Efficient and uniform gas distribution stirring device and process for electroplating bath

Abstract

The invention discloses an efficient and uniform gas distribution stirring device and process for an electroplating bath. Relates to the technical field of metal surface treatment and electrochemical engineering and comprises a stirring device body, an air inlet is formed in one side of the stirring device body, a polymeric membrane is arranged on the stirring device body, a plurality of membrane holes are formed in the surface of the polymeric membrane, and a one-way flow control structure is arranged in the stirring device body. The inner space of the stirring device body is divided into an intra-cavity area and an intra-membrane area through the one-way flow control structure, the intra-cavity area is arranged to be a cavity from the air inlet to the one-way flow control structure, and the intra-membrane area is the space between the outlet of the one-way flow control structure and the membrane holes in the surface of the polymeric membrane. According to the efficient and uniform gas distribution stirring device and process for the electroplating bath, the efficient and uniform gas distribution stirring device is installed at the bottom of the electroplating bath, high-pressure gas is sprayed out from the tiny orifices to form microbubbles, the formed microbubbles can improve flow field distribution in the electroplating bath, uniform distribution of a solution in the electroplating bath is guaranteed, and the electroplating efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal surface treatment and electrochemical engineering, and more particularly to a high-efficiency and uniform gas distribution and stirring device for an electroplating tank and a process. BACKGROUND

[0002] In the industrial processes of metal electroplating and electroplating refining, the electroplating tank is the core reaction equipment. Introducing gas into the electroplating tank is a common and key process operation, which plays an important role in electroplating.

[0003] Using gas to stir the electroplating solution can prevent the polarization of the concentration of additives or metal ions on the electrode surface, make the composition and temperature of the electroplating solution uniform, and improve the uniformity of electroplating. The gas can realize the oxidation or purification function of the ions in the electroplating solution. In the acid copper plating process, the introduction of air can oxidize the cupric ions in the electroplating solution, prevent the generation of "copper powder", and improve the quality of the plating layer. In addition, in some special processes, the gas itself can participate in the electrode reaction as a reactant, and the aeration can also play the function of driving out hydrogen. For example, in the process where the cathode hydrogen evolution reaction is obvious, aeration can accelerate the detachment of hydrogen bubbles, and reduce defects such as plating layer pinholes and hydrogen embrittlement.

[0004] The key to achieving the above functions is whether the gas can be distributed efficiently and uniformly in the entire cross-sectional area of the electroplating tank. The inventors found that the existing gas distribution technology cannot achieve efficient and uniform gas distribution, and the reasons are as follows: At present, the gas distribution methods used in industry mainly include simple pipe gas distribution method and porous material gas distribution method.

[0005] The simple pipe gas distribution method is to directly lay one or several PVC or CPVC pipes drilled with a plurality of holes at the bottom of the electroplating tank. Although this method has a simple structure and low cost, when this method is used, the gas will preferentially escape from the holes close to the gas source inlet, resulting in small or even no gas output from the holes far away from the gas source, and the gas distribution in the tank is seriously uneven. In addition, the bubbles generated by the drilled holes are usually several millimeters or even larger in diameter, and have a small specific surface area, a low contact efficiency with the electroplating solution, a poor gas utilization rate, and a low gas distribution efficiency. Some large bubbles may even cause the appearance of hole defects in the plating layer.

[0006] The porous material cloth gas method uses a material with a microporous structure to make a cloth gas pipe or cloth gas plate, which has the advantage of being able to produce relatively fine bubbles and improve the gas-liquid contact area; however, the concentrated bubble group has a high bubble density in a unit liquid volume, and the occurrence of bubble merging to form large bubbles and the change in the interaction trajectory will affect the uniformity of the flow field in the electroplating tank. In addition, the resistance of the gas passing through the microporous channel is huge, and a higher gas supply pressure is required, and the pressure loss is large; and the microporous structure is very easy to be blocked by the crystallization in the electroplating solution, the decomposition products of the additives or impurities, and as the running time increases, the uniformity of the gas distribution will deteriorate rapidly, Therefore, how to provide a high-efficiency and uniform gas distribution and stirring device and process for an electroplating tank, which can produce fine and uniformly distributed bubbles for a long time and stably under low energy consumption conditions, thereby significantly improving the uniformity of electroplating, improving product quality, reducing production cost and reducing maintenance frequency, is a problem that those skilled in the art need to solve. SUMMARY

[0007] Therefore, the present application provides a high-efficiency and uniform gas distribution and stirring device and process for an electroplating tank, which aims to solve one of the problems in the above background art, and produces fine and uniformly distributed bubbles for a long time and stably under low energy consumption conditions, thereby significantly improving the uniformity of electroplating, improving product quality, reducing production cost and reducing maintenance frequency.

