Preparation Method of High Temperature Superconducting Tape for Stacked Cable

Abstract

The present invention provides a method for preparing a high-temperature superconducting tape for stacked cables, which comprises the following steps: Step S1, an additional protective layer is plated on the side surface of the silver-plated superconducting tape after slitting; Step S2, electroless copper plating is performed on the superconducting tape with an additional protective layer on the side surface. By directionally plating an additional protective layer on the side protective layer of the superconducting tape, the thickness of the side protective layer is increased, solving the problem of the relatively thin side protective layer caused by the traditional roll-to-roll copper plating protective layer method, and enabling the prepared superconducting tape to have good solder dipping resistance during the processing of stacked cables.

Description

Technical Field

[0001] The present invention relates to the technical field of REBCO superconducting tape technology, and specifically, to a method for preparing a high-temperature superconducting tape for stacked cables. Background Art

[0002] The second-generation superconducting tape made of REBCO (Re is a rare earth element), also known as a coated conductor, has a wider and better application prospect in many fields such as medical treatment, military, and energy due to its stronger current-carrying capacity, higher magnetic field performance, and lower material cost compared with bismuth-based tapes. The second-generation high-temperature superconducting tape is generally produced by a multi-layer coating process on a nickel-based alloy substrate because REBCO itself, which is the superconducting current-carrying core, is hard and brittle, so it is also called a coated conductor. It generally consists of a base tape, a buffer layer (transition layer), a superconducting layer, and a protective layer.

[0003] The role of the metal substrate is to provide excellent mechanical properties for the tape. The role of the transition layer is, on the one hand, to prevent the interdiffusion of elements between the superconducting layer and the metal substrate, and on the other hand, the uppermost transition layer needs to provide a good template for the epitaxial growth of the superconducting layer to improve the grain alignment quality. To prepare a coated conductor with excellent superconducting properties, the superconducting layer needs to have a consistent biaxial texture. The biaxial texture means that the grains have an almost consistent alignment in both the a / b axis and the c axis (the c axis is perpendicular to the a / b plane).

[0004] Since it is relatively difficult to achieve the alignment degree (in-plane texture) of the YBCO thin film in the a / b axis direction, and a poor in-plane texture will seriously reduce the superconducting properties. Therefore, the YBCO superconducting thin film needs to grow epitaxially on the transition layer that already has a biaxial texture and a matching lattice. There are two main technical routes to achieve the biaxial texture: one is the rolling-assisted biaxial texture base tape technology, and the other is the ion beam-assisted deposition technology.

[0005] The common technologies for preparing the REBCO superconducting layer are divided into many types, including pulsed laser deposition, metal organic chemical vapor deposition, reactive co-evaporation, etc. The protective layer is mainly used to protect the superconducting film layer. Generally, a silver layer is deposited on the front and back surfaces of the superconducting tape by magnetron sputtering or evaporation. Subsequently, according to the specific application requirements for the tape width, a 10-12 mm tape is cut into 2-8 mm. Finally, copper plating or subsequent encapsulation and strengthening treatment are carried out.

[0006] Breaking through the limits of human magnetic fields is of enormous significance. As the most promising way to achieve controlled fusion energy generation, the tokamak magnetic confinement nuclear fusion device relies heavily on strong magnetic fields to confine high-temperature plasma to produce fusion reactions. Its unit volume fusion power density is proportional to the fourth power of the magnetic field strength (P∝B4). Therefore, increasing the magnetic field strength of the superconducting magnet system can extremely efficiently increase the unit volume fusion power density and greatly reduce the size of the tokamak fusion device, greatly reducing the engineering difficulty of the entire system, and is expected to significantly accelerate the development of commercially available controlled nuclear fusion technology.

[0007] In 2018, the MIT Plasma Science and Fusion Center (PSFC) and Commonwealth Fusion Systems (CFS) developed a new type of magnet using high-temperature superconducting tapes. They manufactured them in a stacking manner and finally impregnated them with solder, making them large, uninsulated magnets, ultimately breaking the 20T limit of large-caliber fusion magnets.

[0008] The entire layer magnet consists of 16 individual pancake coils and two end plates at the top and bottom. The pancake coils are composed of four main sub-components: 1) radial plates; 2) REBCO superconducting tape and copper co-wound stacks; 3) inner and outer bonding layers; and 4) copper caps. Figure 1 As shown, the spiral channel inside is used for REBCO superconducting tape stacking. Approximately 200 REBCO superconducting tapes are stacked and inserted into the machined channel in a semi-automatic winding process. The channel provides a highly conductive path for molten solder to dip solder the stacked tapes. After dipping, the coil becomes an uninsulated coil, as shown in Figure 1. Figure 2 shown.

