Pulse electroplating liquid, preparation method thereof and pulse electroplating process

Abstract

The invention relates to the technical field of electroplating, and discloses a pulse electroplating liquid, which comprises a main salt used for providing metal ions required in the electroplating process; a complexing agent for stabilizing the metal ions; the additive is used for adjusting the performance of the electroplating liquid; the nano particles serve as guide factors to migrate metal ions, the additive is one or more of a brightening agent, a buffering agent or an inhibitor, the buffering agent is acetate or ammonia water, and the inhibitor is thiocyanate or ammonium chloride. According to the method, the pulse electroplating liquid is combined with the nano-particle guiding factors, and the effect of remarkably improving the deposition efficiency and the coating quality is achieved. Compared with a traditional electroplating method in the prior art, the problems that the deposition rate is low, a coating is not uniform and the like often exist in the traditional method, migration of metal ions can be accelerated through the guiding effect of the nano-particles, a deposition layer is more uniform, the deposition rate is also greatly improved, and the defects that in traditional electroplating, the deposition efficiency is low, and the quality is poor are overcome.

Description

Technical Field

[0001] The invention relates to the technical field of electroplating, in particular to a pulse electroplating solution and a preparation method thereof and a pulse electroplating process. Background Art

[0002] With the rapid development of modern manufacturing, electroplating technology has been widely used in electronics, automobiles, aerospace and other industries. Electroplating technology can not only provide excellent surface properties, such as wear resistance, corrosion resistance, conductivity, etc., but also improve the appearance of parts to meet the requirements of beauty and functionality. In these applications, factors such as coating uniformity, adhesion and deposition rate directly affect the quality and service life of the final product. Therefore, improving electroplating efficiency and coating quality has become an important direction of current technical research.

[0003] Existing electroplating technology usually uses direct current for metal deposition. However, the traditional direct current electroplating process has problems such as slow deposition rate, uneven coating, and poor adhesion. In practical applications, these defects limit the further development of electroplating technology in high-precision and high-requirement fields. In order to improve the efficiency and quality of electroplating, pulse electroplating technology has gradually attracted the attention of researchers in recent years. Through the alternating action of pulse current, the migration of metal ions can be effectively controlled, thereby improving the uniformity of the coating and increasing the deposition rate. However, pulse electroplating technology still faces the problem of how to ensure the quality of the coating while maintaining the deposition rate.

[0004] Existing pulse plating technology mainly relies on adjusting current density, solution composition and other means to improve coating quality and deposition efficiency, but these methods are often limited by the uneven distribution of metal ions, resulting in large fluctuations in the quality of the deposited layer. In addition, traditional plating solution formulations and process adjustments rely more on experience and lack intelligent control methods, which makes the optimization of the electroplating process slow and inefficient. Therefore, how to solve the uneven migration of metal ions, improve deposition efficiency and ensure the consistency of coating quality has become a core issue that needs to be urgently addressed in current pulse plating technology. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a pulse plating solution and a preparation method thereof and a pulse plating process, which solve the problems of low deposition efficiency, uneven coating quality and lack of stability in traditional electroplating.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: a pulse plating solution, comprising: Main salt, used to provide the metal ions required in the electroplating process; A complexing agent for stabilizing the metal ions; Additives, used to adjust the properties of the plating solution; Nanoparticles, which act as guide factors to migrate metal ions.

[0007] Preferably, the additive is one or more of a brightener, a buffer or an inhibitor, the buffer is acetate or ammonia water, and the inhibitor is thiocyanate or ammonium chloride.

[0008] Preferably, the additives are brighteners and buffers, the nanoparticles are graphene quantum dots, nano-silicon dioxide or a combination thereof, and the concentration of the nanoparticles is 0.01% to 1% (w / w).

[0009] A method for preparing a pulse plating solution comprises the following steps: Add the main salt and complexing agent into deionized water and stir until completely dissolved; Add additives to the electroplating solution and stir evenly; Adding nanoparticles into the electroplating solution, and using ultrasonic stirring to evenly disperse the nanoparticles; filtering the electroplating solution to remove insoluble matter and impurities; Store the filtered plating solution in a sealed container Preferably, the ultrasonic power is 300 W, the frequency is 40 kHz, and the stirring time is 45 minutes.

[0010] A pulse electroplating process comprises the following steps: Step 1: preparing a pulse plating solution, wherein the pulse plating solution comprises a main salt, a complexing agent, an additive and nanoparticles; Step 2: Place the workpiece to be electroplated in the electroplating tank, immerse the workpiece completely in the electroplating solution, and set the distance between the electrode and the workpiece; Step 3: Use a pulse power supply to apply a pulse current, with a pulse frequency range of 0.1kHz to 10kHz and a duty cycle of 50%; Step 4: Monitor the temperature, pH value and conductivity of the plating solution in real time, and adjust the current density, frequency and duty cycle according to the monitoring data.

[0011] Preferably, the current density is 3A / dm2 to 10A / dm2, the temperature of the electroplating solution is maintained between 25°C and 35°C, and the pH value is maintained between 4.0 and 5.5.

[0012] Preferably, in step three, the frequency of the pulse power supply is adjusted according to the deposition characteristics of different metal ions, and the current density and duty cycle are optimized according to the properties of the metal ions.

[0013] Preferably, in step 4, if an abnormality in the plating solution is found during the electroplating process, an early warning signal is automatically issued and the process parameters are adjusted.

[0014] The present invention provides a pulse electroplating solution and a preparation method thereof and a pulse electroplating process, which have the following beneficial effects: 1. The present invention uses a pulse plating solution combined with a nanoparticle guiding factor to achieve the effect of significantly improving deposition efficiency and coating quality. Compared with the traditional electroplating method in the prior art, the traditional method often faces problems such as slow deposition rate and uneven coating. The present invention can accelerate the migration of metal ions through the guiding effect of nanoparticles, making the deposited layer more uniform, and the deposition rate is also greatly improved, solving the shortcomings of low deposition efficiency and poor quality in traditional electroplating.

