A plating process for improving performance of automotive-grade leds

Abstract

The application relates to the field of electroplating, in particular to an electroplating process for improving the performance of an automotive-grade LED. The electroplating process for improving the performance of an automotive-grade LED comprises the following steps: S1, pretreatment; S2, alkaline copper plating: immersing the automotive-grade LED substrate after the pretreatment into an alkaline copper plating solution for electrodepositing; S3, full silver plating: immersing the automotive-grade LED substrate after the alkaline copper plating into a silver plating solution for electrodepositing; S4, selective nickel plating: sleeving the automotive-grade LED substrate after the silver plating with a selective nickel plating mold, and immersing the automotive-grade LED substrate into a nickel plating solution for electrodepositing; S5, selective palladium plating: sleeving the automotive-grade LED substrate after the nickel plating with a selective palladium plating mold, and immersing the automotive-grade LED substrate into a palladium plating solution for electrodepositing; S6, selective gold plating: sleeving the automotive-grade LED substrate after the palladium plating with a selective gold plating mold, and immersing the automotive-grade LED substrate into a gold plating solution for electrodepositing; and S7, post-treatment. The selective nickel plating can avoid the cracking phenomenon caused by full nickel plating, and improves the performance of the automotive-grade LED.

Description

Technical Field

[0001] This invention relates to the field of electroplating, and in particular to an electroplating process for improving the performance of automotive-grade LEDs. Background Technology

[0002] With the accelerating trend of intelligent and electronic vehicles, consumers' demands for personalization, entertainment, and safety are constantly increasing, and the rapid rise of new energy vehicles is further driving the demand for automotive-grade LEDs. Automotive-grade LED products use ALN ceramic high thermal conductivity material, which features small size, high current, and high reliability, and can effectively improve the thermal shock resistance of automotive lighting LED devices.

[0003] The current electroplating process for automotive-grade LEDs is as follows: degreasing → activation → nickel plating → palladium plating → gold plating → post-treatment. Among these, nickel plating is full nickel plating. Due to the poor ductility of nickel, full nickel plating is prone to cracking. After cracking, copper will be exposed. Under the action of heat, copper atoms will migrate to the palladium gold plating layer, causing the palladium gold plating layer to be contaminated by copper elements, thereby reducing the lifespan and luminous efficacy of automotive-grade LEDs. Summary of the Invention

[0004] To address the issue of easy cracking in the plating process of existing automotive-grade LEDs, this application provides an electroplating process that improves the performance of automotive-grade LEDs.

[0005] Firstly, this application provides an electroplating process for improving the performance of automotive-grade LEDs, achieved through the following technical solution: An electroplating process for improving the performance of automotive-grade LEDs includes the following steps: S1, Pre-processing; S2, Alkaline Copper Plating: Immerse the pretreated automotive-grade LED substrate in an alkaline copper plating solution and electrodeposit for 3-7 seconds at a current density of 3-7 amperes / dm². S3, Full Silver Plating: Immerse the automotive-grade LED substrate after alkaline copper plating into the silver plating solution, with a current density of 20-50 amperes / square decimeter, and electrodeposit for 1-3 seconds; S4. Selective nickel plating: The silver-plated automotive-grade LED substrate is fitted with a selective nickel plating mold and placed in a nickel plating solution. Electrodeposition is performed for 10-20 seconds at a current density of 4-8 amperes / dm². S5. Selective Palladium Plating: The nickel-plated automotive-grade LED substrate is fitted with a selective palladium plating mold and placed in a palladium plating solution. Electrodeposition is performed for 3-5 seconds at a current density of 0.6-2 amperes / dm². S6. Selective Gold Plating: The palladium-plated automotive-grade LED substrate is fitted with a selective gold plating mold and placed in a gold plating solution. Electrodeposition is performed at a current density of 1-2 amperes / square decimeter for 0.7-1.3 seconds. S7, Post-processing.

[0006] By adopting the above technical solution, the performance requirements of automotive-grade LEDs require bending and soldering in areas where silver plating is required. This application selects nickel plating in areas where bending is not necessary, which can avoid the cracking phenomenon caused by full nickel plating and improve the performance of automotive-grade LEDs.