[0009] The entire coil weighs 5,113 kilograms and measures 2.9 meters by 1.9 meters. Therefore, it takes considerable time to fully soak the stacked REBCO superconducting tapes with solder and weld them together with minimal porosity. A key bottleneck is ensuring that the REBCO tapes withstand the high temperatures of solder immersion without degradation.

[0010] The performance degradation of REBCO superconducting tape during solder immersion does not occur instantaneously, but gradually degrades over time. After immersion for 1 minute, the performance of the tape has not changed significantly, and the structure of the tape has not changed significantly, such as Figure 3 After 20 minutes of immersion, the copper protective layer of the strip changes significantly from the two sides to the middle, which damages the superconducting layer and causes a significant degradation of the performance of the strip. Figure 4 As shown, the copper on both sides is almost invisible, while the copper in the middle is partially retained.

[0011] During the production of REBCO superconducting tapes, it is necessary to slit the silver-coated superconducting tapes with a width of 10-12 mm into different widths according to the requirements of the tape width for specific applications. After slitting, there is no silver protection layer on the side of the tape, making it difficult for the copper protection layer to adhere to the side during the subsequent electroless copper plating process, resulting in a thinner copper protection layer on the side compared to the middle part and becoming a weak point for solder impregnation, as Figure 5 shown.

[0012] Patent document CN110797148B discloses a superconducting tape applicable to a non-insulated coil, a non-insulated coil and a preparation method thereof, and a copper layer is plated by physical vapor deposition. Although the problem of copper protection layer adhesion on the side is improved to a certain extent, the traditional roll-to-roll plating is for one surface, and the side is deposited by molecular diffraction, and the thickening effect on the copper protection layer on the side of the tape cross-section is very limited, as Figure 6 shown. If it is necessary to increase the thickness of the protection layer on the side, in the traditional preparation process, it is necessary to increase the thickness of the protection layers on both the front and back sides of the tape together, which will reduce the engineering critical current density performance of the tape and cannot meet the requirements of the application end.

[0013] In summary, the technical problem of directionally increasing the thickness of the protection layer on the side of the REBCO superconducting tape to improve its solder impregnation resistance during the processing of stacked cables needs to be solved urgently. Summary of the Invention

[0014] Aiming at the defects in the prior art, the purpose of the present invention is to provide a preparation method for a high-temperature superconducting tape for stacked cables.

[0015] According to a preparation method for a high-temperature superconducting tape for stacked cables provided by the present invention, the method includes the following steps:

[0016] Step S1, additionally plating a protection layer on the side of the slit silver-coated superconducting tape;

[0017] Step S2, performing electroless copper plating on the superconducting tape with an additional protection layer on the side;

[0018] Regarding step S1, the slit silver-coated superconducting tape is wound alone or wound together with a thin tape to form a disk shape, and a protection layer is directionally additionally plated on the disk surface of the disk-shaped tape by physical vapor deposition;

[0019] Preferably, the material of the thin tape includes any one or more of stainless steel, aluminum or Hastelloy, and the thickness of the thin tape is 30 to 100 μm;

[0020] The physical vapor deposition method includes any one or more of radio frequency sputtering, medium frequency sputtering, direct current sputtering or direct current pulsed sputtering.

[0021] Preferably, when directionally depositing a protective layer on the surface of the disc-shaped strip by physical vapor deposition: the target is located above the disc-shaped strip, and the protective layer is directionally deposited on the surface of the disc-shaped strip by physical vapor deposition;

[0022] Taking the center point of the target as the revolution center, the center point of the disc-shaped strip revolves around this revolution center;

[0023] Taking the center point of the disc-shaped strip as the rotation center, the disc-shaped strip rotates.

[0024] Preferably, for step S1, directionally depositing a silver protective layer on the side of the silver-plated superconducting strip after slitting, the thickness of the silver protective layer directionally deposited on the side of the silver-plated superconducting strip is 0.5 to 5 μm.

[0025] Preferably, for step S1, first directionally deposit a silver protective layer on the side of the silver-plated superconducting strip after slitting, and then directionally deposit a copper protective layer;

[0026] The thickness of the silver protective layer directionally deposited on the side of the silver-plated superconducting strip is 0.5 to 5 μm;

[0027] The thickness of the copper protective layer directionally deposited on the silver protective layer is 0.2 to 5 μm.

