Method of copper plating superconducting tape

Abstract

The application provides a copper plating method for superconducting tape, which comprises the following steps: firstly, carrying out bright copper plating treatment on the processed tape; and then, carrying out sand surface copper plating treatment on the tape. The bright copper plating treatment adopts third current electroplating treatment, and the sand surface copper plating treatment adopts second current electroplating treatment. The current density of the third current is 0.5-3.5 A / dm 2 , and the current density of the second current is 3-8 A / dm 2 . By means of the bright copper plating treatment and then the sand surface copper plating treatment, the outer surface of the tape forms a sand surface, which can effectively prevent the axial sliding deviation of the wound coil cake.

Description

[0001] This application is a divisional application of the following original application:

[0002] --The original application was filed on March 31, 2021.

[0003] --Original application number: 202110352165.5

[0004] --Original application title: Method for pre-plating copper onto superconducting tape, copper plating method and copper plating apparatus Technical Field

[0005] This invention relates to the field of superconducting materials technology, and more specifically, to a method for copper plating on superconducting tapes. Background Technology

[0006] Since Professor Kamerling Onnes of Leiden University in the Netherlands first discovered superconductivity in his laboratory in 1911, superconducting materials and their applications have been one of the most active and cutting-edge research areas in contemporary science and technology. Over the past decade or so, research on superconducting power devices, primarily superconducting, has progressed rapidly, achieving significant results in areas such as superconducting energy storage, superconducting motors, superconducting cables, superconducting current limiters, superconducting transformers, superconducting magnetic levitation, and nuclear magnetic resonance.

[0007] High-temperature superconducting materials are divided into first-generation and second-generation. First-generation materials are mainly composed of silver-clad BSCCO materials, while second-generation materials are mainly composed of ReBCO coating materials with a superconducting layer. Before the maturity of second-generation tapes, large magnets generally used first-generation tapes to fabricate high-temperature superconducting current leads. Since 70% of the material in the first-generation tape is silver, it has a relatively large heat leakage. Therefore, manufacturers of first-generation tapes have developed Bi-2223 / Ag-Au silver-gold tapes.

[0008] Second-generation superconducting tapes using ReBCO (Re being a rare earth element) as the material, also known as coated conductors, have broader and better application prospects in many fields such as medicine, military, and energy due to their stronger current-carrying capacity, higher magnetic field performance, and lower material cost compared to bismuth-based tapes. Because the ReBCO core, which serves as the superconducting current-carrying core, is hard and brittle, second-generation superconducting tapes are generally produced using a multi-layer coating process on a nickel-based alloy substrate, hence the name coated conductor. Second-generation superconducting tapes typically consist of a base tape, a buffer layer (transition layer), a superconducting layer, and a protective layer. The metal substrate provides excellent mechanical properties for the tape. The transition layer serves two purposes: firstly, it prevents inter-element diffusion between the superconducting layer and the metal substrate; secondly, the topmost transition layer provides a good template for the epitaxial growth of the superconducting layer, improving the grain alignment quality of YBCO (yttrium barium copper oxide). To prepare coated conductors with excellent superconducting properties, the superconducting layer needs to have a consistent biaxial texture. Biaxial texture refers to the near-uniform alignment of grains along both the a / b axis and the c-axis (the c-axis is perpendicular to the a / b plane). Since achieving a high degree of alignment along the a / b axis (in-plane texture) in YBCO thin films is relatively difficult, and poor in-plane texture severely degrades superconducting performance, it is necessary to epitaxially grow YBCO superconducting thin films on transition layers that already possess biaxial texture and a matching lattice. There are two main technical routes for fabricating biaxial texture: roll-assisted biaxial texture substrate technology and ion beam-assisted deposition technology. Common techniques for fabricating ReBCO superconducting layers include pulsed laser deposition, metal-organic chemical vapor deposition, and reactive co-evaporation.

