Preparation method of high-temperature superconducting tape for stacked cables

Abstract

The invention provides a preparation method of a high-temperature superconducting tape for a stacked cable. The preparation method comprises the following steps: S1, additionally plating a protective layer on the side surface of a slit silver-plated superconducting tape; and S2, carrying out chemical copper plating on the superconducting tape of which the side surface is additionally plated with the protective layer. According to the method, the side protection layer of the superconducting tape is directionally plated, so that the thickness of the side protection layer is increased, the problem that the side protection layer is thin due to a traditional roll-to-roll copper protection layer plating method is solved, and the prepared superconducting tape has good soldering tin dipping resistance in the cable stacking processing process.

Description

Technical Field

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

[0002] The second-generation superconducting tape made of REBCO (Re is a rare earth element) is also called a coated conductor. Compared with bismuth-based tapes, it has a stronger current-carrying capacity, higher magnetic field performance and lower material cost, and has a wider and better application prospect in many fields such as medicine, military, and energy. The second-generation high-temperature superconducting tape is generally produced by a multi-layer coating process on a nickel-based alloy substrate because REBCO, which is the core of the superconducting current carrier, is hard and brittle. Therefore, it is also called a coated conductor. It is generally composed 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 strip. The role of the transition layer is to prevent the mutual diffusion of elements between the superconducting layer and the metal substrate. On the other hand, the top transition layer needs to provide a good template for the epitaxial growth of the superconducting layer and improve the quality of grain arrangement. To prepare a coated conductor with excellent superconducting properties, the superconducting layer needs to have a consistent biaxial texture. Biaxial texture means that the grains have almost consistent arrangement in both the a / b axis and the c axis (the c axis is perpendicular to the a / b plane).

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

[0005] There are many common technologies for preparing REBCO superconducting layers, 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 plated on the front and back surfaces of the superconducting tape by magnetron sputtering or evaporation. Then, according to the requirements of the tape width for specific applications, the 10 to 12 mm tape is cut into 2 to 8 mm. Finally, copper plating or subsequent packaging reinforcement treatment is performed.

[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 is highly dependent on strong magnetic fields to confine high-temperature plasma to produce fusion reactions. Its fusion power density per unit volume 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 fusion power density per unit volume 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 used a stacking method to manufacture it and finally dipped it in solder to make it a large, uninsulated magnet, ultimately breaking the 20T limit of large-caliber fusion magnets.

[0008] The entire layer magnet contains 16 individual pancake coils and two end plates at the top and bottom. The pancake coils consist of four main sub-components: 1) radial plates; 2) REBCO superconducting tape and copper co-wound stacks; 3) inner and outer bonding layers; 4) copper caps. Figure 1 As shown, the spiral channel inside is used for REBCO superconducting tape stacking. A stack of about 200 REBCO superconducting tapes is 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, it becomes an uninsulated coil, such as Figure 2 shown.

[0009] The entire coil weighs 5,113 kilograms and measures 2.9 meters by 1.9 meters. Therefore, it takes a lot of time for the solder to fully soak the stacked REBCO superconducting tapes and weld them as tightly as possible without any pores. At this time, the key bottleneck is that the REBCO superconducting tapes can withstand the high temperature of solder immersion without degradation.

[0010] The performance degradation of REBCO superconducting tape during solder dipping does not occur instantaneously, but gradually degrades over time. After dipping for 1 minute, the performance of the tape did not change significantly, and the structure of the tape did not change significantly, such as Figure 3 After 20 minutes of immersion, the copper protective layer of the strip changed significantly from the two sides to the middle, which destroyed the superconducting layer and caused 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] In the production process of REBCO superconducting tape, it is necessary to cut the 10-12mm wide silver-plated superconducting tape into different widths according to the specific application requirements. After cutting, there is no silver protective layer on the side of the tape, which makes it difficult for the copper protective layer to adhere to the side in the subsequent chemical copper plating process, resulting in the copper protective layer on the side being thinner than the middle part and becoming a weak point for solder immersion, such as Figure 5 shown.