[0028] Preferably, step S2 includes the following steps:

[0029] Step S2.1, perform a primary cleaning treatment, a pre-copper plating treatment, a sanded copper plating treatment, and a side copper plating treatment on the strip to be processed in sequence, and then perform a secondary cleaning treatment;

[0030] Step S2.2, perform a passivation treatment and a drying treatment on the strip to be processed after the secondary cleaning treatment.

[0031] Preferably, for the sanded copper plating treatment, the surface roughness of the sanded copper is greater than 50 nm.

[0032] Preferably, the pre-copper plating treatment uses a first current electroplating treatment, and the current density used for the first current is 6 - 20 A / dm^2;

[0033] The weight composition of the pre-copper plating electroplating solution is:

[0034] 200 - 240 parts of copper sulfate;

[0035] 50 - 70 parts of sulfuric acid;

[0036] 0.08 - 0.1 part of chloride ion;

[0037] The weight composition of the pre-copper plating acid additive is:

[0038] 6 - 8 parts of bath starter;

[0039] 2 - 3 parts of supplement;

[0040] The copper plating treatment uses the second - current electroplating treatment, and the current density of the second current is 3 - 8 A / dm^2;

[0041] The weight composition of the copper electroplating solution is:

[0042] 180 - 220 parts of copper sulfate;

[0043] 50 - 80 parts of sulfuric acid;

[0044] 0.06 - 0.13 parts of chloride ions;

[0045] The side - added copper plating treatment uses the third - current electroplating treatment, and the current density of the third current is 3 - 8 A / dm^2;

[0046] The weight composition of the side - added copper electroplating solution is:

[0047] 180 - 220 parts of copper sulfate;

[0048] 50 - 80 parts of sulfuric acid;

[0049] 0.06 - 0.13 parts of chloride ions.

[0050] Preferably, in electroless copper plating, a cathode, an anode, and a shielding plate are arranged in the electroplating bath. The cathode is a superconducting tape, the shielding plate is arranged between the cathode and the anode, and the shielding plate, the cathode, and the anode are all arranged parallel to each other;

[0051] The shielding plate is provided with holes or grooves, allowing the electric field lines to extend to the side and / or the front and / or the back of the superconducting tape.

[0052] Preferably, in electroless copper plating, a cathode, an anode, and a shielding plate are arranged in the electroplating bath. The cathode is a superconducting tape, the shielding plate is arranged between the cathode and the anode, and the shielding plate, the cathode, and the anode are all arranged parallel to each other;

[0053] The shielding plate covers the entire width part of the superconducting tape, and the shielding plate only allows the electric field lines to extend to the side of the superconducting tape.

[0054] Compared with the prior art, the present invention has the following beneficial effects:

[0055] 1. By directionally increasing the thickness of the side protective layer of the superconducting tape, the present invention solves the problem of the relatively thin side protective layer caused by the traditional roll - to - roll copper plating protection method, so that the prepared superconducting tape has good solder dip impregnation resistance during the processing of stacked cables.

[0056] 2. In the present invention, with the center point of the target as the center of revolution, the center point of the disc-shaped strip revolves around this center of revolution, and with the center point of the disc-shaped strip as the center of rotation, the disc-shaped strip rotates, which helps to improve the uniformity of physical vapor deposition coating.

[0057] 3. In the present invention, copper is plated by a chemical method and the outermost layer is plated with sand copper, making the surface of the material relatively rough and having a certain friction during use, ensuring that the strip will not skip turns during the winding and impregnation processes under large tension. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Other features, objects, and advantages of the present invention will become more apparent by reading the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0059] Figure 1 Schematic diagram showing a spiral channel radial plate for REBCO superconducting tape stacking;

[0060] Figure 2 Schematic diagram showing REBCO superconducting tape stacking after solder impregnation;

[0061] Figure 3 Schematic diagram showing the cross-section of the strip after 1 minute of solder impregnation of REBCO superconducting tape;

[0062] Figure 4 Schematic diagram showing the cross-section of the strip after 20 minutes of solder impregnation of REBCO superconducting tape;

[0063] Figure 5 Schematic diagram showing that the copper protection layer on the side of the cross-section of the REBCO superconducting tape without a silver protection layer is relatively thin after using the traditional electroplating copper process;

