High-durability environment-friendly earphone charging terminal and electroplating method thereof

Abstract

The invention relates to the technical field of electronic component surface treatment, in particular to a high-durability environment-friendly earphone charging terminal and an electroplating method thereof. The high-durability environment-friendly earphone charging terminal comprises a non-nickel bottom plating layer, a composite environment-friendly protective layer and a hydrophobic nano coating, carrying out electrolytic deposition on a copper-tin alloy plating solution to obtain a copper-tin alloy bottom plating layer, wherein the copper-tin alloy plating solution comprises potassium pyrophosphate, copper sulfate, stannous mono-sulphate and modified Al2O3 nanoparticles; a composite environment-friendly protective layer is obtained through pulse current deposition of an organic-inorganic hybrid plating solution, and the organic-inorganic hybrid plating solution comprises propylene glycol methyl ether acetate, EP-828, KH-550 and surface modified carbon nanotubes; a plasma etching micro-nano structure PTFE coating is introduced into the hydrophobic nano coating; the prepared high-durability environment-friendly earphone charging terminal realizes the integrated protection effects of biosafety, high wear resistance, corrosion resistance and super-hydrophobicity.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic component surface treatment, and in particular to a highly durable and environmentally friendly earphone charging terminal and an electroplating method thereof. Background Art

[0002] Headphone charging terminals are core metal components that connect the headphone cable to the audio device interface. Typically made of alloys such as brass and phosphor bronze, they perform signal transmission, mechanical fastening, and electrical contact functions. To enhance terminal performance, a functional coating is formed on the terminal surface through electroplating. Electroplating protects the substrate from oxygen and moisture, extending service life. Plating with precious metals such as gold and silver reduces contact resistance, increases surface hardness and wear resistance, and reduces plug-in loss, improving welding performance and appearance. Common electroplating methods include nickel plating, gold plating, silver plating, and composite plating.

[0003] Although traditional electroplating technology has been widely used, the following problems still exist in the field of headphone charging terminals: (1) The existing headphone terminal electroplating process generally uses nickel-based plating, such as nickel plating + gold plating, which has the risk of nickel ion sensitization. The EU REACH regulation limits the nickel release rate to ≤0.5μg / cm 2 / week. (2) Although traditional epoxy resin coatings are corrosion-resistant, they have low hardness and poor wear resistance. In addition, conventional hydrophobic coatings (such as silicone oil modification) are not durable enough. After repeated plugging and unplugging, the interface between the coating and the substrate is prone to microcracks due to stress concentration, impurity adsorption or process fluctuations, resulting in coating peeling during plugging and unplugging, and reduced signal transmission stability; (3) Single functionality: Traditional single metal coatings are difficult to meet multiple requirements such as wear resistance, corrosion resistance, and low resistance. Multi-layer plating is complex and has poor interlayer bonding strength; (4) Uniformity control is difficult: The miniaturization of headphone charging terminals, such as the Type-C interface, poses challenges to the consistency of coating thickness in deep holes and narrow gaps, and is prone to edge effects.

[0004] In order to solve the problems of easy peeling of the headphone charging terminal plating, poor corrosion resistance, and the risk of allergies caused by nickel-based plating under frequent plugging and unplugging and sweat corrosion environment, the field urgently needs to develop a highly durable and environmentally friendly composite electroplating method for headphone charging terminals. Summary of the Invention

[0005] In response to the problems in the existing technology that the single organic coating on the headphone charging terminal has insufficient mechanical properties, poor adhesion between the hydrophobic function and the coating, and the nickel-based coating is prone to cause allergic risks, the present application provides a highly durable and environmentally friendly headphone charging terminal and its electroplating method, which is suitable for scenarios with strict biocompatibility requirements.

[0006] In a first aspect, the present application provides a highly durable and environmentally friendly earphone charging terminal, which adopts the following technical solutions: The present invention provides a highly durable and environmentally friendly earphone charging terminal formed by at least one coating, wherein the coating includes a non-nickel base plating layer, a composite environmentally friendly protective layer and a hydrophobic nano coating.

[0007] Preferably, the base material of the earphone charging terminal is any one of 316L stainless steel, H62 brass or C5191 phosphor bronze.

[0008] Preferably, the non-nickel base plating layer is obtained by electrolytically depositing a copper-tin alloy plating solution.

[0009] Preferably, the copper-tin alloy plating solution comprises the following raw materials by weight percentage: 12-15% potassium pyrophosphate, 0.8-1% copper sulfate, 0.3-0.5% stannous sulfate, 1-3% modified Al2O3 nanoparticles, and deionized water to make up the balance.

[0010] By adopting this approach, a copper-tin alloy plating solution replaces nickel plating, combined with silane-coupling-modified Al2O3 nanoparticles, not only eliminates the need for nickel but also enhances the hardness and wear resistance of the coating. The silane-coupling-modified Al2O3 nanoparticles specifically address the issues of nanoparticle agglomeration and adhesion to the metal substrate in the metal plating solution. The copper-tin alloy plating solution formulation eliminates toxic substances such as cyanide and lead, and potassium pyrophosphate, a complexing agent, is more environmentally friendly.