[0015] 2. The present invention uses an intelligent control system to adjust the electroplating parameters, which effectively improves the accuracy of the electroplating process and the consistency of the coating. Compared with the existing technical solution of manually adjusting the electroplating parameters, the present invention monitors the temperature, pH value, conductivity and other parameters of the electroplating solution in real time, and automatically adjusts the current density and frequency, thereby ensuring the stability of the electroplating process, avoiding errors that may be caused by manual operation, and significantly improving the uniformity and adhesion of the coating.

[0016] 3. The present invention optimizes the concentration of nanoparticles and effectively improves the corrosion resistance and adhesion of the coating by using 0.1% (w / w) graphene quantum dots in the electroplating solution. Compared with the practice of not optimizing the concentration of nanoparticles in the prior art, the present invention enhances the compactness and protective performance of the coating by reasonably adjusting the concentration, solves the problem of insufficient corrosion resistance of the coating caused by low concentration of nanoparticles, and makes the electroplating layer have better anti-oxidation and anti-corrosion properties in practical applications.

[0017] 4. The present invention adopts a pulse current and nanoparticle-guided electroplating process, which significantly improves the electroplating efficiency and the uniformity of the coating quality. Compared with the electroplating process that only uses direct current in the prior art, direct current leads to a slow deposition rate and is prone to coating defects. The pulse current of the present invention plus the guiding effect of nanoparticles not only improves the deposition rate, but also improves the uniformity of the coating, solves the problems of uneven coating and low electroplating efficiency in traditional electroplating, meets the needs of high-demand surface treatment, and is particularly suitable for the fields of precision electronics, automotive parts and decorations. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 One of the schematic flow charts of the method of the present invention; Figure 2 This is the second schematic flow chart of the method of the present invention. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the specification of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] Embodiment 1: Please refer to the attached Figure 1-2 The present invention provides a pulse plating solution and a preparation method thereof and a pulse plating process: Preparation of copper pulse plating solution First, the main components of the pulse plating solution are main salt and complexing agent. The main salt provides the required metal ions, while the complexing agent stabilizes the metal ions to prevent them from precipitating or settling. In addition, additives are used to adjust the performance of the plating solution, especially to improve the quality and uniformity of the coating. In order to further optimize the deposition process, the present invention specifically introduces nanoparticles as guiding factors to help metal ions migrate to the workpiece surface more efficiently under the action of the electric field, thereby accelerating the deposition process.

[0021] Specifically, the preparation method of the pulse plating solution first starts with dissolving the main salt and the complexing agent, then sequentially adding additives and nanoparticles, and finally ensuring the uniformity and stability of the plating solution through stirring and ultrasonic dispersion.

[0022] When preparing the pulse plating solution, the main salt and the complexing agent are first added to deionized water for dissolution. As the source of metal ions, the type and concentration of the main salt play a key role in the performance of the plating solution. For example, copper sulfate (CuSO 4 ·5H 2 O) as the main salt, its concentration is usually set to 200g / L. Copper sulfate can provide copper ions for reduction deposition in the electroplating process.

[0023] Alternatively, complexing agents are used to stabilize the metal ions in the main salt to prevent unwanted precipitation. Boric acid (H 3 BO 3 ) is a commonly used complexing agent in copper electroplating solution. Its concentration is generally set to 50g / L, which can improve the stability of metal ions through complexation. Usually, the mixed solution of the main salt and the complexing agent needs to be stirred for 30 to 60 minutes at a temperature of 25°C to 35°C to ensure that it is completely dissolved and forms a uniform solution.

[0024] Additives in the plating solution play an important role in the performance of the deposition process and the quality of the electroplated layer. Generally speaking, additives include brighteners, buffers and inhibitors, which can improve the gloss, uniformity and adhesion of the deposited layer.

[0025] Brightener: Brightener can improve the smoothness and surface gloss of the coating during the electroplating process. Commonly used brighteners include benzoxazole compounds, whose concentration is generally set at 5mL / L, which can effectively improve the gloss and uniformity of the copper coating.

[0026] Buffer: Buffers such as acetate or ammonia are used to adjust the pH of the plating solution to ensure that it is maintained in the range of 4.0 to 5.5. The stability of pH is critical to the electroplating process. Too high or too low pH values ​​will result in unstable precipitation or deposition quality of metal ions.

[0027] Inhibitors: Inhibitors such as ammonium chloride (NH 4 Cl) is used to reduce the occurrence of side reactions, especially the generation of bubbles. The concentration of ammonium chloride is set to 1g / L, which is used to control the side reactions that may occur during the electroplating process and improve the uniformity of the deposited layer.

[0028] In some embodiments, the concentrations of buffers and suppressors can be adjusted according to specific electroplating requirements to further optimize the performance of the electroplating solution.

[0029] Nanoparticles, as guiding factors, can accelerate the migration of metal ions to the workpiece surface, significantly improving the deposition rate and uniformity of the electroplated layer. In the present invention, graphene quantum dots are preferably used as nanoparticles, which are generally less than 10 nm in size, have good conductivity and a high specific surface area. This enables graphene quantum dots to effectively increase the transmission rate of metal ions.

[0030] The concentration of nanoparticles is generally 0.01% to 1% (w / w), and the concentration range can be adjusted according to different application requirements. In an embodiment, the concentration of graphene quantum dots is preferably 0.1% (w / w). Too low a concentration may result in poor dispersion of the particles, while too high a concentration may cause particle agglomeration and affect the stability of the electroplating solution.

[0031] To ensure uniform dispersion of nanoparticles, ultrasonic stirring is usually used. Specifically, the ultrasonic power is set to 300W, the frequency is 40kHz, and the ultrasonic treatment time is 45 minutes. Ultrasonic stirring can effectively break up the agglomeration of nanoparticles, ensure their uniform distribution in the electroplating solution, and prevent particle precipitation.

[0032] In some embodiments, in order to improve the dispersion effect of the nanoparticles, the ultrasonic power or the treatment time may be further optimized to ensure the stability of the nanoparticles in the electroplating solution.

[0033] After the addition and dispersion of nanoparticles, the plating solution needs to be filtered to remove any undissolved matter, impurities or air bubbles that may be present. The pore size of the filter used for filtration is generally 0.45μm to ensure the purity and uniformity of the plating solution.

[0034] The filtered plating solution needs to be stored in a sealed container to prevent impurities in the air from entering the plating solution and affecting its stability. The storage temperature is controlled between 20℃ and 25℃ to ensure that the plating solution does not change its performance over a long period of time.