[0064] Figure 6 Schematic diagram showing the copper protection layer on the side of the cross-section of the traditional physical copper-plated superconducting tape;

[0065] Figure 7 Schematic diagram showing the separately wound disc-shaped silver-plated superconducting tape after slitting;

[0066] Figure 8 Schematic diagram showing the co-wound disc-shaped silver-plated superconducting tape and thin tape after slitting;

[0067] Figure 9 Schematic diagram showing the revolution relationship between the disc-shaped strip and the coating target in the superconducting tape preparation method of the present invention;

[0068] Figure 10 Schematic diagram showing the cross-section of the shielding structure applied between the anode and the cathode during the pre-copper plating treatment and the sanded copper plating treatment in the electroless copper plating of the present invention;

[0069] Figure 11 Schematic cross-sectional view of the shielding structure between the anode and the cathode during side copper plating in electroless copper plating of the present invention;

[0070] Figure 12 Schematic view showing the cross-section of the REBCO superconducting tape obtained by the method for preparing a superconducting tape of the present invention;

[0071] Figure 13 Schematic view showing the cross-section of the REBCO superconducting tape after 60 minutes of solder impregnation obtained by the method for preparing a superconducting tape of the present invention;

[0072] Figure 14 Schematic view showing the attenuation of the copper layer on the side of the superconducting tape of the present invention at different temperatures. Detailed implementation manners

[0073] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several changes and improvements can still be made. These all belong to the protection scope of the present invention.

[0074] Example 1

[0075] As Figure 1 shown, a method for preparing a high-temperature superconducting tape for stacked cables according to the present invention includes the following steps:

[0076] Step S1: Apply a protective layer to the side of the silver-plated superconducting tape after slitting;

[0077] Step S2: Perform electroless copper plating on the superconducting tape with a protective layer applied to the side.

[0078] It should be noted that the protective layer plated in step S1 of the technical solution of the present application can be a silver protective layer or a silver protective layer plus a copper protective layer.

[0079] Regarding step S1, the slit silver-plated superconducting tape is wound alone or wound together with a thin strip to form a disk shape, and a protective layer is directionally applied to the disk surface of the disk-shaped tape by physical vapor deposition. The material of the thin strip includes any one or more of stainless steel, aluminum, or Hastelloy, and the thickness of the thin strip is 30 to 100 μm. The physical vapor deposition method includes any one or more of radio frequency sputtering, medium frequency sputtering, direct current sputtering, or direct current pulsed sputtering.

[0080] In a feasible implementation: When directionally depositing a protective layer on the surface of the disc-shaped strip by physical vapor deposition, the target is located above the disc-shaped strip. The surface of the disc-shaped strip is directionally deposited with a protective layer by physical vapor deposition. With the center point of the target as the center of revolution, the center point of the disc-shaped strip makes a revolution around this center of revolution. With the center point of the disc-shaped strip as the center of rotation, the disc-shaped strip makes a rotation. Specifically, the silver-plated superconducting strip after slitting is wound alone or wound together with a thin strip to form a disc. Any one of the physical vapor deposition methods such as radio frequency sputtering, medium frequency sputtering, direct current sputtering, and direct current pulsed sputtering is used, and the same or different physical vapor deposition methods are used once or multiple times to directionally deposit a silver protective layer on the side of the strip, and the target for coating is a pure silver target. A silver protective layer is directionally deposited on the side of the silver-plated superconducting strip after slitting, and the thickness of the silver protective layer directionally deposited on the side of the silver-plated superconducting strip is 0.5 to 5 μm.

[0081] In another feasible implementation: For step S1, a silver protective layer is first directionally deposited on the side of the silver-plated superconducting strip after slitting, and then a copper protective layer is directionally deposited; the thickness of the silver protective layer directionally deposited on the side of the silver-plated superconducting strip is 0.5 to 5 μm; the thickness of the copper protective layer directionally deposited on the silver protective layer is 0.2 to 5 μm. The silver-plated superconducting strip after slitting is wound alone or wound together with a thin strip to form a disc. First, any one of the physical vapor deposition methods such as radio frequency sputtering, medium frequency sputtering, direct current sputtering, and direct current pulsed sputtering is used, and the same or different physical vapor deposition methods are used once or multiple times to directionally deposit a silver protective layer on the side of the strip, and the target for coating is a pure silver target. Then, a copper protective layer is directionally deposited on the side of the strip, and any one of the physical vapor deposition methods such as radio frequency sputtering, medium frequency sputtering, direct current sputtering, and direct current pulsed sputtering is used, and the same or different physical vapor deposition methods are used once or multiple times to directionally deposit a copper protective layer, and the target for coating is a pure copper target.