[0009] The protective layer primarily protects the superconducting film. Typically, a 0.5–5 μm silver layer is deposited on both sides of the superconducting tape using magnetron sputtering or evaporation. To achieve lower material costs, the silver layer on the superconducting side is usually 1–2 μm thick, while the silver layer on the non-superconducting side is typically 0.5–1 μm thick. Subsequently, depending on the application's width requirements, the 10–12 mm tape is cut into 2–8 mm pieces. Finally, copper plating or subsequent encapsulation reinforcement is performed. The copper plating thickness for subsequent encapsulation can be 1–10 μm. For copper-reinforced tapes, the copper plating thickness on one side is 10–30 μm, while on both sides it reaches 20–60 μm.

[0010] The quality of the copper plating protective layer directly affects the application of superconducting tapes. Patent document CN110797148A discloses a superconducting tape suitable for uninsulated coils, an uninsulated coil, and its preparation method. The superconducting tape uses electrochemical copper plating, and its cross-section exhibits a bone-like structure where the copper plating layer is larger at both ends than in the middle. This affects the winding of the tape. A smooth, flat surface of the superconducting tape can cause axial slippage and displacement of the wound uninsulated coil disc, resulting in a conical shape. Even without a bone-like structure, this problem is prone to occur, making the uninsulated coil unsuitable for subsequent applications. Therefore, products typically require an overall deviation in tape cross-sectional thickness within ±5μm, and some precision equipment requires an overall deviation within ±3μm. There are also certain requirements for the surface roughness of the copper on the tape: Pa > 100nm.

[0011] Copper electroplating also requires high efficiency; however, higher current densities lead to more intense electric field concentration at the ends or sharp points of the strip cross-section, resulting in a bone-like shape. To meet the overall deviation in strip cross-section thickness, the electroplating current density is limited to a low level. Improving copper electroplating efficiency can only be achieved by extending the production line. Typically, electroplating production lines are 10–100 meters long.

[0012] Superconducting tapes undergo thermal cycling during use. During the reheating process, a large amount of water inevitably forms on the surface of the superconducting tape. This water reacts directly with the superconducting material, damaging its performance. Therefore, the ability of the copper plating layer on the superconducting tape to form a complete cladding structure, is crucial to preventing corrosion from moisture. Even with magnetron sputtering or vapor deposition of silver on the superconducting tape surface, micropores still exist, such as... Figure 2 As shown, the silver layer cannot form a complete enclosure for the superconducting layer. During the electroplating process, the liquid reacts directly with the superconducting material, thereby damaging the performance of the superconducting material. Different degrees of blistering will appear on the surface of the strip after silver plating, such as... Figure 6 , Figure 7 The images shown depict blistering on the surface after copper electroplating, which can become severe, as shown in the image. Figure 8 The situation described significantly impacts product quality. Therefore, ensuring that the copper plating layer of the superconducting tape forms a complete sheath structure to isolate the superconducting layer from liquid corrosion becomes crucial. Solving this problem is therefore extremely challenging.

[0013] In terms of electroplating solution selection, there are many types of copper plating solutions. According to the acidity or alkalinity of the solution, copper plating solutions can be divided into acidic copper plating and alkaline copper plating. According to the presence or absence of cyanide, copper plating solutions can be divided into cyanide copper plating and cyanide-free copper plating. According to the type of complexing agent, copper plating solutions can be divided into cyanide copper plating, sulfate copper plating, pyrophosphate copper plating, citric acid-tartrate copper plating, etc. In the electroplating industry, considering the easier treatment of wastewater, acidic copper plating solutions containing organic additives are commonly used. There are two types of acidic copper plating solutions: "high copper, low acid" and "high acid, low copper". Studies have shown that "high copper, low acid" solutions have higher copper plating efficiency, while "high acid, low copper" solutions have better dispersion and coverage. Copper sulfate, as the main salt in the plating solution, provides the copper ions necessary for electroplating. Too low a copper sulfate content will lower the upper limit of current density, ultimately reducing the deposition rate. Too high a copper sulfate content will worsen the dispersion ability of the plating solution. Acidic copper plating solutions contain inorganic salts and organic additives. Inorganic salts include copper sulfate, sulfuric acid, and chloride ions. Organic additives include brighteners, stretching agents, wetting agents, and leveling agents. Regardless of the electroplating solution preparation, the brighter the plated surface, the smaller the bone structure of the strip. The lower the current density, the smaller the bone structure of the strip. During the electroplating process, if a bright copper solution is used entirely to plate the surface of the superconducting strip, the surface will be smooth and flat. If a matte copper solution is used entirely, the surface will have a matte copper structure, affecting the winding of the strip.