[0008] In order to achieve the above-mentioned purpose, in one aspect, the present application discloses a high-efficiency and uniform gas distribution and stirring device for an electroplating tank, comprising: The stirring device body is provided at the bottom of the electroplating tank, one side of the stirring device body is provided with a gas inlet, a high molecular film is arranged on the stirring device body, a plurality of film holes are arranged on the surface of the high molecular film, a one-way flow control structure is arranged inside the stirring device body, the internal space of the stirring device body is divided into an intracavity region and an intramembrane region by the one-way flow control structure, the intracavity region is arranged as a cavity from the gas inlet to the one-way flow control structure, and the intramembrane region is the space between the film holes on the surface of the high molecular film from the outlet of the one-way flow control structure.

[0009] Further, the inside of the one-way flow control structure is provided with a plurality of curved, bifurcated and staggered channels.

[0010] Further, the inner surface of the high molecular film in the intramembrane region is provided with a plurality of micro-cylinders, the micro-cylinders are arranged in a staggered manner, and the distribution density of the micro-cylinders decreases along the gas flow direction.

[0011] Further, the film holes are arranged at equal intervals between adjacent micro-cylinders.

[0012] Further, the air inlet is provided with an air inlet boss for connecting and fixing the air inlet pipe.

[0013] Further, the polymer film is flatly attached to the stirring device body and fixed at both ends of the stirring device body by a clamp.

[0014] Further, the stirring device body is internally provided with a rib plate, which makes the polymer film flatly attached to the stirring device body and ensures the strength of the stirring device body.

[0015] Further, the membrane holes are processed by femtosecond laser and have a diameter of 0.1 mm or less.

[0016] In another aspect, the application discloses a micro-bubble stirring process based on the above-mentioned high-efficiency and uniform air distribution stirring device for an electroplating tank, which specifically comprises the following steps: Step one: high-pressure gas is introduced into the stirring device body through the air inlet, and the high-pressure gas enters the membrane inner area through the one-way flow control structure and uniformly diffuses along the inner surface of the polymer film under the guidance of the micro-cylinder; Step two: the high-pressure gas reaches each membrane hole, and under the elastic deformation and rebounding effect of the polymer film, micro-bubbles are formed and quickly separated, and the separated micro-bubbles enter the electroplating tank liquid; Step three: the generated micro-bubble group has a straight-line motion trajectory and a controllable range during the rising process, and is not easy to merge to form large bubbles; the micro-bubbles uniformly stir the electroplating liquid and optimize the distribution of the flow field in the tank.

[0017] According to the above technical solution, compared with the prior art, the application provides a high-efficiency and uniform air distribution stirring device and process for an electroplating tank, which has the following beneficial effects: 1. The device is fixed to the bottom of the electroplating tank, and high-pressure gas is sprayed from the micro-hole to form micro-bubbles; the micro-bubble flow plays a role in stirring the liquid flow field in the tank, so that the flow field in the electroplating tank is more uniform, the chemical reaction rate is improved, and the micro-bubbles formed can improve the flow field distribution in the electroplating tank and improve the electroplating efficiency; 2. The amount of micro-bubbles is related to the size and processing capacity of the electroplating tank and is controlled by the gas flow and gas inlet pressure; the more the number of micro-bubbles, the more stable the liquid surface in the tank, so that the flow field in the tank is more uniform, and more stable conditions are provided for the electrochemical reaction. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to make the technical solutions in the embodiments of the present application or the prior art clearer, the accompanying drawings needed in the embodiments or prior art description will be briefly introduced. Obviously, the accompanying drawings in the following description only need to be drawn for the embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of the provided drawings.

[0019] Figure 1 A sectional view of the high-efficiency and uniform gas distribution and stirring device for the electroplating tank is provided in the present application. Figure 2 A front view of the high-efficiency and uniform gas distribution and stirring device for the electroplating tank is provided in the present application. Figure 3 An axial view of the high-efficiency and uniform gas distribution and stirring device for the electroplating tank is provided in the present application. Figure 4 A schematic diagram of the high-efficiency and uniform gas distribution and stirring device for the electroplating tank is provided in the present application. Figure 5 A process flow diagram of the high-efficiency and uniform gas distribution and stirring device for the electroplating tank is provided in the present application. Figures 6A-6B The measured bubble flow diagram of the traditional device and the measured effect diagram of the micro-bubble flow provided in the present application are shown respectively.

[0020] Wherein: 1 is a micro-cylinder; 2 is a polymer film; 3 is an air inlet; 4 is an air inlet boss; 5 is a one-way flow control structure; 6 is a one-way air outlet; 7 is a clamp; 8 is a film hole; 9 is a rib plate. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without any creative effort belong to the scope of protection of the present application.