[0082] It should be noted that during the plating by physical vapor deposition, the sputtering target is located above the disc-shaped strip to be plated, and with the center point of the target as the center of revolution, the center point of the disc-shaped strip makes a revolution around this center of revolution. With the center point of the disc-shaped strip as the center of rotation, the disc-shaped strip makes a rotation, which can improve the uniformity of the physical vapor deposition coating.

[0083] Furthermore, step S2 includes the following steps:

[0084] Step S2.1: The strip to be processed is sequentially subjected to a primary cleaning treatment, a pre-copper plating treatment, a sanded copper plating treatment, a side copper plating treatment, and then a secondary cleaning treatment. Step S2.2: The strip to be processed after the secondary cleaning treatment is subjected to a passivation treatment and a drying treatment.

[0085] For the sanded copper plating treatment, the surface roughness of the sanded copper is greater than 50 nm. The pre - copper plating treatment adopts the first - current electroplating treatment, and the current density of the first current is 6 - 20 A / dm^2;

[0086] In the pre - copper plating electroplating solution used for the pre - copper plating treatment, a primary acid copper additive that allows operation at a current density of 6 - 20 A / dm^2 is added. The weight composition of the pre - copper plating electroplating solution is:

[0087] 200 - 240 parts of copper sulfate;

[0088] 50 - 70 parts of sulfuric acid;

[0089] 0.08 - 0.1 part of chloride ion;

[0090] The weight composition of the primary acid copper additive is:

[0091] 6 - 8 parts of starting agent;

[0092] 2 - 3 parts of supplement.

[0093] The copper plating treatment adopts the second - current electroplating treatment, and the current density of the second current is 3 - 8 A / dm^2;

[0094] In the sanded copper electroplating solution used for the copper plating treatment, a sanded copper acid copper additive that allows operation at a current density of 3 - 8 A / dm^2 is added. The weight composition of the sanded copper electroplating solution is:

[0095] 180 - 220 parts of copper sulfate;

[0096] 50 - 80 parts of sulfuric acid;

[0097] 0.06 - 0.13 part of chloride ion.

[0098] The side - added copper plating treatment adopts the third - current electroplating treatment, and the current density of the third current is 3 - 8 A / dm^2;

[0099] In the side - added copper plating electroplating solution used for the side - added copper plating treatment, a side - added copper plating acid copper additive that allows operation at a current density of 3 - 8 A / dm^2 is added. The weight composition of the side - added copper plating electroplating solution is:

[0100] 180 - 220 parts of copper sulfate;

[0101] 50 - 80 parts of sulfuric acid;

[0102] 0.06 - 0.13 part of chloride ion.

[0103] More specifically, in electroless copper plating, a cathode, an anode, and a shielding plate are arranged in an electroplating bath. The shielding plate can shield electric field lines. The cathode is a superconducting tape. The shielding plate is arranged between the cathode and the anode, and the shielding plate, the cathode, and the anode are all arranged parallel to each other. The shielding plate is provided with holes or grooves to allow the electric field lines to extend to the side and / or the front and / or the back of the superconducting tape. When the thickness of the side of the superconducting tape is insufficient after one-time electroless copper plating, the following equipment is continued to be used for secondary electroless copper plating. In electroless copper plating, a cathode, an anode, and a shielding plate are arranged in an electroplating bath. The cathode is a superconducting tape. The shielding plate is arranged between the cathode and the anode, and the shielding plate, the cathode, and the anode are all arranged parallel to each other. The shielding plate covers the entire width portion of the superconducting tape, and the shielding plate only allows the electric field lines to extend to the side of the superconducting tape.

[0104] It should be further noted that: The technical solution of the present application can control the thickness of the copper plating on the surface and side of the superconducting tape by adjusting the size of the holes or grooves and the length of the shielding plate. If the thickness of the copper plating on the side of the superconducting tape does not meet the design requirements, the thickness of the copper plating on the side of the superconducting tape can be directionally enhanced by secondary electroless copper plating, and the secondary electroless copper plating can be carried out multiple times until the thickness of the copper plating on the side of the superconducting tape meets the design requirements.

