Electrolytic corrosion resistant charging interface and electroplating method thereof

Abstract

The invention relates to the technical field of metal surface treatment, and particularly discloses an electrolytic corrosion resistant coating of a charging interface, which sequentially comprises a palladium coating, a nickel-phosphorus-nano titanium dioxide composite coating and a platinum-fluorine alloy coating from inside to outside from a base material, the electrolytic corrosion resistance is effectively improved through the specific plating layer structural design, and the performance is further optimized by optimizing the thickness range of each plating layer. Meanwhile, the invention discloses an electrolytic corrosion-resistant charging interface, and the surface of the charging interface is provided with the coating so as to prolong the service life. In addition, the invention further provides a corresponding electroplating method, through pre-plating treatment, layered electroplating and post-treatment, a specific etching solution, an activating agent and a plating solution are used, the quality and performance of a plating layer are ensured, and efficient production is achieved. According to the electrolytic corrosion resistant charging interface, the electrolytic corrosion resistance is remarkably enhanced, and the service life of the charging interface is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of metal surface treatment, and in particular to a charging interface resistant to electrolytic corrosion and an electroplating method thereof. Background Art

[0002] In modern electronic devices, the charging interface is a key component to ensure the normal operation and continuous power supply of the device. With the changes in people's lifestyles and the increasing diversification of electronic device usage scenarios, the charging interface is often exposed to various complex environments, and liquid media such as sweat and salt water are corroding it more and more frequently. Sweat is rich in various electrolyte components such as sodium chloride, urea, and lactic acid, and salt water directly provides a highly conductive electrolyte environment. When these liquid media come into contact with the charging interface, an electrolyte solution is formed on its surface, which triggers an electrochemical reaction and leads to the occurrence of electrolytic corrosion. The existing charging interface electroplating protective layer shows obvious lack of protection when facing the electrolytic corrosion problem caused by the intrusion of these liquid media, which seriously affects the reliability and service life of the charging interface.

[0003] Existing electroplated protective layers are unable to effectively prevent liquid media from contacting the metal substrate of the charging interface, failing to inhibit the progression of electrolytic corrosion. Particularly at the joints and gaps of the charging interface, due to the unique geometry and stress concentration, liquid media are more likely to accumulate and trigger electrolytic corrosion. Once corrosion occurs, defects such as rust and pits will appear on the interface surface, reducing the interface's conductivity and increasing contact resistance. This not only affects charging efficiency but can also cause safety issues such as overheating and sparks, significantly reducing the reliability and service life of the connector.

[0004] To solve this problem, existing charging interfaces initially introduced rhodium-ruthenium plating to improve the electrolytic corrosion resistance of the charging interface. However, as the price of rhodium continues to rise, the cost of using rhodium-ruthenium plating is too high. To solve this problem, a relatively low-cost composite-plated charging interface was subsequently introduced on the market. This composite plating often uses more than five plating layers, such as copper, nickel, nickel-tungsten, gold, silver, palladium-nickel, platinum, platinum-ruthenium, etc., to improve the electrolytic corrosion resistance through the combination of multiple plating layers. However, the actual electrolytic corrosion resistance of this plating layer is not as good as expected. The multi-layer composite structure makes it difficult to form a uniform plating layer. The electroplating production line design is complex, the process flow is very long, and industrial implementation is very difficult.

[0005] Regarding the above-mentioned related technologies, the inventors believe that the existing electroplating protective layer has many problems that need to be solved in preventing electrolytic corrosion of the charging interface caused by the intrusion of liquid media. A new electroplating method is urgently needed to improve the corrosion resistance of the charging interface in such complex environments, thereby improving the reliability and service life of the connector. Summary of the Invention

[0006] In order to solve the technical defects of the prior art, the present application provides a charging interface that is resistant to electrolytic corrosion and an electroplating method thereof.

[0007] In the first aspect, the present application provides a coating for a charging interface that is resistant to electrolytic corrosion, adopting the following technical solution: a coating for a charging interface that is resistant to electrolytic corrosion, the coating comprising an inner layer, an intermediate layer and a hydrophobic outer layer from the inside to the outside of the charging interface substrate; the inner layer is a palladium coating, the intermediate layer is a nickel-phosphorus-nano-titanium dioxide composite coating, and the hydrophobic outer layer is a platinum-fluorine alloy coating.

[0008] By adopting the above-mentioned technical solution, the coating is sequentially arranged from the inside out on the charging interface substrate, comprising a palladium coating, a nickel-phosphorus-nano-titanium dioxide composite coating, and a platinum-fluorine alloy hydrophobic outer layer, forming a multi-layered synergistic protection system. The inner palladium coating utilizes its chemical stability and catalytic activity to initially block the liquid medium and promote corrosion inhibition. The middle nickel-phosphorus-nano-titanium dioxide composite coating improves corrosion resistance by enhancing hardness and wear resistance and forming a phosphate protective film. The nano-titanium dioxide also has photocatalytic self-cleaning functions. The hydrophobic outer platinum-fluorine alloy achieves super-hydrophobicity due to its micro-nano rough structure and the low surface energy of fluorine, reducing contact with the liquid medium. This coating design can effectively improve the corrosion resistance of the charging interface in complex environments, enhance the adhesion of the coating to the substrate, ensure uniform deposition of the coating on specific parts of the interface, impart super-hydrophobic self-cleaning properties to the surface, and extend the service life of the charging interface. It also offers cost-effectiveness, good compatibility, and environmental protection.

[0009] Preferably, the palladium plating layer has a thickness of 3-5 μm.

[0010] By adopting the above technical solution, the thickness of the palladium coating is controlled at 3-5μm, which can ensure that it forms a good bonding force with the metal substrate. It can not only play the role of initial protection and promote corrosion inhibition reaction by virtue of the chemical stability and catalytic activity of palladium, but also will not affect the subsequent coating deposition and overall flexibility due to excessive thickness. It lays a reliable foundation for the coating system while blocking the intrusion of liquid media.

