Environment-friendly pulse electroplating method
By accurately controlling the pulse plating parameters and using environmentally friendly plating solutions and additives, the electroplating process is optimized, and the problems of environmental pollution and uneven plating quality in traditional electroplating technology are solved, and efficient and environmentally friendly plating quality improvement and wastewater treatment are achieved. It is suitable for Areas with high environmental requirements.
Patent Information
- Application Number
- CN202411379789.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-30
- Publication Date
- 2025-01-03
AI Technical Summary
Traditional electroplating technology has problems such as environmental pollution, high production costs, uneven coating quality and insufficient corrosion resistance, especially in areas with high environmental requirements and strict coating quality requirements, such as aerospace and electronic equipment.
The environmentally friendly pulse plating method is adopted to accurately control the current density, pulse width and pause time of the positive and negative pulses, combined with the environmentally friendly nickel plating solution and additives, optimize the electroplating process, reduce the concentration polarization phenomenon, and improve the deposition efficiency and uniformity of the plating layer. , improve the appearance quality, corrosion resistance and wear resistance of the coating, and remove residues through ultrasonic hot water cleaning.
It significantly improves the density, corrosion resistance and wear resistance of the coating, reduces environmental pollution and production costs, realizes economical and simple wastewater treatment, and is suitable for electroplating treatment of various metal surfaces.
Smart Images
Figure BDA0005069606660000121
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of environmentally friendly electroplating, and in particular to an environmentally friendly pulse electroplating method. Background Art
[0002] In today's era of increasing attention to environmental protection and sustainable development, environmentally friendly electroplating technology has become an important development direction for the electroplating industry. Electroplating, as a technology that covers a layer of metal or alloy on the metal surface, is widely used in many fields such as automobiles, electronics, aviation, and jewelry. However, traditional electroplating technology is often accompanied by serious environmental pollution problems, such as heavy metal emissions and wastewater treatment. Therefore, the research and development and application of environmentally friendly electroplating technology are of great significance to promoting the green transformation of the electroplating industry and global sustainable development.
[0003] Environmentally friendly electroplating technology refers to the use of low-pollution, low-energy consumption processes and materials during the electroplating process to reduce or eliminate negative impacts on the environment. This technology has the following significant features: First, it reduces the emission of heavy metals. By optimizing the process and using environmentally friendly materials, the use and emission of heavy metals in the electroplating process are reduced; second, it reduces the difficulty of wastewater treatment. Advanced wastewater treatment technology and equipment are used to achieve wastewater recycling and zero emission; third, it improves the quality of electroplating. By optimizing the electroplating process and parameters, the uniformity, corrosion resistance and wear resistance of the electroplated layer are improved.
[0004] In practical applications, environmentally friendly electroplating technology has also demonstrated its unique advantages. Taking the automobile manufacturing industry as an example, the use of environmentally friendly electroplating technology can greatly reduce environmental pollution in the automobile production process. For example, by adopting chromium-free electroplating technology, it can replace the traditional chromium-containing electroplating process to reduce chromium emissions and pollution. At the same time, environmentally friendly electroplating technology can also improve the corrosion resistance and wear resistance of the automobile surface and extend the service life of the automobile. In the electronics industry, environmentally friendly electroplating technology also has broad application prospects. With the accelerated replacement of electronic products, the requirements for electroplating technology are also getting higher and higher. The use of environmentally friendly electroplating technology can improve the quality and reliability of electronic products, reduce production costs, and meet market demand.
[0005] Traditional electroplating processes usually use a DC power supply, which can easily lead to a decrease in the concentration of metal ions on the cathode surface, resulting in concentration polarization, which affects the electroplating speed and coating quality. At the same time, the waste gas, waste water and waste residue generated during the DC electroplating process put a lot of pressure on the environment. At present, although environmentally friendly electroplating technology has made certain progress, there are still some problems and challenges, such as how to further improve electroplating efficiency and quality, reduce production costs and energy consumption, achieve zero wastewater discharge, and how to improve the uniformity, corrosion resistance and wear resistance of the electroplating layer. Summary of the invention
[0006] In view of the shortcomings of the prior art, the present application provides an environmentally friendly pulse electroplating method. The environmentally friendly pulse electroplating method of the present application is a pulse electroplating method that can not only improve the quality of the electroplating layer, but also reduce environmental pollution. The electroplating process is optimized by precisely controlling parameters such as the positive and negative pulse current density, the positive and negative pulse pulse width, and the positive and negative pulse pause time. During the pulse pause, the metal ions near the cathode are restored, thereby reducing the concentration polarization phenomenon, improving the deposition efficiency of the electroplating layer, and improving the uniformity and density of the coating thickness, thereby significantly improving the appearance quality of the coating - dense and bright, and the corrosion resistance and wear resistance of the coating. At the same time, the present application adopts an environmentally friendly nickel electroplating solution and environmentally friendly additives, which can reduce the emission of harmful substances generated during the electroplating process and reduce pollution to the environment. The treatment of electroplating wastewater is relatively economical, simple and easy. The environmentally friendly additives can significantly improve the thickness uniformity and density of the electroplated nickel layer, thereby significantly improving the appearance quality, corrosion resistance and wear resistance of the coating. This method is suitable for electroplating treatment of various metal surfaces, especially in fields with high environmental requirements and strict requirements on plating quality, such as aerospace, electronic equipment, automobile manufacturing, etc.