[0105] Specifically, a cathode and an anode are arranged in an electroplating bath. The cathode is a superconducting tape. A shielding plate is arranged between the cathode and the anode. The shielding plate, the cathode, and the anode are all arranged parallel to each other, and the shielding plate is provided with a plurality of through holes or through grooves. The area of the through holes or through grooves is 0.2 to 0.6 times that of the cathode.

[0106] When directionally strengthening the thickness of the side of the superconducting tape, a cathode and an anode are arranged in an electroplating bath. The cathode is a superconducting tape. A shielding plate is arranged between the cathode and the anode. The shielding plate, the cathode, and the anode are all arranged parallel to each other. The shielding plate covers the entire width portion of the superconducting tape, and the area of the anode is 1 to 2 times that of the cathode.

[0107] It should be noted that the electroless copper plating is carried out on the entire silver-plated superconducting tape. Copper is plated by chemical method, and the outermost layer is plated with sand copper, making the surface of the material relatively rough and having a certain friction force during use to ensure that the tape does not skip turns during the winding and impregnation processes under large tension. The shielding plate can ensure that the thickness of the tape after electroless copper plating is within the allowable range of the design. Copper will only be plated at the places where the electric field lines can reach on the superconducting tape during electroless copper plating.

[0108] It should be further noted that: As Figure 14 shown, the attenuation of the copper layer on the side of the superconducting tape at different temperatures. The total thickness of the copper layer on the side of the superconducting tape in the present application satisfies that the copper layer on the side of the superconducting tape does not completely melt during impregnation welding, thereby ensuring that the performance of the superconducting tape does not degenerate.

[0109] Example 2

[0110] Based on Example 1, a method for preparing a high-temperature superconducting tape for stacked cables according to the present invention includes the following steps:

[0111] Step 1: Directionally deposit a protective layer on the side edges of the silver-plated superconducting tape after slitting;

[0112] Step 2: Electrolessly plate copper on the superconducting tape that has completed Step 1.

[0113] In Step 1, after directionally depositing a silver protective layer on the side edges of the superconducting tape slit into different widths, a copper protective layer is directionally deposited or only a silver protective layer is directionally deposited. The thickness of the side silver protective layer is 0.5 to 5 μm. The specific steps are as follows:

[0114] Step 1.1: Wind the silver-plated superconducting tape after slitting alone or in parallel with a thin strip to form a disk shape;

[0115] The winding speed is 100 - 1000 m / H, and the winding tension is 50 - 500 MPa.

[0116] The material of the thin strip is stainless steel, aluminum, or Hastelloy, and the thickness is 30 - 1000 μm.

[0117] Step 1.2: Directionally deposit a silver protective layer on the surface of the tape wound into a disk shape, that is, the side edges of the superconducting tape, by physical vapor deposition.

[0118] Use any one of the following physical vapor deposition methods: radio frequency sputtering, medium frequency sputtering, direct current sputtering, or direct current pulsed sputtering, and use the same or different processes once or multiple times to directionally deposit a protective layer on the side edges of the tape. Silver Protective layer.

[0119] Preferably, the sputtering power is 0.1 - 3 KW, the working gas is argon, the argon flow rate is 10 - 200 sccm, the background vacuum degree is 10 -7 ~10 -5 Torr, the pressure in the chamber during film coating is 10 - 100 mTorr, the target for film coating is a pure silver target, and the target-substrate distance is 20 - 100 mm.

[0120] Preferably, the target is located above the disk-shaped tape. With the center point of the target as the revolution center, the center point of the disk-shaped tape revolves around this revolution center. The revolution diameter is 50 - 500 mm, the revolution rate is 0.5 - 5 revolutions / min, with the center point of the disk-shaped tape as the rotation center, the disk-shaped tape rotates. The rotation rate is 1 - 10 revolutions / min. Through the mode of combining rotation and revolution, it is used to improve the deposition on the side edges of the disk-shaped tape. SilverThe thickness uniformity of the protective layer.

[0121] In step 1.3, specifically, it includes: on the side of the superconducting tape that has completed step 1, directionally depositing an additional Copper protective layer by physical vapor deposition, and the side Copper The thickness of the protective layer is 0.5 - 5 μm.

[0122] Use any one of the following physical vapor deposition methods: radio frequency sputtering, medium frequency sputtering, direct current sputtering, or direct current pulsed sputtering, and use the same or different processes once or multiple times to directionally deposit an additional Copper protective layer on the side of the tape.