[0011] Preferably, the thickness of the nickel-phosphorus-nano-titanium dioxide composite coating is 0.5-8 μm.

[0012] By adopting this technical solution, the nickel-phosphorus-nano-titanium dioxide composite coating thickness is set at 0.5-8μm, meeting the coating performance requirements of different usage scenarios. At a thickness of 0.5μm, the nano-titanium dioxide and nickel-phosphorus alloy still enhance hardness, wear resistance, and corrosion resistance, while also exerting a photocatalytic self-cleaning effect. At a thickness of 8μm, it can fully block corrosive media and buffer stress in harsh environments, ensuring a good bond with the bottom and top coatings, strengthening the overall protective structure.

[0013] Preferably, the thickness of the platinum-fluorine alloy coating is 0.3-5 μm.

[0014] By adopting the above technical solution, the thickness of the platinum-fluorine alloy coating is 0.3-5μm, which can not only ensure that the fluorine element exerts its low surface energy characteristics, combined with the micro-nano rough structure to achieve a super-hydrophobic effect, and enhance the protection ability with the help of the corrosion resistance of platinum, but also further stabilize the super-hydrophobic structure at a thickness of 5μm, enhance the overall protection performance, and will not excessively increase costs or cause a significant decrease in flexibility, thereby achieving a balance between protection performance and economy.

[0015] In a second aspect, the present application provides a charging interface that is resistant to electrolytic corrosion, employing the following technical solutions: A charging interface resistant to electrolytic corrosion, the surface of which is provided with the above-mentioned plating layer.

[0016] In a third aspect, the present application provides a method for electroplating a charging interface that is resistant to electrolytic corrosion, employing the following technical solutions: A method for electroplating a charging interface resistant to electrolytic corrosion comprises the following steps: (1) performing pre-plating treatment on the charging interface, wherein the pre-plating treatment includes degreasing, etching, and activation; (2) Placing the charging interface after pre-plating treatment in an inner layer plating solution for electroplating, then in an intermediate layer plating solution for electroplating, and finally in a hydrophobic outer layer plating solution for electroplating to obtain a plated charging interface; the inner layer plating solution is used for electroplating a palladium plating layer, the intermediate layer plating solution is used for electroplating a nickel-phosphorus-nano-titanium dioxide composite plating layer, and the hydrophobic outer layer plating solution is used for electroplating a platinum-fluorine alloy plating layer; (3) The electroplated charging interface is washed and dried to obtain a product.

[0017] By adopting the above technical solution, this electroplating method can form a three-layer composite coating on the surface of the charging port, and each layer works together to form a highly effective protection system. The inner palladium coating blocks liquid media with its chemical stability, and its catalytic activity also promotes corrosion inhibition reactions. The middle nickel-phosphorus-nano-titanium dioxide composite coating improves corrosion resistance by enhancing hardness and wear resistance. When phosphorus corrodes, it forms a phosphate protective film, and the nano-titanium dioxide also has photocatalytic self-cleaning functions. The hydrophobic outer platinum-fluorine alloy layer achieves super-hydrophobicity through its micro-nano rough structure combined with the low surface energy of fluorine, reducing contact with liquid media, while the corrosion resistance of platinum maintains long-term protection.

[0018] Preferably, the etching solution used in the etching and activation includes sodium hydroxide, sodium carbonate and alkylphenol polyoxyethylene ether-10; the activator used includes palladium chloride and hydrochloric acid.

[0019] By adopting the above technical solution, sodium hydroxide and sodium carbonate in the etching solution can effectively remove the oxide film on the surface of the charging interface. Alkylphenol polyoxyethylene ether-10 as a surfactant can enhance the wettability of the etching solution, make the interface surface micro-roughened, and increase the surface area; the acidic system formed by palladium chloride and hydrochloric acid in the activator can allow active palladium atoms to be adsorbed on the substrate surface, promote subsequent metal ion reduction deposition, provide a clean and highly active substrate for the coating, and significantly improve the mechanical bite ability and bonding strength between the coating and the substrate.

[0020] Preferably, the inner layer plating solution includes palladium chloride, ammonium chloride and aminosulfonic acid.

[0021] By adopting the above technical solution, palladium chloride in the inner plating solution is used as the main salt to provide palladium ions, ammonium chloride is used as a conductive salt to maintain the conductivity of the plating solution, and aminosulfonic acid improves the crystallization of the coating. Under the synergistic effect of the three, a dense and uniform palladium coating can be formed on the surface of the charging interface. The chemical stability of palladium is used to preliminarily block the intrusion of liquid media, and its catalytic activity can also promote the generation of corrosion-inhibiting substances, thereby building an initial protective barrier for the overall plating system and improving the ability to resist electrolytic corrosion.

[0022] Preferably, the intermediate layer plating solution includes nickel sulfate, sodium hypophosphite and nano-titanium dioxide particles.

[0023] By employing this technical solution, nickel sulfate and sodium hypophosphite form a nickel-phosphorus alloy matrix in the intermediate plating solution, within which nano-titanium dioxide particles are evenly dispersed. After pulse electroplating, a composite coating with exceptional hardness, wear resistance, and corrosion resistance is formed on the palladium layer. The nickel-phosphorus alloy provides foundational strength, while the nano-titanium dioxide not only enhances the coating's density but also provides a photocatalytic self-cleaning effect. Furthermore, the phosphorus forms a protective phosphate film when corroded, further enhancing corrosion resistance.

[0024] Preferably, the hydrophobic outer layer plating solution comprises chloroplatinic acid, a fluorine-containing surfactant, potassium chloride and sodium saccharin.