[0011] Preferably, the copper-tin alloy plating solution controls Cu 2+ 8-10g / L, Sn 2+ 3-5g / L.

[0012] Preferably, the modified Al2O3 nanoparticles in the copper-tin alloy plating solution are: the Al2O3 nanoparticles are added to a KH-550 ethanol solution, ultrasonically dispersed at 30-50kHz and 100W for 30 minutes, stirred at a constant temperature of 50-70°C for 1-2 hours, centrifuged at 8000-12000rpm for 10-20 minutes, washed with ethanol 3 times, and vacuum dried at 80°C to obtain Al2O3 nanoparticles modified with a silane coupling agent.

[0013] Preferably, in the copper-tin alloy plating solution, the mass ratio of modified Al2O3 nanoparticles:Al2O3 nanoparticles to KH-550 ethanol solution is 1:(9-11).

[0014] Preferably, the KH-550 ethanol solution is a KH-550 ethanol solution with a concentration of 1-2%, a pH of 6.5-7.5, and an ethanol purity of ≥99.7%.

[0015] Preferably, the composite environmentally friendly protective layer is deposited using an organic-inorganic hybrid plating solution and a pulse current.

[0016] Preferably, the organic-inorganic hybrid plating solution of the composite environmentally friendly protective layer includes the following raw materials in weight percentage: 3-5% propylene glycol methyl ether acetate, 10-15% bisphenol A epoxy resin EP-828, 3-5% KH-550, 0.1-0.5% surface-modified carbon nanotubes, and deionized water to make up the balance.

[0017] Traditional protective layers are mostly composed of a single organic or inorganic material, making it difficult to achieve both mechanical strength and corrosion resistance. The above solution, combining a bisphenol A epoxy resin with surface-modified carbon nanotubes and a pulsed current deposition process, creates a high-strength and high-adhesion composite coating. EP-828 epoxy resin provides flexibility and adhesion, compensating for the brittleness of the inorganic coating. The surface-modified carbon nanotubes, modified with KH-550, improve dispersibility and enhance the coating's conductivity and antistatic properties.

[0018] Preferably, the surface-modified carbon nanotubes are prepared by adding 6-12% carbon nanotubes to a 1-2% KH-550 ethanol solution, ultrasonically treating the solution at 30-50kHz and 180-220W for 30 minutes, stirring the solution at a constant temperature of 50-70°C for 1-2 hours, centrifuging the solution at 8000-12000rpm for 5-15 minutes, washing the solution with ethanol three times, and vacuum drying the solution at 80°C. The surface-modified carbon nanotubes have a diameter of 20-50nm and a length of 1-5μm.

[0019] Preferably, the carbon nanotubes are any one of single-walled carbon nanotubes and multi-walled carbon nanotubes.

[0020] Preferably, the organic-inorganic hybrid plating solution for the composite environmentally friendly protective layer is prepared by mixing EP-828 resin with propylene glycol methyl ether acetate solvent, stirring at 60°C until completely dissolved, slowly adding KH-550 dropwise, and continuing to stir for 30 minutes. Surface-modified carbon nanotubes are added in batches while simultaneously operating a high-shear emulsifier at a speed of 5000-8000 rpm for dispersion for 1 hour. The pH of the plating solution is then adjusted to 6.5-7.5 using 0.1M dilute hydrochloric acid or 0.1M aqueous ammonia.

[0021] Preferably, the hydrophobic nano-coating comprises: APTES and PTFE dispersion.

[0022] Preferably, the APTES has a purity of ≥98%.

[0023] Preferably, the PTFE dispersion is diluted with deionized water to a solid content of 50-60% and does not contain PFOA.

[0024] By adopting the above scheme, the nickel plating is replaced by copper-tin alloy, the interface bonding is enhanced by combining silane / epoxy resin hybrid materials, and the nanostructured PTFE coating is introduced to achieve long-term hydrophobic protection, forming a biosafe composite coating system.

[0025] In a second aspect, the present application provides a method for electroplating a highly durable and environmentally friendly headphone charging terminal, which adopts the following technical solution: S1 Substrate Pretreatment: Clean and activate the headphone charging terminal substrate; S2 non-nickel base coating: Place the pretreated substrate in the copper-tin alloy base coating and deposit the copper-tin alloy base coating by electrolytic deposition with a deposition current density of 2-3A / dm 2 , temperature 45-50 ℃, time 15-20 minutes, forming a dense bottom coating with a thickness of 5-8μm; S3 composite environmental protection layer electroplating: organic-inorganic hybrid plating solution, at 50-60 ℃, pH = 6.5-7.5, using pulse current, duty cycle 40-60%, frequency 50Hz, current density 0.5-1.0A / dm 2 , the deposition time is 40-60 minutes to deposit the protective layer with a thickness of 2-3μm; hot air curing at 80-100℃ for 30 minutes to complete the final cross-linking of the epoxy resin; S4 nano-coating treatment: A transition layer of APTES aminosilane coupling agent is applied to the surface of the S3 composite protective layer, and then PTFE dispersion is sprayed on the transition layer and then cured; S5 etching treatment: perform argon plasma etching treatment and evacuate the reaction chamber to a vacuum of <5×10 -3 Torr, power 80-120W, time 30-60 seconds.