[0012] Patent document CN110797148B discloses a superconducting tape suitable for uninsulated coils, uninsulated coils and preparation methods thereof, which adopts physical vapor deposition to plate the copper layer. Although the problem of copper protective 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 induced by molecular radiation, which has a very limited effect on the thickening effect of the copper protective layer on the side of the strip cross section. Figure 6 If the thickness of the protective layer on the side needs to be thickened, the thickness of the protective layer on the front and back sides of the strip needs to be thickened at the same time in the traditional preparation process, which will reduce the critical current density performance of the strip engineering and cannot meet the needs of the application end.

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

[0014] In view of the defects in the prior art, an object of the present invention is to provide a method for preparing a high temperature superconducting tape for stacked cables.

[0015] A method for preparing a high-temperature superconducting tape for a stacked cable provided by the present invention comprises the following steps: Step S1, adding a protective layer to the side of the cut silver-plated superconducting tape; Step S2, chemically copper plating the superconducting tape with the protective layer added on the side; With respect to step S1, the slit silver-plated superconducting tape is wound alone or together with a thin tape to form a disk, and a protective layer is directionally plated on the disk surface of the disk by a physical vapor deposition method; Preferably, 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 pulse sputtering.

[0016] Preferably, when the protective layer is directionally deposited on the disk surface of the disk-shaped strip by a physical vapor deposition method: the target material is located above the disk-shaped strip, and the protective layer is directionally deposited on the disk surface of the disk-shaped strip by a physical vapor deposition method; The center point of the target material is taken as the revolution center, and the center point of the disk-shaped strip material revolves around the revolution center; The disc-shaped strip rotates with the center point of the disc-shaped strip as the rotation center.

[0017] Preferably, in step S1, the silver protective layer is directionally plated on the side of the slit silver-plated superconducting tape, and the thickness of the silver protective layer directionally plated on the side of the silver-plated superconducting tape is 0.5 to 5 μm.

[0018] Preferably, with respect to step S1, the side surface of the slit silver-plated superconducting tape is first directionally plated with a silver protective layer and then directionally plated with a copper protective layer; The thickness of the silver protective layer directionally plated on the side of the silver-plated superconducting tape is 0.5 to 5 μm; The thickness of the copper protective layer plated by the silver protective layer is 0.2 to 5 μm.

[0019] Preferably, step S2 comprises the following steps: Step S2.1, the processed strip is sequentially subjected to a primary cleaning treatment, a pre-copper plating treatment, a sand surface copper plating treatment, a side copper plating treatment, and then a secondary cleaning treatment; Step S2.2, passivating and drying the processed strip after the secondary cleaning.

[0020] Preferably, for the sand-surface copper plating process, the surface roughness of the sand-surface copper is greater than 50 nm.

[0021] Preferably, the pre-copper plating treatment adopts a first current electroplating treatment, and the current density adopted by the first current is 6 to 20A / dm^2; The weight composition of the pre-copper plating solution is: 200-240 parts of copper sulfate; 50-70 parts of sulfuric acid; Chloride ion 0.08-0.1 part; The weight composition of the pre-plating acid copper additive is: 6 to 8 parts of tank opening agent; 2-3 servings of supplements; The copper plating process adopts a second current electroplating process, and the current density adopted by the second current is 3 to 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; Chloride ion 0.06-0.13 parts; The copper plating treatment on the side is carried out by electroplating with a third current, and the current density of the third current is 3 to 8 A / dm^2; The weight composition of the side copper plating solution is: 180-220 parts of copper sulfate; 50-80 parts of sulfuric acid; Chloride ion 0.06-0.13 parts.

[0022] Preferably, in chemical copper plating, a cathode, an anode and a shielding plate are arranged in the electroplating cell, 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 slots to allow the electric field lines to extend to the side and / or front and / or back sides of the superconducting tape.

[0023] Preferably, in chemical copper plating, a cathode, an anode and a shielding plate are arranged in the electroplating cell, 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 blocks the entire width of the superconducting tape, and the shielding plate only allows the electric field lines to extend to the sides of the superconducting tape.