[0007] The present application provides an environmentally friendly pulse electroplating method, which adopts the following technical solutions: An environmentally friendly pulse electroplating method comprises the following steps: S1. Prepare environmentally friendly electroplating solution; S2, setting multiple groups of pulse electroplating parameters, each group of pulse electroplating parameters corresponds to a corresponding electroplating band; S3, according to the metal parts to be plated, corresponding pulse electroplating parameters are selected, and the metal parts to be plated are subjected to at least three pulse electroplatings with successively increasing pulse current density in the environmentally friendly electroplating solution, wherein the pulse electroplating is repeated forward pulses and reverse pulses in sequence; the electroplating time of the first pulse electroplating is 10-20 minutes, the electroplating time of the second pulse electroplating is 10-30 minutes, and the electroplating time of the third pulse electroplating is 10-20 minutes; S4. After the pulse electroplating is completed, the metal parts are taken out for ultrasonic hot water cleaning and drying. The process parameters of the ultrasonic hot water cleaning are: hot water conductivity is 0.1-0.5μS / cm, temperature is 60-70℃, time is 1-2min, ultrasonic current is 5-6A. Ultrasonic hot water cleaning can remove residues and impurities on the surface of the metal parts, and improve the appearance quality and corrosion resistance of the coating.
[0008] By adopting the above technical scheme, the environmentally friendly pulse electroplating method of the present application is a pulse electroplating method that can not only improve the quality of the electroplating layer, but also reduce environmental pollution. By accurately controlling the parameters such as the positive and negative pulse current density, the positive and negative pulse pulse width, and the positive and negative pulse pause time, the electroplating process is optimized. During the pulse pause, the metal ions near the cathode are restored, thereby reducing the concentration polarization phenomenon, improving the deposition efficiency of the electroplating layer, and improving the uniformity and density of the coating thickness, thereby significantly improving the appearance quality, corrosion resistance and wear resistance of the coating. S1: Prepare an environmentally friendly electroplating solution. This step is to ensure the environmental protection of the electroplating process. The use of environmentally friendly nickel electroplating solution and additives can reduce the emission of harmful substances generated during the electroplating process and reduce pollution to the environment. S2: Set multiple groups of pulse electroplating parameters, and each group of pulse electroplating parameters corresponds to the corresponding electroplating band. This step is to optimize the electroplating process, by accurately controlling the parameters such as the positive and negative pulse current density, the positive and negative pulse pulse width, and the positive and negative pulse pause time, the deposition efficiency and coating quality of the electroplating layer are improved. S3: According to the metal parts to be plated, the corresponding pulse electroplating parameters are selected to perform at least three pulse electroplatings with pulse current density increasing in sequence on the metal parts to be plated in the environmentally friendly electroplating solution, and the pulse electroplating is a forward pulse and a reverse pulse that are repeated in sequence; the electroplating time of the first pulse electroplating is 10-20 minutes, the electroplating time of the second pulse electroplating is 10-30 minutes, and the electroplating time of the third pulse electroplating is 10-20 minutes. This step is to further optimize the electroplating process, and the thickness uniformity and density of the coating are improved by combining the use of segmented pulse electroplating and forward pulses and reverse pulses, thereby significantly improving the appearance quality of the coating-dense and bright, corrosion resistance and wear resistance. S4: After the pulse electroplating is completed, the metal parts are taken out for ultrasonic hot water cleaning and drying. This step is to remove the residues and impurities on the surface of the metal parts and improve the appearance quality and corrosion resistance of the coating. Ultrasonic hot water cleaning can effectively remove the residues and impurities on the surface of the metal parts, and the process parameters of ultrasonic hot water washing also provide convenience for subsequent drying treatment.
[0009] Preferably, the forward pulse current density of the first stage of the pulse electroplating is 5-7A / dm 2 The reverse pulse current density of the first stage of the pulse electroplating is 10-15A / dm 2 The forward pulse width of the first section in the pulse electroplating is 60-80ms, the reverse pulse width of the first section in the pulse electroplating is 2-5ms, the forward pulse of the first section in the pulse electroplating is followed by a pause of 0.1-0.6ms before a reverse pulse is applied, and the reverse pulse of the first section in the pulse electroplating is followed by a pause of 0.1-0.3ms before a forward pulse is applied.
[0010] By adopting the above technical solution, in the environmentally friendly pulse electroplating method, the parameter setting of the first pulse electroplating has an important influence on the entire electroplating process and the final coating quality. The following are the effects of these parameters and their synergistic effects: forward pulse current density (5-7A / dm 2 ): Forward pulse current density refers to the density of current passing through the surface of the metal to be plated during the forward pulse. In this range, the current density is high enough to ensure that the metal ions are reduced on the cathode surface and form a coating, but not too high to cause ablation or roughening of the coating. Reverse pulse current density (10-15A / dm 2 ): Reverse pulse current density is the density of current passing through the surface of the metal part to be plated during the reverse pulse. A higher reverse pulse current density helps to remove hydrogen bubbles and impurities on the surface and improve the adhesion and uniformity of the coating. Forward pulse width (60-80ms): The forward pulse width refers to the duration of the forward pulse. Within this time range, it can ensure that enough metal ions are reduced and deposited on the cathode to form a uniform coating. Reverse pulse width (2-5ms): The reverse pulse width refers to the duration of the reverse pulse. A shorter reverse pulse width helps to quickly remove hydrogen bubbles and impurities on the surface without causing excessive stripping or damage to the already formed coating. Pause time after the forward pulse (0.1-0.6ms): The pause time refers to the interval between the forward pulse and the reverse pulse. This short pause allows the metal ion concentration in the plating solution to recover near the cathode, reducing concentration polarization and improving electroplating efficiency. Pause time after the reverse pulse (0.1-0.3ms): Similar to the pause time after the forward pulse, this pause time helps the metal ions in the plating solution recover near the cathode, providing better plating conditions for the next forward pulse. The synergistic effect of these parameters is that the plating process can be optimized by precisely controlling each stage of pulse plating. The combination of forward and reverse pulses, as well as the appropriate pause time, helps maintain a uniform distribution of metal ions in the plating solution, reduces concentration polarization, and improves the uniformity and density of the coating. At the same time, this control can also reduce the formation of hydrogen bubbles and avoid holes and other defects in the coating. In addition, the use of environmentally friendly plating solutions and additives can reduce the emission of harmful substances and reduce pollution to the environment.