[0026] This solution combines a non-nickel basecoat for wear resistance, an electroplated composite environmentally friendly protective layer for corrosion resistance, and a hydrophobic nanocoating on the surface, creating a gradient protection layer with superior overall performance compared to single or double-layer structures. The pulsed current deposition process creates a dense and uniform composite environmentally friendly protective layer, reducing porosity and extending terminal life. The hydrophobic nanocoating, with a contact angle of ≥150° and super-hydrophobic properties, prevents liquid penetration and reduces the risk of oxidation.

[0027] Preferably, the cleaning and activation treatment in step S1 includes: first alkaline degreasing: using a NaOH solution with a pH of 10-12, a temperature of 50-60°C, and treating for 5-10 minutes; and then acidic activation: using a 10-15% citric acid solution, and treating for 3-5 minutes under ultrasonic conditions of a frequency of 40kHz and a power of 100W.

[0028] Preferably, in step S4, an APTES aminosilane coupling agent transition layer is coated on the surface of the composite protective layer, with a 1-3% APTES ethanol solution, a spraying pressure of 0.3-0.5 MPa, and a thickness of 50-100 nm. After coating, the layer is allowed to stand for 5 minutes to allow the APTES to self-assemble into a film, and then cured in a 120°C hot air circulation oven for 10 minutes.

[0029] Preferably, in step S4, the PTFE dispersion is sprayed on the transition layer at a spraying pressure of 0.3-0.5 MPa to form a 0.5-1 μm coating. The temperature is 25±2°C and the RH is ≤40%. High temperature and high humidity accelerate the volatilization of the solvent, causing the dry-sprayed PTFE particles to melt, flow, and recrystallize to form a continuous film layer, which is then cured at 180-200°C for 20-30 minutes.

[0030] Preferably, the purity of the argon gas is ≥99.99%.

[0031] By adopting the above scheme, replacing nickel plating with copper-tin alloy, combining silane, epoxy resin, and carbon nanotube hybrid materials to enhance interface bonding, and introducing plasma-etched micro-nanostructured PTFE coating, biosafety, high wear resistance, and super-hydrophobic integrated protection can be achieved.

[0032] In summary, this application has the following beneficial effects: This application presents a highly durable, environmentally friendly headphone charging terminal. This terminal replaces nickel plating with a copper-tin alloy, incorporates a silane / epoxy hybrid material to enhance interfacial bonding, and introduces a nanostructured PTFE coating for long-lasting hydrophobic protection, resulting in a biosafe composite coating system. This system exhibits high wear resistance, corrosion resistance, and biosafety.

[0033] 2. The highly durable and environmentally friendly headphone charging terminal of the present application adopts a copper-tin alloy plating solution instead of nickel plating, combined with Al2O3 nanoparticles modified with a silane coupling agent, which not only avoids the use of nickel but also enhances the hardness and wear resistance of the plating. In particular, the Al2O3 nanoparticles modified with a silane coupling agent solve the problem of easy agglomeration of nanoparticles in the metal plating solution and the bonding strength with the metal substrate. The copper-tin alloy plating solution formula does not use toxic substances such as cyanide and lead, and potassium pyrophosphate is used as a chelating agent, which is more environmentally friendly.

[0034] 3. The highly durable and environmentally friendly headphone charging terminal of the present application adopts a mixture of bisphenol A epoxy resin and surface-modified carbon nanotubes, combined with a pulsed current deposition process to achieve a composite coating with high strength and high adhesion; EP-828 epoxy resin provides flexibility and adhesion to compensate for the brittleness of the inorganic coating; the nanotubes are modified with KH-550 to improve dispersibility and enhance the conductivity and antistatic ability of the coating.

[0035] 4. The present application discloses a method for electroplating a highly durable and environmentally friendly headphone charging terminal. The non-nickel base plating layer is wear-resistant, the electroplated composite environmentally friendly protective layer is corrosion-resistant, and the surface hydrophobic nano-coating forms a gradient protection with overall performance better than a single-layer or double-layer structure. The pulse current deposition process makes the composite environmentally friendly protective layer dense and uniform, reduces pores, and extends the life of the terminal. The hydrophobic nano-coating has a contact angle of ≥150° and is super hydrophobic, preventing liquid penetration and reducing the risk of oxidation. The entire process is free of cyanide, hexavalent chromium, PFOA and other toxic substances. DETAILED DESCRIPTION

[0036] The technical solution of the present application is further illustrated below through specific embodiments. The specific embodiments do not limit the scope of protection of the present application; some non-essential modifications and adjustments made by others based on the concept of the present application still fall within the scope of protection of the present application.

