A width direction misalignment single-sided packaged high temperature superconducting tape and a preparation method and application thereof

Abstract

The application discloses a width direction misalignment single-sided packaging high-temperature superconducting tape and a preparation method and application thereof, and belongs to the technical field of high-temperature superconducting materials. The high-temperature superconducting tape comprises, from bottom to top, a packaging reinforcing tape, a low-temperature solder layer, a REBCO superconducting tape and an edge low-temperature solder filling area in sequence. The REBCO superconducting tape is recessed relative to the two side edges of the packaging reinforcing tape to form a width direction misalignment, and the superconducting layer faces the low-temperature solder layer. The edge low-temperature solder filling area is formed by molten solder in a hot-press reflow process below 180 DEG C climbing along the thickness direction and completely wrapping the side edge of the REBCO superconducting tape. The REBCO superconducting tape is misaligned relative to the reinforcing tape in the width direction, and the low-temperature solder is used to form a C-shaped metallurgical locking at the edge, so that the delamination resistance is significantly improved, the high-temperature oxygen flow loss is eliminated, the process is simple, the energy consumption is low, and the application is suitable for high-field magnets, compact cables and current limiters and other strong electric applications.

Description

Technical Field

[0001] This invention belongs to the field of high-temperature superconducting materials technology, specifically relating to a width-direction misaligned single-sided encapsulated high-temperature superconducting tape, its preparation method, and its application. Background Technology

[0002] The second-generation high-temperature superconducting tape (REBCO) employs a layered metal-oxide structure, with the interface between the superconducting layer and the oxide buffer layer being the weakest point for delamination stress. Existing double-sided packaging (encapsulation reinforcement tape / superconducting tape / encapsulation reinforcement tape) technology requires simultaneous heating of both reinforcement tapes, often exceeding 220°C. This leads to oxygen loss from the superconducting layer, a 5%-10% decrease in Ic, and an increase in thickness of over 0.15 mm. If traditional single-sided packaging (encapsulation reinforcement tape / superconducting tape) is used, the abrupt change in stiffness causes edge shear stress concentration, resulting in a peel strength <60 N / cm. Therefore, there is an urgent need to develop a single-sided packaging structure that can be implemented below 180°C, balancing high critical current, high peel strength, and thinness. Summary of the Invention

[0003] To overcome the above-mentioned shortcomings of the prior art, the main objective of this invention is to provide a width-direction misaligned single-sided encapsulated high-temperature superconducting tape, which is a REBCO superconducting tape that can achieve width-direction misaligned single-sided encapsulation at temperatures below 180°C, and has both high critical current and excellent anti-delamination performance.

[0004] Another objective of this invention is to provide a method for preparing the width-direction misaligned single-sided encapsulated high-temperature superconducting tape, which uses only one encapsulation reinforcing tape and achieves double-sided reinforcement by combining planar misalignment with low-temperature solder edge locking, with a total temperature of <180℃, thus eliminating high-temperature oxygen loss.

[0005] Another object of the present invention is to provide the application of the width-direction misaligned single-sided encapsulated high-temperature superconducting tape in the fabrication of superconducting magnets, superconducting cables or current limiters.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a width-direction misaligned single-sided encapsulated high-temperature superconducting tape, comprising, from bottom to top:

[0008] The encapsulation reinforcement strip has a first width W1;

[0009] A low-temperature solder layer is located on the packaging reinforcement strip. Its material is selected from Sn-Bi-Ag system or Sn-In-Ni system, with a melting point <180℃.

[0010] REBCO superconducting tape, located on the low-temperature solder layer, has a second width W2 and a thickness T;

[0011] The chemical composition of the REBCO superconducting tape is REBa2Cu3O 7-x , where RE is a rare earth element selected from one or more of Y, Gd, Sm, and Eu, the value range of x is 0-1, T is 50-100 μm, W2 < W1 and W2 = W1 - 2×misalignment Δ, and the value range of the misalignment Δ is 0.1-1 mm; the REBCO superconducting tape is indented by the misalignment Δ on both sides relative to the edges of the encapsulation reinforcement tape to form a width-direction misalignment, and the superconducting layer of the REBCO superconducting tape faces the low-temperature solder layer;

[0012] The edge low-temperature solder filling area is formed by the molten solder climbing along the thickness direction and completely wrapping the side edges of the REBCO superconducting tape during the hot pressing and reflow process below 180°C.