[0022] Referring to Figures 1-6B The embodiments of the present application disclose a high-efficiency and uniform gas distribution and stirring device for an electroplating tank, which comprises: The stirring device body is arranged at the bottom of the electroplating tank, one side of the stirring device body is provided with an air inlet 3, the stirring device body is provided with a polymer film 2, the surface of the polymer film 2 is provided with a plurality of film holes 8, the inside of the stirring device body is provided with a one-way flow control structure 5, the inside space of the stirring device body is divided into a cavity region and a film region through the one-way flow control structure 5, the cavity region is arranged as a cavity from the air inlet 3 to the one-way flow control structure 5, and the film region is a space between the film holes 8 on the surface of the polymer film 2 from the outlet of the one-way flow control structure 5; the one-way flow control structure 5 is provided with a one-way air outlet 6; the gas flowing out of the one-way air outlet 6 of the one-way flow control structure 5 is more easily uniformly axially flowed along the device surface under the influence of the spacing of the micro cylinders 1 on the device surface, and finally the gas is separated from the film holes 8 in different micro cylinder 1 intervals.

[0023] In the embodiment, the inside of the one-way flow control structure 5 is provided with a plurality of curved, bifurcated and staggered channels; so that the flow resistance of the gas from the air inlet 3 to the film hole 8 direction is small, and the gas can quickly and uniformly reach the film space; and the reverse flow resistance is large, so as to prevent the backflow of the leaked electroplating solution.

[0024] In the embodiment, the inner surface of the polymer film 2 in the film region is provided with a plurality of micro cylinders 1, the micro cylinders 1 are arranged in a forked row manner, and the distribution density of the micro cylinders 1 is changed from dense to sparse along the gas flow direction; the forked row arrangement can optimize the distribution of the gas on the surface of the polymer film 2, and reduce the concentration of the gas flow in some areas.

[0025] In the embodiment, the film holes 8 are arranged at equal intervals between adjacent micro cylinders 1; which is helpful for the uniform distribution of the gas on the surface of the polymer film 2, prevents the gas from concentrating in local areas, ensures that each hole of the polymer film 2 can uniformly produce bubbles, and avoids the aggregation and merging of the bubbles.

[0026] In the embodiment, the air inlet 3 is provided with an air inlet boss 4, and the air inlet boss 4 is used for connecting and fixing the air inlet pipe.

[0027] In the embodiment, the polymer film 2 is fixed on the stirring device body through a clamp 7; which prevents the liquid in the tank from seeping into the cavity through the gap between the two ends of the polymer film 2.

[0028] In the embodiment, the inside of the stirring device body is provided with a rib plate 9, the rib plate 9 supports the whole device, and the purpose is to ensure the strength of the device body structure while lightening, and ensure that the rubber film is uniformly and tightly attached to the pipeline support structure.

[0029] In the embodiment, the film holes 8 are processed by femtosecond laser and the aperture is 0.1mm or below.

[0030] In addition, in the embodiment, the cavity gas is sent from the gas inlet 3, and the fluid domain of the small area is designed in the cavity, so that the gas pressure loss can be reduced.

[0031] As shown in Figure 4 and Figure 5 As shown in the drawings, the array type film hole 8 is arranged on the polymer film 2, when the gas reaches the hole boundary, the polymer film 2 is subjected to the action of the gas pressure, and the interface of the film hole 8 expands outward; with the increase of the bubble size, the aperture of the film hole 8 expands to the maximum; with the deformation of the boundary surface of the film hole 8 on the polymer film 2, the shrinkage force at the film hole 8 reaches the maximum, which helps the bubble to quickly separate. By changing the elastic modulus of the rubber film and enhancing the shrinkage force of the film hole 8, the size of the micro-bubble separated from the film hole 8 can be smaller. Through the process, the micro-bubble group is generated on the surface of the polymer film 2, the bubble group enters the electroplating tank, and the movement of the bubble group improves the flow field inside the electroplating tank and forms a stirring effect on the electroplating solution, which improves the electroplating efficiency. And the size of each hole is uniform, the distribution of each bubble in the generated bubble group is relatively regular and uniform, and uniform gas distribution can be realized to achieve the effect of efficient and uniform gas distribution.

[0032] The minimum pressure formula of the bubble is as follows:

[0033] In the formula, P is the minimum pressure required to overcome the surface tension to discharge the liquid; gamma is the surface tension; theta is the contact angle; d is the aperture; The size of the film hole 8, the gas pressure and the elastic modulus of the polymer film 2 jointly affect the size and quantity of the micro-bubbles.

