Friction-electrolysis assisted jet electro-deposition device and method for small-diameter blind hole piece

Abstract

The invention discloses a friction-electrolysis auxiliary jet electro-deposition device and method for a small-diameter blind hole piece, and belongs to the technical field of electro-deposition. The device is composed of a motion control device, a plating solution filtering and circulating device, an anode rotating device, a rotary power supply device, an auxiliary electrolysis device, a cathode clamp and a heating temperature control device. Wherein the anode rotating device realizes dynamic friction, the rotary power feeding device ensures stable power feeding of an anode in the rotating process, and the auxiliary electrolysis device can synchronously supplement metal ions in a plating solution so as to maintain the stability of the plating solution. Through the synergistic effect of the profiling auxiliary anode, friction-jet assistance and electrolytic ion supplementation, the problems of difficult plating solution mass transfer, uneven electric field distribution, short plating solution service life and the like in small-diameter blind hole piece electro-deposition machining are solved, a high-quality coating can be prepared on the surface of an inner cavity of the small-diameter blind hole piece, the uniformity and compactness of a plating layer are improved, and the service life of the plating layer is prolonged. And the method is suitable for efficient preparation of the coating of the inner cavity of the blind hole with the large depth-diameter ratio.

Description

Technical Field

[0001] This invention belongs to the field of jet electrodeposition, specifically relating to an apparatus and method for depositing coatings on the inner surface of blind orifices with a large aspect ratio in triboelectric-electrolysis assisted jet electrodeposition. Background Technology

[0002] In traditional manufacturing, mature methods for coating large-aperture cylindrical cavities include hot / cold spraying, laser cladding, welding, and CVD / PVD. However, these methods all have significant limitations when the aperture shrinks and the aspect ratio increases dramatically: hot / cold spraying is limited by nozzle size and cannot penetrate deeply, and the high-speed airflow creates vortices within the small aperture, resulting in "excessive thickness at the edges and missed spray in the center"; arc spraying also exhibits thickness polarization when the aspect ratio is greater than 4:1 due to the electrode-hole wall distance constraint; laser cladding and welding are limited by the size of the small aperture structure, and the heat is difficult to dissipate within the aperture, resulting in a large heat-affected zone and high processing costs, thus having significant limitations; although CVD / PVD can form uniform films, the deposition rate is only a few to tens of micrometers per hour, and the equipment and operating costs are high, resulting in poor batch economics. In short, under the condition of "small aperture-large aspect ratio", existing technologies are either limited by size, constrained by thermal effects, or hampered by cost, and the efficient preparation of uniform coatings for internal cavities remains a challenge in the manufacturing field.

[0003] Traditional electrodeposition technology is widely used in coating preparation due to its advantages such as low cost, simple equipment, controllable coating composition, high bonding strength, and absence of a heat-affected zone. However, limited by the large aspect ratio of small holes, traditional electrodeposition technology faces two major challenges in depositing coatings within small hole cavities: difficulty in mass transfer of the plating solution and difficulty in uniformly distributing the electric field within the small hole. In recent years, friction-assisted jet electrodeposition technology has added a frictional external force field to assist coating deposition on the basis of jet electrodeposition. The friction method is roughly divided into rigid friction and flexible friction. Studies have shown that friction assistance has the effects of leveling the coating, removing hydrogen impurities, and refining grains, which can significantly improve the overall performance of the deposited layer. By using assisted contour anodes, jets, and friction assistance, the problems of difficult mass transfer of the plating solution and difficulty in uniformly distributing the electric field within small hole cavities in traditional electrodeposition can be effectively solved. How to achieve dynamic friction within the small hole cavity is an unsolved problem. Currently, the main friction implementation method is to install a friction pair on the outer surface of the anode. According to the movement mode of the anode providing friction, it can be divided into two friction assistance methods: anode translational friction and anode rotational friction. Given the limitations of deep micro-hole structures, rotational friction, compared to translational friction, allows the anode to maintain its spatial position for an extended period, thus preserving electric field stability and making it a more suitable friction method. Auxiliary anodes can be categorized into inert auxiliary anodes and soluble auxiliary anodes based on whether significant oxidation and dissolution occur during electrodeposition. While traditional soluble anodes can replenish metal ions consumed in the solution during electrodeposition, they inevitably undergo dissolution and degradation over prolonged use (significant dimensional changes leading to anode failure). In contrast, inert auxiliary anodes do not undergo oxidation and dissolution reactions during deposition (or the reactions are negligible), acting solely as electronic conductors to provide a discharge site for anions in the electrolyte. They exhibit high chemical stability, withstand harsh electrolysis conditions, have minimal electrode material consumption, and a long service life. Especially for the special structure of micro-hole devices, their long-term stable structural dimensions and shape help ensure the homogenization of the electric field within the micro-hole cavity during deposition. However, the use of inert auxiliary anodes can shorten the electrolyte life because metal ions cannot be replenished through anodic oxidation. At the same time, problems such as how to maintain the long-term stability of the electrolyte after the introduction of inert anodes and how to maintain the stability of the electrical input during the rotational friction process still need to be solved. Summary of the Invention