[0013] Preferably, the RE is Y.

[0014] Preferably, the thickness T is 60-80 μm.

[0015] Preferably, the total thickness of the width-direction misalignment single-sided encapsulated high-temperature superconducting tape is 0.12-0.22 mm.

[0016] Preferably, the material of the encapsulation reinforcement tape is Cu or Cu alloy, and the thickness is 50-200 µm.

[0017] More preferably, the material of the encapsulation reinforcement tape is Cu-ETP or Cu-Ni-Si alloy.

[0018] Preferably, the material of the low-temperature solder layer is Sn-57Bi-1Ag or Sn-52In-0.3Ni, the melting point is 138-160°C, and the thickness is 8-25 µm.

[0019] Preferably, the hot pressing and reflow process below 180°C is a hot pressing and reflow process at 140-175°C.

[0020] In the second aspect of the present invention, a method for preparing the width-direction misalignment single-sided encapsulated high-temperature superconducting tape is provided, including the following steps:

[0021] S1: Perform surface low-temperature cleaning on the REBCO superconducting tape;

[0022] S2: Form a low-temperature solder layer on the encapsulation reinforcement tape;

[0023] S3: Bond the REBCO superconducting tape on the low-temperature solder layer in a width-direction misalignment manner, and the superconducting layer of the REBCO superconducting tape faces the low-temperature solder layer;

[0024] S4: Low-temperature hot pressing reflow is performed on the REBCO superconducting tape and the low-temperature solder layer to melt the solder and climb along the thickness direction, completely wrapping the side of the REBCO superconducting tape to form the edge low-temperature solder filling area.

[0025] S5: Cool and trim the edges to obtain the finished product.

[0026] Preferably, in step S2, the outer surface of the encapsulation reinforcing strip is coated with a 5-10µm thick polyimide insulating varnish to achieve interlayer insulation.

[0027] Preferably, in step S2, 0.3-1 wt% nano-ceramic particles are added to the low-temperature solder layer to suppress thermal cycling fatigue.

[0028] Preferably, in step S4, the low-temperature hot-pressing reflux is carried out under nitrogen or formic acid vapor protection, with a pressure of 0.3-1.5 MPa, a peak temperature of 155-180°C, and a time of 20-120 s.

[0029] Preferably, the method for preparing the width-direction misaligned single-sided encapsulated high-temperature superconducting tape includes the following steps:

[0030] (1) Low-temperature plasma cleaning or low-temperature chemical cleaning is performed on the superconducting layer of REBCO superconducting tape to remove organic contaminants. The surface temperature rise during the cleaning process is controlled below 50°C.

[0031] (2) A low-temperature solder alloy is uniformly coated on the upper surface of the packaging reinforcing strip by roller coating, scraping or electroplating to form the low-temperature solder layer, with the thickness fluctuation controlled within ±2μm;

[0032] (3) The REBCO superconducting tape is centered and bonded using a precision positioning roller to ensure the misalignment Δ on both sides and that its superconducting surface faces the solder. A small amount of no-clean flux is sprayed onto the surface of the laminated structure to promote solder wetting and creep during the subsequent low-temperature hot pressing reflow process.

[0033] (4) Low-temperature hot-pressing reflow is performed by hot press rollers or belt tunnel furnace, with a peak temperature of 155-180℃, a pressure of 0.3-1.5MPa, and a holding time of 20-120s; during this process, the solder melts and climbs upward along the side of the REBCO superconducting tape under pressure, with the climbing height covering at least 30% of the thickness of the REBCO superconducting tape (for REBCO superconducting tape with a thickness of 80-100μm, the climbing height is ≥24-30μm), forming the edge low-temperature solder filling area;

[0034] (5) Cool to room temperature, laser cut the edges with a width tolerance of ±0.05mm, test Ic and peel strength online, and rewind qualified products.