[0123] The sputtering power is 0.1 - 3 KW, the working gas is argon, the argon flow rate is 10 - 200 sccm, the background vacuum degree is 10 -7 ~10 -5 Torr, the pressure in the chamber during coating is 10 - 100 mTorr, the coating target is pure Copper target, and the target-substrate distance is 20 - 100 mm.

[0124] The target is located above the disk-shaped tape. Taking the center point of the target as the revolution center, the center point of the disk-shaped tape revolves around this revolution center, the revolution diameter is 50 - 500 mm, the revolution speed is 0.5 - 5 revolutions per minute, taking the center point of the disk-shaped tape as the rotation center, the disk-shaped tape rotates, the rotation speed is 1 - 10 revolutions per minute. Through the mode of combining rotation and revolution, it is used to improve the thickness uniformity of the additional Copper protective layer on the side of the disk-shaped tape.

[0125] In step 2, electroless copper plating is carried out on the superconducting tape that has completed step 1, and it specifically includes the following steps:

[0126] Step 2.1: The tape to be processed is successively subjected to a primary cleaning treatment, a pre-copper plating treatment, a sanded copper plating treatment, a side additional copper plating treatment, and then a secondary cleaning treatment;

[0127] Step 2.2: The tape to be processed after the secondary cleaning treatment is subjected to a passivation treatment and a drying treatment.

[0128] The surface roughness of the sanded copper is greater than 50 nm.

[0129] The pre-copper plating treatment adopts the first current electroplating treatment, the sanded copper plating treatment adopts the second current electroplating treatment, and the side additional copper plating treatment adopts the third current electroplating treatment.

[0130] The current density of the first current is 6 - 20 A / dm^2, the current density of the second current is 3 - 8 A / dm^2, and the current density of the third current is 3 - 8 A / dm^2.

[0131] In the pre - copper plating treatment, a pre - acid copper plating additive that allows operation at a current density of 6 - 20 A / dm^2 is added to the pre - copper plating solution. The weight composition of the pre - copper plating solution is as follows:

[0132] 200 - 240 parts of copper sulfate;

[0133] 50 - 70 parts of sulfuric acid;

[0134] 0.08 - 0.1 part of chloride ion;

[0135] In the sand - faced copper plating treatment, a sand - faced copper acid copper plating additive that allows operation at a current density of 3 - 8 A / dm^2 is added to the sand - faced copper plating solution. The weight composition of the sand - faced copper plating solution is as follows:

[0136] 180 - 220 parts of copper sulfate;

[0137] 50 - 80 parts of sulfuric acid;

[0138] 0.06 - 0.13 part of chloride ion;

[0139] In the side - added copper plating treatment, a side - added copper acid copper plating additive that allows operation at a current density of 3 - 8 A / dm^2 is added to the side - added copper plating solution. The weight composition of the side - added copper plating solution is as follows:

[0140] 180 - 220 parts of copper sulfate;

[0141] 50 - 80 parts of sulfuric acid;

[0142] 0.06 - 0.13 part of chloride ion.

[0143] The weight composition of the pre - acid copper plating additive is as follows:

[0144] 6 - 8 parts of bath starter;

[0145] 2 - 3 parts of supplement.

[0146] In step 2.1, during the pre - copper plating treatment and the sand - faced copper plating treatment, a shielding plate is arranged between the anode and the cathode. The cathode is a superconducting tape. The shielding plate is arranged between the superconducting tape and the anode and is parallel to the cathode and the anode. Multiple through - holes are arranged on the shielding plate, and the area of the through - holes is 0.2 - 0.6 times that of the cathode.

[0147] In the step 2.1, for the side copper plating treatment, a shielding plate is arranged between the anode and the cathode for side copper plating. The cathode is a superconducting tape. The shielding plate is arranged between the superconducting tape and the anode and is parallel to the cathode and the anode. The shielding plate covers the entire width portion of the superconducting tape, and the area of the anode is 1 to 2 times that of the cathode.

[0148] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present application.

