26 results about "Nickel deposition" patented technology

The invention relates to the technical field of etching waste liquid treatment, and provides a nickel-containing etching waste liquid treatment method which comprises the following steps: 1, neutralizing and extracting copper; step 2, nickel deposition; step 3, evaporative crystallization; wherein the step I specifically comprises the following steps: slowly adding sodium bicarbonate into the nickel-containing waste liquid, stirring to adjust the pH value of the waste liquid to weak acidity, preferentially forming a basic cupric carbonate Cu2 (OH) 2CO3 precipitate when Cu < 2 + > is within the pH value range, and stably remaining Ni < 2 + > in the solution, and carrying out operations such as filtering separation and the like; and the step 2 specifically comprises the treatment of adding sodium hydroxide into the nickel-containing filtrate from which most of copper is removed to adjust the pH value to be neutral and the like. According to the technical scheme, the problems that according to an existing nickel-containing etching waste liquid treatment method, the harmless treatment effect is achieved in a chemical precipitation mode, the main purpose is to stabilize solid nickel, although the emission requirement is met, the waste liquid still contains copper, soluble salt and other components, and huge resource waste is caused by direct emission are solved.

The present invention relates to a method for depositing a zinc-nickel alloy on a substrate, particularly to a method for electrolytically depositing a zinc-nickel alloy on a substrate, wherein a zinc-nickel deposition bath is utilized as a catholyte comprising at least one brightening agent, wherein the at least one brightening agent has a source which is substantially free of, preferably does not comprise, halogen anions. The present invention furthermore relates to a respective aqueous zinc-nickel deposition bath, a respective brightening agent, and a respective use of said brightening agent for replenishing in an aqueous zinc-nickel deposition bath.

The application relates to a high-radiation shielding particle material and a preparation method thereof, and belongs to the technical field of shielding materials. The application aims to solve the problems that the existing radiation shielding materials cannot have the shielding performance of gamma rays, good flexibility and convenient construction performance and the like, and the particle material is composed of glass microspheres, a chemical nickel plating layer, an electroplated lead layer, an electroplated tungsten layer and an electroplated tantalum layer. The thickness of each layer is controlled to be 20 mu m. The method is that nickel is deposited on the surface of the glass microspheres by a chemical nickel plating method, and then an electroplated lead layer, an electroplated tungsten layer and an electroplated tantalum layer are sequentially deposited by an electroplating method. The glass microspheres are pretreated, and nickel is deposited on the surface of the glass microspheres by a chemical nickel plating method, so that other electroplated layers can be more easily deposited on the surface; the electroplated lead layer and the electroplated tungsten layer have the characteristics of good combined shielding performance of gamma rays and neutrons; and the metal tantalum layer has good gamma ray shielding performance and excellent mechanical performance.

The invention discloses an electromagnetic double-gradient composite material containing Ni and CFC and a preparation method and application thereof, and relates to the technical field of electromagnetic shielding materials. The preparation method comprises the following steps: (1) cutting carbon fiber cloth into small blocks, polishing carbon fibers through abrasive paper, immersing a sample into a sensitizing solution at room temperature for 15 minutes, and soaking the sample into an activating solution for 90 seconds; a sensitizer used in the chemical nickel plating process comprises nickel sulfate hexahydrate and diluted hydrochloric acid; and (2) ammonia water is added to adjust the pH of the chemical nickel plating solution, chemical nickel plating treatment is carried out at the temperature of 60 DEG C, nickel deposition is carried out for 1-4 times and 20 min each time, after the reaction is completed, deionized water is used for washing for 2 min, then pressing is carried out for 48 h, and finally drying is carried out in a drying oven, so that the electromagnetic double-gradient composite material is obtained. By depositing Ni on the CFC substrate, the dielectric loss, magnetic loss and heterogeneous interface loss performances are remarkably improved.

The utility model discloses a solid catalyst feeding device which comprises a reaction kettle, a jet orifice of the jet pump is connected with an inlet of the reaction kettle through a pipeline; the catalyst feeding bin and the liquid raw material bin are respectively connected with an inlet of the injection pump through a pipeline and a valve pipeline; the first nitrogen supply equipment is connected with the catalyst feeding bin through a pipeline; and the first industrial water supply equipment is connected with the catalyst feeding bin through a pipeline. The stirring paddle is arranged in the Raney nickel feeding bin, so that unsmooth feeding caused by long-time Raney nickel deposition is prevented. By arranging the nitrogen seal, after feeding is finished, replacement is conducted through nitrogen, and the accident risk caused by air residues in the system is avoided.