[0025] By adopting the above technical solution, chloroplatinic acid in the hydrophobic outer layer plating solution provides platinum ions, fluorinated surfactants impart low surface energy properties, potassium chloride acts as a conductive salt to ensure the conductivity of the plating solution, and sodium saccharin improves the gloss of the coating. Under the auxiliary electroplating of a rotating disk electrode, a micro-nano rough structure can be formed on the surface, which cooperates with the fluorine element to achieve a super-hydrophobic effect, making it difficult for liquid media to adhere, reducing the contact area and time with the coating, and reducing the probability of electrolytic corrosion from the source. At the same time, the corrosion resistance of platinum can maintain the long-term protective performance of the coating.

[0026] In summary, this application has the following beneficial effects: 1. This electroplating method utilizes a three-layer structure design consisting of an inner palladium coating, an intermediate nickel-phosphorus-nano-titanium dioxide composite coating, and an outer platinum-fluorine alloy hydrophobic coating to form a multi-dimensional protection system. The inner palladium coating utilizes its chemical stability to initially block liquid media, and its catalytic activity promotes corrosion inhibition. The intermediate layer, through the composite action of nickel-phosphorus alloy and nano-titanium dioxide, enhances the coating's hardness and wear resistance. At the same time, phosphorus forms a protective film in corrosive environments. The outer platinum-fluorine alloy layer uses super-hydrophobic properties to reduce contact with media. The corrosion resistance of platinum and the low surface energy of fluorine work synergistically to reduce the risk of electrolytic corrosion at the source, achieving long-term protection for the charging port.

[0027] 2. The degreasing, etching, and activation processes in the pre-plating process significantly improve the bonding strength between the substrate and the coating through chemical reactions and surface roughening. Pulse plating and rotating disk electrode assistance are used in the electroplating process to ensure that the coating is evenly deposited in complex areas such as the joints and gaps of the charging interface, avoiding the problem of weak local protection. In addition, the precise ratio of the components of each layer of the plating solution (such as the palladium chloride and ammonium chloride system for palladium plating, and the combination of chloroplatinic acid and fluorinated surfactants for hydrophobic coating) ensures the performance of the coating while taking into account process stability and material cost control, making this method suitable for a variety of charging interface types and having good industrial application compatibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 : The plating structure diagram of the charging interface of the present invention; Among them, 1 is the charging interface substrate, 2 is the inner layer, 3 is the middle layer, and 4 is the hydrophobic outer layer. DETAILED DESCRIPTION

[0029] The present application is further described in detail below with reference to the embodiments.

[0030] The raw materials, consumables and instruments involved in this embodiment are all conventional commercially available products.

[0031] The present invention provides an electroplating method for a charging interface, and the specific steps are as follows: 1. Pre-plating treatment Degreasing: Place the charging port in an organic solvent and use ultrasonic cleaning. The ultrasonic cleaning time is set to 10-15 minutes, and the ultrasonic power is set to 200-300 watts. Organic solvents have good solubility and can effectively dissolve and remove oil, grease, and various organic contaminants attached to the surface of the charging port, thereby creating a clean surface environment for the subsequent electroplating process. The organic solvent can be selected from acetone, isopropyl alcohol, ethanol, gasoline, and kerosene.

[0032] Etching and Activation: After degreasing, remove the charging port and rinse thoroughly with deionized water. Next, place it in an alkaline etchant consisting of sodium hydroxide (15-25 g / L), sodium carbonate (25-35 g / L), and OP-10 (alkylphenol polyoxyethylene ether-10) surfactant (3-5 g / L). Soak for 10-15 minutes at 65°C. The alkaline etchant deeply cleans the surface of the charging port while also micro-roughening it and significantly increasing the surface area. This process significantly improves the mechanical bond between the coating and the substrate, laying the foundation for a secure adhesion of the coating. After the etching process, rinse again with deionized water. Next, immerse the charging port in an activation solution containing 1-2 g / L palladium chloride and 5-10% (volume fraction) hydrochloric acid for 6-10 minutes. During this process, active palladium atoms will be adsorbed on the surface of the substrate. These active palladium atoms can effectively promote the subsequent reduction deposition of metal ions and further optimize the electroplating effect.

[0033] 2. Electroplating treatment (1) Inner layer plating Bath Preparation: Prepare the plating solution with a palladium chloride concentration of 16-20g / L, ammonium chloride concentration of 55-65g / L, and aminosulfonic acid concentration of 0.8-1.2g / L. First, slowly dissolve the palladium chloride in an appropriate amount of deionized water. While stirring continuously, add the ammonium chloride and aminosulfonic acid in sequence, maintaining stirring until completely dissolved to ensure uniform composition of the bath. A controlled stirring speed of 200-300 rpm will help thoroughly mix the components.

[0034] Electroplating process: Place the pre-treated charging interface into the plating solution and use DC electroplating method for electroplating. The current density is set at 0.5-0.7A / dm 2 , the electroplating temperature is maintained at 35-40℃. The electroplating time is flexibly adjusted within the range of 20-30min according to the desired coating thickness. During the electroplating period, the bath temperature and current density must be closely monitored to keep them stable near the set values. The bath temperature is allowed to fluctuate within a range of 2℃, and the current density fluctuation range is controlled within 0.05A / dm 2 , thereby ensuring that the palladium coating can be evenly and densely deposited on the surface of the charging interface substrate, and the coating thickness is controlled at 3-5μm. At the beginning of electroplating, the current density remains relatively stable. As the electroplating time progresses, the current density is fine-tuned with the help of data feedback from real-time coating thickness monitoring equipment. For example, when it is monitored that the coating thickness is growing slightly faster than expected, the current density is appropriately reduced; conversely, if the coating thickness grows too slowly, the current density is appropriately increased to ensure that the final palladium coating thickness falls precisely within the target range.

[0035] Pure palladium plating is selected as the inner layer, taking advantage of palladium's excellent chemical stability, corrosion resistance and catalytic activity.

[0036] (2) Intermediate layer electroplating Bath Preparation and Pretreatment: First, nano-titanium dioxide particles are added to deionized water and pretreated using ultrasonic equipment. The ultrasonic power is set at 300 to 400W and the treatment time is 30 to 50 minutes to ensure that the nano-titanium dioxide particles are fully dispersed.

