Spiral wound electrode for electrodeposition coating on the inner wall of slender tubes and coating preparation method

Abstract

This invention discloses a spiral-wound electrode for electrodeposition coating on the inner wall of a slender tube and a coating preparation method, comprising: an axial conductor; a winding conductor, which is tightly wound spirally along the outer surface of the axial conductor; wherein the axial conductor and the winding conductor together constitute the electrode body, and the surface area to volume ratio of the electrode body is greater than that of a straight rod electrode of the same diameter; the electrode body is placed inside the slender tube and arranged coaxially with the slender tube; an electroplating solution is introduced into the slender tube, and current is applied to perform flow plating with the electrode body as the anode and the inner wall of the slender tube as the cathode, thereby depositing an electrodeposition coating on the inner wall of the slender tube; stable electrodeposition under high current density conditions is achieved in a limited space, effectively solving the problems of poor coating quality and low plating efficiency caused by limited current density in the prior art.

Description

Technical Field

[0001] This invention relates to the field of materials surface engineering technology, and in particular to a spiral wound electrode for electrodeposition coating on the inner wall of a slender tube and a method for preparing the coating. Background Technology

[0002] Electrodeposition coating technology for the inner wall of slender pipes is a method for preparing functional coatings on the inner wall of metal pipes, and it is widely used in aerospace, petrochemical, medical device, nuclear engineering and other fields. By preparing electrodeposited coatings on the inner wall of pipes, their surface wear resistance and corrosion resistance can be significantly improved, extending the service life of the pipes and enhancing safety performance.

[0003] Currently, the preparation of electrodeposited coatings on the inner walls of slender tubes mostly employs a linear anodic flow plating method. However, due to the limitation of the tube's inner diameter, the anode diameter is relatively small, resulting in a low upper limit for current density, poor plating efficiency, and weak coating adhesion and easy peeling at low current densities. Existing technologies attempt to increase the anode diameter or increase the plating solution flow rate, but both have limitations: excessively fast flow rates affect coating adhesion, and excessively large anode diameters alter the electric field distribution and reduce coating quality. Furthermore, the laminar flow field between the straight rod electrode and the inner wall of the tube exhibits a flow boundary layer, hindering solute exchange and further limiting the increase in current density.

[0004] Therefore, existing electrodeposition coating preparation technologies for the inner walls of narrow-diameter long tubes suffer from problems such as limited current density, poor coating quality, and low coating efficiency. Summary of the Invention

[0005] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a spiral-wound electrode for electrodeposition coating on the inner wall of slender tubes and a coating preparation method, which can achieve stable electrodeposition under high current density conditions in a limited space, effectively solving the problems of poor coating quality and low plating efficiency caused by current density limitations in the prior art.

[0006] In a first aspect, a spirally wound electrode for electrodepositing a coating on the inner wall of a slender tube according to an embodiment of the present invention comprises: Axial conductor; The conductor is wound tightly in a spiral manner along the outer surface of the axial conductor; The axial conductor and the wound conductor together constitute the electrode body, and the surface area to volume ratio of the electrode body is greater than that of a straight rod electrode of the same diameter.

[0007] The spiral-wound electrode for electrodepositing coatings on the inner wall of a slender tube according to embodiments of the present invention has at least the following beneficial effects: the winding conductor is tightly wound in a spiral manner along the outer surface of the axial conductor to form a spiral-wound electrode. The spiral-wound electrode, together with the axial conductor, constitutes a high specific surface area electrode body, and its surface area to volume ratio is greater than that of a straight rod electrode of the same diameter. This significantly increases the upper limit of current density under the same electrode volume, optimizes the flow field distribution inside the tube, and overcomes the problems of low current density and poor coating efficiency caused by the limited surface area of ​​traditional straight rod electrodes.

[0008] According to some embodiments of the present invention, the axial conductor is a drawn stainless steel wire, and the winding conductor is an aluminum wire.