The invention relates to the technical field of wire cutting, in particular to a carborundum composite nickel deposition process and a diamond wire, and the carborundum composite nickel deposition process comprises the steps of bus cleaning, bus pretreatment, bus pre-nickel plating, bus sanding, secondary nickel plating, cleaning, heat treatment and the like. Ultrasonic powder in the electroplating liquid can be uniformly dispersed in the suspension liquid through ultrasonic oscillation, and then the ultrasonic powder is deposited on the bus along with metal ions. High-frequency mechanical waves generated by ultrasonic oscillation can enable particles and bubbles in the liquid to generate violent mechanical oscillation, so that the effects of stirring, dispersing and mixing are achieved; in the carborundum deposition process, carborundum powder can make full contact with the bus through ultrasonic waves, and meanwhile diffusion of metal ions in electrolyte and uniformity of metal deposition are promoted.

The invention relates to a method for depositing a zinc-nickel alloy on a substrate, the method comprising the steps of: (a) providing the substrate, (b) providing an aqueous zinc-nickel deposition bath as catholyte in a deposition compartment, wherein - the deposition compartment comprises at least one anode with an anolyte, and - the anolyte is separated from the catholyte by at least one membrane, and the catholyte comprises (i) nickel ions, (ii) at least one nickel ion complexing agent, and (iii) zinc ions, (c) contacting the substrate with the catholyte in the deposition compartment, such that the zinc-nickel alloy is electrolytically deposited onto the substrate and a zinc-nickel coated substrate is obtained thereby, wherein the concentration of the nickel ions in the catholyte is lower after step (c) than before step (c), (d) rinsing the zinc-nickel coated substrate in a rinsing compartment comprising water, such that a rinsed zinc-nickel coated substrate and a rinsing water are obtained, wherein the rinsing water comprises a part of the at least one nickel ion complexing agent and a part of the nickel ions, characterized in that (i) at least a part of the rinsing water and / or at least a part of the catholyte is treated in a first treatment compartment, such that water is separated from the at least one nickel ion complexing agent and the nickel ions, (ii) at least a part of the at least one complexing agent that is separated from the water is returned into the catholyte, and (iii) a source of nickel ions is added to the catholyte, with the proviso that the source of nickel ions does not comprise the at least one nickel ion complexing agent or any other nickel ion complexing agent.

The invention relates to the technical field of advanced materials of an integrated circuit packaging COF technology, in particular to a method for inhibiting diffusion plating and skip plating of chemical nickel plating of a superfine circuit of an integrated circuit packaging flexible substrate and application. According to the method, through the systematic synergistic effect of pre-dipping treatment before activation, activation treatment and post-dipping treatment, the uniformity of line activation can be promoted, the deposition rate of nickel plating around the line can be regulated and controlled, diffusion plating and skip plating phenomena caused by non-uniform adsorption amount of palladium on the two sides of the line are improved, nickel plating deposition between fine lines is reduced, and the service life of the line is prolonged. And the problem of nickel bridging of the fine line caused by over-strong palladium activity or palladium residues at intervals of the fine line is avoided. The method has the advantages of being simple in process, easy and convenient to operate, low in production cost and capable of being suitable for large-scale production, and can be well applied to the chemical nickel plating process of the superfine circuit of the flexible substrate with the line width smaller than 12 micrometers and the line width larger than 50 micrometers at the same time.

The invention discloses a substrate pretreatment process applied to an integrated electrode material, and belongs to the technical field of electrode material preparation. The process sequentially comprises the steps of substrate pretreatment, micro-etching, rough nickel deposition and embroidered ball array skeleton electrodeposition, and a micron-sized rough structure is constructed on the surface of a nickel-based porous substrate through micro-etching so as to provide more nucleation sites; on the basis that rough nickel is deposited on the rough surface of a base body, a compact amorphous metal nickel transition layer is formed, strong mechanical interlocking with the base body is achieved, and high corrosion resistance and high conductivity are achieved; and finally, growing a vertically-oriented nanowire array framework on the metal nickel transition layer by utilizing electro-deposition. Through the synergistic effect of micro-etching, rough nickel deposition and electro-deposition, a complete, stable and efficient three-dimensional conductive carrier from a macroscopic matrix to a microcosmic active skeleton is finally constructed, and the binding force between the integrated electrode material and the matrix, the interface stability and the mass transfer capacity are fundamentally improved.