[0007] In this application, the pretreatment includes a degreasing step and an activation step. Degreasing removes oil stains and other abnormalities from the surface of the automotive-grade LED substrate, improving the adhesion between the subsequent plating layer and the substrate, and thus improving the quality of the plating layer. Activation can remove the oxide film on the surface of the automotive-grade LED substrate, improving the adhesion between the plating layer and the substrate, and activation can also neutralize the alkaline film remaining on the surface of the material.

[0008] Alkali copper plating is first applied to automotive-grade LED substrates, which has a leveling effect and improves the adhesion between the plating layer and the substrate.

[0009] Preferably, the pH of the alkaline copper plating solution is 10-12.

[0010] In this application, the alkaline copper plating solution is composed of cuprous cyanide and sodium cyanide or potassium cyanide.

[0011] In this application's alkaline copper plating solution, the suitable concentration of cuprous cyanide is 85-110 g / L. Too low a cuprous cyanide content results in too low a copper ion content, affecting electroplating efficiency and causing poor leveling. However, too high a copper ion content easily leads to poor plating in high-concentration areas. Sodium cyanide or potassium cyanide are complexing agents that stabilize the alkaline copper plating solution for normal operation. - Not only does it complex with copper ions, but it also exists in a free state in the plating bath. Free CN in the plating bath... - The appropriate content is 30-60 g / L, free CN - If the content is too low, it cannot guarantee a fine coating crystallization, and it also affects the normal dissolution of the anode, but free CN... - Excessive content can affect electroplating efficiency.

[0012] Preferably, the thickness of the copper plating layer corresponding to the alkali-plated copper is 25-35 microinches; more preferably, the thickness of the copper plating layer corresponding to the alkali-plated copper is 30 microinches.

[0013] Adding full silver plating between copper and nickel plating increases subsequent soldering capability, thereby improving the performance of automotive-grade LEDs.

[0014] In this application, the silver plating solution is composed of silver cyanide and potassium cyanide or sodium cyanide.

[0015] In this application, the thickness of the silver plating layer corresponding to the full silver plating is 40-120 microinches.

[0016] In this application, the empty spaces in the selective plating mold correspond to the non-bending areas of the automotive-grade LED, and the shielding strips of the selective plating mold correspond to the bending areas of the automotive-grade LED. Selective nickel plating can effectively avoid cracking at the bending points caused by full nickel plating, thus improving the performance of the automotive-grade LED.

[0017] In this application, the composition of the nickel plating solution is as follows: nickel aminosulfonate 400-600 mL / L, nickel chloride 10-20 g / L, boric acid 30-50 g / L, complexing agent 2-3 g / L, N,N-diallylbenzenesulfonamide 1.5-2.5 mL / L, sodium benzenesulfinate 0.35-0.45 g / L, and thiol-containing fused heterocyclic compound 0.01-0.015 g / L.

[0018] In this application, nickel sulfamate and nickel chloride can introduce nickel ions. However, if the nickel ion concentration is too low, it affects the electroplating efficiency and results in coarse crystals in the plating layer. Conversely, if the nickel ion concentration is too high, poor plating can easily occur in high-concentration areas. The main function of nickel chloride is to increase conductivity and promote anodic dissolution, but if the concentration of nickel chloride is too high, it will reduce the ductility of the nickel layer, making automotive-grade LEDs prone to cracking when bent. Boric acid acts as a buffer to prevent nickel from depositing at a specific point, improving the uniformity of the nickel plating layer. However, if the concentration of boric acid is too high, it can lead to changes in the crystal structure of the plating layer.

[0019] Sodium benzenesulfinate significantly reduces the grain size of nickel plating layers, resulting in a bright and ductile finish. However, the amount of sodium benzenesulfinate used in current nickel plating solutions is generally 0.1-0.3 g / L to ensure a complete and bright coating. But adding too much sodium benzenesulfinate can hinder Ni plating. 2+ The adsorption of sodium benzenesulfinate prevents the formation of a coating, reduces the plating speed, and affects the adhesion of the coating. Adding too little sodium benzenesulfinate will also affect the brightness of the coating, causing it to darken.