[0011] Preferably, the forward pulse current density of the second stage in the pulse electroplating is 9-12A / dm 2 The reverse pulse current density of the second stage of the pulse electroplating is 17-20A / dm 2The forward pulse width of the second section in the pulse electroplating is 100-200ms, the reverse pulse width of the second section in the pulse electroplating is 6-8ms, the forward pulse of the second section in the pulse electroplating is followed by a pause of 0.3-0.8ms, and then a reverse pulse is applied, the reverse pulse of the second section in the pulse electroplating is followed by a pause of 0.4-0.5ms, and then a forward pulse is applied.
[0012] By adopting the above technical solution, the forward pulse current density of the second pulse plating is 9-12A / dm 2 , reverse pulse current density is 17-20A / dm 2 . This setting makes there a certain current density difference between the forward pulse and the reverse pulse during the second pulse electroplating process, which is beneficial to improve the deposition efficiency and thickness uniformity of the coating. At the same time, the forward pulse width of the second pulse electroplating is 100-200ms, and the reverse pulse width is 6-8ms. This pulse width setting makes the time interval between the forward pulse and the reverse pulse shorter, which is beneficial to the recovery of metal ions near the cathode during the pulse pause, thereby reducing the concentration polarization phenomenon and improving the deposition efficiency of the electroplating layer. In addition, the forward pulse of the second pulse electroplating pauses for 0.3-0.8ms before the reverse pulse; the reverse pulse pauses for 0.4-0.5ms before the forward pulse. This pause time setting is beneficial to form a short interval between the forward pulse and the reverse pulse, so that the metal ions near the cathode can be recovered, further reducing the concentration polarization phenomenon and improving the deposition efficiency of the electroplating layer.
[0013] Preferably, the forward pulse current density of the third stage in the pulse electroplating is 15-19A / dm 2 The reverse pulse current density of the third section in the pulse electroplating is 22-25A / dm 2 ; The forward pulse width of the third section in the pulse electroplating is 50-80ms, the reverse pulse width of the third section in the pulse electroplating is 3-5ms, the forward pulse of the third section in the pulse electroplating is followed by a pause of 0.1-0.3ms, and then a reverse pulse is applied, the reverse pulse of the third section in the pulse electroplating is followed by a pause of 0.5-0.7ms, and then a forward pulse is applied.
[0014] By adopting the above technical solution, the forward pulse current density of the third section is 15-19A / dm 2 , reverse pulse current density is 22-25A / dm 2. This current density is chosen to optimize the electroplating process, improve the deposition efficiency of the electroplated layer, and improve the uniformity and density of the coating thickness. The forward pulse width is 50-80ms, and the reverse pulse width is 3-5ms. This pulse width is chosen to allow the metal ions near the cathode to recover during the pulse pause, thereby reducing the concentration polarization phenomenon, improving the deposition efficiency of the electroplated layer, and improving the uniformity and density of the coating thickness. Pause for 0.1-0.3ms after the forward pulse, and then perform a reverse pulse. Pause for 0.5-0.7ms after the reverse pulse, and then perform a forward pulse. This pause time is chosen to further optimize the electroplating process and improve the quality of the electroplated layer. The selection of the above parameters can significantly improve the appearance quality of the coating - dense and bright, and the corrosion resistance and wear resistance of the coating.
[0015] Preferably, the environmentally friendly electroplating solution is an environmentally friendly nickel electroplating solution, which includes the following components in mass concentrations: nickel salt 70-120g / L, boric acid 40-50g / L, composite brightener 30-40mg / L, composite anti-pinhole agent 15-20mg / L, composite dispersant 40-50mg / L, composite leveling agent 50-60mg / L, the balance is deionized water, and the plating solution temperature is 50-55°C.
[0016] By adopting the above technical solution, nickel salt (70-120g / L): as the main metal ion source, nickel ions are provided to form a nickel coating. Its concentration directly affects the deposition rate and quality of the coating. Boric acid (40-50g / L): as a buffer, it maintains the pH value of the plating solution stable and prevents the pH value from fluctuating violently during the electroplating process, thereby ensuring the stability of the electroplating quality. Composite brightener (30-40mg / L): improves the brightness and flatness of the coating and makes the coating more beautiful. Brighteners usually contain organic additives, such as aldehydes, acetylene compounds, etc., which can be adsorbed on the cathode surface, affect the reduction process of metal ions, reduce the crystal size, and improve the smoothness and gloss of the coating. Composite anti-pinhole agent (15-20mg / L): used to reduce the formation of pinholes in the coating and improve the density and corrosion resistance of the coating. Anti-pinhole agents are usually some surfactants that can reduce the surface tension of the plating solution and reduce the residence time of hydrogen bubbles on the cathode surface, thereby reducing the generation of pinholes. Composite dispersant (40-50 mg / L): Promotes uniform distribution of metal ions in the plating solution, avoids metal ion aggregation, and ensures uniformity of the coating. Dispersants can be certain high molecular polymers that disperse metal particles through steric hindrance or charge repulsion. Composite leveling agent (50-60 mg / L): Improves the smoothness and microstructure of the coating and eliminates microscopic unevenness in the coating. Leveling agents usually contain compounds with strong adsorption capacity, such as heterocyclic compounds or organic compounds containing nitrogen and sulfur, which can form a thin film on the cathode surface to inhibit uneven deposition of metals. Deionized water: As a solvent, ensures that the impurity content in the plating solution is minimized to avoid the introduction of unnecessary impurities that affect the quality of electroplating. Plating solution temperature (50-55°C): Suitable temperature can accelerate the migration speed of ions and improve electroplating efficiency. At the same time, maintaining a certain temperature range helps to stabilize the electroplating process and ensure the quality of the coating. The synergistic effect of these components in the plating solution enables the electroplating process to be carried out in a stable and optimized environment, thereby obtaining a high-quality coating. By precisely controlling the pulse plating parameters and the composition of the plating solution, the method of the present application can significantly improve the appearance quality, corrosion resistance and wear resistance of the coating, while achieving the purpose of environmental protection and reducing environmental pollution.