[0014] Patent document CN108342757B discloses a method for preparing a protective layer for high-temperature superconducting tape by electroplating copper, including the following steps: Step 1, preparing a copper protective layer for high-temperature superconducting tape by electroplating copper; Step 2, electroplating copper on the back substrate of the superconducting layer. However, this design still cannot solve the problem that liquids can contact the tape through the holes in the silver-plated surface and affect the performance of the tape.

[0015] In summary, the above-mentioned complex technical problems in copper plating of superconducting tapes urgently need to be solved. Summary of the Invention

[0016] To address the shortcomings of existing technologies, the present invention aims to provide a method for pre-plating copper in superconducting tapes, a copper plating method, and a copper plating apparatus.

[0017] According to the present invention, a method for pre-plating copper on a superconducting tape is provided, wherein the tape to be processed is pre-plated with copper using a first current;

[0018] The pre-plating copper treatment uses a pre-plating copper electroplating solution with added pre-plating additives that allow operation at a first current density.

[0019] Preferably, the preset current uses a current density of 6–20 A / dm². 2 .

[0020] Preferably, the weight composition of the pre-plated copper electroplating solution is as follows:

[0021] 200-240 parts of copper sulfate;

[0022] 50-70 parts of sulfuric acid;

[0023] Chloride ions: 0.08–0.1 parts.

[0024] Preferably, the pre-plating copper electroplating solution is a sand-surface copper electroplating solution, and the weight composition of the sand-surface copper electroplating solution is as follows:

[0025] 180-220 parts of copper sulfate;

[0026] 50-80 parts of sulfuric acid;

[0027] Chloride ions: 0.06–0.13 parts.

[0028] A method for copper plating on superconducting tape according to the present invention includes the following steps:

[0029] S1: The strip to be processed is subjected to a first cleaning treatment, a bright copper plating treatment, a sandblasted copper plating treatment, and then a second cleaning treatment.

[0030] S2: Passivation and drying treatment of the strip material after secondary cleaning.

[0031] Preferably, in S1, a pre-plating copper treatment is performed before the bright copper plating treatment. The pre-plating copper treatment uses a first current electroplating treatment, the bright copper plating treatment uses a third current electroplating treatment, and the sandblasted copper plating treatment uses a second current electroplating treatment.

[0032] Preferably, the current density used for the first current is 6–20 A / dm². 2 The third current uses a current density of 0.5–3.5 A / dm³. 2 The second current uses a current density of 3–8 A / dm³. 2 .

[0033] Preferably, the copper plating solution used in the pre-plating copper treatment contains an allowable concentration of 6-20 A / dm³. 2 The pre-plating acid copper additive for current density operation, and the weight composition of the pre-plating copper electroplating solution are as follows:

[0034] 200-240 parts of copper sulfate;

[0035] 50-70 parts of sulfuric acid;

[0036] Chloride ions: 0.08–0.1 parts;

[0037] The bright copper plating process uses a bright copper plating solution with an allowable concentration of 0.5–3.5 A / dm³.2 The bright copper oxide additive for current density operation, the weight composition of the bright copper plating solution is as follows:

[0038] Copper sulfate 60-100 parts;

[0039] 170-200 parts of sulfuric acid;

[0040] Chloride ions: 0.06–0.09 parts;

[0041] The sandblasted copper plating treatment uses a sandblasted copper electroplating solution with an allowable concentration of 3-8 A / dm³. 2 The current density-operated copper oxide additive for sand-surfaced copper plating solution has the following weight composition:

[0042] 180-220 parts of copper sulfate;

[0043] 50-80 parts of sulfuric acid;

[0044] Chloride ions: 0.06–0.13 parts.

[0045] According to the present invention, a copper plating apparatus for superconducting strips includes a feeding mechanism, a first cleaning mechanism, a bright copper plating mechanism, a sandblasted copper plating mechanism, a second cleaning mechanism, a passivation mechanism, a drying mechanism, and a receiving mechanism.

