Device and method for improving quality of ionic liquid electroplating coating of spring product

Abstract

The invention relates to a device and method for improving the quality of an ionic liquid electroplating coating of a spring product, and belongs to the technical field of ionic liquid electroplating aluminum. The device comprises a center screw rod, an upper clamping head, a lower supporting seat and metal wires, the metal wires are wound on the side wall face of the center screw rod, and the upper end and the lower end of the center screw rod are connected with the metal wires correspondingly; according to the device and the method, through tool design, the metal wires are used as the inner anodes, the thickness uniformity of the coating of the spring part is improved, the electrochemical process parameters of device electroplating are determined, and the problem that the thickness and corrosion resistance indexes are out of tolerance is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of ionic liquid electroplating aluminum, and in particular relates to a device and method for improving the quality of ionic liquid electroplating coatings of spring products. Background Art

[0002] Ionic liquid electroplating technology is a recently emerging electroplating process. It uses ionic liquids as electrolytes. These are organic salts composed of organic cations and inorganic or organic anions that are liquid at room temperature. They are characterized by being anhydrous and oxygen-free, having low vapor pressure, a wide potential window, and high electrical conductivity. The ionic liquid electroplating process is similar to electroplating, using the part as the cathode and the electroplated metal plate as the anode. Electroplating is achieved through electrodeposition on the product surface. Because the electroplating solution is a non-aqueous electrolyte, the entire electroplating process is free of water, and no hydrogen evolution occurs at the cathode, making it a novel, green, hydrogen-free electroplating process.

[0003] Elastic parts are widely used in aerospace manufacturing, and they all require surface anti-corrosion treatment during the production process to improve their corrosion resistance. Traditional surface treatment of elastic parts uses aqueous solution electroplating of zinc and cadmium, but this has the risk of hydrogen embrittlement and is in urgent need of replacement. Due to its environmental advantages and lack of hydrogen embrittlement risk, ionic liquid electroplating technology is considered a good alternative to aqueous solution electroplating for elastic parts. Due to the structural characteristics of spring parts, ionic liquid electroplating can result in poor thickness uniformity between different parts of the inner and outer rings of the spring, leading to problems such as excessive coating thickness and unqualified corrosion resistance. Summary of the Invention

[0004] The purpose of the present invention is to provide a device and method for improving the quality of the ionic liquid electroplating coating of spring products. Through tooling design and using metal wire as the internal anode, the uniformity of the coating thickness of spring parts is improved, the electrochemical process parameters of the electroplating device are determined, and the problem of excessive thickness and corrosion resistance indicators is solved.

[0005] The above-mentioned purpose of the present invention is mainly achieved through the following technical solutions:

[0006] A device for improving the quality of ionic liquid electroplating coating of spring products includes a central screw, an upper clamp, a lower support seat and a metal wire. The central screw is a columnar structure. The upper clamp and the lower support seat are respectively connected to the two ends of the central screw. The metal wire is wrapped around the side wall of the central screw. The upper and lower ends of the central screw are respectively connected to the metal wire. The metal wires at both ends are respectively connected to the anode and the cathode to form an energized circuit. The metal wire is used as an internal anode for consumption; the central screw passes through the spring to be electroplated, and the upper clamp and the lower support seat respectively limit the two ends of the spring to be electroplated.

[0007] The upper clamping head is a columnar structure, a plurality of connecting rods are evenly arranged on the side wall surface of the columnar structure, a conical protrusion is arranged on the lower surface of the connecting rod, and a platform is arranged at the center of the conical protrusion.

[0008] A threaded hole is provided at the center of the upper clamping head, and the upper clamping head is threadedly connected to the central screw through the threaded hole.

[0009] The lower support seat includes a bottom support, a conductive ring and an isolation column. The conductive ring is a cylindrical structure for conducting electricity. A plurality of square protrusions are provided on the side wall of the cylinder. The upper surface of the square protrusions is provided with strip-shaped protrusions. The upper surface of the conductive ring is provided with an isolation column. The conductive ring and the isolation column are provided with through holes. The central screw passes through the through hole, and the bottom support wraps around the side wall and bottom surface of the conductive ring.

[0010] The strip-shaped protrusion has a width of 0.4 to 1 mm.

[0011] The conductive ring comprises a strip-shaped protrusion extending out of the lower support seat, and a metal wire is tied to the tail of the strip-shaped protrusion to connect to the cathode.