[0009] According to some embodiments of the present invention, the diameter of the axial conductor is 2 mm, the diameter of the winding conductor is 2 mm, and the pitch of the winding conductor spirally wound along the axial conductor is 3 mm.

[0010] According to some embodiments of the present invention, the material of the axial conductor and / or the winding conductor is one or more of aluminum, copper, nickel, iron, stainless steel or their alloys.

[0011] According to some embodiments of the present invention, the diameter of the axial conductor is 1-5 mm, the diameter of the winding conductor is 0.5-3 mm, and the pitch of the winding conductor spirally wound along the axial conductor is 1-6 mm.

[0012] Secondly, according to an embodiment of the present invention, a method for preparing an electrodeposited coating on the inner wall of a slender tube includes the following steps: The electrode body is placed inside a slender tube, and the electrode body is arranged coaxially with the slender tube. An electroplating solution is introduced into the elongated tube, with the electrode body as the anode and the inner wall of the elongated tube as the cathode. Current is applied to perform flow plating, and an electrodeposited coating is deposited on the inner wall of the elongated tube.

[0013] The method for preparing an electrodeposited coating on the inner wall of a slender tube according to an embodiment of the present invention has at least the following beneficial effects: by combining a spirally wound electrode with a high specific surface area with an in-tube flow plating process, and through coaxial arrangement and anode power supply, stable electrodeposition under high current density conditions is achieved in a limited space, effectively solving the problems of poor coating quality and low plating efficiency caused by current density limitations in the prior art.

[0014] According to some embodiments of the present invention, the slender tube is a stainless steel tube with an inner diameter of 9-15 mm, a thickness of 0.3-1.0 mm, and a length of 0.5-2 m.

[0015] According to some embodiments of the present invention, the electrodeposited coating is an aluminum coating, a nickel coating, a copper coating, a zinc coating, or a composite coating thereof.

[0016] According to some embodiments of the present invention, the electroplating solution is an AlCl3-EMIC ionic liquid plating solution or other electroplating solutions suitable for the electrodeposited coating.

[0017] According to some embodiments of the present invention, in the step of introducing electroplating solution into the slender tube, the electroplating solution is driven by a peristaltic pump to circulate between the slender tube and the external storage tank to achieve in-tube flow plating; the plating current density is 5-30 mA / cm², and the plating time is 10-40 min.

[0018] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of the spiral wound electrode according to an embodiment of the present invention; Figure 2 This is an enlarged structural schematic diagram of the spiral-wound electrode according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the apparatus used to prepare an electrodeposition coating on the inner wall of a slender tube according to an embodiment of the present invention; Figure 4 This is a flowchart illustrating the method for preparing an electrodeposited coating on the inner wall of a slender tube according to an embodiment of the present invention. Figure 5 This is a schematic diagram of the structure of a slender tube without an electrodeposited coating according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of the present invention after electrodeposition using a straight rod electrode in a slender tube, according to an embodiment of the invention. Figure 7 This is a schematic diagram of the structure of a spiral-wound electrode after electrodeposition in a slender tube, according to an embodiment of the present invention.

[0021] Explanation of reference numerals in the attached drawings: Electrode body 100; Axial conductor 110; Winding conductor 120; Slender tube 200. Detailed Implementation

[0022] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0023] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0024] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. If "first" and "second" are mentioned, this is only for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0025] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation, connection, and linkage" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0026] The following describes, with reference to the accompanying drawings, a spiral-wound electrode for electrodeposition coating on the inner wall of a slender tube and a method for coating preparation according to an embodiment of the present invention.

[0027] Firstly, referring to Figure 1 and Figure 2 According to an embodiment of the present invention, a spiral-wound electrode for electrodepositing a coating on the inner wall of an elongated tube 200 includes: Axial conductor 110; The winding conductor 120 is tightly wound in a spiral manner along the outer surface of the axial conductor 110; The axial conductor 110 and the wound conductor 120 together constitute the electrode body 100, and the surface area to volume ratio of the electrode body 100 is greater than that of a straight rod electrode of the same diameter.