[0046] The unwinding mechanism is used to unwind the strip being processed. During processing, the strip passes through the first cleaning mechanism, the bright copper plating mechanism, the sandblasted copper plating mechanism, the second cleaning mechanism, the passivation mechanism, and the drying mechanism in sequence, and is then wound onto the receiving mechanism.

[0047] Preferably, it further includes a pre-plating copper mechanism, which is disposed between the first cleaning mechanism and the bright copper plating mechanism. The pre-plating copper mechanism uses a first current electroplating process, the bright copper plating mechanism uses a third current electroplating process, and the sandblasted copper plating mechanism uses a second current electroplating process.

[0048] Preferably, the current density used for the first current is 6–20 A / dm². 2 The third current uses a current density of 0.5–3.5 A / dm³. 2 The second current uses a current density of 3–8 A / dm³. 2 .

[0049] Preferably, the width of the strip being processed is greater than 3 mm.

[0050] Preferably, the inlet and outlet of the pre-plating copper mechanism, the inlet and outlet of the bright copper plating mechanism, and the inlet and outlet of the sandblasting copper plating mechanism are respectively equipped with air knives for blowing air;

[0051] The drying mechanism adopts an adjustable carbon fiber far-infrared tube heating mechanism.

[0052] In the pre-plating copper mechanism, the bright copper plating mechanism, and the sandblasting copper plating mechanism, shielding structures are respectively provided on both sides along the length direction of the strip being processed.

[0053] Preferably, the passivation mechanism includes a passivation tank, which provides anti-oxidation protection for the copper layer. The temperature of the passivation solution placed in the passivation tank is between 30 and 90°C, and the passivation tank is made of 20-25mm PP board.

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

[0055] 1. In the electroplating process, the present invention first performs a pre-plating copper operation by using a preset current to quickly coat the surface of the strip with copper. This effectively prevents liquid from contacting the strip through the pores of the silver-plated surface and affecting the performance of the strip. This solves the problem of liquid corrosion of the superconducting layer. The copper plating layer forms a complete cladding, which greatly improves the quality of the strip.

[0056] 2. The present invention forms a sand-like surface on the outer surface of the strip by applying a sand-plated copper treatment, which can effectively prevent axial sliding and displacement of the wound coil disc.

[0057] 3. The copper plating device in this invention adopts a long-line processing structure design, which improves the electroplating efficiency. In addition, a shielding structure is set up during the copper plating process, and the electric field lines are uniform and not concentrated, which can effectively avoid the bone-shaped structure in the prior art. The cross-sectional bone shape is small, and the overall deviation of the strip cross-sectional thickness reaches ±1μm, ensuring the quality of the superconducting strip.

[0058] 4. The copper plating solution used in this invention is preferably a sand-surface copper plating solution, which can also increase the effect and speed of pre-plating to a certain extent.

[0059] 5. The copper plating device in this invention can use multiple processing lines arranged in parallel to process simultaneously, which improves processing efficiency and makes full use of the site space. Attached Figure Description

[0060] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0061] Figure 1 This is a flowchart of the copper plating method for superconducting tapes in this invention;

[0062] Figure 2 This is a schematic diagram of the microscopic pores on the surface of the superconducting silver-plated strip under a high-magnification microscope in this invention;

[0063] Figure 3This is a schematic diagram of the structure of the copper plating device for superconducting strips in this invention. The dashed boxes in the figure represent the processing equipment for the strips. The first cleaning mechanism, the pre-plating copper mechanism, the bright copper plating mechanism, the sandblasted copper plating mechanism, the second cleaning mechanism, the passivation mechanism, the drying mechanism, and the guide wheels are all arranged in a straight production line within the dashed boxes and are omitted in the figure.

[0064] Figure 4 A schematic diagram of the arrangement of multiple parallel superconducting strip copper plating devices;

[0065] Figure 5 This is a structural schematic diagram of the cross-section of the shielding plate and strip;

[0066] Figure 6 This is a schematic diagram of surface blistering after copper plating of superconducting tapes in existing technologies.

[0067] Figure 7 This is another schematic diagram showing blistering on the surface of superconducting strips after copper plating in existing technology.