[0035] Pulse plating process: In the pulse plating process, a specific pulse current is used to deposit metal. Compared with the traditional DC plating process, pulse plating can more efficiently control the deposition rate, optimize the quality of the electroplated layer, and significantly improve the uniformity of the electroplating process. The pulse plating process provided by the present invention combines the characteristics of pulse current, precise parameter adjustment and special formulation of the plating solution, effectively improves the performance of the electroplated layer, and realizes full-process automated monitoring and parameter optimization through an intelligent control system.

[0036] In this embodiment, the pulse plating process is carried out based on the formula of the above-mentioned pulse plating solution. Specifically, the electroplating process is optimized and the electroplating quality is ensured by precise control of parameters such as current frequency, duty cycle, and pulse period.

[0037] First, a pulse plating solution prepared according to the above method is prepared. The plating solution already contains a main salt, a complexing agent, an additive and nanoparticles, which can effectively promote the efficient migration of metal ions and accelerate the deposition process. Compared with the traditional plating solution, the pulse plating solution used in the present invention can not only increase the deposition rate, but also reduce defects such as pores and cracks that occur during the deposition process.

[0038] When performing pulse plating, first pour the plating solution into the plating tank and immerse the workpiece to be plated in the plating solution. According to the size, shape and material of the workpiece, set the appropriate distance between the electrode and the workpiece, generally set to 1 to 2 times the workpiece, to ensure that the metal ions can be evenly deposited on the surface of the workpiece.

[0039] Next, a pulse current is applied using a customized pulse power supply. The frequency of the pulse current is set to 1kHz to 10kHz, and the frequency can be adjusted within this range according to the requirements of different electroplating processes. Lower frequencies can improve the deposition efficiency of metal ions, while higher frequencies help increase the smoothness and uniformity of the electroplated layer.

[0040] In a possible implementation, the pulse frequency is 2 kHz, at which the deposition rate and deposition quality are well balanced. The smoothness and uniformity of the deposited layer can be further optimized by setting an appropriate duty cycle during the pulse current process.

[0041] Current density is a key parameter for controlling the deposition rate during electroplating. The pulse electroplating process of the present invention has a high degree of flexibility in controlling the current density. By adjusting the current density, the deposition rate and the coating quality can be balanced. In this embodiment, the current density is set to 6A / dm 2 This current density is suitable for the copper electroplating process and can effectively increase the deposition rate without damaging the coating quality.

[0042] The duty cycle refers to the ratio of the time the current is on during the current pulse cycle to the total cycle time. The adjustment of the duty cycle directly affects the migration speed of metal ions and the deposition quality. Generally, the duty cycle is set to 50%, that is, the on time of the current switching cycle is equal to the off time, which helps to maintain a stable electroplating rate and reduce the risk of metal ion aggregation.

[0043] In some embodiments, the duty cycle may be adjusted to a range of 30% to 70% depending on the properties of the deposited material and the surface requirements of the workpiece. A lower duty cycle helps reduce over-deposition in the early stages of electroplating, while a higher duty cycle helps accelerate the deposition process of metal ions and is suitable for applications where a thicker deposition layer is required.

[0044] In order to ensure the stability of the electroplating process and the uniformity of the deposited layer, the pulse electroplating process of the present invention monitors the state of the electroplating solution in real time through an intelligent control system. The system can collect key parameters such as the temperature, pH value and conductivity of the electroplating solution in real time, and automatically adjust the process parameters according to the monitoring results.

[0045] The temperature of the plating solution has a significant impact on the deposition process. Too high or too low a temperature will affect the deposition rate of metal ions and the quality of the deposited layer. Generally, the temperature of the plating solution should be maintained between 28°C and 32°C. Through an intelligent control system, if the temperature deviates from the set range, the system will automatically adjust the heating or cooling device to ensure that the temperature remains within the ideal range.

[0046] The pH value of the plating solution plays an important role in the solubility and deposition behavior of metal ions. During copper electroplating, the pH value is usually maintained between 4.0 and 5.5. If the pH value exceeds this range, it will cause precipitation or uneven deposition of metal ions. Therefore, the system can monitor the pH value based on real-time data and adjust the pH value in time by adding an appropriate amount of buffer or acid-base regulator.

[0047] Conductivity reflects the concentration of metal ions in the plating solution. Changes in conductivity usually indicate a change in the concentration of metal ions. By monitoring conductivity in real time, the system can determine whether the composition of the plating solution is stable, thereby adjusting the amount of metal ions added to ensure the smooth progress of the electroplating process.

[0048] When implementing the pulse electroplating process of the present invention, real-time data feedback and automatic adjustment enable the electroplating process to be continuously optimized. In some embodiments, the system optimizes the deposition process in real time by adjusting the frequency, duty cycle, and current density of the pulse power supply based on the aforementioned monitored parameters such as temperature, pH value, and conductivity. If an abnormality is found in the electroplating solution, the system can automatically issue an early warning signal and restore the stability of the electroplating process by adjusting the operating parameters.

[0049] For example, when the pH value of the plating solution exceeds the set range, the system will automatically add acidic or alkaline additives and adjust the current density to reduce the risk of uneven deposition. In addition, the quality monitoring and feedback of the deposited layer during the electroplating process enables timely adjustments at each deposition stage to avoid defects.

[0050] In the pulse plating process, the quality of the deposited layer directly affects the performance of the workpiece. In order to ensure the uniformity, adhesion and corrosion resistance of the electroplated layer, a variety of quality control methods are used during the implementation process. For example, the microstructure of the deposited layer is observed using a scanning electron microscope to ensure the uniformity and smoothness of the deposited layer; at the same time, the mechanical strength and corrosion resistance of the coating are evaluated using adhesion tests and salt spray tests.

[0051] Through the process of the present invention, the quality of the deposited layer is significantly improved while ensuring a high deposition rate. The adhesion of the coating is improved by more than 15% compared with the traditional electroplating process, and the corrosion resistance is also significantly enhanced, which is suitable for various industrial environments, especially in applications requiring wear resistance and corrosion resistance.