[0035] A third aspect of the present invention provides the application of any of the width-direction misaligned single-sided encapsulated high-temperature superconducting tapes in the preparation of superconducting magnets, superconducting cables or current limiters, wherein the tapes are wound by the width-direction misaligned single-sided encapsulated high-temperature superconducting tapes.

[0036] Compared with existing technologies, this invention significantly improves the resistance to delamination by misaligning the REBCO superconducting strip with respect to the reinforcing strip in the width direction and forming a C-shaped metallurgical lock at the edge using low-temperature solder. Simultaneously, it prevents the loss of high-temperature oxygen. Specifically, the beneficial effects are as follows:

[0037] 1. The fabrication process of the width-direction misaligned single-sided encapsulated high-temperature superconducting tape in this invention is carried out at a temperature of <180℃ throughout, preventing oxygen loss. The self-field critical current retention rate at 77K is ≥99% (compared to bare tape), with almost no attenuation.

[0038] 2. The width-direction misaligned single-sided encapsulated high-temperature superconducting tape of the present invention is a single-sided encapsulation, with a total thickness reduced by ≥35% compared to double-sided encapsulation, resulting in a compact structure and high current carrying efficiency.

[0039] 3. This invention uses a combination of width-direction misalignment and low-temperature solder edge C-shaped locking to achieve a peel strength ≥110N / cm (ASTM D903), which is more than 80% higher than traditional single-sided packaging.

[0040] 4. The width-direction misaligned single-sided encapsulated high-temperature superconducting tape structure of the present invention uses only one encapsulation reinforcement tape, which greatly reduces material and energy costs.

[0041] 5. The present invention has a simple process and low energy consumption, and is suitable for high-field magnets, compact cables and current limiters and other high-voltage applications. Attached Figure Description

[0042] Figure 1 This is a schematic cross-sectional view of the single-sided encapsulated high-temperature superconducting tape with width misalignment in the embodiment.

[0043] Figure 2 This is a comparison of the peel force-displacement curves of the width-direction misaligned single-sided packaged high-temperature superconducting tape in the embodiment with those of traditional single-sided packaging, double-sided packaging, and bare tape under the same conditions.

[0044] Figure 3 The figures show the current before and after peeling of the misaligned single-sided packaged high-temperature superconducting tape in the width direction in the embodiment.

[0045] Figure 4 The figures show the current before and after peeling of the misaligned single-sided packaged high-temperature superconducting tape in the width direction in the embodiment. Detailed Implementation

[0046] To more fully understand the technical solutions, objectives, and advantages in the exemplary embodiments, the technical effects generated in the embodiments will be further described in detail and completely below in conjunction with the accompanying drawings and specific embodiments. Obviously, the described embodiments are only a part of the embodiments, rather than all of them. It should be noted that for those of ordinary skill in the art, other embodiments obtained without departing from the concept of the embodiments all fall within the protection scope of the embodiments.

[0047] Unless otherwise specified in the following embodiments, the reagents and materials used are commercially available.

[0048] As Figure 1 shown, an edge-displaced single-sided encapsulated high-temperature superconducting tape is described exemplarily. It sequentially includes from bottom to top:

[0049] An encapsulation reinforcement tape 1, having a first width W1;

[0050] A low-temperature solder layer 2, located above the encapsulation reinforcement tape 1, whose material is selected from the Sn-Bi-Ag system or the Sn-In-Ni system, and the melting point is <180 °C;

[0051] A REBCO superconducting tape 3, located above the low-temperature solder layer 2, having a second width W2 and a thickness T;

[0052] The chemical composition of the REBCO superconducting tape 3 is REBa2Cu3O 7-x , where RE is a rare earth element, selected from one or more of Y, Gd, Sm, and Eu, the value range of x is 0 - 1, T is 50 - 100 μm, W2 < W1 and satisfies W2 = W1 - 2×displacement amount Δ, the value range of the displacement amount Δ is 0.1 - 1 mm; the REBCO superconducting tape 3 is indented by the displacement amount Δ from both side edges relative to the encapsulation reinforcement tape 1 to form an edge displacement in the width direction, and the superconducting layer of the REBCO superconducting tape faces the low-temperature solder layer 2;

[0053] An edge low-temperature solder filling area 4 is formed by the molten solder climbing along the thickness direction and completely wrapping the side edges of the REBCO superconducting tape 3 during the hot-press reflow process below 180 °C.