[0037] Unless otherwise specified, the experimental methods described in the following examples are conventional methods. The reagents and materials used are all commercially available. PTFE: Chemours Teflon, PTFE DISP 30, PFOA-free.

[0038] The present application is further described in detail below with reference to the following examples and comparative examples.

[0039] Preparation Example Preparation Example 1 Preparation of modified Al2O3 nanoparticles Silane coupling agent modified Al2O3 nanoparticles: 100 g of Al2O3 nanoparticles were added to 1000 mL of 1-2% KH-550 ethanol solution, ultrasonically dispersed at 40 kHz and 100 W for 30 minutes, stirred at a constant temperature of 60°C for 2 hours, centrifuged at 10,000 rpm for 15 minutes, washed with ethanol three times, and vacuum dried at 80°C to obtain silane coupling agent modified Al2O3 nanoparticles.

[0040] The KH-550 ethanol solution is a KH-550 ethanol solution with a concentration of 1-2%, a pH of 6.5-7.5, and an ethanol purity of ≥99.7%.

[0041] Preparation Example 2 Preparation of modified Al2O3 nanoparticles Modified Al2O3 nanoparticles: 100 g of Al2O3 nanoparticles were added to 900 mL of 1-2% KH-550 ethanol solution, ultrasonically dispersed at 300 kHz and 100 W for 30 minutes, stirred at a constant temperature of 50°C for 1 hour, centrifuged at 8000 rpm for 10 minutes, washed with ethanol three times, and vacuum dried at 80°C to obtain silane coupling agent-modified Al2O3 nanoparticles.

[0042] The KH-550 ethanol solution is a KH-550 ethanol solution with a concentration of 1-2%, a pH of 6.5-7.5, and an ethanol purity of ≥99.7%.

[0043] Preparation Example 3 Preparation of modified Al2O3 nanoparticles Silane coupling agent modified Al2O3 nanoparticles: 100 g of Al2O3 nanoparticles were added to 1100 mL of 1-2% KH-550 ethanol solution, ultrasonically dispersed at 50 kHz and 100 W for 30 minutes, stirred at 70°C for 1.5 hours, centrifuged at 12000 rpm for 20 minutes, washed with ethanol three times, and vacuum dried at 80°C to obtain silane coupling agent modified Al2O3 nanoparticles.

[0044] The KH-550 ethanol solution is a KH-550 ethanol solution with a concentration of 1-2%, a pH of 6.5-7.5, and an ethanol purity of ≥99.7%.

[0045] Preparation Example 4 Preparation of surface-modified carbon nanotubes 100 g of carbon nanotubes were added to 1000 mL of 1-2% KH-550 ethanol solution, ultrasonicated at 40 kHz and 200 W for 30 minutes, stirred at 60° C. for 2 hours, centrifuged at 8000 rpm for 15 minutes, washed with ethanol three times, and dried in a vacuum at 80° C.

[0046] Preparation Example 5 Preparation of surface-modified carbon nanotubes 60 g of carbon nanotubes were added to 1000 mL of 1-2% KH-550 ethanol solution, ultrasonicated at 30 kHz and 180 W for 30 minutes, stirred at 50° C. for 2 hours, centrifuged at 12000 rpm for 10 minutes, washed with ethanol three times, and dried in a vacuum at 80° C.

[0047] Preparation Example 6 Preparation of surface-modified carbon nanotubes 120 g of carbon nanotubes were added to 1000 mL of 1-2% KH-550 ethanol solution, ultrasonicated at 40 kHz and 200 W for 30 minutes, stirred at 70°C for 1 hour, centrifuged at 10,000 rpm for 10 minutes, washed with ethanol three times, and dried in a vacuum at 80°C. Example

[0048] Examples 1-4 The present application provides a highly durable and environmentally friendly earphone charging terminal, which adopts the following technical solution: the protective coating includes a non-nickel base plating layer, a composite environmentally friendly protective layer and a hydrophobic nano coating.

[0049] A non-nickel base coating is obtained by electrolytically depositing a copper-tin alloy plating solution. The copper-tin alloy plating solution includes potassium pyrophosphate, copper sulfate, stannous sulfate, modified Al2O3 nanoparticles, and deionized water as the remainder.

[0050] The composite environmentally friendly protective layer is deposited using a pulsed current through an organic-inorganic hybrid plating solution. The organic-inorganic hybrid plating solution for the composite environmentally friendly protective layer includes: propylene glycol methyl ether acetate, EP-828, KH-550, surface-modified carbon nanotubes, and deionized water as the balance.

[0051] Hydrophobic nanocoatings, including: APTES and PTFE dispersions.

[0052] High-durability and environmentally friendly earphone charging terminal plating solution was prepared by different ratios. The mass of each component is shown in Table 1.