[0068] Figure 8 This is another schematic diagram showing blistering on the surface of superconducting tape after copper plating in existing technology.

[0069] The diagram shows:

[0070] Feeding mechanism 1, Drying mechanism 7

[0071] First cleaning unit 2, material receiving unit 8

[0072] Pre-plating copper mechanism 3 Workpiece strip 9

[0073] Copper plating mechanism 4, guide wheel 10

[0074] Second cleaning mechanism 5 Shielding plate 11

[0075] Passivation mechanism 6 Detailed Implementation

[0076] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0077] Example 1:

[0078] This invention provides a method for pre-plating copper onto superconducting strips, applicable not only to electroplating narrow strips (e.g., strips with widths of 1 mm to 3 mm) but also to wide strips (e.g., strips with widths greater than 3 mm). The pre-plating method achieves the desired effect. The method involves pre-plating the strip 9 with a first current. The pre-plating solution contains pre-plating additives that allow operation at the first current density. The preset current density is 6–20 A / dm³. 2 The weight composition of the pre-plated copper electroplating solution is as follows:

[0079] 200-240 parts of copper sulfate;

[0080] 50-70 parts of sulfuric acid;

[0081] Chloride ions: 0.08–0.1 parts.

[0082] Specifically, the pre-plating additive is an acid copper additive, and the weight composition of the acid copper additive is as follows:

[0083] Use 6-8 parts of starter and 2-3 parts of supplement.

[0084] In the actual copper pre-plating process, since the growth rate of matte copper on the strip is greater than that of bright copper, in order to ensure smooth pre-plating and obtain better pre-plating speed and effect, the pre-plating copper electroplating solution is preferably a matte copper electroplating solution, and the weight composition of the matte copper electroplating solution is as follows:

[0085] 180-220 parts of copper sulfate;

[0086] 50-80 parts of sulfuric acid;

[0087] Chloride ions: 0.06–0.13 parts.

[0088] This invention also provides a method for copper plating on superconducting tapes, such as... Figure 1 As shown, it includes the following steps:

[0089] S1: The strip 9 to be processed undergoes a first cleaning treatment, a bright copper plating treatment, a sandblasted copper plating treatment, and then a second cleaning treatment. Before the bright copper plating treatment, a pre-copper plating treatment is performed. The pre-copper plating treatment uses a first current electroplating treatment, the bright copper plating treatment uses a third current electroplating treatment, and the sandblasted copper plating treatment uses a second current electroplating treatment. The current density used in the first current plating treatment is 6-20 A / dm. 2 The third current uses a current density of 0.5–3.5 A / dm³. 2 The second current uses a current density of 3–8 A / dm³. 2The surface roughness Pa of the copper in the superconducting tape produced in this invention is greater than 200 nm.

[0090] S2: Passivation and drying treatment are performed on the strip material 9 after secondary cleaning.

[0091] Furthermore, the copper plating solution used in the pre-plating copper treatment contains an allowable concentration of 6–20 A / dm³. 2 The pre-plating copper plating solution used for current density operation has the following weight composition: 200-240 parts copper sulfate; 50-70 parts sulfuric acid; and 0.08-0.1 parts chloride ions. For example, the pre-plating copper plating solution may have a composition of 200-240 g / L copper sulfate, 50-70 g / L sulfuric acid, and 80-100 mg / L chloride ions. The bright copper plating treatment uses a bright copper plating solution with an allowable addition of 0.5-3.5 A / dm³. 2 The bright copper plating solution used for current density operation contains copper sulfate additives. The bright copper plating solution has the following weight composition: 60-100 parts copper sulfate; 170-200 parts sulfuric acid; and 0.06-0.09 parts chloride ions. For example, the bright copper plating solution may have a composition of 60-100 g / L copper sulfate, 170-200 g / L sulfuric acid, and 60-90 mg / L chloride ions. The sandblasted copper plating solution used for the sandblasted copper plating treatment contains an allowable additive of 3-8 A / dm³. 2 The copper sulfate additive for sand-surfaced copper plating solution operates at current density. The weight composition of the sand-surfaced copper plating solution is: 180-220 parts copper sulfate; 50-80 parts sulfuric acid; and 0.06-0.13 parts chloride ions. For example, the sand-surfaced copper plating solution uses 180-220 g / L copper sulfate, 50-80 g / L sulfuric acid, and 60-130 mg / L chloride ions.