[0004] This invention provides an apparatus and method for triboelectric-electrolysis-assisted jet electrodeposition of small-diameter blind holes. Addressing the problems of mass transfer difficulties in the electroplating solution, uneven electric field distribution in small holes, and insufficient ion replenishment in existing jet electrodeposition methods, this invention, based on jet electrodeposition technology, develops an anode support device. Simultaneously, it relies on jet and triboelectric assistance to improve the overall mechanical properties and surface quality of the coating, increasing the limiting current density and enabling rapid preparation of high-quality coatings on the inner surface of deep, small-hole workpieces. Furthermore, electrolysis is performed synchronously with the electroplating process in the deposition tank to replenish the required metal cations in the plating solution, maintaining a stable metal ion concentration in the solution. This ensures a uniform and dense coating while extending the service life of the plating solution and improving production efficiency.

[0005] A triboelectric-electrolysis assisted jet electrodeposition apparatus and method for small-diameter blind hole components, comprising the following steps:

[0006] S1: A device for triboelectric-electrolysis assisted jet electrodeposition of small-diameter blind hole parts, including a motion control device, a plating solution filtration and circulation device, an anode rotation device, a rotation power supply device, an auxiliary electrolysis device, a cathode clamp, and a heating and temperature control device, etc.

[0007] S1-1: The motion control device includes a cross slide component that can move freely on the Y and Z axes, a motor, and a synchronous belt rotary transmission component from the motor to the anode spindle, etc. The control system is a Dopcon TC55 motion controller.

[0008] S1-2: The plating solution filtration and circulation device includes a deposition tank, a submersible pump, a filter, plating solution pipelines, a flow meter with a regulating valve, and a rotary joint. The deposition tank is surrounded by a water bath heating tank. The flow meter can regulate and detect the flow rate of the plating solution in the circulation pipeline. The pipeline is wrapped with a layer of heat insulation cotton during operation to prevent excessive temperature loss during plating solution transmission. A rotary joint is used at the end of the plating solution pipeline to connect to the anode device. Both ends of the rotary joint can rotate freely to ensure that the plating solution transmission pipeline does not interfere with the normal rotation of the anode.

[0009] S1-3: The anode rotation device includes a slide table connector, bearings, a rotating spindle, a motor, and a synchronous belt drive. The motor drives the rotating spindle to rotate via the synchronous belt, thereby rotating the contour-following auxiliary anode connected to it. The rotating spindle is connected to the plating solution pipe via a rotary joint, completing the liquid feeding without interfering with the rotation of the contour-following auxiliary anode.

[0010] S1-4: The rotating energizing device includes an anode connector, a bearing connector, a conductive set screw, a sealing ring, a contoured auxiliary anode, a bearing, a bearing retainer, and nylon connecting bolts. The anode connector connects to the contoured auxiliary anode, driving its rotation. Simultaneously, the bearing retainer, connected to the positive terminal of an external power supply, maintains a continuous and stable energization of the anode during its rotation.

[0011] S1-5: The auxiliary electrolysis device includes a deposition tank baffle, sealing gaskets, and an anion exchange membrane. The anode is clamped and fixed to the plating solution side, and the cathode is clamped and fixed to the cathode solution side on the other side of the baffle. A DC power supply is connected, and electrolysis replenishes ions from the plating solution simultaneously during electroplating.