[0052] Embodiment 2: This embodiment provides a preparation method of a nickel pulse electroplating solution and a process thereof, comprising: 1. Preparation of Pulse Plating Solution Step 1: Dissolve the main salt and complexing agent In this embodiment, nickel sulfate (NiSO 4 6H 2 O) is added to deionized water as the main salt, and the concentration is set to 150g / L. Use a magnetic stirrer and stir at a speed of 250rpm to ensure that the nickel sulfate is completely dissolved. During the dissolution process, the temperature is controlled at about 30°C and the dissolution takes about 30 minutes to ensure the uniformity of the solution. As an option, if other metal ion sources are used, their dissolution concentration and dissolution time need to be adjusted.

[0053] Next, add the complexing agent boric acid (H 3 BO 3 ), and its concentration is set to 30g / L. Boric acid can help stabilize nickel ions and prevent them from precipitation, while adjusting the pH value of the electroplating solution. In this embodiment, after boric acid is mixed with nickel sulfate, the nickel ions in the solution remain stable.

[0054] Step 2: Add additives According to the requirements of this embodiment, brightener and buffer need to be added to the electroplating solution to improve the glossiness and surface quality of the deposited layer.

[0055] Brightener: To ensure the smooth surface of the nickel coating, select an appropriate amount of benzoxazole brightener with a concentration of 4 mL / L. This brightener can improve the gloss of the deposited layer and reduce surface defects during the nickel electroplating process.

[0056] Buffer: Sodium acetate (NaOAc) is used as a buffer with a concentration of 15 g / L. Sodium acetate helps maintain the pH value of the plating solution in the range of 4.0 to 5.5 to ensure the stability of nickel ions.

[0057] Inhibitor: To avoid the formation of bubbles or other unwanted side reactions during electroplating, ammonium chloride (NH 4 Cl), the concentration is 1g / L Step 3: Adding Nanoparticles In order to increase the transmission rate of metal ions, nanoparticle graphene quantum dots are added with a concentration set to 0.1% (w / w). Due to their high specific surface area and conductivity, graphene quantum dots can promote the migration of nickel ions and accelerate the deposition process. In order to ensure uniform dispersion of nanoparticles, ultrasonic stirring is used. The ultrasonic power is set to 300W, the frequency is 40kHz, and the stirring time is 45 minutes. This process effectively prevents the agglomeration of nanoparticles and ensures their uniform distribution in the electroplating solution.

[0058] Step 4: Filter and store The prepared plating solution is filtered through a 0.45 μm filter membrane to remove impurities and bubbles in the solution to ensure the purity and uniformity of the plating solution. The filtered plating solution should be stored in a sealed container at a storage temperature between 20°C and 25°C to avoid changes in the composition or contamination of the plating solution.

[0059] 2. Pulse plating process Step 1: Prepare the plating solution Pour the prepared nickel pulse plating solution into the plating tank, and adjust the liquid level according to the size of the workpiece to be plated to ensure that the workpiece is completely immersed in the plating solution. In order to ensure that the metal ions can be evenly deposited on the surface of the workpiece, the distance between the electrode and the workpiece is generally set to 1 to 2 times the size of the workpiece.

[0060] Step 2: Apply pulse current A pulse current was applied using a custom pulse power supply. The pulse frequency was set to 3kHz with a duty cycle of 50%, which enables a high deposition rate in a short time while maintaining coating uniformity. The current density was set to 5A / dm 2, which is the current density suitable for the nickel electroplating process, which can not only increase the deposition rate but also ensure the uniformity and good adhesion of the electroplated layer.

[0061] Step 3: Real-time monitoring and adjustment During the electroplating process, the intelligent control system monitors the status of the electroplating solution in real time. The temperature should be maintained between 28°C and 32°C, the pH value should be kept in the range of 4.0 to 5.5, and the conductivity is determined by monitoring the metal ion concentration. The system will adjust parameters such as pulse frequency, duty cycle and current density based on real-time data.

[0062] Specifically, if the temperature of the plating solution is too high or too low, the system will automatically adjust the temperature control system to ensure that the temperature is always within the appropriate range. Similarly, when the pH value changes beyond the set range, the system can automatically adjust the acidity and alkalinity to maintain the stability of the plating solution.

[0063] Step 4: Deposit quality control After the electroplating is completed, the surface structure and uniformity of the nickel electroplated layer are checked by scanning electron microscopy. The deposited layer has no obvious pores or cracks, and the surface is smooth and uniform. Adhesion tests, such as tensile strength tests, are used to verify the adhesion of the coating. Test results show that the adhesion of the nickel layer deposited using this pulse electroplating process is about 20% higher than that of the traditional electroplating process.

[0064] In addition, the corrosion resistance of the nickel coating was evaluated using a salt spray test. The test results showed that the electroplated layer exhibited strong corrosion resistance and was suitable for use in humid or highly corrosive environments.

[0065] Embodiment three: This embodiment provides a preparation method of a silver pulse electroplating solution and a process thereof, comprising: 1. Preparation of Pulse Plating Solution Step 1: Dissolve the main salt and complexing agent In this embodiment, silver chloride (AgCl) is first selected as the main salt, and the concentration is set to 150g / L. Due to the low solubility of silver chloride, an appropriate dissolution method is required. When silver chloride is dissolved in deionized water, an appropriate amount of sodium chloride (NaCl) is added to promote the release of silver ions. The stirring speed is set to 250rpm, the temperature is controlled at 30°C, and stirring is continued for 30 minutes until the solution is completely transparent to ensure that the silver ions are evenly dissolved.

[0066] Next, boric acid (H 3 BO 3 ) as a complexing agent, the concentration of which is set to 40 g / L. Boric acid can stabilize the dissolved state of silver ions, prevent them from precipitating, and adjust the pH value of the electroplating solution. In this embodiment, after the addition of boric acid, stirring is continued for 30 minutes to ensure that it forms a stable complex with the silver ions. Step 2: Add additives In order to improve the quality of the electroplating layer, the following additives are also added in this embodiment: Brightener: Use an appropriate amount of benzoxazole brightener with a concentration of 6mL / L. This brightener can significantly enhance the glossiness of the silver coating and improve the surface smoothness.

[0067] Buffer: To control the pH value of the plating solution, sodium acetate buffer is used with a concentration of 25 g / L. Sodium acetate ensures that the pH value of the plating solution is maintained between 4.5 and 5.0, thereby improving the uniformity of deposition.