[0053] Table 1 Mass of each component in Examples 1-4 (g) Example 5 This application provides a highly durable and environmentally friendly electroplating method for earphone charging terminals, which adopts the following technical solutions: S1 Substrate Pretreatment: Clean and activate the headphone charging terminal substrate; first perform alkaline degreasing using a NaOH solution with a pH of 11 at 55°C for 8 minutes; then perform acidic activation using a 13% citric acid solution at a frequency of 40kHz and a power of 100W for 5 minutes.

[0054] S2 non-nickel base coating: Place the pretreated substrate in a copper-tin alloy plating solution and electrolytically deposit a copper-tin alloy base coating at a deposition current density of 2A / dm 2 , temperature 40 ℃, time 18 minutes, forming a dense bottom coating with a thickness of 5-8μm; S3 composite environmental protection layer electroplating: organic-inorganic hybrid plating solution, at 50 ℃, pH = 6.5, using pulse current, duty cycle 50%, frequency 50Hz, current density 0.8A / dm 2 , the deposition time is 50 minutes to deposit the protective layer with a thickness of 2μm, and it is hot-air cured at 95℃ for 30 minutes to complete the final cross-linking of the epoxy resin; S4 nano-coating treatment: 2% APTES ethanol solution is coated on the surface of the S3 composite protective layer, the spraying pressure is 0.4MPa, the thickness is 80nm, and it is allowed to stand for 5 minutes after coating to allow the APTES to self-assemble into a film, and it is cured in a hot air circulation oven at 120℃ for 10 minutes; then the PTFE dispersion is sprayed on the transition layer with a spraying pressure of 0.4MPa to form a 0.8μm coating, 25±2℃, RH≤40%, high temperature and high humidity accelerate the volatilization of the solvent, causing the dry-sprayed PTFE particles to melt, flow and recrystallize to form a continuous film layer, which is cured at 200℃ for 20 minutes.

[0055] S5 etching treatment: perform argon plasma etching treatment, evacuate the reaction chamber to a vacuum of less than 5×10-3 Torr, use a power of 100 W, and perform etching for 40 seconds.

[0056] The base material of the earphone charging terminal is 316L stainless steel.

[0057] During the preparation process, the copper-tin alloy plating solution, the organic-inorganic hybrid plating solution and the PTFE dispersion were prepared according to the formula content in Example 1.

[0058] Example 6 This application provides a highly durable and environmentally friendly electroplating method for earphone charging terminals, which adopts the following technical solutions: S1 Substrate Pretreatment: Clean and activate the headphone charging terminal substrate; first perform alkaline degreasing: use NaOH solution with pH = 10, temperature and treatment for 10 minutes at 50°C; then perform acid activation: use 15% citric acid solution, ultrasonic treatment at a frequency of 40kHz and power of 100W for 3 minutes.

[0059] S2 non-nickel base coating: Place the pretreated substrate in a copper-tin alloy plating solution and electrolytically deposit a copper-tin alloy base coating at a deposition current density of 3A / dm 2 , temperature 45 ℃, time 20 minutes, forming a dense bottom plating layer with a thickness of 5μm; S3 composite environmental protection layer electroplating: organic-inorganic hybrid plating solution, at 50 ℃, pH = 6.5, using pulse current, duty cycle 40%, frequency 50Hz, current density 0.5A / dm 2 , the deposition time is 40 minutes to deposit the protective layer with a thickness of 2μm, and it is hot-air cured at 80℃ for 30 minutes to complete the final cross-linking of the epoxy resin; S4 nano-coating treatment: 1% APTES ethanol solution is coated on the surface of the S3 composite protective layer, the spraying pressure is 0.3MPa, the thickness is 50nm, and it is allowed to stand for 5 minutes after coating to allow the APTES to self-assemble into a film, and it is cured in a hot air circulation oven at 120℃ for 10 minutes; then the PTFE dispersion is sprayed on the transition layer with a spraying pressure of 0.3MPa to form a 0.5μm coating, 25±2℃, RH≤40%, high temperature and high humidity accelerate the volatilization of the solvent, causing the dry-sprayed PTFE particles to melt, flow and recrystallize to form a continuous film layer, which is cured at 180℃ for 30 minutes.

[0060] S5 etching treatment: perform argon plasma etching treatment, evacuate the reaction chamber to a vacuum of less than 5×10-3 Torr, use a power of 80 W, and perform etching for 30 seconds.

[0061] The base material of the earphone charging terminal is H62 brass.

[0062] During the preparation process, the copper-tin alloy plating solution, the organic-inorganic hybrid plating solution and the PTFE dispersion were prepared according to the formula content in Example 2.

[0063] Example 7 This application provides a highly durable and environmentally friendly electroplating method for earphone charging terminals, which adopts the following technical solutions: S1 Substrate Pretreatment: Clean and activate the headphone charging terminal substrate; first perform alkaline degreasing: use NaOH solution with pH = 12, temperature and treatment for 10 minutes at 60°C; then perform acid activation: use 15% citric acid solution, ultrasonic treatment at a frequency of 40kHz and power of 100W for 5 minutes.