[0020] This application employs N,N-diallylbenzenesulfonamide and a thiol-containing fused heterocyclic compound. The combined effect of these two compounds significantly improves the adhesion and ductility of the plating layer. The plating layer does not blister after baking at 260°C for 5 hours and undergoing salt spray treatment for 7 days. This is likely because the thiol-containing fused heterocyclic compound can form a thin and dense complex protective film on the electroplated nickel surface, improving the plating layer's ductility, while N,N-diallylbenzenesulfonamide can promote the adhesion of Ni... 2+ Adsorption, thereby reducing the excessive sodium benzenesulfinate content on Ni 2+ The adsorption barrier enhances the adhesion of the coating.

[0021] Preferably, the nickel plating solution comprises: nickel aminosulfonate 500 mL / L, nickel chloride 15 g / L, boric acid 40 g / L, complexing agent 2.5 g / L, N,N-diallylbenzenesulfonamide 2 mL / L, sodium benzenesulfinate 0.4 g / L, and thiol-containing fused heterocyclic compound 0.015 g / L.

[0022] By adopting the above technical solution, the nickel layer has good crystallinity, thereby improving the adhesion and ductility of the coating.

[0023] Preferably, the complexing agent is a mixture of benzotriazole and hydroxyethylethylenediaminetriacetic acid in a mass ratio of 1:(3-5).

[0024] The combination of benzotriazole and hydroxyethylethylenediaminetriacetic acid (HDETA) as a complexing agent not only exhibits excellent complexation effects on nickel ions but also enhances the adhesion and ductility of the coating. No blistering occurs after baking at 260℃ for 48 hours and salt spray treatment for 30 days. This is due to the interaction between benzotriazole and the thiol-containing fused heterocyclic compound, which improves the stability and weather resistance of the protective film on the coating surface. Furthermore, the interaction between HDETA and nickel aminosulfonate and N,N-diallylbenzenesulfonamide further promotes the complexation of Ni ions. 2+ Adsorption.

[0025] Preferably, the mass ratio of benzotriazole to hydroxyethylethylenediaminetriacetic acid is 1:4.

[0026] By adopting the above technical solution, the coating has good adhesion, ductility and weather resistance, and the coating does not blister for a long time after salt spray treatment.

[0027] Preferably, the thiol-containing fused heterocyclic compound is 5-amino-2-mercaptobenzimidazole.

[0028] 5-Amino-2-mercaptobenzimidazole has an amino group, which promotes its interaction with ethylenediaminetriacetic acid, nickel aminosulfonate, and N,N-diallylbenzenesulfonamide, further improving the weather resistance of the coating and the time before the coating does not bubble after salt spray treatment. It does not bubble after 180 days of salt spray treatment.

[0029] Preferably, the nickel plating corresponds to a nickel plating layer thickness of 35-45 microinches; more preferably, the nickel plating corresponds to a nickel plating layer thickness of 40 microinches.

[0030] Preferably, the current density for the selective nickel plating is 6 amperes per square decimeter, and the electrodeposition time is 15 seconds.

[0031] In this application, palladium plating eliminates the need for a subsequent palladium removal step, simplifying the post-processing steps, saving costs, and avoiding palladium waste.

[0032] In this application, the palladium plating solution is composed of: 12 g / L tetraammonium palladium chloride, 50 g / L conductive salt, 7 g / L polyethyleneimine, 7 g / L ethylenediamine, 4 g / L ammonium bromide, and 3 g / L phosphoric acid.

[0033] In this application, the palladium plating corresponds to a palladium coating thickness of 0.5-1 microinch; more preferably, the palladium plating corresponds to a palladium coating thickness of 0.8 microinch.

[0034] LED chips require metal materials with optimal electrical conductivity, thermal conductivity, and light reflection. Gold has low resistivity, high thermal conductivity, and high reflectivity within the visible spectrum. In this application, gold plating eliminates the need for subsequent gold stripping, simplifying post-processing, saving costs, and avoiding gold waste.

[0035] In this application, the composition of the gold plating solution is: gold plating starter, conductive salt, and gold ions.

[0036] In this application, the gold plating corresponds to a gold plating layer thickness of 0.3 microinches.