[0068] Inhibitor: Add ammonium chloride (NH 4 Cl), with a concentration of 2 g / L, is used to inhibit the generation of bubbles, avoid unnecessary side reactions, and reduce the unevenness during the deposition process.

[0069] In this embodiment, graphene quantum dots are used as nanoparticles at a concentration of 0.1% (w / w). Graphene quantum dots can effectively accelerate the migration of silver ions and increase the deposition rate due to their excellent conductivity and large specific surface area. In order to ensure the uniform dispersion of nanoparticles, ultrasonic stirring technology is used. The ultrasonic power is set to 350W, the frequency is 40kHz, and the ultrasonic treatment time is 45 minutes. This method can effectively avoid the agglomeration of graphene quantum dots and ensure their uniform dispersion in the electroplating solution.

[0070] Step 4: Filter and store After completing the above steps, the plating solution needs to be filtered through a 0.45μm filter membrane to remove impurities and insoluble matter in the solution to ensure the purity of the plating solution. The filtered plating solution should be stored in a sealed container to avoid contact with air. The storage temperature should be maintained between 20℃ and 25℃ to maintain the stability of the plating solution and the electroplating effect.

[0071] 2. Pulse plating process Step 1: Prepare the plating solution During the electroplating process, first pour the prepared silver pulse plating solution into the plating tank, ensure that the liquid level is high enough and the workpiece is completely immersed in the plating solution. According to the size and shape of the workpiece to be electroplated, adjust the distance between the electrode and the workpiece. Generally, the distance between the electrode and the workpiece is set to 1 to 2 times the length of the workpiece, which can ensure that the metal ions are evenly deposited under the action of the electric field.

[0072] Step 2: Apply pulse current A pulse current was applied using a customized pulse power supply, with the pulse frequency set to 4kHz and the duty cycle set to 50%. This frequency can accelerate the deposition of silver ions in a shorter time without affecting the deposition quality. The current density was set to 4A / dm 2, this current density helps to increase the deposition rate and ensure the uniformity of the silver layer.

[0073] In one possible implementation, the pulse frequency and current density can be adjusted according to actual needs to meet the deposition requirements of different workpieces. For example, in applications with larger surfaces or thicker deposited layers, the current density can be appropriately increased or the frequency can be adjusted to meet production requirements.

[0074] Step 3: Real-time monitoring and adjustment During the electroplating process, the state of the electroplating solution is monitored in real time through an intelligent control system. The temperature should be maintained between 28°C and 32°C, the pH value should be kept in the range of 4.5 to 5.0, and the conductivity reflects the concentration changes of metal ions in the electroplating solution. The intelligent system adjusts the parameters such as the frequency, duty cycle and current density of the pulse power supply according to real-time data.

[0075] For example, if the temperature of the plating solution is too high or too low, the system will automatically adjust the heating or cooling device to ensure that the temperature remains within the set range. Similarly, if the pH value of the plating solution changes, the system will automatically add buffers or acid-base regulators to restore its stability.

[0076] Step 4: Deposit quality control After the electroplating is completed, the surface structure of the silver deposited layer is observed using a scanning electron microscope to ensure that the coating is uniform and smooth, and there are no defects such as pores or cracks. The thickness of the deposited layer is uniform and meets the predetermined requirements. The adhesion test shows that the adhesion of the silver layer deposited using the pulse plating solution of the present invention is improved by about 10% compared with the traditional method.

[0077] The corrosion resistance of the silver coating was evaluated by salt spray testing. The test results show that the electroplated layer has strong corrosion resistance and maintains stability for a long time in a corrosive environment, making it suitable for high-end electronic components and decorative items.

[0078] Comparative Example 1: This embodiment provides a conventional copper electroplating solution, which does not contain any nanoparticles, for comparison with the pulse electroplating solution in Example 1, and includes: Dissolve the main salt and complexing agent: Dissolve copper sulfate (CuSO 4 ·5H 2 O) 200 g / L was added into deionized water, stirred with a magnetic stirrer at a rate of 200 rpm, and dissolved until completely transparent. The temperature was maintained at 30°C and the dissolution time was 30 minutes.

[0079] Add additives: Add common brighteners (such as benzoxazole compounds) at a concentration of 5 mL / L, and add sodium acetate buffer at a concentration of 20 g / L to adjust the pH value to around 4.5.4 Cl) was used as an inhibitor at a concentration of 1 g / L.

[0080] No nanoparticles: Different from Example 1, the electroplating solution in this comparative example does not contain any nanoparticles, so the migration of metal ions cannot be accelerated by nanoparticles.

[0081] Filtration and storage: After all dissolution is completed, the plating solution is filtered through a 0.45μm filter membrane to remove undissolved impurities to ensure the purity of the plating solution, and then stored in a sealed container to avoid contact with air.

[0082] In Comparative Example 1, nanoparticles such as graphene quantum dots are not added, so effective guidance and rapid migration of metal ions cannot be achieved.

[0083] Comparative Example 2: This embodiment provides a conventional pulse electroplating process, which does not use an intelligent control system, for comparison with the pulse electroplating process in the embodiment, specifically including: Preparation of electroplating solution: The same copper pulse electroplating solution as in Example 1 was used, but there was no intelligent control system in this solution, and all parameters (such as temperature, pH value, conductivity) were manually monitored and adjusted.

[0084] A pulse current was applied using a pulse power supply with a frequency of 2 kHz, a duty cycle of 50%, and a current density of 6 A / dm 2 .

[0085] In this comparative example, the temperature and pH value are controlled by the operator by manually adjusting the heating device and the acid-base agent. The temperature is maintained between 28°C and 32°C, and the pH value is maintained within the range of 4.0 to 5.5.

[0086] Due to the lack of an intelligent control system, all parameters in the electroplating process (such as frequency, duty cycle, current density) are manually adjusted by the operator, lacking real-time monitoring and automatic adjustment.

[0087] This comparative example does not use an intelligent control system, so there is a certain uncertainty in parameter control. Compared with the intelligent real-time adjustment in Example 2, more manual intervention may lead to instability of coating quality during the electroplating process.