[0024] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention increases the thickness of the side protective layer by directional plating on the side protective layer of the superconducting tape, solves the problem of thin side protective layer caused by the traditional roll-to-roll copper plating protective layer method, and makes the prepared superconducting tape have good resistance to solder immersion during the stacking cable processing.

[0025] 2. The present invention uses the center point of the target material as the revolution center, and the center point of the disc-shaped strip revolves around the revolution center, and uses the center point of the disc-shaped strip as the rotation center, and the disc-shaped strip rotates, which helps to improve the uniformity of physical vapor deposition coating.

[0026] 3. The present invention uses chemical copper plating, and the outermost surface is plated with sand copper, so that the surface of the material is relatively rough, and there is a certain friction in use, ensuring that the strip will not skip turns during high-tension stacking, winding and dipping. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings: Figure 1 Schematic diagram showing a spiral channel radial plate for REBCO superconducting tape stacking; Figure 2 Schematic diagram showing REBCO superconducting tape stack after solder dipping; Figure 3 Schematic diagram showing the cross section of a REBCO superconducting tape after immersion in solder for 1 minute; Figure 4A schematic diagram showing the cross section of a REBCO superconducting tape after 20 minutes of solder immersion; Figure 5 A schematic diagram showing that the copper protective layer on the side of the cross section of a REBCO superconducting tape without a silver protective layer on the side is thin after using the traditional electrochemical copper plating process; Figure 6 A schematic diagram showing the copper protective layer on the side of the cross section of a copper superconducting tape plated by the conventional physical method; Figure 7 This is a schematic diagram showing that the slit silver-coated superconducting tape is wound into a disk individually; Figure 8 A schematic diagram showing the slit silver-coated superconducting tape and thin ribbon wound into a disk; Fig. 9 A schematic diagram showing the revolution relationship between the disk-shaped strip and the coating target in the method for preparing the superconducting strip of the present invention; Fig.10 A cross-sectional schematic diagram is provided to show the shielding structure between the anode and the cathode during the pre-copper plating process and the sand surface copper plating process in the chemical copper plating of the present invention; Fig.11 A schematic cross-sectional view showing the shielding structure between the anode and the cathode when the side copper plating process is performed in the chemical copper plating of the present invention; Fig.12 A schematic diagram showing the cross section of a REBCO superconducting tape obtained by the method for preparing a superconducting tape of the present invention; Fig.13 A schematic diagram showing a cross section of a REBCO superconducting tape obtained by the method for preparing a superconducting tape of the present invention after being immersed in solder for 60 minutes; Fig.14 The figure is a schematic diagram showing the attenuation of the copper layer on the side of the superconducting tape of the present invention at different temperatures. DETAILED DESCRIPTION

[0028] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0029] Embodiment 1 like Figure 1 As shown, a method for preparing a high-temperature superconducting tape for a stacked cable provided by the present invention comprises the following steps: Step S1, adding a protective layer to the side of the cut silver-plated superconducting tape; Step S2, chemically copper plating the superconducting tape with the protective layer added on the side.

[0030] 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.

[0031] With respect to step S1, the slit silver-plated superconducting tape is wound alone or together with a thin tape to form a disk, and a protective layer is directionally plated on the disk surface of the disk-shaped tape by a physical vapor deposition method. The material of the thin tape includes any one or more of stainless steel, aluminum or Hastelloy alloy, and the thickness of the thin tape 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 pulse sputtering.

[0032] In a feasible embodiment: when the disk surface of the disk-shaped strip is directionally coated with a protective layer by a physical vapor deposition method: the target material is located above the disk-shaped strip, and the disk surface of the disk-shaped strip is directionally coated with a protective layer by a physical vapor deposition method, with the center point of the target material as the revolution center, the center point of the disk-shaped strip undergoes an orbital motion around the revolution center, and the center point of the disk-shaped strip is taken as the rotation center, and the disk-shaped strip undergoes a rotational motion. Specifically, the slit silver-plated superconducting tape is wound alone or wound with a thin tape to form a disk. Any one of the physical vapor deposition methods of radio frequency sputtering, medium frequency sputtering, direct current sputtering, and direct current pulse sputtering is used, and the same or different physical vapor deposition methods are used once or multiple times to directionally coat the side of the tape with a silver protective layer, and the target material for coating is a pure silver target. The side of the slit silver-plated superconducting tape is directionally coated with a silver protective layer, and the thickness of the silver protective layer directionally coated on the side of the silver-plated superconducting tape is 0.5 to 5 μm.