[0037] In this application, the post-processing includes an electrolytic cleaning step, an anti-oxidation step, a water washing step, and a drying step. Before encapsulation, automotive-grade LEDs are exposed to air and require an anti-oxidation step to protect the coating. This process generates a nanoscale organic solid film on the coating surface, which acts as a shield against corrosive media, thereby protecting the coating.

[0038] In summary, this application has the following beneficial effects: 1. By selecting nickel plating in areas where bending is not required, this application avoids the cracking phenomenon caused by full nickel plating, thus improving the performance of automotive-grade LEDs.

[0039] 2. This application uses N,N-diallylbenzenesulfonamide and a thiol-containing fused heterocyclic compound, which work together to significantly improve the adhesion and ductility of the coating.

[0040] 3. This application uses a complex of benzotriazole and hydroxyethylethylenediaminetriacetic acid as a complexing agent, which not only has a good complexing effect on nickel ions, but also improves the adhesion and ductility of the coating. The coating does not blister after baking at 260°C for 48 hours and after salt spray treatment for 30 days.

[0041] 4. This application uses 5-amino-2-mercaptobenzimidazole to further improve the weather resistance of the coating, and the coating does not blister after 180 days of salt spray treatment. Detailed Implementation

[0042] The present application will be further described in detail below with reference to the embodiments.

[0043] Preparation Example 1 provides an alkaline copper plating solution, the preparation steps of which are as follows: Mix 100g of cuprous cyanide, 180g of sodium cyanide and 500mL of deionized water evenly, then add deionized water to 1L to obtain an alkaline copper plating solution.

[0044] Preparation Example 2 provides a silver plating solution, the preparation steps of which are as follows: Mix 100g of silver cyanide, 70g of potassium cyanide and 600mL of deionized water evenly, then add deionized water to 1L to obtain the silver plating solution.

[0045] Preparation Example 3-10 provides a nickel plating solution, and the following description will be based on Preparation Example 3.

[0046] The preparation steps for the nickel plating solution provided in Example 3 are as follows: Mix 400 mL of nickel aminosulfonate, 10 g of nickel chloride, 30 g of boric acid, 2 g of hydroxyethylethylenediaminetriacetic acid, 1.5 mL of N,N-diallylbenzenesulfonamide, 0.35 g of sodium benzenesulfinate, 0.01 g of 2-mercaptobenzothiazole and 300 mL of deionized water thoroughly, then add deionized water to 1 L to obtain the nickel plating solution.

[0047] Preparation Examples 4-5 differ from Preparation Example 3 only in the amount of each raw material used in the nickel plating solution, as detailed in Table 1.

[0048] Table 1. Amounts of each raw material used in the nickel plating solution of Examples 3-5 Nickel aminosulfonate 400mL 600mL 500mL Nickel chloride 10g 20g 15g boric acid 30g 50g 40g Hydroxyethylethylenediaminetriacetic acid 2g 3g 2.5g N,N-diallylbenzenesulfonamide 1.5mL 2.5mL 2mL Sodium benzenesulfonate 0.35g 0.45g 0.4g 2-Mercaptobenzothiazole 0.01g 0.015g 0.015g Preparation Example 6 differs from Preparation Example 5 only in that the mass of hydroxyethylethylenediaminetriacetic acid is replaced with benzotriazole.

[0049] Preparation Example 7 differs from Preparation Example 5 only in that: the same mass of hydroxyethylethylenediaminetriacetic acid is replaced with a mixture of hydroxyethylethylenediaminetriacetic acid and benzotriazole, with a mass ratio of benzotriazole to hydroxyethylethylenediaminetriacetic acid of 1:3.

[0050] Preparation Example 8 differs from Preparation Example 7 only in that the mass ratio of benzotriazole and hydroxyethylethylenediaminetriacetic acid is 1:5.

[0051] Preparation Example 9 differs from Preparation Example 7 only in that the mass ratio of benzotriazole and hydroxyethylethylenediaminetriacetic acid is 1:4.

[0052] Preparation Example 10 differs from Preparation Example 9 only in that 2-mercaptobenzothiazole is replaced by 5-amino-2-mercaptobenzoimidazole.