[0017] Preferably, the nickel salt consists of nickel chloride and nickel sulfamate, and the mass concentration ratio of the two when used is 1:3.
[0018] Preferably, the composite brightener is composed of L-alanine benzyl p-toluenesulfonate and sodium propargyl sulfonate in a mass ratio of 3:2.
[0019] By adopting the above technical solution, the composite brightener is composed of L-alanine benzyl p-toluenesulfonate and sodium propargyl sulfonate in a mass ratio of 3:2, and has the following effects in an environmentally friendly nickel electroplating solution: Improving the brightness of the coating: L-alanine benzyl p-toluenesulfonate and sodium propargyl sulfonate as brighteners can increase the brightness of the coating. They change the deposition mode of metal ions to make the surface of the coating smoother and flatter, thereby improving the appearance quality of the coating. Improving the performance of the coating: L-alanine benzyl p-toluenesulfonate and sodium propargyl sulfonate in the composite brightener can work synergistically to improve the performance of the coating. L-alanine benzyl p-toluenesulfonate can improve the corrosion resistance of the coating, while sodium propargyl sulfonate can improve the wear resistance of the coating. The combination of the two makes the coating have better comprehensive performance. Stabilizing the performance of the plating solution: L-alanine benzyl p-toluenesulfonate and sodium propargyl sulfonate in the composite brightener can stabilize the performance of the plating solution. They can interact with other components in the plating solution to form stable complexes, thereby maintaining the stability of the plating solution and reducing the decomposition and precipitation of the plating solution. In summary, the composite brightener is composed of L-alanine benzyl p-toluenesulfonate and sodium propargyl sulfonate in a mass ratio of 3:2, which has the effects of improving the brightness of the coating, improving the coating performance and stabilizing the plating solution performance in an environmentally friendly electroplating nickel plating solution. At the same time, the synergistic effect between L-alanine benzyl p-toluenesulfonate and sodium propargyl sulfonate can further enhance the performance of the coating, making it have better corrosion resistance and wear resistance.
[0020] Preferably, the composite leveler is composed of 4-(N-ethyl-N-hydroxyethyl)-2-methylphenylenediamine sulfate, 2-(4-bromo-1H-pyrazol-1-yl)pyrimidine and 4-pyrrolidin-1-ylpiperidine dihydrochloride in a mass ratio of 3:2:3.
[0021] By adopting the above technical scheme, the role of the composite leveler in the environmentally friendly nickel electroplating solution is mainly to improve the flatness of the coating, reduce defects such as pinholes and pitting, and improve the appearance quality of the coating. 4-(N-ethyl-N-hydroxyethyl)-2-methylphenylenediamine sulfate has good leveling performance, which can effectively improve the flatness of the coating, reduce defects such as pinholes and pitting. 2-(4-bromo-1H-pyrazol-1-yl) pyrimidine has a good brightening effect, which can make the coating brighter and improve the appearance quality of the coating. 4-pyrrolidine-1-ylpiperidine dihydrochloride can increase the stability of the plating solution, prevent the decomposition of the plating solution, and extend the service life of the plating solution. These three components cooperate with each other, which can not only improve the flatness of the coating, but also improve the brightness of the coating, and at the same time increase the stability of the plating solution. It is a very excellent composite leveler.
[0022] Preferably, the composite anti-pinhole agent is composed of L-thioproline and p-amino-N,N-diethylaniline sulfate in a mass ratio of 2:3.
[0023] By adopting the above technical scheme, during the electroplating process, pinhole-shaped defects are easily formed on the surface of the coating due to uneven current density distribution or insufficient metal ion concentration. L-thioproline and p-amino-N,N-diethylaniline sulfate as composite anti-pinhole agents can effectively prevent the formation of pinholes. L-thioproline has a strong adsorption capacity and can form a protective film on the cathode surface, reducing the deposition rate of metal ions, thereby reducing the generation of pinholes. P-amino-N,N-diethylaniline sulfate can improve the stability of the electroplating solution, make the distribution of metal ions on the cathode surface more uniform, and further reduce the formation of pinholes. The synergistic effect of L-thioproline and p-amino-N,N-diethylaniline sulfate in the environmentally friendly nickel electroplating solution is mainly reflected in the following aspects: a) Improving the quality of the coating: The two work together to prevent the formation of pinholes and improve the density and brightness of the coating, thereby improving the overall quality of the coating. b) Enhance corrosion resistance: By reducing the formation of pinholes, the defects on the surface of the coating can be reduced, thereby improving the corrosion resistance of the coating. c) Improve electroplating efficiency: The two work together to improve the stability of the electroplating solution and the uniformity of the distribution of metal ions on the cathode surface, thereby improving the electroplating efficiency. d) Reduce environmental pollution: The use of environmentally friendly nickel electroplating solutions and environmentally friendly additives can reduce the emission of harmful substances generated during the electroplating process and reduce pollution to the environment.
[0024] Preferably, the composite dispersant is composed of 3-[[(benzylthio)thiocarbonyl]thio]propionic acid and isomeric tridecanol polyoxyethylene ether in a mass ratio of 5:1.
[0025] In summary, the present application includes at least one of the following beneficial technical effects: 1. Improve the quality of the electroplating layer: By accurately controlling the parameters such as the positive and negative pulse current density, the positive and negative pulse width, and the positive and negative pulse pause time, the electroplating process is optimized, the concentration polarization phenomenon is reduced, the deposition efficiency of the electroplating layer is improved, and the thickness uniformity and density of the coating are improved, thereby significantly improving the appearance quality (dense and bright), corrosion resistance, and wear resistance of the coating.
[0026] 2. Reduce environmental pollution: Using environmentally friendly nickel electroplating solution and environmentally friendly additives can reduce the emission of harmful substances generated during the electroplating process and reduce environmental pollution. At the same time, electroplating wastewater treatment is relatively economical and simple.