[0033] In another feasible implementation manner: for step S1, the side of the silver-plated superconducting tape after slitting is first directionally plated with a silver protective layer and then directionally plated with a copper protective layer; the thickness of the silver protective layer directionally plated on the side of the silver-plated superconducting tape is between 0.5 and 5 μm; the thickness of the copper protective layer directionally plated on the silver protective layer is between 0.2 and 5 μm. The slitting silver-plated superconducting tape is wound alone or wound with a thin tape to form a disc. First, any one of the physical vapor deposition methods of radio frequency sputtering, medium frequency sputtering, direct current sputtering, and direct current pulse sputtering is used, and the same or different physical vapor deposition methods are used once or multiple times to directionally plate a silver protective layer on the side of the tape, and the target material for the coating is a pure silver target. Then, a copper protective layer is directionally plated on the side of the tape, and any one of the physical vapor deposition methods of radio frequency sputtering, medium frequency sputtering, direct current sputtering, and direct current pulse sputtering is used, and the same or different physical vapor deposition methods are used once or multiple times to directionally plate a copper protective layer, and the target material for the coating is a pure copper target.

[0034] It should be noted that when the physical vapor deposition method is used for coating, the sputtering target is located above the disc-shaped strip to be plated, and the center point of the target is used as the revolution center, and the center point of the disc-shaped strip revolves around the revolution center. The center point of the disc-shaped strip is used as the rotation center, and the disc-shaped strip rotates, which can improve the uniformity of the physical vapor deposition coating.

[0035] Further, step S2 includes the following steps: Step S2.1: The processed strip is subjected to a primary cleaning process, a pre-coppering process, a sand surface copper plating process, and a side copper plating process, followed by a secondary cleaning process. Step S2.2: The processed strip after the secondary cleaning process is subjected to a passivation process and a drying process.

[0036] For the sand-coated copper treatment, the surface roughness of the sand-coated copper is greater than 50nm. The pre-copper plating treatment adopts a first current electroplating treatment, and the current density of the first current is 6 to 20 A / dm^2; The pre-copper plating solution used in the pre-copper plating treatment is added with a primary pre-plating acid copper additive that allows a current density of 6 to 20 A / dm^2 to work. The weight composition of the pre-copper plating solution is: 200-240 parts of copper sulfate; 50-70 parts of sulfuric acid; Chloride ion 0.08-0.1 part; The weight composition of the pre-plating acid copper additive is: 6 to 8 parts of tank opening agent; 2-3 servings of supplement.

[0037] The copper plating process adopts a second current electroplating process, and the current density adopted by the second current is 3 to 8 A / dm^2; The copper plating treatment uses a Shamian copper electroplating solution in which a Shamian copper acid copper additive that allows operation at a current density of 3 to 8 A / dm^2 is added. The weight composition of the Shamian copper electroplating solution is: 180-220 parts of copper sulfate; 50-80 parts of sulfuric acid; Chloride ion 0.06-0.13 parts.

[0038] The copper plating treatment on the side is carried out by electroplating with a third current, and the current density of the third current is 3 to 8 A / dm^2; The copper plating solution used for the copper plating treatment on the side is added with a copper acid additive that allows a current density of 3 to 8 A / dm^2 to work. The weight composition of the copper plating solution on the side is: 180-220 parts of copper sulfate; 50-80 parts of sulfuric acid; Chloride ion 0.06-0.13 parts.