[0064] S2 non-nickel base coating: Place the pretreated substrate in a copper-tin alloy plating solution and electrolytically deposit a copper-tin alloy base coating at a deposition current density of 3A / dm 2 , temperature 50 ℃, time 20 minutes, forming a dense bottom plating layer with a thickness of 8μm; S3 composite environmental protection layer electroplating: organic-inorganic hybrid plating solution, at 60 ℃, pH = 7.5, using pulse current, duty cycle 60%, frequency 50Hz, current density 1.0A / dm 2 , the deposition time is 60 minutes to deposit the protective layer with a thickness of 3μm, and it is hot-air cured at 100℃ for 30 minutes to complete the final cross-linking of the epoxy resin; S4 nano-coating treatment: 3% APTES ethanol solution is coated on the surface of the S3 composite protective layer, the spraying pressure is 0.5MPa, the thickness is 100nm, and it is allowed to stand for 5 minutes after coating to allow the APTES to self-assemble into a film, and it is cured in a hot air circulation oven at 120℃ for 10 minutes; then the PTFE dispersion is sprayed on the transition layer with a spraying pressure of 0.5MPa to form a 1μm coating, 25±2℃, RH≤40%, high temperature and high humidity accelerate the volatilization of the solvent, causing the dry-sprayed PTFE particles to melt, flow and recrystallize to form a continuous film layer, and cure at 200℃ for 30 minutes.

[0065] S5 etching treatment: perform argon plasma etching treatment, evacuate the reaction chamber to a vacuum of less than 5×10-3 Torr, use a power of 120 W, and perform etching for 60 seconds.

[0066] The base material of the earphone charging terminal is C5191 phosphor bronze.

[0067] During the preparation process, the copper-tin alloy plating solution, the organic-inorganic hybrid plating solution and the PTFE dispersion were prepared according to the formula content in Example 3.

[0068] Example 8 This application provides a highly durable and environmentally friendly electroplating method for earphone charging terminals, which adopts the following technical solutions: S1 Substrate Pretreatment: Clean and activate the headphone charging terminal substrate; first perform alkaline degreasing: use NaOH solution with pH = 12, temperature and treatment for 10 minutes at 50°C; then perform acid activation: use 13% citric acid solution, ultrasonic treatment at a frequency of 40kHz and power of 100W for 3 minutes.

[0069] S2 non-nickel base coating: Place the pretreated substrate in a copper-tin alloy plating solution and electrolytically deposit a copper-tin alloy base coating at a deposition current density of 2A / dm 2 , temperature 45 ℃, time 20 minutes, forming a dense bottom plating layer with a thickness of 5μm; S3 composite environmental protection layer electroplating: organic-inorganic hybrid plating solution, at 50 ℃, pH = 7.5, using pulse current, duty cycle 60%, frequency 50Hz, current density 0.5A / dm 2 , the deposition time is 40 minutes to deposit the protective layer with a thickness of 2μm, and it is hot-air cured at 80℃ for 30 minutes to complete the final cross-linking of the epoxy resin; S4 nano-coating treatment: 3% APTES ethanol solution is coated on the surface of the S3 composite protective layer, the spraying pressure is 0.5MPa, the thickness is 50nm, and it is allowed to stand for 5 minutes after coating to allow the APTES to self-assemble into a film, and it is cured in a hot air circulation oven at 120℃ for 10 minutes; then the PTFE dispersion is sprayed on the transition layer with a spraying pressure of 0.3MPa to form a 0.5μm coating, 25±2℃, RH≤40%, high temperature and high humidity accelerate the volatilization of the solvent, causing the dry-sprayed PTFE particles to melt, flow and recrystallize to form a continuous film layer, which is cured at 180℃ for 30 minutes.

[0070] S5 etching treatment: perform argon plasma etching treatment, evacuate the reaction chamber to a vacuum of less than 5×10-3 Torr, use a power of 80 W, and perform etching for 60 seconds.

[0071] The base material of the earphone charging terminal is 316L stainless steel.

[0072] During the preparation process, the copper-tin alloy plating solution, the organic-inorganic hybrid plating solution and the PTFE dispersion were prepared according to the formula content in Example 4.

[0073] Example 9 The same as Example 5, except that the base material of the earphone charging terminal is C5191 phosphor bronze.

[0074] Example 10 The same as Example 5, except that the base material of the earphone charging terminal is H62 brass.

[0075] Comparative Example Comparative Example 1 The same as Example 5, except that the copper-tin alloy plating solution includes: 300 g / L potassium pyrophosphate, 17 g / L copper pyrophosphate, 25 g / L stannous chloride, 25 g / L tin chloride pentahydrate, and 30 g / L potassium chloride.

[0076] Comparative Example 2 The same as Example 5, except that the copper-tin alloy plating solution includes: 80 g / L hydrochloric acid, 15 g / L copper chloride, 10 g / L stannous chloride, 15 g / L stannous pyrophosphate, 15 g / L copper pyrophosphate, 5 g / L sodium chloride, 20 g / L succinimide, and 0.01 g / L sodium citrate.