[0012] S1-6: The cathode fixture is fixedly connected to the deposition tank. Conductive screws are used on both sides of the fixture to fix the workpiece with deep small holes and transmit the external negative current to the workpiece. The contact part between the conductive screw and the fixture is made of insulating material. At the same time, the surface of the fixture is coated with an insulating material in the later stage to prevent the fixture from being corroded or damaged during the processing or the deposited coating from affecting the clamping and positioning of subsequent workpieces. A small hole is opened on the lower side of the fixture to allow the plating solution to flow out.

[0013] S1-7: The heating and temperature control device includes a heating rod and a temperature controller, wherein the heating rod is connected to the temperature controller switch, the temperature controller is set to the target control temperature, and the temperature sensor of the temperature controller is placed in the deposition tank to monitor the temperature of the plating solution.

[0014] S2: Prepare the required electroplating solution in advance, put it into the plating solution storage tank described in S1-2, and control the temperature of the plating solution to the preset value through the heating rod and temperature controller in S1-7. Wrap the outside of the plating solution pipe with heat insulation cotton and adjust the pH of the plating solution to the preset value.

[0015] S3: A flexible friction pair is installed on the outer circumference of the conforming anode, which provides a frictional external force field to assist cathode deposition when the anode rotates;

[0016] S4: Grind, polish and degrease the inner surface of the cathode substrate of the small-diameter blind hole workpiece, then clean it with acetone, alcohol and deionized water respectively, and dry it for later use.

[0017] S5: Before formal processing, turn on the submersible pump power and start the rotation of the anode. Adjust the flow rate of the plating solution jet to the preset value through the flow meter with regulating valve in S1-2. Control the flow rate of the plating solution circulation pipeline at 4-12L / min and set the rotation speed of the anode at 5-15r / min. Then let the device run stably for a period of time and then stop it to ensure the stability of the device.

[0018] S6: Clamp the cathode workpiece in the fixture in S1-6 for clamping and fixing, connect the positive terminal of the power supply to the anode conductive screw to ensure normal connection of the positive terminal of the power supply; then move the anode device in S1-4 to a suitable position through motion control to ensure that the electrode body and the workpiece are aligned and a suitable gap is maintained.

[0019] S7: Turn on the submersible pump and rotate the anode. After running for about 3-5 minutes, turn on the power to process the coating.

[0020] The triboelectric-electrolysis assisted jet electrodeposition device for small-diameter blind hole workpieces used in the above method includes: 1-DC power supply, 2-aluminum profile frame, 3-temperature controller, 4-anion exchange membrane, 5-deposition tank, 6-water bath, 7-heating rod, 8-submersible pump, 9-cathode clamp, 10-filter device, 11-rotary power supply device, 12-flow meter with regulating valve, 13-plating solution circulation pipe, 14-anode rotation device, 15-rotary joint, 16-Y and Z axis transmission device; 1101-anode connector, 1102-bearing connector, 1103-conductive set screw, 1104-sealing gasket, 1105-contact auxiliary anode, 1106-conductive metal sheet, 1107-bearing, 1108-bearing fastener, 1109-nylon connecting bolt;

[0021] The overall frame of the device is constructed from aluminum profiles. A fixed cross slide table on the frame primarily controls the vertical movement of the Z-axis and the horizontal movement of the Y-axis. Movement in the X-direction requires manual adjustment of the deposition tank 5. The cathode clamp 9 is mounted on the deposition tank, and its surface is insulated to prevent premature corrosion or plating during use, which could affect the clamping and positioning of subsequent workpieces and extend its own service life. The deposition tank also collects and stores the electroplating solution flowing out of deep-hole workpieces. This solution is then filtered by a filter device 10 and returned to the deposition tank. A submersible pump 8 is built into the deposition tank to transfer the plating solution to the anode via a pipeline. A flow meter 12 with a regulating valve is installed on the pipeline to adjust and monitor the flow rate of the plating solution. The temperature controller 3 and the heating rod 7 work together to maintain the plating solution temperature within a preset range. The end of the plating solution pipeline is connected to the rotating spindle via a rotary joint 15 to input the plating solution, and the pipeline is wrapped with heat-insulating cotton to prevent excessive heat dissipation.