[0088] Comparative Example 3: This comparative example uses a pulse plating solution similar to that of Example 1, but the concentration of the nanoparticles is set to 0.05% (w / w) for comparison with the pulse plating solution of Example 1 with a concentration of 0.1% (w / w).

[0089] Copper sulfate (CuSO 4 ·5H 2O) 200g / L and boric acid (H 3 BO 3 )50g / L was added into deionized water and stirred until completely dissolved. The dissolution time was 30 minutes.

[0090] Same as Example 1, brightener (5 mL / L), buffer (sodium acetate 20 g / L) and inhibitor (ammonium chloride 1 g / L) were added.

[0091] Graphene quantum dots were used as nanoparticles, the concentration was set to 0.05% (w / w), and the nanoparticles were dispersed by ultrasonic stirring. The ultrasonic power was set to 300 W, the frequency was 40 kHz, and the treatment time was 45 minutes.

[0092] Filter through a 0.45μm filter membrane to remove insoluble matter and impurities to ensure the purity of the plating solution, and then store it in a sealed container.

[0093] The nanoparticle concentration in this comparative example is 0.05% (w / w), which is lower than the 0.1% (w / w) concentration in Example 1, resulting in a weaker guiding effect and migration speed of metal ions. This comparison can show the effect of different nanoparticle concentrations on the quality and deposition rate of the electroplated layer.

[0094] Comparative Example 4: In this comparative example, a conventional direct current electroplating process is used for comparison to differentiate it from the pulse electroplating process in the embodiment.

[0095] The same copper pulse plating solution as in Example 1 was used, but in this process a direct current was used for electroplating.

[0096] A DC power supply was used to apply current with a current density set to 6 A / dm 2 , which is consistent with the pulse current density in Example 1, but without the adjustment of the pulse signal.

[0097] There is no periodic change of pulse current in the electroplating process, and the current density remains constant throughout the process. The temperature and pH value of the plating solution are still manually controlled by the operator, with the temperature maintained between 28°C and 32°C and the pH value maintained between 4.0 and 5.5.

[0098] This comparative example uses direct current for electroplating, and there is no periodic change of pulse current during the electroplating process. In comparison, pulse current can effectively improve the migration efficiency of metal ions and reduce defect generation.

[0099] Experiment 1: Effect of Nanoparticle Concentration on Deposition Rate Experimental steps: The purpose of this experiment is to compare the effect of different concentrations of nanoparticles on the deposition rate during copper electroplating. The experiment was divided into two groups, using different concentrations of nanoparticles. The experimental group used a nanoparticle concentration of 0.1% (w / w), while the comparison group 1 used a concentration of 0.05% (w / w). The following are the experimental steps: Preparation of electroplating solution: According to the above experimental design, copper sulfate (CuSO 4 ·5H 2 O) 200g / L was dissolved in deionized water, and boric acid (H 3 BO 3 )50g / L as complexing agent to ensure complete dissolution, dissolution time 30 minutes. Then, add brightener, buffer and inhibitor, all concentrations are added in the specified ratio.

[0100] Preparation of nanoparticles: Graphene quantum dots were prepared for the experimental group and the control group. The experimental group used a concentration of 0.1% (w / w), and the control group 1 used a concentration of 0.05% (w / w) of graphene quantum dots. The nanoparticles were added to the plating solution and ultrasonic stirring (power 300 W, frequency 40 kHz, treatment time 45 minutes) was used to ensure uniform dispersion.

[0101] Electroplating process: Pour the prepared electroplating solution into the electroplating tank, and set the distance between the electrode and the workpiece to 1.5 times the length of the workpiece. Use a pulse power supply to apply pulse current, with the frequency set to 2kHz, the duty cycle to 50%, and the current density set to 6A / dm 2 The plating time was 30 minutes, the temperature was controlled between 28°C and 32°C, and the pH value was maintained between 4.0 and 5.5.

[0102] Deposition layer measurement: After electroplating, remove the workpiece and measure the coating thickness using a microscope. The deposition rate is calculated by the ratio of coating thickness to electroplating time.

[0103] Table 1: Experimental data on the effect of different nanoparticle concentrations on deposition rate The experimental results reveal the significant effect of nanoparticle concentration on the deposition rate. In the experimental group, the deposition rate of the coating with a nanoparticle concentration of 0.1% (w / w) was significantly higher than that of the control group with a concentration of 0.05% (w / w). This phenomenon shows that higher concentrations of nanoparticles can more effectively guide the migration of metal ions to the workpiece surface and accelerate the deposition process. This is also consistent with the previous theoretical mechanism. Nanoparticles, as guiding factors, promote the rapid migration of metal ions in the plating solution through the action of the electric field, making the deposition process more efficient. This finding verifies the key role of nanoparticles in pulse plating solutions, which can increase the deposition rate and improve the quality of coatings.

[0104] However, as the concentration of nanoparticles increases further, particle agglomeration may occur, which will affect the stability of the electroplating solution and thus the deposition rate. By comparing nanoparticles of different concentrations, this experiment found that at a concentration of 0.1% (w / w), the deposition rate reached the optimal value and the coating quality was relatively high. Although low-concentration nanoparticles (such as 0.05%) can provide a certain promotion effect, due to their low guiding efficiency, the deposition rate is significantly reduced in comparison. Therefore, choosing an appropriate nanoparticle concentration is of great significance to improving electroplating efficiency and coating quality. In terms of the mechanism of the process, the size, dispersibility and conductivity of the nanoparticles all play a key role in determining the efficiency of metal ion migration and deposition. Higher concentrations of nanoparticles provide more surface sites, which help metal ions to aggregate and deposit more quickly on the workpiece surface under the action of the electric field, thereby significantly increasing the deposition rate.

[0105] Experimental Example 2: The influence of intelligent control system on the quality of deposited layer Experimental steps: The purpose of this experiment is to evaluate the improvement of the deposited layer quality by the intelligent control system, especially in terms of coating uniformity, adhesion and smoothness. The advantages of intelligent control are demonstrated by comparing the use of intelligent control system and conventional manual control system. The following are the experimental steps: Preparation of electroplating solution: The same copper pulse electroplating solution formula as in Example 2 was used. First, copper sulfate (CuSO 4 ·5H 2 O) 200g / L and boric acid (H 3 BO 3 ) 50g / L was dissolved in deionized water to ensure complete dissolution. Then, a brightener (5mL / L), a buffer (sodium acetate 20g / L) and an inhibitor (ammonium chloride 1g / L) were added. Compared with the experimental group (Example 2), this comparative example did not use an intelligent control system, and all parameters (such as temperature, pH value, conductivity, etc.) were manually adjusted.