[0039] More specifically, in chemical copper plating, a cathode, an anode and a shielding plate are arranged in the electroplating pool, the shielding plate can shield the 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 arranged parallel to each other; the shielding plate is arranged with holes or slots, allowing 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 the first chemical copper plating of the superconducting tape is completed, the following equipment is used to carry out secondary chemical copper plating. In chemical copper plating, a cathode, an anode and a shielding plate are arranged in the electroplating pool, 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 arranged parallel to each other; the shielding plate blocks the entire width of the superconducting tape, and the shielding plate only allows the electric field lines to extend to the side of the superconducting tape.

[0040] It should be further explained 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 hole or slot 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 copper plating thickness on the side of the superconducting tape can be directionally enhanced by secondary chemical copper plating, and the secondary chemical copper plating can be performed multiple times until the thickness of the copper plating on the side of the superconducting tape meets the design requirements.

[0041] Specifically, a cathode and an anode are arranged in the electroplating cell, 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 a plurality of through holes or through grooves are arranged on the shielding plate, and the area of ​​the through holes or through grooves is 0.2 to 0.6 times that of the cathode.

[0042] When directionally strengthening the thickness of the side of the superconducting tape, a cathode and an anode are arranged in the electroplating pool. The cathode is the superconducting tape, and 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 of the superconducting tape, and the area of ​​the anode is 1 to 2 times that of the cathode.

[0043] It should be noted that chemical copper plating is copper plating for the entire silver-plated superconducting strip. The copper is plated by chemical method, and the outermost surface is plated with sand copper, which makes the surface of the material rougher. There is a certain friction in use to ensure that the strip will not skip turns during high-tension stacking and impregnation. The shielding plate can ensure that the thickness of the strip after chemical copper plating is within the design allowable range. During chemical copper plating, copper is only plated where the electric field lines on the superconducting strip can reach.

[0044] It needs further explanation: Fig.14 As 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 of the present application satisfies: the copper layer on the side of the superconducting tape is not completely melted during immersion welding, thereby ensuring that the performance of the superconducting tape is not degraded.

[0045] Embodiment 2 Based on the first embodiment, a method for preparing a high temperature superconducting tape for a stacked cable provided by the present invention comprises the following steps: Step 1: Directly increase the protective layer on the side of the cut silver-plated superconducting tape; Step 2: Electroless copper plating is performed on the superconducting tape after step 1.

[0046] In step 1, the side edges of the superconducting tapes cut into different widths are subjected to directionally increasing silver protective layer plating and then directionally increasing copper protective layer plating or only directionally increasing silver protective layer plating. The thickness of the silver protective layer on the side edges is 0.5 to 5 μm. The specific steps are: Step 1.1: Winding the slit silver-plated superconducting tape alone or together with a thin tape to form a disk; The winding speed is 100-1000 m / h, and the winding tension is 50-500 MPa.

[0047] The thin strip is made of stainless steel, aluminum or Hastelloy, and has a thickness of 30-1000 μm.

[0048] Step 1.2: The surface of the coiled tape, i.e., the side of the superconducting tape, is directionally plated with a silver protective layer by physical vapor deposition.

[0049] Use any of the following physical vapor deposition methods: RF sputtering, medium frequency sputtering, DC sputtering or DC pulsed sputtering, one or more times using the same or different processes to increase the side direction of the strip silver Protective layer.

[0050] Preferably, the sputtering power is 0.1-3KW, the working gas is argon, the argon flow rate is 10-200sccm, and the back vacuum is 10 -7 ~10 -5 Torr, the pressure in the chamber during coating is 10~100mTorr, the target material for coating is pure silver target, and the target-substrate distance is 20~100mm.

[0051] Preferably, the target is located above the disc-shaped strip, with the center point of the target as the revolution center, the center point of the disc-shaped strip revolves around the revolution center, the revolution diameter is 50-500 mm, the revolution rate is 0.5-5 revolutions / min, the center point of the disc-shaped strip is the rotation center, the disc-shaped strip revolves, the rotation rate is 1-10 revolutions / min, and the mode of self-rotation combined with revolution is used to improve the plating of the side of the disc-shaped strip. silver Thickness uniformity of the protective layer.