[0053] Preparation Example 11 provides a palladium plating solution, the preparation steps of which are as follows: Mix 9g tetraamminepalladium chloride, 30g potassium chloride, 5g polyethyleneimine SP-018 (purchased from Wuhan Zhuochuang Yuanhang Chemical Co., Ltd.), 5g ethylenediamine, 3g ammonium bromide, 2g phosphoric acid, and 400mL deionized water thoroughly, then add deionized water to 1L to obtain the palladium plating solution.

[0054] Preparation Example 12 provides a gold plating solution, the preparation steps of which are as follows: Mix 750mL of AURALL 364 pre-plating gold starter, 5g of AURALL 364 pre-plating gold conductive salt, 2.2g of potassium gold cyanide and 100mL of deionized water evenly, and then add deionized water to 1L to obtain the gold plating solution. AURALL 364 pre-plating gold starter and AURALL 364 pre-plating gold conductive salt were both purchased from Rohm and Haas Electronic Materials (Dongguan) Co., Ltd.

[0055] Preparation Example 13 provides an electrolytic film-removing agent solution, the preparation steps of which are as follows: S1. Mix 200g potassium hydroxide, 200g potassium carbonate, 300g glucose and 300g basic lead carbonate at 30℃ by dry mixing at a stirring speed of 100rpm to obtain a powdered electrolytic film-removing agent. S2. Add deionized water to the above electrolytic film-removing agent to prepare a 20wt% electrolytic film-removing agent solution.

[0056] Comparative Example 1 was prepared, and the only difference from Preparation Example 3 was that 2-mercaptobenzothiazole was not added.

[0057] Comparative Example 2 was prepared, and the only difference from Preparation Example 3 was that N,N-diallylbenzenesulfonamide was not added. Example

[0058] Example 1 provides an electroplating process to improve the performance of automotive-grade LEDs. The following description uses Example 1 as an example.

[0059] The electroplating process for improving the performance of automotive-grade LEDs provided in Example 1 includes the following steps: S1, Preprocessing S11. Electrolytic degreasing: Using automotive-grade LED substrate as cathode, 364 stainless steel plate as anode, and 10wt% degreasing powder (purchased from Zhongshan Jundun Washing Materials Co., Ltd.) aqueous solution as electrolyte, the surface of automotive-grade LED substrate is degreased at 50℃ for 10s with a current density of 2 amps / dm². S12, Three-stage water washing: Wash three times with deionized water to remove the residue of the degreasing powder solution; S13. Activation: Immerse the automotive-grade LED substrate after electrolytic degreasing in 10wt% sulfuric acid for 5 seconds. S14, Three-stage water washing: Wash three times with deionized water to remove sulfuric acid residue; S2, Alkali-plated copper S21. The pretreated automotive-grade LED substrate is immersed in an alkaline copper plating solution (from Preparation Example 1) and electrodeposited at 50°C with a current density of 3 amperes / dm² for 7 seconds. S22, Three-stage water rinse: Rinse three times with deionized water to remove alkaline copper plating solution residue; S3, Full Silver Plating S31. The automotive-grade LED substrate after alkaline copper plating is immersed in silver plating solution (from preparation example 2) and electrodeposited at 50°C with a current density of 20 amperes / dm² for 3 seconds. S32, Three-stage water rinse: Rinse three times with deionized water to remove silver plating solution residue; S4, Selected nickel plating S41. The automotive-grade LED substrate, which has been fully silver-plated, is fitted with a selective nickel plating mold and immersed in a nickel plating solution (from Preparation Example 3). Selective nickel plating is performed by strip plating at 50°C with a current density of 4 amperes / square decimeter for 20 seconds. S42, Three-stage water rinse: Rinse three times with deionized water to remove residual nickel plating solution; S5, Palladium plating optional S51. The automotive-grade LED substrate after selective nickel plating is fitted with a selective palladium plating mold and immersed in a palladium plating solution (from Preparation Example 11). Selective palladium plating is performed by spot plating at 40°C with a current density of 0.6 amperes / dm² for 5 seconds. S52, Three-stage water washing: Wash three times with deionized water to remove palladium plating solution residue; S6, Gold Plating Option S61. The palladium-plated automotive-grade LED substrate is fitted with a gold-plating mold and placed in a gold plating solution (from Preparation Example 12). Gold plating is performed by spot plating at 40°C with a current density of 1 ampere / dm² for 1.3 s. S62, Three-stage water rinse: Rinse three times with deionized water to remove gold plating solution residue; S7, Post-processing S71. Electrolytic cleaning: The gold-plated automotive-grade LED substrate is used as the cathode, 364 stainless steel plate is used as the anode, and an electrolytic film-removing agent solution (derived from Preparation Example 13) is used as the electrolyte. The gold-plated automotive-grade LED substrate is cleaned by passing an electric current at a current density of 1 ampere / dm² for 10 seconds at 40°C. S72, Three-stage water washing: Wash three times with deionized water to remove any residue of the electrolytic film-removing agent solution; S73, Anti-oxidation: After electrolytic cleaning, the automotive-grade LED substrate is immersed in an anti-oxidant solution PET-880 (purchased from METALOR) for 15 seconds; S74, Three-stage water washing: Wash three times with deionized water to remove the antioxidant solution PET-880; S75, Drying.