[0037] Subsequently, nickel sulfate (at a concentration range of 240 to 280 g / L) and sodium hypophosphite (at a concentration range of 30 to 40 g / L) are added to the mixture while stirring. Stirring is continued until they are completely dissolved, thereby forming a plating solution with uniform composition. During the stirring process, the stirring speed can be controlled at 300 to 500 r / min to promote thorough mixing of the ingredients.

[0038] In the subsequent electroplating process, the plating solution is continuously stirred by a magnetic stirrer, and the rotation speed is maintained at 350 to 450 r / min, so as to ensure that the nano-titanium dioxide particles are always in a good state of uniform dispersion in the plating solution.

[0039] Electroplating process: Pulse electroplating is used to immerse the charging interface with the inner layer electroplated into the electroplating solution. The pulse current density is set at 1.4 to 1.8A / dm 2 , the pulse frequency is set to 500 to 700 Hz, the duty cycle is controlled at 40% to 50%, the electroplating temperature is maintained at 45 to 55 ° C, and the electroplating time is adjusted in the range of 5 to 60 min according to the required coating thickness.

[0040] By precisely controlling these parameters, nano-titanium dioxide particles are co-deposited with nickel-phosphorus alloy to form a uniform, dense and high-performance nickel-phosphorus-nano-titanium dioxide composite coating on the inner palladium coating, with a thickness controlled at 0.5 to 8 μm.

[0041] During the electroplating process, the coating thickness can be adjusted by controlling the pulse parameters and plating time. When the target thickness is close to the lower limit of 0.5μm, deposition is carried out at a moderate pulse current density and frequency in the early stage of electroplating. The current density and frequency are gradually reduced in the later stage to ensure that the coating is uniform and reaches the target thickness. When the target thickness is close to the upper limit of 8μm, the coating is deposited rapidly at a higher pulse current density. As the thickness increases, the pulse parameters are gradually fine-tuned, such as reducing the current density, adjusting the duty cycle and frequency, to ensure the coating quality and thickness uniformity.

[0042] This layer enhances the hardness, wear resistance and corrosion resistance of the coating, buffers stress, and forms a phosphate protective film when corroded. Nano-titanium dioxide also has a photocatalytic self-cleaning effect.

[0043] (3) Preparation of hydrophobic outer layer electroplating solution: Add chloroplatinic acid (concentration controlled at 10-14 g / L), fluorinated surfactant (ammonium perfluorooctane sulfonate, concentration at 6-10 g / L), potassium chloride (concentration at 45-55 g / L), and sodium saccharin (concentration at 1-1.4 g / L) to deionized water in this order. Dissolve them fully under continuous stirring to prepare a uniform plating solution. The stirring speed can be set at 200-300 r / min to ensure that the components are evenly mixed.

[0044] Electroplating process: A rotating disk electrode device is used to assist electroplating. The charging interface after the intermediate layer electroplating is used as an electrode and installed on the rotating disk electrode. The current density is set at 0.7-0.9A / dm 2 The electroplating temperature is maintained at 50-60°C, and the disc speed is set at 450-550 rpm. The electroplating time is flexibly adjusted within the range of 3-30 minutes based on actual needs. The goal is to form a micro-nanoscale rough structure on the surface of the coating, combined with the low surface energy of fluorine, to achieve super-hydrophobic properties, while also controlling the coating thickness to 0.3-5μm.

[0045] In terms of controlling the coating thickness, it is mainly achieved by adjusting parameters such as the electroplating time and the rotation speed of the rotating disk electrode. In the early stage of electroplating, the disk speed is adjusted to a higher level, such as 500-550r / min, to promote uniform distribution of the plating solution and accelerate the deposition rate of the coating. When the coating thickness approaches the lower limit of 0.3μm, the speed is appropriately reduced to 450-500r / min, and the current density is fine-tuned to reduce it to 0.7-0.8A / dm 2 , to ensure that the coating thickness reaches the lower limit accurately. If the target thickness is close to the upper limit of 5μm, as the electroplating progresses, gradually reduce the speed to 450-500r / min and reduce the current density to 0.7-0.8A / dm 2 , so that the coating is evenly thickened, eventually reaching the target thickness, while maintaining good superhydrophobic properties and overall quality.

[0046] 3. Post-plating cleaning: After the electroplating process is complete, the charging interface requires a thorough cleaning. Rinse the charging interface with ample deionized water to thoroughly remove any residual plating solution and impurities on its surface, ensuring a clean surface and paving the way for subsequent steps. During the rinsing process, adjust the water pressure appropriately, maintaining it at 0.2-0.3 MPa to ensure that the water fully contacts all parts of the charging interface and ensure a thorough cleaning.

[0047] Drying: After cleaning, place the charging port in an oven to dry. Set the oven temperature to 80-90°C and the drying time to 20-30 minutes. This temperature and drying time ensures complete evaporation of moisture from the charging port's surface, resulting in a thorough drying process. This effectively prevents corrosion caused by residual moisture and improves the durability and stability of the charging port. Before placing it in the oven, place the charging port on a stand to fully expose all surfaces, allowing for moisture dissipation and ensuring even drying.

[0048] like Figure 1 As shown, a coating structure of a charging interface that is resistant to electrolytic corrosion is provided. The coating is composed of an inner layer 2, an intermediate layer 3 and a hydrophobic outer layer 4 from the inside to the outside of the charging interface substrate 1.

[0049] In order to verify the performance of the present invention, 90 charging interfaces with the same size, shape and material were selected from the charging interfaces produced in the same batch and divided into 9 groups with 10 interfaces in each group as the substrates of Examples 1-4 and Comparative Examples 1-5.