[0149] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A preparation method of a high-temperature superconducting tape for a stacked cable, characterized in that, It includes the following steps: Step S1: Apply a protective layer to the side of the silver-plated superconducting strip after slitting; Step S2: Electrolessly plate copper on the superconducting strip with a protective layer applied to the side; Regarding Step S1: Wind the silver-plated superconducting strip after slitting alone or co-wind it with a thin strip to form a disk shape, and directionally apply a protective layer to the disk surface of the disk-shaped strip by physical vapor deposition; When directionally applying a protective layer to the disk surface of the disk-shaped strip by physical vapor deposition: The target is located above the disk-shaped strip, and a protective layer is directionally applied to the disk surface of the disk-shaped strip by physical vapor deposition; Taking the center point of the target as the revolution center, the center point of the disk-shaped strip makes a revolution around this revolution center; Taking the center point of the disk-shaped strip as the rotation center, the disk-shaped strip makes a rotation movement.

2. The preparation method of the high-temperature superconducting tape for stacked cables according to claim 1, characterized in that, The material of the thin strip includes any one or more of stainless steel, aluminum, or Hastelloy, and the thickness of the thin strip is 30 to 100 μm; The physical vapor deposition method includes any one or more of radio frequency sputtering, medium frequency sputtering, or direct current sputtering.

3. The preparation method of the high-temperature superconducting tape for stacked cables according to claim 1, wherein Regarding Step S1: Directionally apply a silver protective layer to the side of the silver-plated superconducting strip after slitting, and the thickness of the silver protective layer directionally applied to the side of the silver-plated superconducting strip is 0.5 to 5 μm.

4. The preparation method of the high-temperature superconducting tape for stacked cables according to claim 1, characterized in that, Regarding Step S1: First directionally apply a silver protective layer to the side of the silver-plated superconducting strip after slitting, and then directionally apply a copper protective layer; The thickness of the silver protective layer directionally applied to the side of the silver-plated superconducting strip is 0.5 to 5 μm; The thickness of the copper protective layer directionally applied on the silver protective layer applied to the side of the silver-plated superconducting strip is 0.2 to 5 μm.

5. The preparation method of the high-temperature superconducting tape for stacked cables according to claim 1, wherein, Step S2 includes the following steps: Step S2.1: Perform a primary cleaning treatment, a pre-copper plating treatment, a copper plating treatment, a side copper plating treatment on the strip to be processed in sequence, and then perform a secondary cleaning treatment; Step S2.2: Perform a passivation treatment and a drying treatment on the strip to be processed after the secondary cleaning treatment.

6. The preparation method of the high-temperature superconducting tape for stacked cables according to claim 5, wherein, Regarding the copper plating on the sanded surface, the surface roughness of the copper on the sanded surface is greater than 50 nm.

7. The preparation method of the high-temperature superconducting tape for stacked cables according to claim 5, characterized in that, The pre - copper plating treatment adopts the first - current electroplating treatment, and the current density adopted by the first current is 6 - 20 A / dm 2 ; The weight composition of the pre-copper plating electroplating solution is: 200 - 240 parts of copper sulfate; 50 - 70 parts of sulfuric acid; 0.08 - 0.1 part of chloride ion; The weight composition of the pre-acid copper plating additive is: 6 - 8 parts of the bath starter; 2 - 3 parts of the supplement; The copper plating treatment adopts a second-current electroplating treatment, and the current density adopted by the second current is 3-8 A / dm 2 ; The weight composition of the copper electroplating solution is: 180 - 220 parts of copper sulfate; 50 - 80 parts of sulfuric acid; 0.06 - 0.13 part of chloride ion; The side copper plating treatment adopts the third current electroplating treatment, and the current density adopted by the third current is 3-8 A / dm 2 ; The weight composition of the side copper plating electroplating solution is: 180 - 220 parts of copper sulfate; 50 - 80 parts of sulfuric acid; 0.06 - 0.13 part of chloride ion.

8. The preparation method of the high-temperature superconducting tape for stacked cables according to claim 5, wherein In electroless copper plating, a cathode, an anode, and a shielding plate are arranged in the electroplating cell. The cathode is the superconducting strip, the shielding plate is arranged between the cathode and the anode, and the shielding plate, the cathode, and the anode are all arranged parallel to each other; The shielding plate is provided with holes or grooves to allow the electric field lines to extend to the side and / or the front and / or the back of the superconducting strip.

9. The preparation method of the high-temperature superconducting tape for stacked cables according to claim 5, characterized in that, In electroless copper plating, a cathode, an anode, and a shielding plate are arranged in the electroplating cell. The cathode is the superconducting strip, the shielding plate is arranged between the cathode and the anode, and the shielding plate, the cathode, and the anode are all arranged parallel to each other; The shielding plate blocks the entire width part of the superconducting strip, and the shielding plate only allows the electric field lines to extend to the side of the superconducting strip.

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