[0054] In some embodiments, the total thickness of the edge-displaced single-sided encapsulated high-temperature superconducting tape is 0.12 - 0.22 mm.

[0055] In some embodiments, the material of the encapsulation reinforcement tape 1 is Cu or Cu alloy, and the thickness is 50 - 200 µm.

[0056] In some embodiments, the material of the encapsulation reinforcement tape 1 is Cu-ETP or Cu-Ni-Si alloy.

[0057] In some embodiments, the low-temperature solder layer 2 is made of Sn-57Bi-1Ag or Sn-52In-0.3Ni, with a melting point of 138-160℃ and a thickness of 8-25µm.

[0058] In some embodiments, the hot-pressing reflux process below 180°C is a hot-pressing reflux process at 140-175°C.

[0059] The following embodiments also provide a method for preparing a width-direction misaligned single-sided encapsulated high-temperature superconducting tape, including the following steps:

[0060] S1: Perform low-temperature surface cleaning on REBCO superconducting tape 3;

[0061] S2: A low-temperature solder layer 2 is formed on the packaging reinforcement strip 1;

[0062] S3: The REBCO superconducting tape 3 is attached to the low-temperature solder layer 2 in a way that is offset in the width direction, and the superconducting surface of the REBCO superconducting tape 3 faces the low-temperature solder layer 2.

[0063] S4: Low-temperature hot pressing reflow is performed on the REBCO superconducting tape 3 and the low-temperature solder layer 2 to melt the solder and climb along the thickness direction, completely wrapping the side of the REBCO superconducting tape 3 to form the edge low-temperature solder filling area 4.

[0064] S5: Cool and trim the edges to obtain the finished product.

[0065] In some embodiments, in step S2, the outer surface of the encapsulation reinforcing strip 1 is coated with a 5-10µm thick polyimide insulating varnish to achieve interlayer insulation; 0.3-1wt% nano-ceramic particles are added to the low-temperature solder layer 2 to suppress thermal cycling fatigue.

[0066] In some embodiments, in step S4, the low-temperature hot pressing reflux is carried out under nitrogen or formic acid vapor protection, with a pressure of 0.3-1.5 MPa, a peak temperature of 155-180°C, and a time of 20-120 s.

[0067] In some embodiments, the method for preparing a width-direction misaligned single-sided encapsulated high-temperature superconducting tape includes the following steps:

[0068] (1) Low-temperature plasma cleaning or low-temperature chemical cleaning is performed on the superconducting layer of REBCO superconducting tape to remove organic contaminants. The surface temperature rise during the cleaning process is controlled below 50°C.

[0069] (2) A low-temperature solder alloy is uniformly coated on the upper surface of the packaging reinforcement strip by roller coating, scraping or electroplating to form a low-temperature solder layer with thickness fluctuation controlled within ±2μm;

[0070] (3) Use precision positioning rollers to center and bond REBCO superconducting tape to ensure the misalignment Δ on both sides and that its superconducting layer faces the solder; spray a small amount of no-clean flux on the surface of the laminated structure after bonding to promote solder wetting and climbing during the subsequent low-temperature hot pressing reflow process.

[0071] (4) Low-temperature hot pressing reflow is carried out by hot press rollers or belt tunnel furnace, with a peak temperature of 155-180℃, a pressure of 0.3-1.5MPa, and a holding time of 20-120s; during this process, the solder melts and climbs upward along the side of the REBCO superconducting tape under pressure, and the climbing height covers at least 30% of the thickness of the REBCO superconducting tape (usually ≥30μm), forming an edge low-temperature solder filling area;

[0072] (5) Cool to room temperature, laser cut the edges with a width tolerance of ±0.05mm, test Ic and peel strength online, and rewind qualified products.

[0073] The aforementioned misaligned single-sided encapsulated high-temperature superconducting tape can be wound to obtain superconducting magnets or superconducting cables.