The invention discloses a preparation method of a diamond micro-powder chemical nickel plating solution for a fretsaw, and relates to the technical field of chemistry and materials. The diamond micro-powder chemical nickel plating solution for the fret saw is prepared from the following components in parts by weight: 10 to 40 g / L of nickel sulfate hexahydrate, 20 to 40 g / L of sodium hypophosphite, 10 to 20 g / L of sodium citrate, 20 to 40 g / L of ammonium chloride, 0.001 to 0.0012 g / L of thiourea, 1 g / L of sodium dodecyl benzene sulfonate and 0.06 to 0.12 g / L of saccharin sodium salt. The formula of the nickel plating solution is optimized through a Taguchi design method, so that a plating layer is compact and uniform, skip plating and agglomeration are reduced, the efficiency is improved, and the cost is reduced; the water washing time is shortened by adopting a micro-powder filtering device; the sensitization activating solution promotes nickel deposition; a plating layer with the phosphorus content of 1%-6% can be obtained, and the problem that the plating solution is poor in stability is solved.

The invention discloses a high-hardness nickel imprinting template based on nanostructure reshaping and a preparation method of the high-hardness nickel imprinting template, and belongs to the technical field of nanostructure machining.The preparation method of the high-hardness nickel imprinting template comprises the following steps that a PMMA solution with gradient concentration is adopted for conducting spin coating on a mother-structure aluminum cone for multiple times, gaps of the aluminum cone are completely filled, and the mother-structure aluminum cone is obtained; forming a PMMA complementary structure complementary with the mother structure aluminum cone; a mother structure aluminum cone is thoroughly removed through a chemical corrosion method, and a PMMA complementary structure is reserved; plating a silver layer on the surface of the PMMA complementary structure by adopting a magnetron sputtering method to obtain a PMMA complementary structure coated with the silver layer; the PMMA complementary structure coated with the silver layer is placed in nickel deposition liquid to be subjected to electrochemical nickel plating, and a nickel layer is formed; pMMA is removed through a dissolution method, and the high-hardness nickel imprinting template is obtained. The preparation method is high in reshaping precision, the complex nanometer morphology can be accurately copied, the hardness of the prepared nickel imprinting template is remarkably improved, and the nickel imprinting template can bear imprinting for at least hundreds of times without obvious abrasion deformation.

The application discloses a wiring terminal and a preparation method thereof. The wiring terminal comprises a wiring terminal body and a composite layer. The composite layer comprises, from inside to outside, a copper deposition layer connected to the surface of the wiring terminal body, a tin deposition layer arranged on the surface of the copper deposition layer, and a nickel deposition layer arranged on the surface of the tin deposition layer. The copper deposition layer connected to the surface of the wiring terminal body, the tin deposition layer arranged on the surface of the copper deposition layer, and the nickel deposition layer arranged on the surface of the tin deposition layer can effectively absorb interface thermal stress and eliminate micro-pores, thereby significantly improving the corrosion resistance and fatigue fracture resistance of the wiring terminal under high-low temperature impact, high-frequency micro-motion and salt spray environment.

The invention discloses a method for preparing a pure nickel substance through an electrolytic method. The method comprises the following steps that S1, electrolyte is prepared; s2, electrolytic reaction, wherein the cathode and the anode are inserted into the electrolyte, and the electrolyte is subjected to the electrolytic reaction under continuous stirring; s3, product separation: after the reaction is completed, stripping the product from the cathode, and collecting to obtain a pure nickel substance; the pure nickel substance comprises dendritic nickel powder and a nickel film. According to the method, the dendritic nickel powder and the nickel film can be obtained on the cathode at the same time by regulating the current density to be 150-360 A / m < 2 > or 360-560 A / m < 2 >, the production process is simple and convenient, and the cost is low. The electrolyte is stirred at the constant speed of 200-800 r / min, and the additive containing sulfur groups is added, so that the concentration of the electrolyte can be kept stable, and nickel near a cathode can be stably and uniformly deposited.