[0050] Example 1 The coating of the electrolytic corrosion-resistant charging interface of this embodiment includes an inner layer 2, an intermediate layer 3 and a hydrophobic outer layer 4, wherein the thickness of the inner layer 2 is 3 μm, the thickness of the intermediate layer 3 is 0.5 μm, and the thickness of the hydrophobic outer layer 4 is 0.3 μm.

[0051] 1. Degreasing before plating: Place the charging port in kerosene, soak for 10 minutes, and perform ultrasonic assisted cleaning with an ultrasonic power of 200W and a frequency of 30kHz for 10 minutes.

[0052] Etching and activation: put into alkaline etching solution containing 20g / L sodium hydroxide, 30g / L sodium carbonate, and 4g / L OP-10 surfactant, soak at 60℃ for 10min, rinse with deionized water, and immerse in activation solution containing 0.8g / L palladium chloride and 7% volume fraction hydrochloric acid for 6min.

[0053] 2. Preparation of inner layer electroplating solution: palladium chloride concentration 16g / L, ammonium chloride concentration 55g / L, aminosulfonic acid concentration 0.8g / L. Slowly dissolve palladium chloride in an appropriate amount of deionized water, then add ammonium chloride and aminosulfonic acid in sequence while stirring at 200r / min until completely dissolved.

[0054] Electroplating process: DC electroplating, current density 0.5A / dm 2 , electroplating temperature 35℃, electroplating time 20min, coating thickness 3μm.

[0055] 3. Electroplating intermediate layer Bath preparation and pretreatment: Nano-titanium dioxide particles were ultrasonically pretreated at 300W for 30 minutes. Nickel sulfate concentration was 240g / L, and sodium hypophosphite concentration was 30g / L. Stirring was performed at 300r / min until completely dissolved. A magnetic stirrer was used to stir the bath at 350r / min.

[0056] Electroplating process: pulse electroplating, pulse current density 1.4A / dm 2 , pulse frequency 500Hz, duty cycle 40%, electroplating temperature 45℃, electroplating time 5min, coating thickness 0.5μm.

[0057] 4. Preparation of electroplating outer layer plating solution: chloroplatinic acid concentration 10g / L, ammonium perfluorooctane sulfonate concentration 6g / L, potassium chloride concentration 45g / L, saccharin sodium concentration 1g / L, stirring speed 200r / min until uniformly dissolved.

[0058] Electroplating process: Rotating disk electrode assisted electroplating, current density 0.7A / dm 2 , electroplating temperature 50℃, disk speed 450r / min, electroplating time 3min, coating thickness 0.3μm.

[0059] 5. Post-plating treatment Cleaning: Rinse with deionized water, water pressure 0.2MPa.

[0060] Drying: oven dried at 80°C for 20 min.

[0061] Example 2 The coating of the electrolytic corrosion-resistant charging interface of this embodiment includes an inner layer 2, an intermediate layer 3 and a hydrophobic outer layer 4, wherein the thickness of the inner layer 2 is 4 μm, the thickness of the intermediate layer 3 is 4 μm, and the thickness of the hydrophobic outer layer 4 is 2.5 μm.

[0062] 1. Degreasing before plating: Place the charging interface in an ethanol solution (volume fraction 70%) and perform ultrasonic cleaning with an ultrasonic power of 200W and a frequency of 35kHz for 10 minutes.

[0063] Etching and activation: Place in alkaline etching solution containing 25g / L sodium hydroxide, 35g / L sodium carbonate, and 5g / L OP-10 surfactant, soak at 65°C for 12 minutes, rinse with deionized water, and then immerse in activation solution containing 1g / L palladium chloride and 8% volume fraction hydrochloric acid for 8 minutes.

[0064] 2. Preparation of inner layer electroplating solution: palladium chloride concentration 18g / L, ammonium chloride concentration 60g / L, aminosulfonic acid concentration 1g / L. Slowly dissolve palladium chloride in an appropriate amount of deionized water, then add ammonium chloride and aminosulfonic acid in sequence while stirring at 250r / min until completely dissolved.

[0065] Electroplating process: DC electroplating, current density 0.6A / dm 2 , electroplating temperature 38℃, electroplating time 25min, coating thickness 4μm.

[0066] 3. Electroplating intermediate layer Bath preparation and pretreatment: Nano-titanium dioxide particles were ultrasonically pretreated at 350W for 40 minutes. Nickel sulfate concentration was 260g / L, and sodium hypophosphite concentration was 35g / L. Stirring was performed at 400 rpm until completely dissolved. A magnetic stirrer was used to stir the bath at 400 rpm.

[0067] Electroplating process: pulse electroplating, pulse current density 1.6A / dm 2 , pulse frequency 600Hz, duty cycle 45%, electroplating temperature 50℃, electroplating time 30min, and coating thickness 4μm.

[0068] 4. Preparation of electroplating outer layer plating solution: chloroplatinic acid concentration 12g / L, ammonium perfluorooctane sulfonate concentration 8g / L, potassium chloride concentration 50g / L, saccharin sodium concentration 1.2g / L, stirring speed 250r / min until uniformly dissolved.

[0069] Electroplating process: Rotating disk electrode assisted electroplating, current density 0.8A / dm 2 , electroplating temperature 55℃, disc speed 500r / min, electroplating time 15min, coating thickness 2.5μm.

[0070] 5. Post-plating treatment Cleaning: rinse with deionized water, water pressure 0.25MPa.

[0071] Drying: oven dried at 85°C for 25 min.

[0072] Example 3 The coating of the electrolytic corrosion-resistant charging interface of this embodiment includes an inner layer 2, an intermediate layer 3 and a hydrophobic outer layer 4, wherein the thickness of the inner layer 2 is 5 μm, the thickness of the intermediate layer 3 is 8 μm, and the thickness of the hydrophobic outer layer 4 is 5 μm.

[0073] 1. Degreasing before plating: Place the charging interface in an isopropyl alcohol solution (80% by volume) and perform ultrasonic cleaning with an ultrasonic power of 300W and a frequency of 45kHz for 15 minutes.