[0027] 3. Applicable to electroplating treatment of various metal surfaces: This method is suitable for electroplating treatment of various metal surfaces, especially in fields with high environmental protection requirements and strict requirements on plating quality, such as aerospace, electronic equipment, automobile manufacturing, etc.
[0028] 4. Economical and convenient electroplating wastewater treatment: Due to the use of environmentally friendly additive formula pulse electroplating, electroplating wastewater treatment becomes more economical, simple and easy. DETAILED DESCRIPTION
[0029] The embodiments of the present application will be described in detail below in conjunction with the examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. In the examples, if specific conditions are not specified, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.
[0030] Example 1 An environmentally friendly pulse electroplating method comprises the following steps: S1. Prepare an environmentally friendly electroplating solution; the environmentally friendly electroplating solution is an environmentally friendly nickel electroplating solution, which includes the following components in mass concentrations: nickel salt 70g / L, boric acid 40g / L, composite brightener 30mg / L, composite anti-pinhole agent 15mg / L, composite dispersant 40mg / L, composite leveling agent 50mg / L, the balance is deionized water, the plating solution temperature is 50°C, the nickel salt is composed of nickel chloride and aminosulfonic acid nickel, and the mass concentration ratio of the two when used is 1:3, the composite brightener is L-alanine benzyl p-toluenesulfonate and propargyl sulfone The composite leveler is composed of 4-(N-ethyl-N-hydroxyethyl)-2-methylphenylenediamine sulfate, 2-(4-bromo-1H-pyrazol-1-yl)pyrimidine and 4-pyrrolidin-1-ylpiperidine dihydrochloride in a mass ratio of 3:2:3, the composite anti-pinhole agent is composed of L-thioproline and p-amino-N,N-diethylaniline sulfate in a mass ratio of 2:3, and the composite dispersant is composed of 3-[[(benzylthio)thiocarbonyl]thio] propionic acid and isomeric tridecanol polyoxyethylene ether in a mass ratio of 5:1; S2, setting multiple groups of pulse electroplating parameters, each group of pulse electroplating parameters corresponds to a corresponding electroplating band; S3. According to the aluminum alloy metal parts to be plated, corresponding pulse electroplating parameters are selected, and at least three pulse electroplatings with successively increasing pulse current density are performed on the metal parts to be plated in the environmentally friendly electroplating solution. The pulse electroplating is repeated forward pulses and reverse pulses in sequence. The electroplating time of the first pulse electroplating is 10 minutes, the electroplating time of the second pulse electroplating is 30 minutes, and the electroplating time of the third pulse electroplating is 10 minutes. The forward pulse current density of the first section of the pulse electroplating is 5A / dm 2 The reverse pulse current density of the first stage of the pulse electroplating is 10A / dm 2The forward pulse width of the first section of the pulse electroplating is 60ms, the reverse pulse width of the first section of the pulse electroplating is 2ms, the forward pulse of the first section of the pulse electroplating is followed by a pause of 0.1ms, and then a reverse pulse is applied, the reverse pulse of the first section of the pulse electroplating is followed by a pause of 0.1ms, and then a forward pulse is applied; the forward pulse current density of the second section of the pulse electroplating is 9A / dm 2 The reverse pulse current density of the second stage of the pulse electroplating is 20A / dm 2 The forward pulse width of the second section of the pulse electroplating is 100ms, the reverse pulse width of the second section of the pulse electroplating is 6ms, the forward pulse of the second section of the pulse electroplating is followed by a pause of 0.3ms before the reverse pulse is applied, the reverse pulse of the second section of the pulse electroplating is followed by a pause of 0.4ms before the forward pulse is applied; the forward pulse current density of the third section of the pulse electroplating is 15A / dm 2 The reverse pulse current density of the third section in the pulse electroplating is 22A / dm 2 The forward pulse width of the third section in the pulse electroplating is 50ms, the reverse pulse width of the third section in the pulse electroplating is 3ms, the forward pulse of the third section in the pulse electroplating is followed by a pause of 0.1ms before the reverse pulse is applied, and the reverse pulse of the third section in the pulse electroplating is followed by a pause of 0.5ms before the forward pulse is applied; S4. After the pulse electroplating is completed, the aluminum alloy metal parts are taken out for ultrasonic hot water cleaning and drying. The process parameters of the ultrasonic hot water cleaning are: hot water conductivity is 0.1μS / cm, temperature is 60°C, time is 2min, and ultrasonic current is 5A. Ultrasonic hot water cleaning can remove residues and impurities on the surface of the metal parts, thereby improving the appearance quality and corrosion resistance of the coating.