The utility model provides a precise metering and proportioning device for electroless nickel deposition in electroplating, which comprises a cabinet body, a plurality of feeding boxes fixedly mounted in the cabinet body, electromagnetic valves and flow meters sequentially mounted below the feeding boxes, and a plurality of auxiliary rods arranged at the bottom in the cabinet body. According to the precise metering and proportioning device for electroplating chemical nickel deposition, the gear, the rotating wheel, the auxiliary rod, the blades and other structures are arranged, the gear is driven by the motor to rotate, power is transmitted to the rotating wheel through meshing with the rotating wheel, and the rotating wheel rotates to further drive the auxiliary rod to rotate; the blades on the surface of the auxiliary rod stir the chemical liquid in the proportioning box along with the rotation of the auxiliary rod, so that different chemical liquids can be quickly and uniformly mixed together, the quality of electroplating chemical nickel deposition is ensured, meanwhile, the proportioning accuracy can be ensured by accurately metering the flow of the chemical liquid, and the production efficiency is improved. And electroplating requirements under different process requirements are met.

The application relates to the technical field of electro-catalysis, and particularly relates to a nickel-based electrode, a preparation method and application. In view of the technical problems of uneven coverage of a deposition layer, large interface resistance and large UOR output performance fluctuation caused by unreasonable selection of process parameters of the nickel-based electrode electrodeposition, the application provides a preparation method of a nickel-based electrode, which comprises the following steps: taking foamed nickel as a conductive substrate, performing surface pretreatment on the foamed nickel to remove the surface oxide layer and internal impurities of the foamed nickel; preparing an electroplating solution, the electroplating solution being a nickel nitrate hexahydrate aqueous solution, and the concentration of the electroplating solution being 0.10 M; taking the pretreated foamed nickel substrate as a working electrode, and placing the working electrode in the electroplating solution to perform direct current electrodeposition, wherein the direct current voltage applied during the electrodeposition is-1.15 V, and the electrodeposition time is 400 s, so as to form a nickel deposition layer on the surface of the foamed nickel substrate; taking out the electrode after the electrodeposition, cleaning and drying the electrode to obtain the nickel-based electrode. The application improves the UOR current output and operation stability.

This invention discloses a coupled coated carbon fiber, its preparation method, and its application. A pretreatment process of degumming, roughening, sensitization, activation, and reduction, combined with a post-treatment of chemically deposited calcium-nickel, yields a carbon fiber-calcium-nickel deposited layer coupled with a wear-resistant surface material that can enhance the wear resistance of synchronizing ring surfaces. The carbon fiber composite material with coupled calcium-nickel layer deposition exhibits approximately 60% lower friction coefficient compared to single carbon fiber material, thus improving the wear resistance of the synchronizing ring material surface. During synchronizing ring operation, the harder calcium-nickel coating surface is directly worn first, hindering the wear of the carbon fiber itself. This invention is simple to prepare, low in cost, and applicable to wear protection of metals in various physical environments, covering wear-resistant surfaces of metal parts in numerous fields such as automobiles, ships, and aerospace.

The utility model belongs to the field of nickel deposition equipment, and particularly relates to nickel deposition equipment which comprises a nickel deposition tank, supporting legs are fixedly connected to the edge of the bottom of the nickel deposition tank, a stirring device is arranged on the inner side of the nickel deposition tank, a mounting plate is placed on the left side of the upper end of the nickel deposition tank, and a heating rod and an electrode are fixedly mounted in the middle of the mounting plate. The bottom of the mounting plate is fixedly connected with a clamping block, the clamping block is connected with the nickel deposition tank in a clamped mode, and the interior of the nickel deposition tank is slidably connected with a push pin. A driving bevel gear driven by a motor is arranged on the inner side of a nickel deposition tank, then the driving bevel gear can simultaneously drive an upper bevel gear with a seat and a lower bevel gear with a seat which are coaxial, and stirring rods are arranged on the upper bevel gear with the seat and the lower bevel gear with the seat, so that the upper stirring rods and the lower stirring rods simultaneously stir in different stirring directions; the stirring efficiency is higher after the nickel deposition tank is emptied, anode liquid is added and the temperature is raised, and the cleaning effect is better.