[0092] This invention also provides a copper plating apparatus for superconducting strips. This invention is particularly suitable for processing strips 9 with a width greater than 3 mm. During processing, the strip being processed in one operation is relatively long, for example, 33 meters. The copper plating apparatus for superconducting strips includes a feeding mechanism 1, a first cleaning mechanism 2, a bright copper plating mechanism 4, a sandblasted copper plating mechanism 5, a second cleaning mechanism 5, a passivation mechanism 6, a drying mechanism 7, and a receiving mechanism 8. It adopts a long-line processing method. A linearly arranged processing production line is formed sequentially. The first cleaning mechanism 2 includes a first cleaning tank, the second cleaning mechanism 5 includes a second cleaning tank, the bright copper plating mechanism 4 includes a bright copper plating tank, the sandblasted copper plating mechanism includes a sandblasted copper plating tank, and the passivation mechanism 6 includes a passivation tank. The unwinding mechanism 1 is used to unwind the processed strip 9, which passes sequentially through the first cleaning mechanism 2, the bright copper plating mechanism 4, the sandblasted copper plating mechanism, the second cleaning mechanism 5, the passivation mechanism 6, and the drying mechanism 7 before being wound onto the receiving mechanism 8. The processed strip 9 is preferably a superconducting strip. This invention employs a linearly arranged processing production line structure, allowing for multiple processing lines to be arranged in parallel during processing, such as... Figure 4 As shown, this can improve processing efficiency and increase the space utilization efficiency of the factory.

[0093] Specifically, it also includes a pre-plating copper mechanism 3, which includes a copper pre-plating tank. The pre-plating copper mechanism 3 is disposed between the first cleaning mechanism 2 and the bright copper plating mechanism 4. The pre-plating copper mechanism 3 uses a first current electroplating treatment, the bright copper plating mechanism 4 uses a third current electroplating treatment, and the sandblasted copper plating mechanism uses a second current electroplating treatment. The current density of the first current is 6-20 A / dm³. 2 The third current uses a current density of 0.5–3.5 A / dm³. 2 The second current uses a current density of 3–8 A / dm³. 2 .

[0094] Specifically, the inlet and outlet of the pre-plating copper mechanism 3, the inlet and outlet of the bright copper plating mechanism 4, and the inlet and outlet of the sandblasting copper plating mechanism are respectively equipped with air knives to reduce the loss of electroplating solution. The drying mechanism 7 uses an adjustable carbon fiber far-infrared tube heating mechanism to dry the strip. Shielding structures are respectively provided on both sides of the processed strip 9 along the length direction of the pre-plating copper mechanism 3, the bright copper plating mechanism 4, and the sandblasting copper plating mechanism. The shielding structure preferably uses a shielding plate 11. Figure 5 As shown, the shielding plate 11 ensures that the current passes through a relatively flat electric field, thus ensuring the electroplating effect.

[0095] The copper plating apparatus for superconducting strips in this invention can preferably be used to perform electroplating operations using the copper plating method for superconducting strips in this invention.

[0096] Example 2:

[0097] This embodiment is a preferred example of Embodiment 1.

[0098] In this embodiment, the superconducting tape is first cleaned with pure water, then pre-plated with copper using a first current, then plating with bright copper using a third current, then plating with a sand-copper layer using a second current, and finally cleaned with pure water again. After passivation, blowing, and drying, the copper plating operation of the superconducting tape is completed.

[0099] After ultrasonic cleaning of the superconducting tape with pure water, it was then subjected to a current density of 10 A / dm. 2 A rapid copper pre-plating layer is applied using a current of 2A / dm², allowing copper to quickly coat the surface of the double-sided silver-plated superconducting bare tape. After pre-plating, a further application of 2A / dm² is used. 2 A bright copper layer is electroplated using a current density that increases the thickness in the middle and makes the surface smooth. Then, a 6A / dm² current is used. 2 The current density plated surface has a sand-like copper coating. After the copper plating operation is completed, it is washed with pure water multiple times, passivated with a certain temperature, dried with an air knife, and then dried at high temperature to remove residual moisture.