[0028] In this embodiment, the winding conductor 120 is tightly wound in a spiral manner along the outer surface of the axial conductor 110 to form a spiral wound electrode. The spiral wound electrode together with the axial conductor 110 and the winding conductor 120 constitutes a high specific surface area electrode body 100. Its surface area to volume ratio is greater than that of a straight rod electrode of the same diameter, thereby significantly increasing the upper limit of current density under the same electrode volume, optimizing the flow field distribution inside the tube, and overcoming the problems of low current density and poor plating efficiency caused by the limited surface area of ​​traditional straight rod electrodes.

[0029] According to some embodiments of the present invention, for example, Figure 1 and Figure 2 As shown, the axial conductor 110 is a drawn stainless steel wire, and the winding conductor 120 is an aluminum wire.

[0030] In this embodiment, drawn stainless steel wire is used as the axial conductor 110 and aluminum wire is used as the winding conductor 120. This ensures the mechanical strength and structural stability of the electrode, while taking advantage of the good conductivity and machinability of aluminum to facilitate the realization of the spiral winding structure. At the same time, it provides an anode material that matches the composition of the plating solution for the subsequent deposition of aluminum coating on the inner wall of the tube.

[0031] Preferably, the diameter of the axial conductor 110 is 2 mm, the diameter of the winding conductor 120 is 2 mm, and the pitch of the winding conductor 120 spirally wound along the axial conductor 110 is 3 mm.

[0032] In this embodiment, the diameter of both the axial conductor 110 and the winding conductor 120 is set to 2 mm and the pitch to 3 mm. This electrode can achieve optimal spatial adaptation and flow channel distribution within the slender tube 200. It has been verified that it can successfully and stably deposit an aluminum coating inside a tube with an inner diameter of 11 mm, while traditional straight rod electrodes cannot complete the deposit under these conditions.

[0033] According to some embodiments of the present invention, for example, Figure 1 and Figure 2 As shown, the materials of the axial conductor 110 and / or the winding conductor 120 are one or more of aluminum, copper, nickel, iron, stainless steel or their alloys.

[0034] In this embodiment, by flexibly selecting the material types of the axial conductor 110 and / or the winding conductor 120, the electrode can be adapted to different plating solution systems and deposited metal types, expanding the versatility and applicability of the electrode and meeting the needs of preparing electrodeposited coatings on the inner wall of various slender tubes 200.

[0035] According to some embodiments of the present invention, the diameter of the axial conductor 110 can be set to 1-5 mm, the diameter of the winding conductor 120 can be set to 0.5-3 mm, and the pitch of the winding conductor 120 spirally wound along the axial conductor 110 can be set to 1-6 mm.

[0036] It retains the adjustment space for different pipe diameters and coating conditions, while ensuring that the advantages of high specific surface area and good flow field distribution can be maintained within this parameter range.

[0037] Secondly, referring to Figures 1-4 The method for preparing an electrodeposited coating on the inner wall of a slender tube 200 according to an embodiment of the present invention includes the following steps: The electrode body 100 is placed inside the slender tube 200 and the electrode body 100 and the slender tube 200 are arranged coaxially. Electroplating solution is introduced into the slender tube 200. With the electrode body 100 as the anode and the inner wall of the slender tube 200 as the cathode, current is applied to perform flow plating, and an electrodeposited coating is deposited on the inner wall of the slender tube 200.

[0038] In this embodiment, the preparation method combines a spirally wound electrode with a high specific surface area with an in-tube flow plating process. Through coaxial arrangement and anode power supply, stable electrodeposition under high current density conditions is achieved in a limited space, effectively solving the problems of poor coating quality and low plating efficiency caused by current density limitations in the prior art.

[0039] According to some embodiments of the present invention, the slender tube 200 is a stainless steel tube with an inner diameter of 9-15 mm, a thickness of 0.3-1.0 mm, and a length of 0.5-2 m.

[0040] In this embodiment, the method has been verified to successfully complete the preparation of the aluminum coating on the inner wall of the tube, while traditional straight rod electrodes cannot complete the coating on tubes of this size.