The invention relates to the technical field of wafer packaging processes, in particular to an electronickelling solution for a chip packaging RDL process and a preparation method of the electronickelling solution. Raw materials of the solution comprise main salt, an anode activating agent, a buffering agent, a brightening agent, a light-emitting agent, a wetting agent and an inhibitor, the inhibitor comprises a quaternary ammonium salt compound, preferably a long-chain quaternary ammonium salt compound, a large number of cations generated by hydrolysis of the inhibitor can be adsorbed to a cathode high-current-density area to form an electrostatic shielding layer, nickel deposition is slowed down, and the edge ox horn phenomenon is reduced. The solution can be used for an electroplating process of a metal film layer in a chip packaging RDL process, and is adaptive to 1-10 ASD current density, a smooth pinhole-free nickel film can be obtained through electroplating at 40 DEG C, and the roughness Ra is smaller than 0.05 mu m, and the roughness Rz is smaller than 0.2 mu m; according to the manufacturing process of the thick film with the thickness of 20-30 microns, the thickness uniformity of the film layer is excellent, the ox horn phenomenon is remarkably improved, the thickness difference between the edge and the middle area can be accurately controlled within 1 micron, and a guarantee is provided for stable development of the subsequent technological manufacturing process and improvement of the final product quality.

The present application relates to an environmentally friendly electroplating method for plastic workpieces, which includes internal stress removal, alkaline washing and oil removal, roughening, sensitization and activation treatment, chemical nickel deposition, water-plated metal coating, coating of surface treatment agent, wire drawing and vacuum nickel plating. The present application has the following advantages and effects: a metal layer is plated on the plastic workpiece by combining water plating and vacuum plating to meet the requirements for color variability, and the coating is thicker and has strong adhesion; trivalent chromium is used to replace hexavalent chromium with high toxicity to reduce damage to the ecological environment; a microporous structure is formed by roughening, sensitizing and activation treatment in sequence, and the molecules on the surface are activated, so that the coating is easier to adhere and has higher adhesion strength; a surface treatment agent layer is coated and formed between the water-plated coating and the vacuum-plated coating to improve the relative adhesion between each coating and assist in improving the overall coating adhesion strength of the plastic workpiece surface, so as to achieve the purpose of improving the overall performance of the product.

The invention provides an electrodeposited nickel anode and a preparation method thereof. The anode comprises a substrate, and a SnOx intermediate layer and a PbO2 active layer which are sequentially laminated on the surface of the substrate. The anode of the electrodeposited nickel provided by the invention comprises a SnOx intermediate layer and a PbO2 active layer which are sequentially laminated on the surface of a substrate, wherein the SnOx intermediate layer has relatively high conductivity and corrosion resistance and can enhance the conductivity and corrosion resistance of the anode, the PbO2 active layer has relatively high catalytic activity, and the synergistic effect of the SnOx intermediate layer and the PbO2 active layer effectively reduces the oxygen evolution potential of the anode and prolongs the service life of the anode; and meanwhile, the anode does not contain expensive noble metal, so that the preparation cost is relatively low.

The present application belongs to the field of heavy metal wastewater resource treatment, and relates to a real-time regulation system for electrodepositing and recovering metal nickel from nickel-containing wastewater concentrate liquid, characterized in that the real-time regulation system comprises an electrochemical analysis unit, a software analysis unit, an intelligent decision unit and a regulation execution unit; the electrochemical analysis unit comprises an online water quality analysis module and an electrochemical analysis module, the electrochemical analysis module is used for measuring a parameter curve of a cathode electrodeposition process, the online water quality analysis module is used for acquiring parameter data of the nickel wastewater concentrate liquid, and the software analysis unit is used for acquiring key electrochemical parameters in real time and analyzing current efficiency, nickel deposition efficiency and a change trend of the electrodepositing of the nickel wastewater concentrate liquid. The current efficiency of the electrodepositing of the nickel wastewater concentrate liquid can be improved, and the operation cost of the electrodepositing of the nickel-containing wastewater concentrate liquid can be reduced.