[0074] Etching and activation: Place in alkaline etching solution containing 30g / L sodium hydroxide, 40g / L sodium carbonate, and 6g / L OP-10 surfactant, soak at 70°C for 15min, rinse with deionized water, and immerse in activation solution containing 1.2g / L palladium chloride and 9% volume fraction hydrochloric acid for 10min.

[0075] 2. Preparation of inner layer electroplating solution: palladium chloride concentration 20g / L, ammonium chloride concentration 65g / L, aminosulfonic acid concentration 1.2g / L. Slowly dissolve palladium chloride in an appropriate amount of deionized water, then add ammonium chloride and aminosulfonic acid in sequence while stirring at 300r / min until completely dissolved.

[0076] Electroplating process: DC electroplating, current density 0.7A / dm 2 , electroplating temperature 40℃, electroplating time 30min, coating thickness 5μm.

[0077] 3. Electroplating intermediate layer Bath preparation and pretreatment: Nano-titanium dioxide particles were ultrasonically pretreated at 400W for 50 minutes. Nickel sulfate concentration was 280g / L, and sodium hypophosphite concentration was 40g / L. Stirring was performed at 500r / min until completely dissolved. A magnetic stirrer was used to stir the bath at 450r / min.

[0078] Electroplating process: pulse electroplating, pulse current density 1.8A / dm 2 , pulse frequency 700Hz, duty cycle 50%, electroplating temperature 55℃, electroplating time 60min, and coating thickness 8μm.

[0079] 4. Preparation of electroplating outer layer plating solution: chloroplatinic acid concentration 14g / L, ammonium perfluorooctane sulfonate concentration 10g / L, potassium chloride concentration 55g / L, saccharin sodium concentration 1.4g / L, stirring speed 300r / min until uniformly dissolved.

[0080] Electroplating process: Rotating disk electrode assisted electroplating, current density 0.9A / dm 2 , electroplating temperature 60℃, disk speed 550r / min, electroplating time 30min, coating thickness 5μm.

[0081] 5. Post-plating treatment Cleaning: Rinse with deionized water, water pressure 0.3MPa.

[0082] Drying: oven drying at 90°C for 30 min.

[0083] Example 4 The coating of the electrolytic corrosion-resistant charging interface of this embodiment includes an inner layer 2, an intermediate layer 3 and a hydrophobic outer layer 4, wherein the thickness of the inner layer 2 is 3.5 μm, the thickness of the intermediate layer 3 is 2 μm, and the thickness of the hydrophobic outer layer 4 is 1 μm.

[0084] 1. Degreasing before plating: Place the charging interface in trichloroethylene solution (volume fraction 85%), soak for 12 minutes, and perform ultrasonic assisted cleaning with an ultrasonic power of 250W and a frequency of 40kHz for 12 minutes.

[0085] Etching and activation: Place in an alkaline etching solution containing 22 g / L sodium hydroxide, 32 g / L sodium carbonate, and 4.5 g / L OP-10 surfactant, soak at 62°C for 11 minutes, rinse with deionized water, and then immerse in an activation solution containing 0.9 g / L palladium chloride and 7.5% volume fraction hydrochloric acid for 7 minutes.

[0086] 2. Preparation of inner layer electroplating solution: palladium chloride concentration 17g / L, ammonium chloride concentration 58g / L, aminosulfonic acid concentration 0.9g / L. Slowly dissolve palladium chloride in an appropriate amount of deionized water, then add ammonium chloride and aminosulfonic acid in sequence while stirring at 220r / min until completely dissolved.

[0087] Electroplating process: DC electroplating, current density 0.55A / dm 2 , electroplating temperature 36℃, electroplating time 22min, coating thickness 3.5μm.

[0088] 3. Electroplating intermediate layer Bath preparation and pretreatment: Nano-titanium dioxide particles were ultrasonically pretreated at 320W for 35 minutes. Nickel sulfate concentration was 250g / L, and sodium hypophosphite concentration was 32g / L. Stirring was performed at 350r / min until completely dissolved. A magnetic stirrer was used to stir the bath at 370r / min.

[0089] Electroplating process: pulse electroplating, pulse current density 1.5A / dm 2 , pulse frequency 550Hz, duty cycle 42%, electroplating temperature 48℃, electroplating time 15min, and coating thickness 2μm.

[0090] 4. Preparation of electroplating outer layer plating solution: chloroplatinic acid concentration 11g / L, ammonium perfluorooctane sulfonate concentration 7g / L, potassium chloride concentration 48g / L, saccharin sodium concentration 1.1g / L, stirring speed 220r / min until uniformly dissolved.

[0091] Electroplating process: Rotating disk electrode assisted electroplating, current density 0.75A / dm 2 , electroplating temperature 52℃, disk speed 470r / min, electroplating time 8min, coating thickness 1μm.

[0092] 5. Post-plating treatment Cleaning: rinse with deionized water, water pressure 0.22MPa.

[0093] Drying: Oven drying at 82°C for 22 min.

[0094] In order to verify the anti-electrolytic corrosion effect of the coating of the present invention in practical applications, comparative examples 1-3 were set based on example 4.

[0095] Comparative Example 1 1. Pre-plating treatment: same as Example 4.

[0096] 2. Electroplating inner layer (replaced with traditional nickel plating) Preparation of plating solution: Add 250g / L nickel sulfate, 45g / L nickel chloride, and 40g / L boric acid into deionized water and stir until completely dissolved at a stirring speed of 220r / min.

[0097] Electroplating process: DC electroplating, current density 0.8A / dm 2 , electroplating temperature is 55℃, electroplating time is 25min, and coating thickness is controlled at 3.5μm.

[0098] 3. Electroplating intermediate layer: same as Example 4.

[0099] 4. Electroplating of hydrophobic outer layer: same as Example 4.

[0100] 5. Post-plating treatment: same as Example 4.

[0101] Comparative Example 2 1. Pre-plating treatment: same as Example 4.