[0041] Preferably, the inner diameter of the slender tube 200 can be set to 11 mm, the thickness to 0.5 mm, and the length to 1 m.

[0042] According to some embodiments of the present invention, the electrodeposited coating is an aluminum coating, a nickel coating, a copper coating, a zinc coating, or a composite coating thereof.

[0043] In this embodiment, the preparation method is not limited to aluminum coatings, but can also be used for the deposition of nickel, copper, zinc or their composite coatings, covering the main types of protective coatings required for the inner wall of slender tubes 200, including scenarios with high requirements for the performance of the inner wall of pipes such as aerospace, petrochemical, and nuclear engineering.

[0044] According to some embodiments of the present invention, the electroplating solution is an AlCl3-EMIC ionic liquid plating solution or other electroplating solutions suitable for electrodeposition coatings.

[0045] In this embodiment, an AlCl3-EMIC ionic liquid plating solution or other suitable plating solution is used. This preparation method can achieve high-quality metal deposition at room temperature or under mild conditions, avoiding side reactions such as hydrogen evolution and oxidation that are common in aqueous plating solutions. At the same time, the good conductivity and wide electrochemical window of the ionic liquid further ensure the plating stability under high current density.

[0046] According to some embodiments of the present invention, for example, Figure 3 As shown, in the step of introducing electroplating solution into the slender tube 200, the electroplating solution is driven by a peristaltic pump to circulate between the slender tube 200 and the external storage tank to achieve in-tube flow plating; the plating current density is 5-30 mA / cm², and the plating time is 10-40 min.

[0047] In this embodiment, in-tube plating is achieved by circulating the electroplating solution using a peristaltic pump, and the current density and plating time are controlled. Specifically, the plating current density can be further set to 15 mA / cm², and the plating time to 20 min. This method ensures continuous replenishment of the plating solution and maintains uniform concentration while completing the preparation of a high-quality coating in a short time. Verification has shown that the tank voltage is stable and the coating adhesion is good, achieving efficient, controllable, and repeatable process conditions.

[0048] According to some embodiments of the present invention, for example, Figure 3 As shown, a method for preparing an aluminum coating on the inner wall of a slender 304 stainless steel tube using a spirally wound electrode is provided. The specific steps are as follows: (1) The slender tube 200 is made of 304 stainless steel with an inner diameter of 11mm, a wall thickness of 0.5mm and a length of 1m.

[0049] (2) A 2mm diameter drawn 304 stainless steel wire is used as the core conductor 110, and an aluminum wire with a diameter of 2mm is used as the winding conductor 120. The aluminum wire is spirally wound along the outer surface of the stainless steel core conductor 110 with a pitch of 3mm to form a spiral wound electrode.

[0050] (3) The spiral-wound electrode was placed coaxially inside a 304 stainless steel tube, and an AlCl3-EMIC ionic liquid plating solution was supplied to the tube using a peristaltic pump. The spiral-wound electrode was used as the anode, and the inner wall of the 304 stainless steel tube was used as the cathode. Current was applied for flow plating. The plating conditions were: current density 15 mA / cm², plating time 20 min.

[0051] In comparison, this embodiment also uses a conventional straight rod electrode (aluminum rod with a diameter of 6 mm) to conduct a flow plating experiment on the inner wall of a 304 stainless steel tube of the same specification under the same plating solution (AlCl3-EMIC ionic liquid plating solution), the same current density (15 mA / cm²), and the same time (20 min).

[0052] Experimental results show that Figure 5 The image shows the original surface morphology of the inner wall of an uncoated 304 stainless steel pipe, which has not yet been effectively coated with aluminum.

[0053] like Figure 6 As shown, when using conventional straight rod electrodes for plating, the tank voltage became unstable during the plating process, preventing the plating process from proceeding normally. As a result, the aluminum coating on the inner wall of the tube was not successfully prepared, and no effective aluminum coating was observed to form.