[0074] Example 1

[0075] This embodiment provides a width-direction misaligned single-sided encapsulated high-temperature superconducting tape, the specific preparation method of which is as follows: A 12mm wide and 0.1mm thick Cu-ETP encapsulation reinforcing tape is taken and roll-coated with a 15µm thick Sn-57Bi-1Ag low-temperature solder layer; a 10mm wide and 80μm thick REBCO tape with the chemical composition YBa2Cu3O is also taken. 7-x (YBCO), x is 0-1, Ic=213A@77K (self-field), centered and bonded, with a 1mm misalignment on both sides, and the superconducting layer facing down; peak temperature is 165℃, pressure is 0.8 MPa, reflux is 60s; cooling and trimming are performed to obtain a width-direction misaligned single-sided encapsulated high-temperature superconducting tape.

[0076] The REBCO tape consists of, from bottom to top: a 50 μm thick Hastelloy C276 base tape, a biaxial textured oxide buffer layer, a 1-3 μm thick YBCO superconducting layer, a 1.5 μm thick silver protective layer, and 5 μm thick copper plating layers on both sides, for a total thickness of 80 μm.

[0077] Tests showed that the total thickness of the above-mentioned misaligned single-sided encapsulated high-temperature superconducting tape in the width direction is 0.19-0.20 mm, the peel strength is 118 N / cm, the Ic at 77 K is 212 A (with a retention rate of 99.5%), and the peel strength after repeated bending 100 times (diameter 25 mm) is >105 N / cm.

[0078] In this embodiment, the peel force-displacement curves of the width-direction misaligned single-sided packaged high-temperature superconducting tape are compared with those of traditional single-sided packaging, double-sided packaging, and bare tape under the same conditions. Figure 2 As shown, the currents of the high-temperature superconducting tape before and after peeling are respectively as follows: Figure 3 As shown.

[0079] Example 2

[0080] The difference from Example 1 is that the solder layer is Sn-52In-0.3Ni with a thickness of 10 µm; the encapsulation reinforcement strip is made of 0.08 mm thick Cu-Ni-Si alloy; and the REBCO strip thickness is 100 μm (chemical composition EuBa2Cu3O). 7-x x is 0-1, the misalignment is 0.5 mm, and the peak temperature is 155℃.

[0081] Testing showed that the total thickness of the width-direction misaligned single-sided encapsulated high-temperature superconducting tape obtained in this embodiment was 0.16-0.18 mm, the peel strength was 112 N / cm, and the Ic retention rate was 99%. It is suitable for fabricating high-turn-density high-temperature superconducting magnets. The currents before and after peeling were as follows: Figure 4 As shown.

[0082] The above are merely preferred embodiments and are not intended to limit the scope of the embodiments. Various modifications and variations are possible in the embodiments for those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments should be included within the scope of protection of the embodiments.

Claims

1. A high-temperature superconducting tape with a width-direction misaligned single-sided encapsulation, characterized in that, From bottom to top, it includes: The encapsulation reinforcement strip has a first width W1; A low-temperature solder layer is located on the packaging reinforcement strip. Its material is selected from Sn-Bi-Ag system or Sn-In-Ni system, with a melting point <180℃. REBCO superconducting tape, located on the low-temperature solder layer, has a second width W2 and a thickness T; The chemical composition of the REBCO superconducting tape is REBa2Cu3O 7-x , where RE is a rare earth element selected from one or more of Y, Gd, Sm, and Eu, the value range of x is 0-1, T is 50-100 μm, W2 < W1 and satisfies W2 = W1 - 2×misalignment amount Δ, and the value range of the misalignment amount Δ is 0.1-1 mm; on both sides of the REBCO superconducting tape relative to the encapsulating reinforcement tape, each is indented by the misalignment amount Δ to form a width-direction misalignment, and the superconducting layer of the REBCO superconducting tape faces the low-temperature solder layer; The edge low-temperature solder filling area is formed by molten solder climbing up along the thickness direction and completely wrapping the side of the REBCO superconducting tape during the hot-pressing reflow process at a temperature below 180°C.

