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