[0022] The anode frame assembly is the core component of this design, and its specific structure and functions are as follows: 1. Sealing connection mechanism: The anode connector 1101 and the contoured auxiliary anode 1105 are fastened together by nylon connecting bolts and nuts 1109. A sealing gasket 1104 is installed at the joint surface of the two to effectively block the penetration path of the electroplating solution and ensure the sealing of the device. 2. Rotary conductive mechanism: The inner ring of the bearing connector 1102 is rigidly connected to the contoured auxiliary anode via conductive set screws 1103, while the outer ring is equipped with a bearing 1107 and a bearing fixing part 1108. The rotational characteristics of the bearing enable the anode to rotate under energized conditions. To ensure synchronous current conduction, the bearing connector has a groove on the outer side at the connection position with the two conductive set screws, with a conductive metal sheet 1106 inside. This groove can further transmit the current conducted by the bearing to the contoured auxiliary anode, thereby achieving continuous and stable energization of the anode during rotation. 3. Integrated Motion and Liquid Supply System: The anode connector and the rotating spindle in the anode rotating device 14 are connected by threads. During assembly, waterproof adhesive is wrapped around the thread section to enhance the sealing effect and prevent the electroplating solution from leaking out along the thread gap. The rotation of the rotating spindle is provided by a motor and a synchronous belt drive, which is connected to the plating solution circulation pipeline through the rotary joint 15, so that the plating solution can be stably transported while the spindle is rotating. The slide table connector is linked with the Y and Z axis motion platform, which can drive the anode to complete precise displacement in the corresponding plane to meet the needs of different processing positions. 4. Expandable and Optimizable Design: By designing auxiliary contoured anodes with different internal flow channel structures and installing different types of friction pairs on the anode surface, it is possible to achieve coordinated control of the flow field, mass transfer field, electric field and friction external force field, thereby effectively improving processing quality and efficiency.

[0023] Beneficial effects: This invention provides a triboelectric-electrolysis-assisted jet electrodeposition apparatus and method for small-diameter blind hole workpieces, which has the following advantages compared with the prior art: 1. Based on existing jet electrodeposition technology, this invention independently designs and adds an anode support device, which effectively solves the problem of mass transfer of plating solution faced by traditional electrodeposition process when depositing coatings in the cavity of small holes; at the same time, the device can realize continuous and stable current introduction, which provides a guarantee for the uniform distribution of electric field in the small holes. 2. Based on existing jet electrodeposition technology, this invention introduces an auxiliary electrolysis device, which can simultaneously carry out electrolysis reactions during the coating process. By replenishing the metal ions in the electroplating solution, the concentration of the solution is maintained stably, thereby extending the life of the plating solution and improving the coating quality. It is worth noting that the auxiliary electrolysis device makes the current density during the electroplating process adjustable, further enhancing the process flexibility. 3. The surface of the contoured auxiliary anode designed in this invention is equipped with a friction pair: when an inert auxiliary anode is used, its high chemical stability, resistance to electrolytic corrosion, and almost no self-consumption can ensure the uniformity of the electric field distribution in the orifice; in addition, this structure not only facilitates the replacement of the anode during the processing, but also adapts to contoured anodes with different structures (such as irregular holes), thus expanding the applicability of the device. Attached Figure Description

[0024] Figure 1 A schematic diagram of the assembly of a triboelectric-electrolysis-assisted jet electrodeposition device for small-diameter blind hole workpieces;

[0025] Figure 2 A schematic diagram of the anode main assembly of a friction-electrolysis assisted jet electrodeposition device for small-diameter blind hole workpieces;

[0026] In the diagram, 1-DC power supply, 2-aluminum profile frame, 3-temperature controller, 4-anion exchange membrane, 5-deposition tank, 6-water bath, 7-heating rod, 8-submersible pump, 9-cathode clamp, 10-filtration device, 11-rotary power supply device, 12-flow meter with regulating valve, 13-plating solution circulation pipe, 14-anode rotation device, 15-rotary joint, 16-Y and Z axis transmission devices; 1101-anode connector, 1102-bearing connector, 1103-conductive set screw, 1104-sealing gasket, 1105-contouring auxiliary anode, 1106-conductive metal sheet, 1107-bearing, 1108-bearing fastener, 1109-nylon connecting bolt. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but it is not limited to the specific structure described in this embodiment.