[0077] Comparative Example 3 The same as Example 5, except that the organic-inorganic hybrid plating solution includes: 20 g / L of polyether polyol, 5 g / L of diphenylmethane diisocyanate, 3 g / L of stannous decanoate, 9 g / L of polybutylene glycol, 5 g / L of nano-calcium sulfate, 5 g / L of nano-silicon oxide, 6 g / L of nano-iron oxide, and 7 g / L of ethyl methyl phosphate.

[0078] Comparative Example 4 The same as Example 5, except that the organic-inorganic hybrid plating solution includes: propylene glycol methyl ether acetate 4g / L, EP-828 13g / L, KH-550 4g / L.

[0079] Comparative Example 5 The method is the same as Example 5, except that the nanocoating is not coated using a 2% APTES ethanol solution and has no APTES transition layer.

[0080] Comparative Example 6 Same as Example 5, except that the copper-tin alloy plating solution contains 130 g / L potassium pyrophosphate, 9 g / L copper sulfate, 4 g / L stannous sulfate, 20 g / L Al2O3 nanoparticles, and the balance is made up of deionized water. Performance testing 1. Terminal durability test At a temperature of 25° C. and 65% RH, a durability test was performed on the earphone charging terminal prepared in the embodiment using a manual pressure testing machine.

[0081] 2. Corrosion resistance test Place the coated sample in a 35°C, 5% NaCl salt spray chamber, spray continuously, and observe corrosion regularly. Evaluation criteria: Excellent: No corrosion (white rust or red rust) for ≥ 72 hours; Poor: Obvious corrosion spots appear within 24 hours.

[0082] 3. Hardness test A diamond indenter is used to apply a 10g load to the coating surface. The diagonal length of the indentation is measured to calculate the hardness. Evaluation criteria: Excellent: Hardness ≥ 400 HV; Poor: Hardness < 200 HV.

[0083] 4. Ultraviolet aging Using a UVA-340 lamp, after 8 hours of UV exposure, turn off the light source and maintain humidity for 4 hours. This cycle should be completed 4 times over a total of 48 hours. Evaluation criteria: Determine whether the "48-hour no-fading" requirement is met.

[0084] Table 2 Test results of durability, corrosion resistance, hardness and ultraviolet aging of Examples 1-10 and Comparative Examples 1-6 It can be seen from the above table that before plugging and unplugging, the impedance value of the terminal of Example 1-10 is in the range of 6.32mΩ-6.69mΩ. After 1500 repeated plugging and unplugging, the impedance value of the terminal increases to the range of 6.43mΩ-6.90mΩ. After another 1500 repeated plugging and unplugging, its impedance increases again to the range of 8.56mΩ-9.34mΩ. At the same time, the corrosion resistance and hardness test results are both excellent, and the ultraviolet aging test is non-fading. From these data, it can be seen that the impedance value of the terminal increases after multiple plugging and unplugging, but the impedance value floating range is small, indicating that the corrosion resistance and wear resistance of the terminal are improved, which can effectively ensure the service life of the terminal.

[0085] For comparative examples 1-6, after 1500 repeated plugging and unplugging, the impedance value of the terminal increased to the range of 13.07mΩ-16.00mΩ. After another 1500 repeated plugging and unplugging, a total of 3000 times, its impedance increased again to the range of 19.35mΩ-24.78mΩ. The corrosion resistance and hardness test results were both poor, and the ultraviolet aging test showed fading. Its impedance value increased significantly, indicating that the corrosion resistance and wear resistance of the headphone charging terminal are poor.

[0086] The above test results show that the highly durable and environmentally friendly headphone charging terminal prepared in this application replaces nickel plating with a copper-tin alloy, combines a silane / epoxy resin hybrid material to enhance interfacial bonding, and introduces a nanostructured PTFE coating to achieve long-lasting hydrophobic protection. The entire process is free of cyanide, hexavalent chromium, PFOA and other toxic substances, forming a biosafe composite coating system. The pulsed current deposition process makes the composite environmentally friendly protective layer dense and uniform, reduces porosity, and extends the life of the terminal; the hydrophobic nanocoating has a contact angle of ≥150° and is super hydrophobic, preventing liquid penetration and reducing the risk of oxidation. It has high wear resistance, corrosion resistance, and biosafety.

[0087] This specific embodiment is merely an explanation of the present invention and is not intended to limit the present invention. After reading this specification, those skilled in the art may make non-creative modifications to this embodiment as needed. However, as long as they are within the scope of the present invention, they are protected by patent law.

Claims

1. A highly durable and environmentally friendly earphone charging terminal, characterized in that: The invention is formed by at least one coating, wherein the coating comprises a non-nickel base plating layer, a composite environmental protection layer and a hydrophobic nano coating.

2. The high-durability and environmentally friendly earphone charging terminal according to claim 1, characterized in that: The non-nickel base plating layer is obtained by electrolytically depositing a copper-tin alloy plating solution. The copper-tin alloy plating solution includes the following raw materials in percentage by weight: 12-15% potassium pyrophosphate, 0.8-1% copper sulfate, 0.3-0.5% stannous sulfate, 1-3% modified Al2O3 nanoparticles, and deionized water to make up the balance.