[0031] Example 2 An environmentally friendly pulse electroplating method comprises the following steps: S1. Prepare an environmentally friendly electroplating solution; the environmentally friendly electroplating solution is an environmentally friendly nickel electroplating solution, which includes the following components in mass concentrations: 120 g / L nickel salt, 50 g / L boric acid, 40 mg / L composite brightener, 20 mg / L composite anti-pinhole agent, 50 mg / L composite dispersant, 60 mg / L composite leveler, the remainder is deionized water, the plating solution temperature is 55°C, the nickel salt is composed of nickel chloride and nickel sulfamate, and the mass concentration ratio of the two when used is 1:3, the composite brightener is composed of L-alanine benzyl p-toluenesulfonate and propargyl sulfone The composite leveler is composed of 4-(N-ethyl-N-hydroxyethyl)-2-methylphenylenediamine sulfate, 2-(4-bromo-1H-pyrazol-1-yl)pyrimidine and 4-pyrrolidin-1-ylpiperidine dihydrochloride in a mass ratio of 3:2:3, the composite anti-pinhole agent is composed of L-thioproline and p-amino-N,N-diethylaniline sulfate in a mass ratio of 2:3, and the composite dispersant is composed of 3-[[(benzylthio)thiocarbonyl]thio] propionic acid and isomeric tridecanol polyoxyethylene ether in a mass ratio of 5:1; S2, setting multiple groups of pulse electroplating parameters, each group of pulse electroplating parameters corresponds to a corresponding electroplating band; S3. Select corresponding pulse plating parameters according to the aluminum alloy metal parts to be plated, and perform at least three pulse platings with increasing pulse current density in an environmentally friendly plating solution on the metal parts to be plated, wherein the pulse plating is repeated forward pulses and reverse pulses in sequence; the plating time of the first pulse plating is 20 minutes, the plating time of the second pulse plating is 10 minutes, and the plating time of the third pulse plating is 20 minutes; the forward pulse current density of the first section of the pulse plating is 7A / dm 2 The reverse pulse current density of the first stage of the pulse electroplating is 15A / dm 2 The forward pulse width of the first section of the pulse electroplating is 80ms, the reverse pulse width of the first section of the pulse electroplating is 5ms, the forward pulse of the first section of the pulse electroplating is followed by a pause of 0.6ms, and then a reverse pulse is applied, the reverse pulse of the first section of the pulse electroplating is followed by a pause of 0.3ms, and then a forward pulse is applied; the forward pulse current density of the second section of the pulse electroplating is 12A / dm 2 The reverse pulse current density of the second stage of the pulse electroplating is 17A / dm 2 The forward pulse width of the second section of the pulse electroplating is 200ms, the reverse pulse width of the second section of the pulse electroplating is 8ms, the forward pulse of the second section of the pulse electroplating is followed by a pause of 0.8ms before the reverse pulse is applied, the reverse pulse of the second section of the pulse electroplating is followed by a pause of 0.5ms before the forward pulse is applied; the forward pulse current density of the third section of the pulse electroplating is 19A / dm 2The reverse pulse current density of the third section in the pulse electroplating is 25A / dm 2 The forward pulse width of the third section in the pulse electroplating is 80ms, the reverse pulse width of the third section in the pulse electroplating is 5ms, the forward pulse of the third section in the pulse electroplating is followed by a pause of 0.3ms before a reverse pulse is applied, and the reverse pulse of the third section in the pulse electroplating is followed by a pause of 0.7ms before a forward pulse is applied; S4. After the pulse electroplating is completed, the aluminum alloy metal parts are taken out for ultrasonic hot water cleaning and drying. The process parameters of the ultrasonic hot water cleaning are: hot water conductivity is 0.5μS / cm, temperature is 70°C, time is 1min, and ultrasonic current is 6A. Ultrasonic hot water cleaning can remove residues and impurities on the surface of the metal parts, thereby improving the appearance quality and corrosion resistance of the coating.
[0032] Example 3 An environmentally friendly pulse electroplating method comprises the following steps: S1. Prepare an environmentally friendly electroplating solution; the environmentally friendly electroplating solution is an environmentally friendly nickel electroplating solution, which includes the following components in mass concentrations: nickel salt 90g / L, boric acid 45g / L, composite brightener 35mg / L, composite anti-pinhole agent 18mg / L, composite dispersant 45mg / L, composite leveling agent 55mg / L, the balance is deionized water, the plating solution temperature is 53°C, the nickel salt is composed of nickel chloride and aminosulfonic acid nickel, and the mass concentration ratio of the two when used is 1:3, the composite brightener is L-alanine benzyl p-toluenesulfonate and propargyl sulfone The composite leveler is composed of 4-(N-ethyl-N-hydroxyethyl)-2-methylphenylenediamine sulfate, 2-(4-bromo-1H-pyrazol-1-yl)pyrimidine and 4-pyrrolidin-1-ylpiperidine dihydrochloride in a mass ratio of 3:2:3, the composite anti-pinhole agent is composed of L-thioproline and p-amino-N,N-diethylaniline sulfate in a mass ratio of 2:3, and the composite dispersant is composed of 3-[[(benzylthio)thiocarbonyl]thio] propionic acid and isomeric tridecanol polyoxyethylene ether in a mass ratio of 5:1; S2, setting multiple groups of pulse electroplating parameters, each group of pulse electroplating parameters corresponds to a corresponding electroplating band; S3. Select corresponding pulse plating parameters according to the aluminum alloy metal parts to be plated, and perform at least three pulse platings with increasing pulse current density in an environmentally friendly plating solution on the metal parts to be plated, wherein the pulse plating is repeated forward pulses and reverse pulses in sequence; the plating time of the first pulse plating is 15 minutes, the plating time of the second pulse plating is 15 minutes, and the plating time of the third pulse plating is 20 minutes; the forward pulse current density of the first section of the pulse plating is 6A / dm 2The reverse pulse current density of the first stage of the pulse electroplating is 12A / dm 2 The forward pulse width of the first section of the pulse electroplating is 70ms, the reverse pulse width of the first section of the pulse electroplating is 3ms, the forward pulse of the first section of the pulse electroplating is followed by a pause of 0.4ms, and then a reverse pulse is applied, the reverse pulse of the first section of the pulse electroplating is followed by a pause of 0.2ms, and then a forward pulse is applied; the forward pulse current density of the second section of the pulse electroplating is 11A / dm 2 The reverse pulse current density of the second stage of the pulse electroplating is 18A / dm 2 The forward pulse width of the second section of the pulse electroplating is 150ms, the reverse pulse width of the second section of the pulse electroplating is 7ms, the forward pulse of the second section of the pulse electroplating is followed by a pause of 0.5ms, and then a reverse pulse is applied, the reverse pulse of the second section of the pulse electroplating is followed by a pause of 0.5ms, and then a forward pulse is applied; the forward pulse current density of the third section of the pulse electroplating is 17A / dm 2 The reverse pulse current density of the third section in the pulse electroplating is 24A / dm 2 The forward pulse width of the third section in the pulse electroplating is 60ms, the reverse pulse width of the third section in the pulse electroplating is 4ms, the forward pulse of the third section in the pulse electroplating is followed by a pause of 0.2ms before a reverse pulse is applied, and the reverse pulse of the third section in the pulse electroplating is followed by a pause of 0.6ms before a forward pulse is applied; S4. After the pulse electroplating is completed, the aluminum alloy metal parts are taken out for ultrasonic hot water cleaning and drying. The process parameters of the ultrasonic hot water cleaning are: hot water conductivity is 0.3μS / cm, temperature is 65°C, time is 1.5min, and ultrasonic current is 5.5A. Ultrasonic hot water cleaning can remove residues and impurities on the surface of the metal parts, thereby improving the appearance quality and corrosion resistance of the coating.