[0012] The center screw, conductive ring and metal wire are made of pure aluminum with a purity of not less than 99.9%; the upper clamp, isolation column and bottom support are made of polytetrafluoroethylene.

[0013] The exposed part of the side wall of the central screw is covered with a polytetrafluoroethylene tube.

[0014] A method for improving the quality of the ionic liquid electroplating coating of a spring product according to the above device comprises the following steps:

[0015] (1) Remove the upper clamp and pass the spring to be electroplated through the central screw so that the spring to be electroplated is in a vertical state and contacts the metal on the lower support seat;

[0016] (2) Install the upper clamp and adjust the installation height of the upper clamp according to the height of the spring so that the spring is in close contact with the tooling and does not shake; connect the metal wires, with the upper metal wire connected to the anode and the lower metal wire connected to the cathode, and place them in the electroplating solution;

[0017] (3) Electroplating is performed. After electroplating is completed, the power supply is cut off, cleaning is performed, and then the product and tooling are taken out together;

[0018] (4) Remove the upper clamping block, then remove the electroplated spring to end the experiment.

[0019] The electroplating process parameters are as follows: electroplating temperature is 30°C to 40°C, the anode to cathode current ratio is 1:3 to 1:4, the electroplating time is 60 to 80 minutes, and the electroplating solution is AlCl3-EMIC.

[0020] Compared with the prior art, the present invention has at least the following beneficial effects:

[0021] This invention, through the use of a dedicated device, ensures the quality and stability of the ionic liquid aluminum electroplating coating on spring components, providing technical support for comprehensively addressing the replacement of ionic liquid aluminum electroplating processes for elastic components. The invention also features simple operation, adaptable tooling for products of varying sizes, and reusability. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of a device for improving the quality of ionic liquid Al plating on spring products according to the present invention;

[0023] Figure 2 A three-dimensional diagram of a device for improving the quality of ionic liquid Al plating on spring products according to the present invention;

[0024] Figure 3 This is a schematic diagram of the central screw of the present invention;

[0025] Figure 4 It is a schematic diagram of the lower support seat of the present invention. DETAILED DESCRIPTION

[0026] The present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments:

[0027] The ionic liquid aluminum electroplating of the present invention is carried out by rack plating, and the main process flow is as follows:

[0028] Degreasing → Sand blasting (removing oxide scale) → Activation → Aluminum electroplating → Cleaning → Shot blasting → Cleaning → Passivation → Drying

[0029] The activation and aluminum electroplating processes are carried out in a closed nitrogen atmosphere chamber. Except for loading, which is a manual operation, the rest of the operations are automated. The process equipment used should be special equipment that does not react with the atmosphere and plating solution in the chamber, and is simple to operate and does not require manual intervention.

[0030] The performance of elastic parts after aluminum plating must meet the following requirements:

[0031] a) Appearance: The film layer should be uniform and continuous, without defects such as bubbles, powdering, looseness, etc.

[0032] b) Thickness: The film thickness is 7-12 μm;

[0033] c) Adhesion: The film adhesion is tested by the cross-hatch method, and the performance is not less than level 0.

[0034] d) Corrosion resistance: The corrosion resistance requirements for steel parts are that the time for white corrosion products to appear in the neutral salt spray test shall be no less than 96 hours, and the time for red corrosion products to appear shall be no less than 336 hours.

[0035] In order to improve the uniformity of the coating thickness of spring parts, a special spring device was designed and the electrochemical parameters of the device were determined to improve the uniformity of the coating thickness of the inner and outer rings during the electroplating process and solve the problem of excessive thickness and corrosion resistance indicators.

[0036] like Figure 1 and Figure 2 As shown, a device for improving the quality of ionic liquid electroplating coating of spring products includes a central screw 1, an upper clamp 2, a lower support seat 3 and a metal wire 4, as shown in FIG. Figure 3 As shown, the central screw 1 is a columnar structure, the upper clamp 2 and the lower support seat 3 are respectively connected to the two ends of the central screw 1, the metal wire 4 is wrapped around the side wall of the central screw 1, the upper and lower ends of the central screw 1 are respectively connected with the metal wire 4, the metal wires 4 at both ends are respectively connected to the anode and the cathode to form an energized circuit, and the metal wire 4 is used as an internal anode consumption; the central screw 1 passes through the spring to be electroplated, and the upper clamp 2 and the lower support seat 3 limit the two ends of the spring to be electroplated respectively.