3. The high-durability and environmentally friendly earphone charging terminal according to claim 2, characterized in that: The modified Al2O3 nanoparticles are prepared by adding Al2O3 nanoparticles to a KH-550 ethanol solution, ultrasonically dispersing the solution at 30-50 kHz and 100W for 30 minutes, stirring the solution at a constant temperature of 50-70°C for 1-2 hours, centrifuging the solution at 8000-12000 rpm for 10-20 minutes, washing the solution with ethanol three times, and vacuum drying the solution at 80°C to obtain Al2O3 nanoparticles modified with a silane coupling agent.

4. The high-durability and environmentally friendly earphone charging terminal according to claim 2, characterized in that: The mass ratio of the modified Al2O3 nanoparticles: Al2O3 nanoparticles to the KH-550 ethanol solution is 1:(9-11).

5. The high-durability and environmentally friendly earphone charging terminal according to claim 1, characterized in that: The composite environmentally friendly protective layer is deposited using a pulsed current using an organic-inorganic hybrid plating solution. The organic-inorganic hybrid plating solution includes the following raw materials by weight percentage: 3-5% propylene glycol methyl ether acetate, 10-15% bisphenol A epoxy resin EP-828, 3-5% KH-550, 0.1-0.5% surface-modified carbon nanotubes, and deionized water to make up the balance.

6. The high-durability and environmentally friendly earphone charging terminal according to claim 1, characterized in that: The composite environmentally friendly protective layer is deposited using a pulsed current through an organic-inorganic hybrid plating solution. The organic-inorganic hybrid plating solution is prepared by mixing EP-828 resin and propylene glycol methyl ether acetate solvent, stirring at 60°C until completely dissolved, slowly adding KH-550 dropwise, and continuing to stir for 30 minutes; adding surface-modified carbon nanotubes in batches, and simultaneously turning on a high-shear emulsifier at a speed of 5000-8000 rpm for dispersion for 1 hour, and adjusting the pH of the plating solution to 6.5-7.5 with 0.1M dilute hydrochloric acid or 0.1M ammonia water.

7. The high-durability and environmentally friendly earphone charging terminal according to claim 5, characterized in that: The surface modified carbon nanotubes are prepared by adding 6-12% carbon nanotubes to a 1-2% KH-550 ethanol solution, ultrasonically treating at 30-50kHz and 180-220W for 30 minutes, stirring at a constant temperature of 50-70°C for 1-2 hours, centrifuging at 8000-12000rpm for 5-15 minutes, washing with ethanol three times, and vacuum drying at 80°C.

8. A method for electroplating a high-durability and environmentally friendly earphone charging terminal according to any one of claims 1 to 7, characterized in that: It includes the following steps: S1 Substrate pretreatment: Clean and activate the headphone charging terminal substrate; S2 Non-nickel base coating: Place the pretreated substrate in a copper-tin alloy base coating, and electrolytically deposit the copper-tin alloy base coating at a deposition current density of 2-3A / dm², a temperature of 45-50°C, and a time of 15-20 minutes to form a dense base coating with a thickness of 5-8μm. S3 composite environmentally friendly protective layer electroplating: organic-inorganic hybrid plating solution, at 50-60℃, pH=6.5-7.5, using pulse current, duty cycle 40-60%, frequency 50Hz, current density 0.5-1.0A / dm², deposition time 40-60 minutes to deposit a protective layer with a thickness of 2-3μm; hot air curing at 80-100℃ for 30 minutes to complete the final crosslinking of the epoxy resin; S4 nano-coating treatment: A transition layer of APTES aminosilane coupling agent is applied to the surface of the S3 composite protective layer, and then PTFE dispersion is sprayed on the transition layer and then cured; S5 Etching treatment: Perform argon plasma etching and evacuate the reaction chamber to a vacuum of <5×10 -3 Torr, power 80-120W, time 30-60 seconds.

9. The electroplating method for a high-durability and environmentally friendly earphone charging terminal according to claim 8, characterized in that: In step S4, an APTES aminosilane coupling agent transition layer is coated on the surface of the composite protective layer, with a 1-3% APTES ethanol solution, a spraying pressure of 0.3-0.5 MPa, and a thickness of 50-100 nm. After coating, the coating is allowed to stand for 5 minutes to allow the APTES to self-assemble into a film, and then cured in a hot air circulation oven at 120° C. for 10 minutes.

10. The electroplating method for a high-durability and environmentally friendly earphone charging terminal according to claim 8, characterized in that: In step S4, the PTFE dispersion is sprayed on the transition layer at a spraying pressure of 0.3-0.5 MPa to form a 0.5-1 μm coating. The high temperature and humidity at 25±2°C and 40% RH accelerate the volatilization of the solvent, causing the dry-sprayed PTFE particles to melt, flow, and recrystallize to form a continuous film layer, which is then cured at 180-200°C for 20-30 minutes.

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