[0102] 2. Electroplating inner layer: same as Example 4.

[0103] 3. Electroplating intermediate layer (replaced with pure nickel plating) Preparation of plating solution: Add 300g / L nickel sulfate, 10g / L sodium chloride, and 40g / L boric acid into deionized water, stir evenly at a stirring speed of 350r / min.

[0104] Electroplating process: DC electroplating, current density 1.2A / dm 2 , electroplating temperature is 60℃, electroplating time is 20min, and the coating thickness reaches 2μm.

[0105] 4. Electroplating of hydrophobic outer layer: same as Example 4.

[0106] 5. Post-plating treatment: same as Example 4.

[0107] Comparative Example 3 1. Pre-plating treatment: same as Example 4.

[0108] 2. Electroplating inner layer: same as Example 4.

[0109] 3. Electroplating intermediate layer: same as Example 4.

[0110] 4. Electroplating hydrophobic outer layer (replaced with ordinary hydrophobic plating) Preparation of plating solution: Dissolve 10g / L stearic acid and 5g / L paraffin in an appropriate amount of ethanol, stir evenly, and stir at a speed of 220r / min.

[0111] Electroplating process: Using the dip coating method, immerse the charging interface in the plating solution for 5 minutes, take it out and dry it at 60°C for 15 minutes to form a normal hydrophobic coating with a thickness of about 1μm.

[0112] 5. Post-plating treatment: same as Example 4.

[0113] In order to verify the performance difference between the coating of the present invention and the corrosion-resistant coating of the prior art, comparative examples 4 and 5 were set up, and both comparative examples 4 and 5 adopted the existing conventional electroplating technology.

[0114] Comparative Example 4 In comparative example 4, 5 layers of composite coatings are electroplated on the charging port, the first layer is a nickel coating with a thickness of 2 μm, the second layer is a copper coating with a thickness of 1.5 μm, the third layer is a silver coating with a thickness of 0.8 μm, the fourth layer is a palladium-nickel alloy coating with a thickness of 1 μm, and the fifth layer is a gold coating with a thickness of 0.5 μm.

[0115] Comparative Example 5 In comparative example 5, 7 layers of composite coatings are electroplated on the charging port. The first layer is a zinc coating with a thickness of 2.5 μm, the second layer is a nickel coating with a thickness of 2 μm, the third layer is a nickel-tungsten alloy coating with a thickness of 1.8 μm, the fourth layer is a chromium coating with a thickness of 1.2 μm, the fifth layer is a tin coating with a thickness of 1 μm, the sixth layer is a palladium coating with a thickness of 0.8 μm, and the seventh layer is a platinum-ruthenium alloy coating with a thickness of 0.5 μm.

[0116] Performance Testing The charging interfaces of Examples 1-4 and Comparative Examples 1-5 were tested in accordance with GB / T10125-2021 “Artificial atmosphere corrosion test salt spray test” standard.

[0117] Dissolve chemically pure or higher-purity sodium chloride in distilled or deionized water to prepare a 5% by mass sodium chloride solution. (The total content of heavy metals, including copper, nickel, and lead, in the sodium chloride must be controlled below 0.005% by mass.) Measure the pH of the solution with a potentiometer and adjust it by adding analytically pure hydrochloric acid or sodium hydroxide. Adjust the pH of the spray solution collected in the salt spray chamber to a range of 6.5-7.2 at 25°C ± 2°C. Secure the samples to the sample rack within the salt spray chamber, ensuring that the samples do not touch each other and that the salt spray settles evenly on the sample surface.

[0118] Open the salt spray test chamber, set the temperature to 35℃±2℃, and the spray pressure control to 98kPa, ensuring that the effective space of the salt spray chamber is 80cm 2The average hourly salt spray deposition rate collected over a horizontal area of ​​1.5 mL / h ± 0.5 mL / h was 1.5 mL / h. The test duration was set to three weeks, during which the test chamber was maintained in stable operation. The surface of the charging interface samples was regularly observed every hour, with the presence of corrosion spots exceeding 0.05 mm in diameter being the standard. If any corrosion spots were present, the time of their appearance was recorded. Each group of samples was tested three times, and the average value was taken as the test result. The test results are detailed in Table 1. Table 1 Salt spray test results sample Corrosion occurrence time / h Example 1 193 Example 2 287 Example 3 324 Example 4 243 Comparative Example 1 175 Comparative Example 2 203 Comparative Example 3 146 Comparative Example 4 95 Comparative Example 5 121 The corrosion occurrence time of Examples 1-4 is 193h, 287h, 324h and 243h respectively. Although the embodiments differ in specific coating parameters (such as plating solution composition, electroplating time, current density, etc.), they all show good corrosion resistance. This result shows that the coating system of the present invention is not a simple superposition of the coating performance of each layer, but the layers cooperate and work together to build a powerful corrosion-resistant protective barrier. The present invention uses a carefully designed three-layer composite coating structure. The inner palladium coating initially resists corrosion and promotes corrosion inhibition reaction by virtue of its chemical stability and catalytic activity; the middle layer nickel-phosphorus-nano titanium dioxide composite coating enhances hardness, wear resistance and forms a phosphate protective film to improve corrosion resistance; the hydrophobic outer layer platinum-fluorine alloy coating uses super-hydrophobicity to reduce contact with liquid media, and the synergistic effect of each layer greatly improves the corrosion resistance to liquid media.

[0119] Comparative Example 1: This comparative example only replaces the inner palladium coating of Example 4 with a traditional nickel coating, and the corrosion onset time is sharply reduced from 243h to 175h, which is shortened by 68h. This not only shows that the inner coating material has a significant impact on the overall corrosion resistance, but also highlights the synergy of the coating system of the present invention. The inner palladium coating plays a vital initial protective role in the entire system. Once replaced with a traditional nickel coating with weaker protective performance, the subsequent intermediate and outer coatings remain unchanged. However, due to insufficient protection of the inner layer, the corrosive medium is more likely to break through the defense line, thereby accelerating the corrosion of the entire coating system, causing the corrosion to occur significantly earlier. This shows that there is a close synergistic relationship between the inner coating of the present invention and the other coating layers, and the good protection of the inner layer is the basis for the other coating layers to fully play their role.