[0100] In the actual copper plating process, the superconducting tape is fed and unloaded as a whole through a linear arrangement. First, the superconducting tape is cleaned of impurities on the surface by an adjustable ultrasonic pure water first cleaning tank. Then, it is quickly coated with copper in multiple copper pre-plating tanks to protect the surface of the superconducting tape and prevent liquid from contacting the tape through the holes of the silver-plated surface, thus affecting the performance of the tape. Then, it is uniformly thickened by a relatively large number of bright copper plating tanks. Next, it is coated with a relatively rough sand-surface copper layer by multiple sand-surface copper plating tanks. Then, it is washed away with residual electroplating solution by multiple separate pure water second cleaning tanks. Then, it is protected against oxidation by a long heated passivation tank. The drying mechanism 7 is equipped with air knives and heated drying tanks. Most of the water is blown away by the flat-nozzle air knives and the remaining moisture is completely dried by the adjustable heated drying tank.

[0101] Example 3:

[0102] This embodiment is another preferred example of Embodiment 1.

[0103] In this embodiment, the superconducting tape is carried out in a linear arrangement. After exiting the feeding end of the feeding mechanism 1, it first passes through an adjustable ultrasonic pure water cleaning tank of 60-180 cm to clean surface impurities. Continuing its journey, it passes through 2-8 copper pre-plating tanks for rapid copper plating of the silver layer surface. The pre-plating copper electroplating solution used for pre-plating contains an additive with an allowable concentration of 6-20 A / dm³. 2The pre-plated acid copper additive, operating at current density, allows for a relatively uniform increase in copper layer thickness through 6–36 bright copper plating baths. The mother bath bright copper plating solution contains a bright copper acid copper additive with exceptionally high leveling and dispersing capabilities, operating at 0.5–3.5 A / dm². 2 The current density can obtain an ideal intermediate copper layer. The strip will continue to pass through 2 to 8 sand-surface copper tanks to coat the copper layer with a relatively rough sand-surface copper layer. Then, the strip will pass through 2 to 6 separate pure water first cleaning tanks to clean the residual electroplating solution on the surface of the copper strip. Then, the moisture on the surface of the strip will be blown away by a flat-nozzle air knife. Next, the copper layer will be protected against oxidation by a 100 to 500 cm long passivation tank with heating. Then, the surface will be completely dried by a 100 to 300 cm long adjustable drying and heating tank before entering the receiving end of the final receiving mechanism (8).

[0104] Example 4:

[0105] This embodiment is another preferred example of Embodiment 1.

[0106] In this embodiment, the superconducting tape is linearly arranged for transport. After exiting from the feeding end, the tape first passes through a 60-180 cm adjustable pure water ultrasonic cleaning tank with an ultrasonic frequency of 40 kHz to remove surface impurities. After this cleaning, the tape continues to travel through three independently circulating electroplating work tanks. Each work tank includes a front conductive spray area consisting of a stainless steel conductive wheel with a mercury slip ring, a tape-tracing limiting wheel, and a conductive wheel spray device with independent circulating automatic overflow and pure water replacement. The stainless steel conductive wheel needs to be connected to the power cathode, but since the guide wheel 10 rotates continuously, directly fixing the power cord to it would prevent the guide wheel 10 from rotating. The mercury slip ring is a conductive rotary joint using mercury as the fluid medium; therefore, this reliable and durable component is needed to solve the conductivity problem of the rotating guide wheel 10. A 60-160 cm long titanium-plated copper area with phosphor bronze balls is placed before and after the tape (a shielding plate 11 with continuous 3-8 mm through holes is placed before and after the tape, such as...). Figure 5 As shown, the shielding plate 11 is preferably made of PP material. The shielding plate 11 blocks part of the current curve to help improve the uniformity of copper plating, and the rear conductive wheel spray area.