[0052] The step 1.3 specifically comprises: directing the coating of the side of the superconducting tape after the step 1 by physical vapor deposition. copper Protective layer, side copper The thickness of the protective layer is 0.5~5μm.

[0053] Use any of the following physical vapor deposition methods: RF sputtering, medium frequency sputtering, DC sputtering or DC pulsed sputtering, one or more times using the same or different processes to increase the side direction of the strip copper Protective layer.

[0054] The sputtering power is 0.1~3KW, the working gas is argon, the argon flow rate is 10~200sccm, and the back vacuum is 10 -7 ~10 -5 Torr, the pressure in the chamber during coating is 10~100mTorr, and the target material for coating is pure copper Target, target-base distance is 20~100mm.

[0055] The target is located above the disc-shaped strip. The center point of the target is the revolution center. The center point of the disc-shaped strip revolves around the revolution center. The revolution diameter is 50~500mm, and the revolution rate is 0.5~5 turns / min. The center point of the disc-shaped strip is the rotation center. The disc-shaped strip rotates at a rotation rate of 1~10 turns / min. The mode of combining rotation with revolution is used to improve the plating of the side of the disc-shaped strip. copper Thickness uniformity of the protective layer.

[0056] In the step 2, chemical copper plating is performed on the superconducting tape after the step 1, which specifically includes the following steps: Step 2.1: The processed strip is sequentially subjected to a primary cleaning process, a pre-copper plating process, a sand surface copper plating process, a side copper plating process, and then a secondary cleaning process; Step 2.2: Passivation treatment and drying treatment are performed on the processed strip after the secondary cleaning treatment.

[0057] The surface roughness of the sanded copper is greater than 50 nm.

[0058] The pre-copper plating treatment adopts a first current electroplating treatment, the sand surface copper plating treatment adopts a second current electroplating treatment, and the side copper plating treatment adopts a third current electroplating treatment.

[0059] The current density used by the first current is 6-20 A / dm^2, the current density used by the second current is 3-8 A / dm^2, and the current density used by the third current is 3-8 A / dm^2.

[0060] The pre-copper plating solution used in the pre-copper plating treatment is added with a pre-copper acid additive that allows operation at a current density of 6 to 20 A / dm^2, and the weight composition of the pre-copper plating solution is: 200-240 parts of copper sulfate; 50-70 parts of sulfuric acid; Chloride ion 0.08-0.1 part; The copper electroplating solution used in the copper plating treatment is added with copper acid additives that allow operation at a current density of 3 to 8 A / dm^2. The copper electroplating solution has a weight composition of: 180-220 parts of copper sulfate; 50-80 parts of sulfuric acid; Chloride ion 0.06-0.13 parts; The copper plating solution used in the copper plating treatment on the side is added with a copper acid additive that allows the current density of 3 to 8 A / dm^2 to work. The weight composition of the copper plating solution on the side is: 180-220 parts of copper sulfate; 50-80 parts of sulfuric acid; Chloride ion 0.06-0.13 parts.

[0061] The weight composition of the pre-plating acid copper additive is: 6 to 8 parts of tank opening agent; 2-3 servings of supplement.

[0062] In the step 2.1, the pre-copper plating treatment and the sand-surface copper plating treatment are performed, a shielding plate is arranged between the anode and the cathode, the cathode is a superconducting tape, and the shielding plate is arranged between the superconducting tape and the anode, and is arranged parallel to the cathode and the anode; a plurality of through holes are arranged on the shielding plate, and the area of ​​the through holes is 0.2 to 0.6 times that of the cathode.

[0063] In the step 2.1, the side is copper-plated, and a shielding plate is arranged between the anode and the cathode with copper-plated sides. The cathode is a superconducting tape, and the shielding plate is arranged between the superconducting tape and the anode, and is arranged parallel to the cathode and the anode; the shielding plate blocks the full width of the superconducting tape, and the area of ​​the anode is 1 to 2 times that of the cathode.