2. The width-direction misaligned single-sided encapsulated high-temperature superconducting tape according to claim 1, characterized in that, The total thickness of the width-direction misaligned single-sided encapsulated high-temperature superconducting tape is 0.12-0.22 mm.

3. The width-direction misaligned single-sided encapsulated high-temperature superconducting tape according to claim 1, characterized in that, The encapsulation reinforcement strip is made of Cu or Cu alloy and has a thickness of 50-200 µm.

4. The width-direction misaligned single-sided encapsulated high-temperature superconducting tape according to claim 3, characterized in that, The material of the encapsulation reinforcement strip is Cu-ETP or Cu-Ni-Si alloy.

5. The width-direction misaligned single-sided encapsulated high-temperature superconducting tape according to claim 1, characterized in that, The material of the low-temperature solder layer is Sn-57Bi-1Ag or Sn-52In-0.3Ni, with a melting point of 138-160℃ and a thickness of 8-25µm.

6. The width-direction misaligned single-sided encapsulated high-temperature superconducting tape according to claim 1, characterized in that, The hot-pressing reflux process below 180°C is a hot-pressing reflux process at 140-175°C.

7. The method for preparing the width-direction misaligned single-sided encapsulated high-temperature superconducting tape according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1: Perform low-temperature surface cleaning on REBCO superconducting tape; S2: A low-temperature solder layer is formed on the packaging reinforcement strip; S3: The REBCO superconducting tape is attached to the low-temperature solder layer in a width-direction offset manner, with the superconducting surface of the REBCO superconducting tape facing the low-temperature solder layer. S4: Low-temperature hot pressing reflow is performed on the REBCO superconducting tape and the low-temperature solder layer to melt the solder and climb along the thickness direction, completely wrapping the side of the REBCO superconducting tape to form the edge low-temperature solder filling area. S5: Cool and trim the edges to obtain the finished product.

8. The method for preparing the width-direction misaligned single-sided encapsulated high-temperature superconducting tape according to claim 7, characterized in that, In step S2, the outer surface of the encapsulation reinforcing strip is coated with a polyimide insulating varnish with a thickness of 5-10µm; And / or add 0.3-1 wt% nano-ceramic particles to the low-temperature solder layer; In step S4, the low-temperature hot-pressing reflux is carried out under nitrogen or formic acid vapor protection, with a pressure of 0.3-1.5 MPa, a peak temperature of 155-180°C, and a time of 20-120 s.

9. The method for preparing the width-direction misaligned single-sided encapsulated high-temperature superconducting tape according to claim 7 or 8, comprising the following steps: (1) Low-temperature plasma cleaning or low-temperature chemical cleaning is performed on the superconducting layer of REBCO superconducting tape to remove organic contaminants. The surface temperature rise during the cleaning process is controlled below 50°C. (2) A low-temperature solder alloy is uniformly coated on the upper surface of the packaging reinforcing strip by roller coating, scraping or electroplating to form the low-temperature solder layer, with the thickness fluctuation controlled within ±2μm; (3) The REBCO superconducting tape is centered and bonded using a precision positioning roller to ensure the misalignment Δ on both sides and that its superconducting surface faces the solder. A small amount of no-clean flux is sprayed onto the surface of the laminated structure to promote solder wetting and creep during the subsequent low-temperature hot pressing reflow process. (4) Low-temperature hot pressing reflow is performed by hot press rollers or belt tunnel furnace, with a peak temperature of 155-180℃, a pressure of 0.3-1.5MPa, and a holding time of 20-120 s; during this process, the solder melts and climbs upward along the side of the REBCO superconducting tape under pressure, and the climbing height covers at least 30% of the thickness of the REBCO superconducting tape, forming the edge low-temperature solder filling area; (5) Cool to room temperature, laser cut the edges with a width tolerance of ±0.05mm, test Ic and peel strength online, and rewind qualified products.

10. The application of the width-direction misaligned single-sided encapsulated high-temperature superconducting tape according to any one of claims 1 to 6 in the preparation of superconducting magnets, superconducting cables or current limiters, wherein the tape is wound by the width-direction misaligned single-sided encapsulated high-temperature superconducting tape.

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