[0054] When using the spiral-wound electrode of this embodiment for plating, the tank voltage remains stable during the plating process, and the plating process is completed smoothly. Metallographic samples of the plated pipe are prepared and observed. Figure 7 As shown, a continuous and uniform aluminum coating with a thickness of approximately 16 μm was successfully deposited on the inner wall of a 304 stainless steel tube.

[0055] The above comparison results fully demonstrate that the spiral wound electrode proposed in this invention can effectively solve the problem of plating failure caused by limited current density during the electrodeposition process of the inner wall of the slender tube 200, and significantly improve the preparation quality and feasibility of the coating on the inner wall of the slender tube 200.

[0056] In the description of this specification, the references to terms such as "an embodiment, some embodiments, illustrative embodiments, example, specific example, or examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0057] The terms "first," "second," "third," "fourth," etc. (if applicable) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in a sequence other than that illustrated or described herein.

[0058] It should also be noted that, in the description of this specification, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0059] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, such that a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may also include other steps or units that are not explicitly listed or that are inherent to such processes, methods, products, or apparatus.

[0060] Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0061] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A spiral-wound electrode for electrodepositing a coating on the inner wall of a slender tube, characterized in that, include: Axial conductor; The conductor is wound tightly in a spiral manner along the outer surface of the axial conductor; The axial conductor and the wound conductor together constitute the electrode body, and the surface area to volume ratio of the electrode body is greater than that of a straight rod electrode of the same diameter.

2. The spiral-wound electrode for electrodeposition coating on the inner wall of a slender tube according to claim 1, characterized in that, The axial conductor is a drawn stainless steel wire, and the winding conductor is an aluminum wire.

3. The spiral-wound electrode for electrodepositing a coating on the inner wall of a slender tube according to claim 1 or 2, characterized in that, The diameter of the axial conductor is 2mm, the diameter of the winding conductor is 2mm, and the pitch of the winding conductor spirally wound along the axial conductor is 3mm.

4. The spiral-wound electrode for electrodeposition coating on the inner wall of a slender tube according to claim 1, characterized in that, The material of the axial conductor and / or the winding conductor is one or more of aluminum, copper, nickel, iron, stainless steel or their alloys.

5. The spiral-wound electrode for electrodeposition coating on the inner wall of a slender tube according to claim 1, characterized in that, The diameter of the axial conductor is 1-5 mm, the diameter of the winding conductor is 0.5-3 mm, and the pitch of the winding conductor spirally wound along the axial conductor is 1-6 mm.

6. A method for preparing an electrodeposited coating on the inner wall of a slender tube, characterized in that, Includes the following steps: The electrode body as described in any one of claims 1 to 5 is placed inside the elongated tube, and the electrode body is arranged coaxially with the elongated tube; An electroplating solution is introduced into the elongated tube, with the electrode body as the anode and the inner wall of the elongated tube as the cathode. Current is applied to perform flow plating, and an electrodeposited coating is deposited on the inner wall of the elongated tube.

7. The method for preparing an electrodeposited coating on the inner wall of a slender tube according to claim 6, characterized in that, The slender tube is made of stainless steel and has an inner diameter of 9-15 mm, a thickness of 0.3-1.0 mm, and a length of 0.5-2 m.

8. The method for preparing an electrodeposited coating on the inner wall of a slender tube according to claim 6, characterized in that, The electrodeposited coating is an aluminum coating, a nickel coating, a copper coating, a zinc coating, or a composite coating thereof.

9. The method for preparing an electrodeposited coating on the inner wall of a slender tube according to claim 6, characterized in that, The electroplating solution is an AlCl3-EMIC ionic liquid plating solution or other electroplating solutions suitable for the electrodeposited coating.

10. The method for preparing an electrodeposited coating on the inner wall of a slender tube according to claim 6, characterized in that, In the step of introducing the electroplating solution into the slender tube, the electroplating solution is driven by a peristaltic pump to circulate between the slender tube and the external storage tank to achieve in-tube plating; the plating current density is 5-30 mA / cm², and the plating time is 10-40 min.

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