[Problem] To provide a surface-treated copper foil which comprises a heat-resistant treated layer and a chromate-treated layer and does not comprise a roughening-treated layer. The surface-treated copper foil is suitable for a copper-clad laminated plate to be used for a printed wiring board compatible with high-speed transmission, because said surface-treated copper foil exhibits excellent heat resistance and rust prevention, and because the conductor loss due to different kinds of metals is small due to having a small adhesion amount of nickel and chromium on the treated surface and the conductor loss caused by roughening particles does not occur due to having low roughness. [Solution] A surface-treated copper foil wherein: the arithmetic average height Sa of the surface of an untreated copper foil is less than 0.27 μm; the developed interfacial area ratio Sdr is less than 6%; when the surface area ratio calculated from the Sdr is defined as A, and the nickel adhesion amount (mg) per two-dimensional area of 1 m2 of the treated surface of the surface-treated copper foil is defined as B, the nickel adhesion amount [B / A] per surface area of 1 m2 is 5-31 mg; and when the chromium adhesion amount (mg) per two-dimensional area of 1 m2 of the treated surface of the surface-treated copper foil is defined as C, the chromium adhesion amount [C / A] per surface area of 1 m2 is 1-4 mg.

The application discloses a coating preparation method for enhancing the interface bonding force of nickel / nickel-based superalloy, adopts double-layer glow plasma surface metallurgy technology, takes pure nickel as a target material, controls the surface temperature of the nickel-based superalloy workpiece and grows the coating through two-step regulation, the first step is to form the Ni-Fe-Cr interdiffusion layer interface with the micron-sized pinning structure, and the second step is to form the nickel deposition layer with the columnar crystal structure, so that the coating with high interface bonding strength is obtained. The application utilizes the high interface compatibility of the nickel layer and the nickel-based superalloy, the coating structure is composed of the interface pinning and the columnar crystal of the pure nickel layer, the single interface pin size is 20-50 microns and is embedded into the base material, the pure nickel layer is the columnar crystal structure, and the bonding strength of the coating and the base interface is improved. In the 800 DEG C thermal shock experiment, the thermal shock resistance times of the coating are greater than 200 times, the coating bonding force is higher than 70 N through the scratch test, and the mechanical properties are excellent.

To provide a surface-treated copper foil for a lithium ion secondary battery, a current collector for the lithium ion secondary battery, and a lithium ion secondary battery.SOLUTION: A surface-treated copper foil for a lithium-ion secondary battery includes a copper layer having a first surface and an opposite second surface, and nickel-containing treatment layers disposed on the first and second surfaces of the copper layer, and each treatment layer has a nickel coating weight of 3.0×104 μg / dm2 or more, and each treatment layer provides a treated surface, and the treated surface has a chromaticity L* value of 30 to 60 and a protruding valley depth Svk of 0.10 to 0.65 μm.SELECTED DRAWING: Figure 2-2

The present application relates to the advanced material technology field of integrated circuit packaging COF technology, and in particular to a method for inhibiting the chemical nickel plating and plating leakage of ultra-fine lines of a flexible substrate of an integrated circuit package and application. The method, through the systematic synergistic effect of pre-activation pre-dipping treatment, activation treatment and post-dipping treatment, can promote the uniformity of line activation, can control the deposition rate of nickel plating around the line, can improve the plating and plating leakage phenomenon caused by the uneven palladium adsorption amount on both sides of the line, can reduce the nickel plating deposition between fine lines, and can avoid the nickel bridging problem of fine lines caused by the excessive activity of palladium or the palladium residue between fine lines. The method has the characteristics of simple process, simple operation, low production cost and being suitable for large-scale production, and can be well applied to the chemical nickel plating process of the ultra-fine lines of the flexible substrate containing line width and line spacing below 12 microns and line width greater than 50 microns.

The nickel deposition prevention structure comprises a flow guide base at the bottom of the electroplating bath and a deposition prevention assembly in the middle of the electroplating bath, and spoilers are arranged on the two sides in the electroplating bath. The anti-deposition assembly comprises a deposition plate with a protective plate, lifting is achieved through a threaded lead screw and a driving motor, and a movable groove accommodates and fixes a threaded sleeve and the threaded lead screw; two sides of the top of the deposition plate are inclined planes and provided with filtrate holes to form a flow guide and filtration dual mode, a triangular flow guide block of a flow guide base divides fluid at the bottom of the groove into three channels, and the spoiler adjusts the angle through a spoiler motor and cooperates with a spoiler hole to generate turbulent flow; according to the structure, a nickel layer is stripped through dynamic lifting, fluid distribution is optimized, ion enrichment and vortex dead angles are reduced, and the uniformity of a plating layer is improved.