[0033] Comparative Example 1 The same as Example 3, except that: the composite brightener is L-alanine benzyl ester p-toluenesulfonate.
[0034] Comparative Example 2 The same as Example 3, except that: the composite brightener is sodium propargyl sulfonate.
[0035] Comparative Example 3 The same as Example 3, except that: the composite leveling agent is 4-(N-ethyl-N-hydroxyethyl)-2-methylphenylenediamine sulfate.
[0036] Comparative Example 4 The same as Example 3, except that: the composite leveler is 2-(4-bromo-1H-pyrazol-1-yl)pyrimidine.
[0037] Comparative Example 5 The same as Example 3, except that: the composite leveler is 4-pyrrolidin-1-ylpiperidine dihydrochloride.
[0038] Comparative Example 6 The same as Example 3, except that: the composite anti-pinhole agent is L-thioproline.
[0039] Comparative Example 7 The same as Example 3, except that: the composite anti-pinhole agent is p-amino-N,N-diethylaniline sulfate.
[0040] Performance testing The aluminum alloy metal parts prepared in Examples 1 to 3 and Comparative Examples 1 to 7 were sampled and subjected to the following tests. The test results are shown in Table 1. 1. Nickel plating appearance test: Test method: Observe under a 10-20x microscope; Observation content: Before various environmental experiments, coating appearance and bonding strength test; Inspection after various environmental tests: Inspection and testing shall be carried out according to the contents after various environmental tests; Evaluation criteria: Determine by the density and brightness of the coating surface.
[0041] 2. Nickel coating thickness uniformity test method: The nickel coating thickness of each sample was tested using the FISCHERSCOPE X-RAY XDV-SDD film thickness meter manufactured by Fischer; Nickel coating thickness uniformity = maximum sample thickness - minimum sample thickness; Evaluation criteria: The thickness difference is used to represent the uniformity of nickel plating thickness. The larger the difference, the worse the uniformity, and the smaller the difference, the better the uniformity. It is represented by Mh, which is expressed in nanometers (nm).
[0042] 3. Nickel coating hardness test purpose: the ability to resist mechanical effects such as impact, notch, scratch; and the density of the coating. The better the density, the higher the hardness of the coating. The poorer the density, the lower the hardness of the coating. Test method: Use the triangular indenter of a microhardness tester to measure the coating; Implementation standard: GB / T 9790-2021 Vickers and Knoop microhardness test for metal materials, metals and other inorganic coatings; Test equipment: Hardness tester Evaluation standard: Hardness unit: kg / mm 2 , generally expressed in HV.
[0043] 4. Salt spray test of nickel-plated parts Test plan: neutral salt spray test; Implementation standards: GB / T2423.17-2008 "Basic environmental testing procedures for electric and electronic products Test Ka: Salt spray test method", GB / T2423.18-2000 "Environmental testing for electric and electronic products Part 2: Test Test Kb: Salt spray, alternating (sodium chloride solution)"; Test time: 36 hours; Test equipment: MRT-YWX-90 90 type salt spray corrosion test machine; Test content: Corrosion spots, bubbles, peeling, cracking and discoloration defects on the sample appearance; Evaluation criteria: expressed as defect area percentage Y%; no defects is 0.00%.
[0044] Table 1 Performance test Analyzing the data in Table 1, we can see that: 1) The appearance quality of the coating of the aluminum alloy metal parts obtained in Examples 1 to 3 is dense and bright, with uniform thickness, good corrosion resistance, high hardness and good wear resistance. The present application optimizes the electroplating process by accurately controlling the parameters such as the positive and negative pulse current density, the positive and negative pulse width, and the positive and negative pulse pause time. During the pulse pause, the metal ions near the cathode are restored, thereby reducing the concentration polarization phenomenon, improving the deposition efficiency of the electroplated layer, and improving the thickness uniformity and density of the coating, thereby significantly improving the appearance quality, corrosion resistance and wear resistance of the coating. At the same time, the present application adopts an environmentally friendly nickel electroplating solution and environmentally friendly additives, which can reduce the emission of harmful substances generated during the electroplating process and reduce pollution to the environment. The treatment of electroplating wastewater is relatively economical, simple and easy. The environmentally friendly additives can significantly improve the thickness uniformity and density of the electroplated nickel layer, thereby significantly improving the appearance quality, corrosion resistance and wear resistance of the coating.
[0045] 2) The comparative analysis of the performance of the aluminum alloy metal parts prepared in Example 3 and Comparative Examples 1-2 shows that the composite brightener is composed of L-alanine benzyl p-toluenesulfonate and sodium propargyl sulfonate in a mass ratio of 3:2, and the synergistic effect between them is utilized to improve the brightness of the coating and improve the coating performance, thereby better improving the comprehensive performance of the nickel coating.
[0046] 3) The comparative analysis of the performance of the aluminum alloy metal parts prepared in Example 3 and Comparative Examples 3 to 5 shows that the composite leveling agent is composed of 4-(N-ethyl-N-hydroxyethyl)-2-methylphenylenediamine sulfate, 2-(4-bromo-1H-pyrazol-1-yl)pyrimidine and 4-pyrrolidin-1-ylpiperidine dihydrochloride in a mass ratio of 3:2:3. The synergistic effect between them is utilized to improve the flatness of the coating, reduce defects such as pinholes and pitting, improve the appearance quality of the coating, improve the brightness of the coating and improve the coating performance, thereby better improving the comprehensive performance of the nickel coating.