[0106] Electroplating condition setting: Pour the prepared electroplating solution into the electroplating tank to ensure that the liquid surface can cover the workpiece. The distance between the workpiece and the electrode is set to 1.5 times the length of the workpiece. Use a pulse power supply to apply pulse current, the frequency is set to 2kHz, and the current density is 6A / dm 2 , the duty cycle is 50%.

[0107] Real-time monitoring and adjustment (experimental group): In the experimental group, an intelligent control system was used to monitor the temperature, pH value, conductivity and other parameters of the plating solution in real time. The temperature was controlled between 28°C and 32°C, the pH value was between 4.0 and 5.5, and the conductivity was within the specified range. The system automatically adjusted the current density, frequency and duty cycle based on the monitoring data.

[0108] Manual control (control group): In the control group, the experimenter manually adjusted the temperature and pH value, and the current density and frequency were set at the beginning of electroplating and no longer adjusted.

[0109] Deposited layer measurement and testing: After electroplating, the uniformity, adhesion and surface smoothness of the coating are analyzed using a scanning electron microscope (SEM). The adhesion of the coating is verified by a tensile strength test, and the surface smoothness is evaluated by a gloss test.

[0110] Table 2: Impact of intelligent control system on deposition quality It can be seen from the experimental results that the intelligent control system has significant advantages in improving the quality of the deposited layer. Compared with the control group, the experimental group implementing intelligent control not only performed better in the uniformity and adhesion of the coating, but also significantly improved the glossiness. This shows that the intelligent control system can adjust key parameters in the electroplating process, such as temperature, pH value and conductivity, in real time, thereby ensuring the stability of the electroplating process and the quality of the coating. Compared with traditional manual control, the intelligent system can effectively avoid human operation errors, making the deposition process more precise and controllable, and the consistency of the coating has also been greatly improved.

[0111] In terms of mechanism, the intelligent control system can automatically adjust parameters such as current density, frequency and duty cycle through real-time data feedback to maintain the optimal working state of the electroplating solution, thereby promoting the uniform migration and deposition of metal ions. Through this control mechanism, the common parameter fluctuations and inconsistencies in the manual adjustment process can be avoided, so that the electroplated layer has better smoothness and stronger adhesion. In addition, the intelligent control system can optimize the microstructure of the coating, reduce deposition defects such as pores and cracks, and further improve the quality and performance of the coating.

[0112] Therefore, the introduction of intelligent control systems not only improves the physical properties of the deposited layer, but also makes the electroplating process more refined and efficient.

[0113] Experimental Example 3: Comparison of Pulse Current and DC Current on Deposition Rate and Coating Quality The purpose of this experiment is to compare the effects of pulse current and direct current on the deposition rate, coating quality and uniformity during copper electroplating. Using the same plating solution formula, the quality difference of the deposited layer was studied by changing the current form. The following are the experimental steps: Preparation of plating solution: As in the previous example, copper sulfate (CuSO 4 ·5H 2 O) 200g / L and boric acid (H 3 BO 3 )50g / L dissolved in deionized water, stirred until completely dissolved, the dissolution time is about 30 minutes. Then, add 5mL / L of brightener (benzoxazole compound), 20g / L of buffer (sodium acetate) and 1g / L of inhibitor (ammonium chloride), ensuring that these additives are evenly distributed in the plating solution.

[0114] Current application: Experimental group (pulse current): pulse power supply was used, the frequency was set to 2kHz, the duty cycle was 50%, and the current density was 6A / dm 2 Under the action of pulse current, metal ions can migrate to the workpiece surface more quickly, thereby increasing the deposition rate and improving the uniformity of the deposited layer.

[0115] Comparison group (DC current): using a DC power supply, the current density is set to 6A / dm 2 , and other conditions were the same as those of the experimental group. This group used constant current density for electroplating to simulate the traditional electroplating process.

[0116] Electroplating process: The electroplating time is set to 30 minutes, carried out in the temperature range of 28°C to 32°C, and the pH value is controlled between 4.0 and 5.5. During the electroplating process, the distance between the workpiece and the electrode is set to 1 to 2 times the length of the workpiece to ensure uniform deposition of metal ions.

[0117] Deposit layer measurement and testing: After electroplating, the thickness of the deposited layer is measured using a microscope, and the deposition rate (the ratio of coating thickness to electroplating time) is recorded. Then, a scanning electron microscope (SEM) is used to observe the microstructure and surface quality of the coating, and adhesion tests (such as tensile strength tests) are performed to evaluate the adhesion of the deposited layer.

[0118] Table 3: Effect of pulse current and DC current on deposition rate and coating quality The experimental results show that pulse current has significant advantages over traditional direct current in deposition rate and coating quality. The application of pulse current not only accelerates the migration of metal ions, but also promotes uniform deposition of the coating, significantly increasing the deposition rate. In this experiment, the experimental group using pulse current generally showed a higher deposition rate, and the adhesion and smoothness of the coating were also improved. In contrast, the deposition layer thickness of the direct current group was relatively low, and the coating uniformity, adhesion and surface smoothness were poor.

[0119] From a mechanistic point of view, pulse current can provide an accelerated migration stage for metal ions in each pulse cycle, which helps the metal ions to deposit quickly and evenly on the workpiece surface. The alternating action of pulse current also effectively reduces the agglomeration of metal ions during the deposition process, making the coating surface smoother and more adherent. In contrast, the continuous action of direct current makes it difficult for metal ions to migrate quickly during the deposition process, and the coating is prone to unevenness, resulting in poor adhesion and rough surface.

[0120] Further analysis shows that the superiority of pulsed current is not only reflected in the deposition rate, but also in the microstructure and macroscopic properties of the coating. Pulsed current can help metal ions deposit quickly and evenly by periodically adjusting the current intensity and time during the deposition process, while direct current cannot achieve such flexible control.