[0028] like Figure 1 and Figure 2 As shown, Figure 1 This is a 3D model assembly drawing of a triboelectric-electrolysis-assisted jet electrodeposition device for small-diameter blind hole workpieces. Figure 2 This is a schematic diagram of the anode main assembly of a triboelectric-electrolysis assisted jet electrodeposition apparatus for small-diameter blind hole workpieces; the following is an implementation description of the coating preparation on the inner surface of the small-diameter blind hole workpiece:

[0029] The first step is to prepare the required electroplating solution in advance and pour it into the deposition tank; adjust the temperature of the plating solution to the preset value using a heater and temperature controller, and adjust the pH value of the plating solution to the preset range, then set it aside for use.

[0030] The second step is to pre-treat the workpiece: first, grind and polish the inner cavity of the deep small hole part, then clean the workpiece with acetone, alcohol and deionized water in turn to remove surface oil and impurities, and finally dry the workpiece for later use.

[0031] Third, start the submersible pump and rotating spindle, and adjust the flow meter valve to make the flow rate of the plating solution in the circulation pipe reach the preset parameters; keep the device running for a certain period of time to ensure system stability, and then shut down the above equipment.

[0032] The fourth step is to clamp the workpiece on the cathode fixture, and then, in conjunction with the control system and manual adjustment, correctly position the contour-guided anode so that the anode is placed in the appropriate position within the small hole of the workpiece.

[0033] Finally, connect the positive terminal of the electroplating power supply to the conductive screw on the anode body, and the negative terminal to the conductive screw on the outside of the fixture; simultaneously, connect the positive and negative terminals of the electrolysis power supply to the anode and cathode areas of the auxiliary electrolysis device, respectively. Start the rotation mechanism of the drive spindle and the submersible pump, and wait for the device to run stably for about 3 minutes to ensure uniform distribution of the plating solution in the pipeline before turning on the electroplating power supply and the electrolysis power supply for plating processing. After processing is completed, first turn off the two power supplies, then turn off the rotating spindle and the submersible pump, and finally disconnect the main power supply of the device, and remove the workpiece for subsequent processing and performance evaluation.

[0034] It should be noted in the description of this invention that the above description using a small-diameter blind hole workpiece as an example is intended to illustrate the implementation process of the device in detail and does not constitute a limitation on the scope of application of this invention. Specifically: regarding the anode configuration, the device can flexibly replace the anode component; in addition to the above-described embodiments, soluble anodes are also applicable to this device; regarding the processing object, the shape of the small hole is not limited to cylindrical, and other types of hole structures can also be adapted; regarding the friction form, it is not limited to rotational friction, and the friction characteristics are not limited to flexible friction; rigid friction can also be implemented, but in practical applications, the effect of flexible dynamic friction is more significant. All the above adjustments are within the scope of the technical concept of this invention and are intended to reflect the adaptability and flexibility of the device and method.

Claims

1. A triboelectric-electrolysis assisted jet electrodeposition apparatus and method for small-diameter blind hole components, characterized in that, The process includes the following steps: preparing and maintaining a constant temperature plating solution; grinding, polishing, degreasing, and cleaning the inner cavity of the blind hole before clamping it in the cathode fixture; the anode frame drives the contoured auxiliary anode to extend into the blind hole and rotate, and the friction pair dynamically rubs the hole wall; connecting the electrodeposition power supply and the electrolysis power supply to begin processing; cleaning and drying the workpiece after processing.

2. The triboelectric-electrolysis assisted jet electrodeposition apparatus and method for small-diameter blind hole components according to claim 1, characterized in that, The pretreatment steps for the inner cavity of the small hole include: using a flap wheel grinding head to grind and polish the inner cavity of the small hole in sequence from small mesh to large mesh, cleaning and then removing oil with alkaline cleaning solution, followed by cleaning with acetone, alcohol and deionized water in sequence, and finally drying for later use.