[0120] Comparative Example 2: When the intermediate layer of Example 4 is replaced with a pure nickel coating, the corrosion onset time is reduced from 243h to 203h, a reduction of 40h. The nano-titanium dioxide particles in the nickel-phosphorus-nano-titanium dioxide composite coating can fill the pores of the coating, enhance the density of the coating, and synergize with the nickel-phosphorus alloy to improve the barrier ability to corrosive media. After replacing with a pure nickel coating, due to the lack of this synergistic enhancement mechanism, even if the inner layer and the hydrophobic outer coating remain the same, the corrosive medium can more easily penetrate the intermediate layer, resulting in a decrease in overall corrosion resistance. This reflects the synergistic effect between the intermediate layer coating of the present invention and the inner layer and the hydrophobic outer coating. The special structure and composition of the intermediate layer play a key connecting role in maintaining the corrosion resistance of the entire coating system.

[0121] Comparative Example 3: In Comparative Example 3, the hydrophobic outer layer of Example 4 is replaced by an ordinary hydrophobic coating, and the corrosion onset time is significantly shortened from 243h to 146h, a reduction of 97h. The platinum-fluorine alloy hydrophobic coating can effectively prevent salt mist from adhering to and penetrating the surface due to its special micro-nano structure and the low surface energy of the fluorine element, and cooperates with the inner and middle layer coatings to build an efficient corrosion-resistant system. Ordinary hydrophobic coatings are far inferior to platinum-fluorine alloy hydrophobic coatings in terms of hydrophobicity and protective performance, and cannot form a good synergistic protection with the inner and middle layers, making it easier for salt mist to remain and cause corrosion, greatly shortening the corrosion onset time. This further proves that there is an indispensable synergistic effect between the hydrophobic outer layer coating of the present invention and other layer coatings, and the high-performance protection of the hydrophobic outer layer is crucial to improving the corrosion resistance of the entire coating system.

[0122] Comparative Examples 4 and 5: These two comparative examples used existing conventional electroplating technology to form multilayer composite coatings. The corrosion onset time was only 95 hours and 121 hours, respectively, significantly different from the corrosion onset time of the examples. This shows that the coating system formed by existing conventional electroplating technology does not achieve the same efficient synergistic effect between the layers as the present invention, and cannot effectively resist salt spray corrosion. However, the present invention, through the careful design of the coating materials, structure, and process, enables the mutual cooperation and complementary advantages of the coating layers, resulting in a significant synergistic effect, thus far surpassing the corrosion resistance of existing conventional electroplating technology.

[0123] In summary, through comparative analysis of the embodiments and comparative examples, it can be seen that there is a close and efficient synergistic effect between the layers of the coating system of the present invention. This synergistic effect enables the coating to have excellent corrosion resistance as a whole, which has obvious advantages over the existing technology and can better meet the strict requirements of actual application scenarios for the anti-electrolytic corrosion performance of the charging interface.

[0124] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A coating for a charging interface that resists electrolytic corrosion, characterized by: The coating includes an inner layer, an intermediate layer and a hydrophobic outer layer from the inside to the outside of the charging interface substrate; the inner layer is a palladium coating, the intermediate layer is a nickel-phosphorus-nano-titanium dioxide composite coating, and the hydrophobic outer layer is a platinum-fluorine alloy coating.

2. The electrolytic corrosion resistant charging interface plating according to claim 1, characterized in that: The thickness of the palladium plating layer is 3-5 μm.

3. The electrolytic corrosion resistant charging interface plating according to claim 1, characterized in that: The thickness of the nickel-phosphorus-nano titanium dioxide composite coating is 0.5-8 μm.

4. The electrolytic corrosion resistant charging interface plating according to claim 1, characterized in that: The thickness of the platinum-fluorine alloy coating is 0.3-5 μm.

5. A charging interface resistant to electrolytic corrosion, characterized by: The surface of the charging interface is provided with the coating according to any one of claims 1 to 4.

6. A method for electroplating a charging interface resistant to electrolytic corrosion, characterized in that: The steps include: (1) performing pre-plating treatment on the charging interface, wherein the pre-plating treatment includes degreasing, etching and activation; (2) Placing the charging interface after pre-plating treatment in an inner layer plating solution for electroplating, then electroplating in an intermediate layer plating solution, and finally electroplating in a hydrophobic outer layer plating solution to obtain a plated charging interface; the inner layer plating solution is used for electroplating a palladium plating layer, the intermediate layer plating solution is used for electroplating a nickel-phosphorus-nano-titanium dioxide composite plating layer, and the hydrophobic outer layer plating solution is used for electroplating a platinum-fluorine alloy plating layer; (3) The electroplated charging interface is washed and dried to obtain the product.

7. The electroplating method for a charging interface resistant to electrolytic corrosion according to claim 6, characterized in that: The etching solution used in the etching and activation includes sodium hydroxide, sodium carbonate and alkylphenol polyoxyethylene ether-10; the activating agent used includes palladium chloride and hydrochloric acid.

8. The electroplating method for a charging interface resistant to electrolytic corrosion according to claim 6, characterized in that: The inner layer plating solution comprises palladium chloride, ammonium chloride and aminosulfonic acid.

9. The electroplating method for a charging interface resistant to electrolytic corrosion according to claim 6, characterized in that: The intermediate layer plating solution comprises nickel sulfate, sodium hypophosphite and nano titanium dioxide particles.

10. The electroplating method for a charging interface resistant to electrolytic corrosion according to claim 6, characterized in that: The hydrophobic outer layer plating solution comprises chloroplatinic acid, a fluorine-containing surfactant, potassium chloride and sodium saccharin.

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