[0064] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0065] The above describes the specific embodiments of the present invention. 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 does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A method for preparing a high temperature superconducting tape for stacked cables, characterized in that: The steps include: Step S1, adding a protective layer to the side of the cut silver-plated superconducting tape; Step S2, chemically copper plating the superconducting tape with the protective layer added on the side; With respect to step S1, the slit silver-plated superconducting tape is wound alone or together with a thin tape to form a disk, and a protective layer is directionally plated on the disk surface of the disk by a physical vapor deposition method.

2. The method for preparing a 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, direct current sputtering or direct current pulse sputtering.

3. The method for preparing a high temperature superconducting tape for stacked cables according to claim 2, characterized in that: When the protective layer is directionally deposited on the disk surface of the disk-shaped strip by the physical vapor deposition method: the target material is located above the disk-shaped strip, and the protective layer is directionally deposited on the disk surface of the disk-shaped strip by the physical vapor deposition method; The center point of the target material is taken as the revolution center, and the center point of the disk-shaped strip material revolves around the revolution center; The disc-shaped strip rotates with the center point of the disc-shaped strip as the rotation center.

4. The method for preparing a high temperature superconducting tape for stacked cables according to claim 1, characterized in that: With respect to step S1, a silver protective layer is directionally plated on the side of the slit silver-plated superconducting tape, and the thickness of the silver protective layer directionally plated on the side of the silver-plated superconducting tape is 0.5 to 5 μm.

5. The method for preparing a high temperature superconducting tape for stacked cables according to claim 1, characterized in that: In step S1, a silver protective layer is firstly directionally plated and then a copper protective layer is directionally plated on the side of the cut silver-plated superconducting tape; The thickness of the silver protective layer directionally plated on the side of the silver-plated superconducting tape is 0.5 to 5 μm; The thickness of the copper protective layer directionally plated on the silver protective layer plated on the side of the silver-plated superconducting tape is 0.2 to 5 μm.

6. The method for preparing a high temperature superconducting tape for stacked cables according to claim 1, characterized in that: Step S2 includes the following steps: Step S2.1, the processed strip is sequentially subjected to a primary cleaning treatment, a pre-copper plating treatment, a copper plating treatment, a side copper plating treatment, and then a secondary cleaning treatment; Step S2.2, passivating and drying the processed strip after the secondary cleaning.

7. The method for preparing a high temperature superconducting tape for stacked cables according to claim 6, characterized in that: For the sand-surface copper plating treatment, the surface roughness of the sand-surface copper is greater than 50nm.

8. The method for preparing a high temperature superconducting tape for stacked cables according to claim 6, characterized in that: The pre-copper plating treatment adopts a first current electroplating treatment, and the current density adopted by the first current is 6 to 20A / dm^2; The weight composition of the pre-copper plating solution is: 200-240 parts of copper sulfate; 50-70 parts of sulfuric acid; Chloride ion 0.08-0.1 part; The weight composition of the pre-plating acid copper additive is: 6 to 8 parts of tank opening agent; 2-3 servings of supplements; The copper plating process adopts a second current electroplating process, and the current density adopted by the second current is 3 to 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; Chloride ion 0.06-0.13 parts; The copper plating treatment on the side is carried out by electroplating with a third current, and the current density of the third current is 3 to 8 A / dm^2; The weight composition of the side copper plating solution is: 180-220 parts of copper sulfate; 50-80 parts of sulfuric acid; Chloride ion 0.06-0.13 parts.

9. The method for preparing a high temperature superconducting tape for stacked cables according to claim 6, characterized in that: In chemical copper plating, a cathode, an anode and a shielding plate are arranged in the electroplating cell, 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 slots to allow the electric field lines to extend to the side and / or front and / or back sides of the superconducting tape.

10. The method for preparing a high temperature superconducting tape for stacked cables according to claim 6, characterized in that: In chemical copper plating, a cathode, an anode and a shielding plate are arranged in the electroplating cell, 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 blocks the entire width of the superconducting tape, and the shielding plate only allows the electric field lines to extend to the sides of the superconducting tape.

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