[0060] Examples 2-3 differ from Example 1 only in that the current density and electroplating time are different in each step of the electroplating process, as detailed in Table 2.

[0061] Table 2 Current density and electroplating time for each step in Examples 1-3 S21 current density 3 amperes per square decimeter 7 amperes per square decimeter 5 amperes per square decimeter S21 plating time 7s 3s 5s S31 Current Density 20 amperes per square decimeter 50 amperes per square decimeter 35 amperes per square decimeter S31 plating time 3s 1s 2s S41 Current Density 4 amperes per square decimeter 8 amperes per square decimeter 6 amperes per square decimeter S41 plating time 20s 10s 15s S51 current density 0.6 amperes per square decimeter 2 amperes per square decimeter 1.3 Amperes per square decimeter S51 plating time 5s 3s 4s S61 Current Density 1 ampere / square decimeter 2 amperes per square decimeter 1.5 amperes per square decimeter S61 plating time 1.3s 0.7s 1s Examples 4-12 differ from Example 3 only in that the source of the nickel plating solution is different, as detailed in Table 3.

[0062] Table 3 Source of nickel plating solution in Example 3-12 Source of nickel plating solution Preparation Example 3 Preparation Example 4 Preparation Example 5 Preparation Example 6 Preparation Example 7 Example Example 8 Example 9 Example 10 Example 11 Example 12 Source of nickel plating solution Preparation Example 8 Preparation Example 9 Preparation Example 10 Preparation of Comparative Example 1 Preparation of Comparative Example 2

[0063] The electroplating process for automotive-grade LEDs provided in Comparative Example 1 includes the following steps: S1, Preprocessing S11. Electrolytic degreasing: Using automotive-grade LED substrate as cathode, 364 stainless steel plate as anode, and 10wt% degreasing powder (purchased from Zhongshan Jundun Washing Materials Co., Ltd.) aqueous solution as electrolyte, the surface of automotive-grade LED substrate is degreased at 50℃ for 10s with a current density of 2 amps / dm². S12, Three-stage water washing: Wash three times with deionized water to remove the residue of the degreasing powder solution; S13. Activation: Immerse the automotive-grade LED substrate after electrolytic degreasing in 10wt% sulfuric acid for 5 seconds. S14, Three-stage water washing: Wash three times with deionized water to remove sulfuric acid residue; S2, Fully Nickel Plated S21. The activated automotive-grade LED substrate is immersed in a nickel plating solution (from Preparation Example 3) and electrodeposited at 50°C with a current density of 4 amperes / dm² for 20 seconds. S22, Three-stage water rinse: Rinse three times with deionized water to remove residual nickel plating solution; S3, Palladium plating selected S31. The automotive-grade LED substrate, which is fully nickel-plated, is fitted with a palladium plating mold and immersed in a palladium plating solution (from Preparation Example 11). Palladium is selectively plated using a spot plating method at 40°C with a current density of 0.6 amperes per square decimeter for 5 seconds. S32, Three-stage water washing: Wash three times with deionized water to remove palladium plating solution residue; S4, Gold Plating Option S41. The palladium-plated automotive-grade LED substrate is fitted with a gold-plating mold and placed in a gold plating solution (from Preparation Example 12). Gold plating is performed by spot plating at 40°C with a current density of 1 ampere / dm² for 1.3 s. S42, Three-stage water rinse: Rinse three times with deionized water to remove gold plating solution residue; S5, Post-processing S51. Electrolytic cleaning: The gold-plated automotive-grade LED substrate is used as the cathode, 364 stainless steel plate is used as the anode, and an electrolytic film-removing agent solution (derived from Preparation Example 13) is used as the electrolyte. The gold-plated automotive-grade LED substrate is cleaned by passing an electric current at a current density of 1 ampere / dm² for 10 seconds at 40°C. S52, Three-stage water washing: Wash three times with deionized water to remove any residue of the electrolytic film-removing agent solution; S53, Anti-oxidation: After electrolytic cleaning, the automotive-grade LED substrate is immersed in an anti-oxidant solution PET-880 (purchased from METALOR) for 15 seconds; S54, Three-stage water washing: Wash three times with deionized water to remove the antioxidant solution PET-880; S55, Drying.