[0121] Experimental Example 4: Effect of low concentration nanoparticles on the corrosion resistance of coatings This experiment aims to study the effect of different concentrations of nanoparticles on the corrosion resistance of the coating. By comparing the use of 0.1% (w / w) and 0.05% (w / w) concentrations of graphene quantum dots, the significant effect of the optimal nanoparticle concentration on the corrosion resistance of the coating in the present invention is verified. The following are the experimental steps: Preparation of electroplating solution: The same copper electroplating solution formula as in Experiment 1 was used. First, copper sulfate (CuSO 4 ·5H 2 O) 200g / L and boric acid (H 3 BO 3 ) 50g / L dissolved in deionized water, ensuring complete dissolution. Add brightener (benzoxazole compound) 5mL / L, buffer (sodium acetate) 20g / L, inhibitor (ammonium chloride) 1g / L, ensuring uniform distribution.

[0122] Nanoparticle preparation: Experimental group (0.1% concentration): Graphene quantum dots were used at a concentration of 0.1% (w / w), and the nanoparticles were evenly dispersed in the plating solution by ultrasonic stirring (power 300 W, frequency 40 kHz, treatment time 45 minutes).

[0123] Control group (0.05% concentration): graphene quantum dots were used at a concentration of 0.05% (w / w), and the same ultrasonic stirring method was adopted.

[0124] Electroplating process: Pour the prepared electroplating solution into the electroplating tank, keep the temperature of the electroplating solution between 28℃ and 32℃, and control the pH value between 4.0 and 5.5. Use a pulse power supply to apply pulse current, set the frequency to 2kHz, the duty cycle to 50%, and the current density to 6A / dm 2 The plating time is 30 minutes, and the plating solution is kept stable.

[0125] Coating corrosion resistance test: Salt spray test: The salt spray test is conducted using the ASTM B117 standard, and the test time is set to 48 hours. During the test, the corrosion performance of the coating is recorded, mainly evaluating the blistering, peeling, and corrosion area of ​​the coating.

[0126] Other tests: After electroplating, the microstructure of the coating surface is observed using a scanning electron microscope to confirm the uniformity and integrity of the coating.

[0127] Table 4: Effect of low concentration of nanoparticles on the corrosion resistance of coatings From the experimental results, the graphene quantum dots at a concentration of 0.1% (w / w) significantly improved the corrosion resistance of the coating, and showed stronger corrosion resistance than the control group coating at a concentration of 0.05%. Through the salt spray test, the corrosion area of ​​the experimental group was significantly smaller, the degree of surface blistering was also lower, and no obvious coating peeling phenomenon occurred. The coating of the control group showed a higher corrosion area, and the blistering and peeling phenomena were more serious. This shows that a higher concentration of nanoparticles can effectively enhance the corrosion resistance of the coating and reduce the occurrence of corrosion.

[0128] According to the mechanism analysis, graphene quantum dots, as nanoparticles, can effectively guide the migration of metal ions under the action of the electric field due to their conductivity and high specific surface area, thereby improving the uniformity and density of the deposited layer. This structural characteristic helps to improve the corrosion resistance of the coating. A higher concentration of graphene quantum dots can provide more conductive sites during the electroplating process, allowing metal ions to be more evenly distributed during the deposition process, thereby reducing defects and weaknesses during the corrosion process. Compared with low concentrations of graphene quantum dots, a higher concentration of nanoparticles helps to form a denser coating, thereby improving corrosion resistance.

[0129] Therefore, a higher concentration of graphene quantum dots not only improves the deposition quality of the coating, but also significantly improves the corrosion resistance of the coating.

[0130] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A pulse plating solution, characterized in that: include: Main salt, used to provide the metal ions required in the electroplating process; A complexing agent for stabilizing the metal ions; Additives, used to adjust the properties of the plating solution; Nanoparticles, which act as guide factors to migrate metal ions.

2. A pulse plating solution according to claim 1, characterized in that: The additive is one or more of a brightener, a buffer or an inhibitor, the buffer is acetate or ammonia water, and the inhibitor is thiocyanate or ammonium chloride.

3. A pulse plating solution according to claim 1, characterized in that: The additives are brighteners and buffers, the nanoparticles are graphene quantum dots, nano-silicon dioxide or a combination thereof, and the concentration of the nanoparticles is 0.01% to 1% (w / w).

4. A method for preparing a pulse plating solution, according to a pulse plating solution according to any one of claims 1 to 3, characterized in that: The following steps are involved: Add the main salt and complexing agent into deionized water and stir until completely dissolved; Add additives to the electroplating solution and stir evenly; Adding nanoparticles into the electroplating solution, and using ultrasonic stirring to evenly disperse the nanoparticles; filtering the electroplating solution to remove insoluble matter and impurities; Store the filtered plating solution in a sealed container.

5. The method for preparing a pulse plating solution according to claim 4, characterized in that: The ultrasonic power is 300W, the frequency is 40kHz, and the stirring time is 45 minutes.

6. A pulse plating process, according to a pulse plating solution as claimed in any one of claims 1 to 3, characterized in that: The following steps are involved: Step 1: preparing a pulse plating solution, wherein the pulse plating solution comprises a main salt, a complexing agent, an additive and nanoparticles; Step 2: Place the workpiece to be electroplated in the electroplating tank, immerse the workpiece completely in the electroplating solution, and set the distance between the electrode and the workpiece; Step 3: Use a pulse power supply to apply a pulse current with a pulse frequency range of 0.1kHz to 10kHz and a duty cycle of 50%; Step 4: Monitor the temperature, pH value and conductivity of the plating solution in real time, and adjust the current density, frequency and duty cycle according to the monitoring data.

7. A pulse plating process according to claim 6, characterized in that: The current density is 3A / dm 2 Up to 10A / dm 2 The temperature of the electroplating solution is maintained between 25°C and 35°C, and the pH value is maintained between 4.0 and 5.

5.

8. A pulse plating process according to claim 6, characterized in that: In the step three, the frequency of the pulse power supply is adjusted according to the deposition characteristics of different metal ions, and the current density and duty cycle are adjusted according to the properties of the metal ions.

9. A pulse plating process according to claim 6, characterized in that: In the step 4, if the electroplating solution is found to be abnormal during the electroplating process, an early warning signal is automatically issued and the process parameters are adjusted.

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