3. The triboelectric-electrolysis assisted jet electrodeposition apparatus and method for small-diameter blind hole components according to claim 1, characterized in that, The device includes: a motion control device, a plating solution filtration and circulation device, an anode rotation device, a rotation power supply device, an auxiliary electrolysis device, a cathode clamp, and a heating and temperature control device; wherein: the motion control system achieves precise positioning of the anode and the pinhole through the movement of the cross slide; the temperature control system maintains a constant temperature for the plating solution; the plating solution circulation and filtration system controls the jet and filters impurities using filters, regulating valves, and flow meters; the cathode clamp is used for clamping and positioning the pinhole workpiece; the anode frame integrates a rotation drive and a conductive structure, and the friction pair dynamically rubs the deposited layer as the anode rotates.

4. The triboelectric-electrolysis assisted jet electrodeposition apparatus and method for small-diameter blind hole components according to claim 3, characterized in that, The aforementioned anode frame device adapts to electrodeposition processes of anodes made of different materials by replacing the contoured auxiliary anode. At the same time, by designing different internal flow channel structures for the auxiliary contoured anode and installing different types of friction pairs on its surface, the device achieves coordinated control of the flow field, mass transfer field, electric field, and external friction force field, thereby improving processing quality and efficiency.

5. The triboelectric-electrolysis assisted jet electrodeposition apparatus and method for small-diameter blind hole components according to claims 3 and 4, characterized in that, The anode frame is mounted on a cross slide, and the anode rotating spindle, drive motor and synchronous belt drive device are all set on the anode frame; the top of the rotating spindle is connected to the liquid inlet pipe through a rotary joint, which ensures the normal delivery of plating solution when the spindle rotates, and the bottom of the spindle is connected to the contour auxiliary anode.

6. The triboelectric-electrolysis assisted jet electrodeposition apparatus and method for small-diameter blind hole components according to claim 3, characterized in that, The outer ring of the rotating power supply device in the anode frame is fixed with a bearing. The bearing conducts current to the contour auxiliary anode through the built-in metal plate in the inner ring of the connector and the conductive screw. The rotational characteristics of the bearing enable the contour auxiliary anode to receive continuous and stable power during the rotation process.

7. The triboelectric-electrolysis assisted jet electrodeposition apparatus and method for small-diameter blind hole components according to claim 3, characterized in that, The auxiliary electrolysis device performs an electrolysis reaction simultaneously during the electroplating process to replenish metal ions in the electroplating solution and maintain a stable concentration of the electroplating solution.

8. The triboelectric-electrolysis assisted jet electrodeposition apparatus and method for small-diameter blind hole components according to claim 3, characterized in that, The contoured auxiliary anode maintains a gap of about 1.5 mm with the side of the small hole cavity, and the bottom of the anode maintains a gap of about 3 mm with the bottom of the small hole.

9. The triboelectric-electrolysis assisted jet electrodeposition apparatus and method for small-diameter blind hole components according to claim 3, characterized in that, The flow rate of the plating solution in the circulating filtration system is adjusted to 4-12 L / min, and the rotation speed of the anode frame is controlled at 5-15 r / min by adjusting the motor speed.

10. The triboelectric-electrolysis assisted jet electrodeposition apparatus and method for small-diameter blind hole components according to claims 1-9, characterized in that, Improve processing performance through the following methods: Design an anode frame device and install a contoured auxiliary anode at the bottom of the anode frame, extending into the inner cavity of the small hole workpiece, so that the electric field distribution in the inner cavity of the small hole is uniform. The mass transfer of the plating solution is enhanced by jet impact, and the current density is increased to accelerate the deposition rate, while ensuring uniform distribution of the plating solution in the cavity of the small hole. The deposition layer is dynamically rubbed by a rotating friction pair to achieve grain refinement, hydrogen removal and impurity removal, and coating leveling. An auxiliary electrolysis device is designed to simultaneously electrolyze during the electroplating process to replenish metal ions, extend the life of the plating solution, and improve the coating quality.

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