[0037] The upper clamping head 2 is a columnar structure with a herringbone bottom surface, a conical protrusion 401 is provided on the lower surface, and a platform is provided at the center of the conical protrusion 401.

[0038] A threaded hole is provided at the center of the upper clamp 2 , and the upper clamp 2 is threadedly connected to the central screw 1 through the threaded hole.

[0039] like Figure 4 As shown, the lower support seat 3 includes a base 301, a conductive ring 302 and an isolation column 303. The conductive ring 302 is a cylindrical structure for conducting electricity. A plurality of square protrusions are provided on the side wall of the cylinder. The upper surface of the square protrusions is provided with strip-shaped protrusions. The upper surface of the conductive ring 302 is provided with an isolation column 303. The conductive ring 302 and the isolation column 303 are provided with through holes. The central screw 1 passes through the through hole, and the base 301 wraps the side wall and bottom surface of the conductive ring 302.

[0040] The strip-shaped protrusion has a width of 0.4 to 1 mm.

[0041] The conductive ring 302 includes a strip-shaped protrusion extending out of the lower support seat 3, and a metal wire 4 is tied to the tail of the strip-shaped protrusion to connect to the cathode.

[0042] The center screw 1 , the conductive ring 302 and the metal wire 4 are made of pure aluminum with a purity of not less than 99.9%; the upper clamp 2 , the isolation column 303 and the bottom bracket 301 are made of polytetrafluoroethylene.

[0043] The exposed portion of the side wall of the central screw 1 is sheathed with a polytetrafluoroethylene tube.

[0044] A method for improving the quality of an ionic liquid electroplating coating on a spring product comprises the following steps:

[0045] (1) Remove the upper clamp 2 and pass the spring to be electroplated through the central screw 1 so that the spring to be electroplated is in a vertical state and contacts the metal on the lower support seat 3;

[0046] (2) Install the upper clamp 2 and adjust the installation height of the upper clamp 2 according to the spring height so that the spring is in close contact with the tooling and does not shake; connect the metal wire 4, the upper metal wire 4 is connected to the anode, and the lower metal wire 4 is connected to the cathode, and place it in the electroplating solution;

[0047] (3) Electroplating is performed. After electroplating is completed, the power supply is cut off, cleaning is performed, and then the product and tooling are taken out together;

[0048] (4) Remove the upper clamping block 2, then remove the electroplated spring to end the experiment.

[0049] The electroplating process parameters are as follows: electroplating temperature is 30°C to 40°C, the anode to cathode current ratio is 1:3 to 1:4, the electroplating time is 60 to 80 minutes, and the electroplating solution is AlCl3-EMIC.

[0050] Example 1

[0051] A method for improving the quality of ionic liquid Al plating on spring products comprises the following steps:

[0052] ((1) Remove the upper clamp 2, pass the spring to be electroplated through the central screw 1, and make the spring to be electroplated vertically contact the metal on the lower support seat 3;

[0053] (2) Install the upper clamp 2 and adjust the installation height of the upper clamp 2 according to the spring height so that the spring is in close contact with the tooling and does not shake; connect the metal wire 4, the upper metal wire 4 is connected to the anode, and the lower metal wire 4 is connected to the cathode, and place it in the electroplating solution;

[0054] (3) The electroplating solution is AlCl3-EMIC, the electroplating temperature is 30°C, the anode current is 2A, the cathode current is 7A, and the electroplating time is 70 minutes. After the electroplating is completed, the power supply is turned off, the product and the tooling are cleaned, and then the product and the tooling are taken out together;

[0055] (4) Remove the upper clamping block 2, then remove the electroplated spring to end the experiment.

[0056] Metallographic inspection was performed on the electroplated spring. The outer ring coating thickness was 8.1μm~11.6μm, and the inner ring coating thickness was 7.5μm~11.2μm. The difference in coating thickness between the inner and outer rings was not large, both meeting the design requirement of 7-12μm. Salt spray test was performed on the plated specimen. White rust appeared after 224 hours and red rust appeared after 637 hours, which met the design requirement of no white rust after 96 hours and no red rust after 336 hours.