[0047] 4) The comparative analysis of the performance of the aluminum alloy metal parts prepared in combination with Example 3 and Comparative Examples 6-7 shows that the composite anti-pinhole agent is composed of L-thioproline and p-amino-N,N-diethylaniline sulfate in a mass ratio of 2:3. The synergistic effect between them is utilized to improve the flatness of the coating, reduce defects such as pinholes and pitting, and improve the thickness uniformity and density of the electroplated nickel layer, thereby significantly improving the appearance quality, corrosion resistance and wear resistance of the coating.
[0048] The above embodiments are only used to explain the technical solutions of the present application rather than to limit them. Although the above embodiments provide a specific description of the present application, relevant technical personnel should understand that the specific implementation methods of the present application can still be modified or replaced by equivalents, and any modifications and equivalent replacements that do not depart from the spirit and scope of the present application should be included in the protection scope of the present application.
Claims
1. An environmentally friendly pulse electroplating method, characterized in that: The following steps are involved: S1. Prepare environmentally friendly electroplating solution; S2, setting multiple groups of pulse electroplating parameters, each group of pulse electroplating parameters corresponds to a corresponding electroplating band; S3, according to the metal parts to be plated, corresponding pulse electroplating parameters are selected, and the metal parts to be plated are subjected to at least three pulse electroplatings with successively increasing pulse current density in the environmentally friendly electroplating solution, wherein the pulse electroplating is repeated forward pulses and reverse pulses in sequence; the electroplating time of the first pulse electroplating is 10-20 minutes, the electroplating time of the second pulse electroplating is 10-30 minutes, and the electroplating time of the third pulse electroplating is 10-20 minutes; S4. After the pulse electroplating is completed, the metal parts are taken out for ultrasonic hot water cleaning and drying. The process parameters of the ultrasonic hot water cleaning are: hot water conductivity is 0.1-0.5μS / cm, temperature is 60-70℃, time is 1-2min, ultrasonic current is 5-6A. Ultrasonic hot water cleaning can remove residues and impurities on the surface of the metal parts, and improve the appearance quality and corrosion resistance of the coating.
2. An environmentally friendly pulse electroplating method according to claim 1, characterized in that: The forward pulse current density of the first stage of the pulse electroplating is 5-7A / dm 2 The reverse pulse current density of the first stage of the pulse electroplating is 10-15A / dm 2 The forward pulse width of the first section in the pulse electroplating is 60-80ms, the reverse pulse width of the first section in the pulse electroplating is 2-5ms, the forward pulse of the first section in the pulse electroplating is followed by a pause of 0.1-0.6ms before a reverse pulse is applied, and the reverse pulse of the first section in the pulse electroplating is followed by a pause of 0.1-0.3ms before a forward pulse is applied.
3. An environmentally friendly pulse electroplating method according to claim 1, characterized in that: The forward pulse current density of the second stage of the pulse electroplating is 9-12A / dm 2 The reverse pulse current density of the second stage of the pulse electroplating is 17-20A / dm 2 The forward pulse width of the second section in the pulse electroplating is 100-200ms, the reverse pulse width of the second section in the pulse electroplating is 6-8ms, the forward pulse of the second section in the pulse electroplating is followed by a pause of 0.3-0.8ms, and then a reverse pulse is applied, the reverse pulse of the second section in the pulse electroplating is followed by a pause of 0.4-0.5ms, and then a forward pulse is applied.
4. An environmentally friendly pulse electroplating method according to claim 1, characterized in that: The forward pulse current density of the third stage in the pulse electroplating is 15-19A / dm 2 The reverse pulse current density of the third section in the pulse electroplating is 22-25A / dm 2 ; The forward pulse width of the third section in the pulse electroplating is 50-80ms, the reverse pulse width of the third section in the pulse electroplating is 3-5ms, the forward pulse of the third section in the pulse electroplating is followed by a pause of 0.1-0.3ms, and then a reverse pulse is applied, the reverse pulse of the third section in the pulse electroplating is followed by a pause of 0.5-0.7ms, and then a forward pulse is applied.
5. An environmentally friendly pulse electroplating method according to claim 1, characterized in that: The environmentally friendly electroplating solution is an environmentally friendly nickel electroplating solution, which includes the following components in mass concentrations: nickel salt 70-120g / L, boric acid 40-50g / L, composite brightener 30-40mg / L, composite anti-pinhole agent 15-20mg / L, composite dispersant 40-50mg / L, composite leveling agent 50-60mg / L, the balance is deionized water, and the plating solution temperature is 50-55°C.
6. An environmentally friendly pulse electroplating method according to claim 5, characterized in that: The nickel salt is composed of nickel chloride and nickel sulfamate, and the mass concentration ratio of the two when used is 1:
3.
7. An environmentally friendly pulse electroplating method according to claim 5, characterized in that: The composite brightener is composed of L-alanine benzyl p-toluenesulfonate and sodium propargyl sulfonate in a mass ratio of 3:
2.
8. An environmentally friendly pulse electroplating method according to claim 5, characterized in that: The composite leveler is composed of 4-(N-ethyl-N-hydroxyethyl)-2-methylphenylenediamine sulfate, 2-(4-bromo-1H-pyrazol-1-yl)pyrimidine and 4-pyrrolidin-1-ylpiperidine dihydrochloride in a mass ratio of 3:2:
3.
9. An environmentally friendly pulse electroplating method according to claim 5, characterized in that: The composite anti-pinhole agent is composed of L-thioproline and p-amino-N,N-diethylaniline sulfate in a mass ratio of 2:
3.
10. An environmentally friendly pulse electroplating method according to claim 5, characterized in that: The composite dispersant is composed of 3-[[(benzylthio)thiocarbonyl]thio]propionic acid and isomeric tridecanol polyoxyethylene ether in a mass ratio of 5:1.