[0107] In this embodiment, firstly, a rapid copper protective coating is applied to the silver layer surface of the strip using 2 to 8 copper pre-plating tanks. The master plating solution formula is: copper sulfate 200-240 g / L, sulfuric acid 50-70 g / L, chloride ion 80-100 mg / L. An allowable concentration of 6-20 A / dm³ is added to the pre-plating copper plating solution. 2 Pre-plating acid copper additives for current density operation (6-8 ml / L for starter and 2-3 ml / L for supplement).

[0108] Secondly, the thickness of a uniform copper layer was increased by comparing 6 to 36 bright copper plating baths. The master bath electroplating solution formula was: copper sulfate 60-100 g / L, sulfuric acid 170-200 g / L, chloride ion 60-90 mg / L. A bright copper acid additive with extremely high leveling and dispersing capabilities (tank starter 6-10 ml / L, leveling agent 0.6-2 ml / L, brightener 0.3-1 ml / L) was added to the bright copper electroplating solution, using 0.5-3.5 A / dm². 2 The current density can produce a highly uniform intermediate copper layer.

[0109] Finally, the strip undergoes a final, relatively rough sand-copper layer coating through 2-8 sand-copper plating baths. The formula for the mother bath's sand-copper plating solution is: copper sulfate 180-220 g / L, sulfuric acid 50-80 g / L, chloride ions 60-130 mg / L. A specially formulated sand-copper acid additive is added to the solution at a concentration of 16-25 ml / L. The strip continues to pass through 2-6 separate, independently circulating pure water second cleaning tanks. These tanks are designed with automatic overflow to maintain the cleaning water at a clean level. After cleaning, any residual plating solution on the copper strip surface is removed, and the strip continues to move. The copper layer is protected against oxidation by passing through a 100-500 cm long passivation tank. The passivation solution temperature range is 30-90℃. The mother tank plate needs to be made of 20-25 mm PP board. A reinforcing rib is made in the middle of the tank to effectively prevent the tank from deforming due to temperature changes. The conveyor belt continues to pass through a drying zone equipped with adjustable flat-nozzle air knives 12-24 cm wide to blow away the moisture on the surface of the strip. The conveyor belt continues to pass through an adjustable drying tank (1-3 sets of carbon fiber far-infrared heating tubes) 100-300 cm long to completely dry the surface of the strip before entering the continuous thickness measurement device and finally entering the receiving end.

[0110] Example 5:

[0111] This embodiment is a variation of Embodiment 1.

[0112] In this embodiment, a sand-surface copper plating solution is used for pre-plating to ensure the speed of copper encapsulation of the strip. This ensures that the rapid copper encapsulation operation is completed before the liquid enters through the tiny pores of the silver-plated surface, thus guaranteeing the effectiveness of the pre-plating.

[0113] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0114] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, 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. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A method for copper plating on superconducting tapes, characterized in that, The strip (9) to be processed is first electroplated with bright copper and then electroplated with sandblasted copper. The bright copper plating process employs a third-current electroplating treatment, while the sandblasted copper plating process employs a second-current electroplating treatment. The third current uses a current density of 0.5–3.

5. The second current uses a current density of 3 to 8. .

2. The method for copper plating of superconducting tape according to claim 1, characterized in that, The bright copper plating process uses a bright copper plating solution with an allowable concentration of 0.5–3.5%. The bright copper oxide additive for current density operation, the weight composition of the bright copper plating solution is as follows: Copper sulfate 60-100 parts; 170-200 parts of sulfuric acid; Chloride ions: 0.06–0.09 parts.

3. The method for copper plating of superconducting tape according to claim 1, characterized in that, The sandblasted copper plating treatment uses a sandblasted copper electroplating solution containing an allowable concentration of 3-8%. The current density-operated copper oxide additive for sand-surfaced copper plating solution has the following weight composition: 180-220 parts of copper sulfate; 50-80 parts of sulfuric acid; Chloride ions: 0.06–0.13 parts.

4. The method for copper plating of superconducting tape according to claim 1, characterized in that, A shielding structure is installed during both bright copper plating and sandblasted copper plating processes.

5. The method for copper plating of superconducting tape according to claim 1, characterized in that, The surface roughness of the copper in the produced superconducting tape is greater than 200 nm.

Images