[0034] On the other hand, the application discloses a micro-bubble stirring process based on the above-mentioned efficient and uniform gas distribution stirring device for an electroplating tank, and specifically includes the following steps: Step one: high-pressure gas is introduced into the inside of the stirring device body through the gas inlet 3, the high-pressure gas enters the film inner area through the one-way flow control structure 5, and is uniformly diffused along the inner surface of the polymer film 2 under the guidance of the micro-cylinder 1; Step two: the high-pressure gas reaches everywhere of the film hole 8, and under the elastic deformation and rebound effect of the polymer film 2, micro-bubbles are formed and separated, and enter the electroplating tank liquid; Step three: in the rising process of the micro-bubble group, the movement track is a straight line, the range is controllable, and it is not easy to merge to form large bubbles; the electroplating liquid is uniformly stirred, and the flow field distribution in the tank is optimized.

[0035] The bubble group size is small, and the horizontal movement offset of each bubble is small, so that uniform gas distribution can be realized on the electrolytic tank; The flow of bubble groups will drive the liquid in the tank to flow around, the liquid in the electroplating tank flows around the two electrodes, and when the inlet pressure is appropriate, it helps the rapid separation of bubbles at the orifice, and rapidly stirs the liquid in the electroplating tank; The size of bubble separation depends on the deformation of the membrane hole 8 boundary surface of the polymer film 2, the contraction force of the membrane hole 8 boundary surface will accelerate the rapid separation of the bubble, change the elastic modulus of the rubber film, enhance the contraction force of the membrane hole 8, and make the size of the micro-bubble separated from the membrane hole 8 smaller; Connect the air inlet 3 with the air compressor, change the gas flow and inlet pressure to improve the uniformity of the gas in the polymer film 2, and the fine bubbles are uniformly separated from the membrane hole 8, thereby improving the liquid flow field in the tank.

[0036] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the difference from other embodiments. The same or similar parts between the various embodiments can be referred to each other. For the device disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple, and the related parts can be referred to the method part.

[0037] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to the embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A high efficiency uniform gas distribution and agitation device for use in an electroplating cell, characterized by, The utility model relates to a kind of electroplating agitator, including: The utility model discloses an electroplating agitator, comprising: a stirring device body is arranged at the bottom of electroplating tank, one side of the stirring device body is equipped with air inlet, the stirring device body is equipped with polymer film, the surface of the polymer film is equipped with a plurality of membrane holes, the stirring device body is equipped with one-way flow control structure inside, the internal space of the stirring device body is divided into cavity area and membrane area by the one-way flow control structure, the cavity area is arranged as the cavity from the air inlet to the one-way flow control structure, the membrane area is the space between the membrane hole of the surface of the polymer film from the outlet of the one-way flow control structure.

2. The device for efficient and uniform gas distribution and agitation in an electroplating cell according to claim 1, wherein, The one-way flow control structure is equipped with a plurality of curved, bifurcated and staggered channels inside.

3. The device for efficient and uniform gas distribution and agitation in an electroplating cell according to claim 1, wherein, The inner surface of the polymer film in the membrane area is equipped with a plurality of groups of micro-cylinders, the micro-cylinders are arranged in a staggered manner, and the distribution density of the micro-cylinders changes from dense to sparse along the gas flow direction.

4. The device for efficiently and uniformly distributing gas and agitation in an electroplating cell of claim 3, wherein, The membrane holes are arranged at equal intervals between adjacent micro-cylinders.

5. The device for efficient and uniform gas distribution and agitation in an electroplating cell according to claim 1, wherein, The air inlet is equipped with an air inlet boss, and the air inlet boss is used to connect and fix the air inlet pipe.

6. The device for efficient and uniform gas distribution and agitation in an electroplating cell according to claim 1, wherein, The polymer film is flatly attached to the stirring device body and is fixed at both ends of the stirring device body by a clamp.

7. The device for efficient and uniform gas distribution and agitation in an electroplating cell according to claim 1, wherein, The stirring device body is equipped with a rib plate inside, so that the polymer film is flatly attached to the stirring device body by the rib plate, and the strength of the stirring device body is guaranteed.

8. The device for efficient and uniform gas distribution and agitation in an electroplating cell according to claim 1, wherein, The membrane holes are processed by femtosecond laser and have a pore size of 0.1 mm or less.

9. A micro-bubble agitation process, a device for efficient and uniform gas agitation in an electroplating tank according to any one of claims 1-8, characterized in that, Specifically, the method comprises the following steps: Step one: high-pressure gas is introduced into the stirring device body through the air inlet, and the high-pressure gas enters the membrane area through the one-way flow control structure and uniformly diffuses along the inner surface of the polymer film under the guidance of the micro-cylinders; Step two: the high-pressure gas reaches each membrane hole, and under the elastic deformation and rebound of the polymer film, micro-bubbles are formed and quickly detach, and the detached micro-bubbles enter the electroplating tank; Step three: the generated micro-bubble group has a straight-line motion trajectory and a controllable range during the rising process, and is not easy to merge to form large bubbles; the electroplating liquid is uniformly stirred, and the flow field distribution in the tank is optimized.

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