[0064] The following performance tests were conducted on the automotive-grade LEDs after electroplating in Examples 1-12 and Comparative Example 1 of this application.

[0065] 1. The automotive-grade LEDs of Examples 1-12 and Comparative Example 1 of this application, after electroplating, are bent to 90 degrees. o Then, use needle-nose pliers to press it firmly, and observe under a microscope at 50x magnification whether there are cracks at the bend. The test results are shown in Table 4.

[0066] 2. The automotive-grade LEDs of Examples 1-12 and Comparative Example 1 of this application were baked at 260°C for 5 hours. They were observed under a microscope at 50x magnification to see if there was any bubbling. The test results are shown in Table 4.

[0067] 3. The automotive-grade LEDs of Examples 1-12 and Comparative Example 1 of this application were baked at 260°C for 48 hours and observed under a microscope at 50x magnification to see if there was bubbling. The test results are shown in Table 4.

[0068] 4. The automotive-grade LEDs of Examples 1-12 and Comparative Example 1 after electroplating were placed in a neutral salt spray environment for 7 days. The presence of bubbles was observed under a microscope at 50x magnification. The test results are shown in Table 4.

[0069] 5. The automotive-grade LEDs of Examples 1-12 and Comparative Example 1 after electroplating were placed in a neutral salt spray environment for 30 days. The presence of bubbles was observed under a microscope at 50x magnification. The test results are shown in Table 4.

[0070] 6. The automotive-grade LEDs of Examples 1-12 and Comparative Example 1 after electroplating were placed in a neutral salt spray environment for 180 days. The presence of bubbles was observed under a microscope at 50x magnification. The test results are shown in Table 4.

[0071] Table 4 Test Data Example 1 No cracks No bubbles foaming No bubbles foaming foaming Example 2 No cracks No bubbles foaming No bubbles foaming foaming Example 3 No cracks No bubbles foaming No bubbles foaming foaming Example 4 No cracks No bubbles foaming No bubbles foaming foaming Example 5 No cracks No bubbles foaming No bubbles foaming foaming Example 6 No cracks No bubbles foaming No bubbles foaming foaming Example 7 No cracks No bubbles No bubbles No bubbles No bubbles foaming Example 8 No cracks No bubbles No bubbles No bubbles No bubbles foaming Example 9 No cracks No bubbles No bubbles No bubbles No bubbles foaming Example 10 No cracks No bubbles No bubbles No bubbles No bubbles No bubbles Example 11 No cracks foaming foaming foaming foaming foaming Example 12 No cracks foaming foaming foaming foaming foaming Comparative Example 1 Cracks foaming foaming foaming foaming foaming The following section, with reference to the data in Table 4, details this application.

[0072] Based on the test data from Example 1 and Comparative Example 1, it can be seen that by selecting nickel plating in areas where there is no bending, this application can avoid the cracking phenomenon caused by full nickel plating and improve the performance of automotive-grade LEDs.