[0057] The above description is only the best specific implementation method of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or replacements that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

[0058] The contents not described in detail in the specification of the present invention belong to the common knowledge of professionals in this field.

Claims

1. A device for improving the quality of ionic liquid electroplating coatings on spring products, characterized by: The invention comprises a central screw (1), an upper clamp (2), a lower support seat (3) and a metal wire (4); the central screw (1) is a columnar structure; the upper clamp (2) and the lower support seat (3) are respectively connected to the two ends of the central screw (1); the metal wire (4) is wound on the side wall surface of the central screw (1); the upper and lower ends of the central screw (1) are respectively connected to the metal wire (4); the metal wires (4) at the two ends are respectively connected to the anode and the cathode to form an electric circuit; the metal wire (4) is used as an internal anode for consumption; the central screw (1) passes through the spring to be electroplated; the upper clamp (2) and the lower support seat (3) respectively limit the two ends of the spring to be electroplated.

2. The device for improving the quality of ionic liquid electroplating coatings on spring products according to claim 1, characterized in that: The upper clamping head (2) is a columnar structure, a plurality of connecting rods are evenly arranged on the side wall of the columnar structure, a conical protrusion (401) is arranged on the lower surface of the connecting rod, and a platform is arranged at the center of the conical protrusion (401).

3. The device for improving the quality of ionic liquid electroplating coatings on spring products according to claim 1, characterized in that: A threaded hole is provided at the center of the upper clamp (2), and the upper clamp (2) is threadedly connected to the central screw (1) through the threaded hole.

4. The device for improving the quality of ionic liquid electroplating coatings on spring products according to claim 1, characterized in that: The lower support seat (3) comprises a bottom bracket (301), a conductive ring (302) and an isolation column (303); the conductive ring (302) is a cylindrical structure for conducting electricity; a plurality of square protrusions are provided on the side wall surface of the cylinder; a strip-shaped protrusion is provided on the upper surface of the square protrusion; an isolation column (303) is provided on the upper surface of the conductive ring (302); the conductive ring (302) and the isolation column (303) are provided with through holes; the central screw (1) passes through the through holes; the bottom bracket (301) wraps around the side wall surface and bottom surface of the conductive ring (302).

5. The device for improving the quality of ionic liquid electroplating coatings on spring products according to claim 4, characterized in that: The strip-shaped protrusion has a width of 0.4 to 1 mm.

6. The device for improving the quality of ionic liquid electroplating coatings on spring products according to claim 4, characterized in that: The conductive ring (302) includes a strip-shaped protrusion extending out of the lower support seat (3), and a metal wire (4) is tied to the tail of the strip-shaped protrusion to connect to the cathode.

7. The device for improving the quality of ionic liquid electroplating coatings on spring products according to claim 4, characterized in that: The central screw (1), the conductive ring (302) and the metal wire (4) are made of pure aluminum with a purity of not less than 99.9%; the upper clamp (2), the isolation column (303) and the bottom support (301) are made of polytetrafluoroethylene.

8. The device for improving the quality of ionic liquid electroplating coatings on spring products according to claim 1, characterized in that: The exposed part of the side wall of the central screw (1) is covered with a polytetrafluoroethylene tube.

9. A method for improving the quality of ionic liquid electroplating coatings on spring products using the device according to any one of claims 1 to 8, characterized in that: The following steps are involved: (1) Remove the upper clamp (2), pass the spring to be electroplated through the central screw (1), and make the spring to be electroplated vertically contact the metal on the lower support seat (3); (2) Install the upper clamp (2), adjust the installation height of the upper clamp (2) according to the height of the spring, so that the spring is in close contact with the tooling and does not shake; connect the metal wire (4), the upper metal wire (4) is connected to the anode, and the lower metal wire (4) is connected to the cathode, and place it in the electroplating solution; (3) Electroplating is performed. After electroplating is completed, the power supply is cut off, cleaning is performed, and then the product and tooling are taken out together; (4) Remove the upper clamping block (2), then remove the electroplated spring, and end the experiment.

10. The method for improving the quality of ionic liquid electroplating coatings on spring products according to claim 9, characterized in that: The electroplating process parameters are as follows: electroplating temperature is 30°C to 40°C, the anode to cathode current ratio is 1:3 to 1:4, the electroplating time is 60 to 80 minutes, and the electroplating solution is AlCl3-EMIC.

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