[0073] Based on the test data from Examples 1 and 11-12, the nickel plating solution in Example 1 contains N,N-diallylbenzenesulfonamide and a thiol-containing fused heterocyclic compound. The two work together to significantly improve the adhesion and ductility of the coating. The coating does not bubble when baked at 260°C for 5 hours or treated with salt spray for 7 days.

[0074] Based on the test data from Examples 7 and 5-6, Example 7 used a complex of benzotriazole and hydroxyethylethylenediaminetriacetic acid as a complexing agent, Example 5 used hydroxyethylethylenediaminetriacetic acid, and Example 6 used benzotriazole. The coatings corresponding to Example 7 did not blister after baking at 260°C for 48 hours and undergoing salt spray treatment for 30 days. This is because the complex of benzotriazole and hydroxyethylethylenediaminetriacetic acid, and the interaction between benzotriazole and the thiol-containing fused heterocyclic compound, improve the stability and weather resistance of the protective film on the coating surface. Furthermore, the interaction between hydroxyethylethylenediaminetriacetic acid and nickel aminosulfonate and N,N-diallylbenzenesulfonamide further promotes the Ni... 2+ Adsorption not only has a good complexing effect on nickel ions, but also improves the adhesion and ductility of the coating.

[0075] Based on the test data from Examples 10 and 9, Example 10 used 5-amino-2-mercaptobenzimidazole, while Example 9 used 2-mercaptobenzothiazole. The coating in Example 10 did not blister after 180 days of salt spray treatment. This is because 5-amino-2-mercaptobenzimidazole has an amino group, which promotes its interaction with ethylenediaminetriacetic acid, nickel aminosulfonate, and N,N-diallylbenzenesulfonamide, further improving the weather resistance of the coating and further increasing the time before the coating does not blister after salt spray treatment.

[0076] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. An electroplating process for improving the performance of automotive-grade LEDs, characterized in that, Includes the following steps: S1, Pre-processing; S2, Alkaline Copper Plating: Immerse the pretreated automotive-grade LED substrate in an alkaline copper plating solution and electrodeposit for 3-7 seconds at a current density of 3-7 amperes / dm². S3, Full Silver Plating: Immerse the automotive-grade LED substrate after alkaline copper plating into the silver plating solution, with a current density of 20-50 amperes / square decimeter, and electrodeposit for 1-3 seconds; S4. Selective nickel plating: The silver-plated automotive-grade LED substrate is fitted with a selective nickel plating mold and placed in a nickel plating solution. Electrodeposition is performed for 10-20 seconds at a current density of 4-8 amperes / dm². The empty space of the nickel plating mold corresponds to the non-bending area of ​​the automotive-grade LED, and the shielding strip of the nickel plating mold corresponds to the bending area of ​​the automotive-grade LED. S5. Selective Palladium Plating: The nickel-plated automotive-grade LED substrate is fitted with a selective palladium plating mold and placed in a palladium plating solution. Electrodeposition is performed for 3-5 seconds at a current density of 0.6-2 amperes / dm². S6. Selective Gold Plating: The palladium-plated automotive-grade LED substrate is fitted with a selective gold plating mold and placed in a gold plating solution. Electrodeposition is performed at a current density of 1-2 amperes / square decimeter for 0.7-1.3 seconds. S7, Post-processing; The nickel plating solution comprises: nickel aminosulfonate 400-600 mL / L, nickel chloride 10-20 g / L, boric acid 30-50 g / L, complexing agent 2-3 g / L, N,N-diallylbenzenesulfonamide 1.5-2.5 mL / L, sodium benzenesulfinate 0.35-0.45 g / L, and thiol-containing fused heterocyclic compound 0.01-0.015 g / L. The complexing agent is composed of benzotriazole and hydroxyethylethylenediaminetriacetic acid in a mass ratio of 1:(3-5); the thiol-containing fused heterocyclic compound is 2-mercaptobenzothiazole or 5-amino-2-mercaptobenzimidazole.

2. The electroplating process for improving the performance of automotive-grade LEDs according to claim 1, characterized in that, The nickel plating solution is composed of: nickel aminosulfonate 500 mL / L, nickel chloride 15 g / L, boric acid 40 g / L, complexing agent 2.5 g / L, N,N-diallylbenzenesulfonamide 2 mL / L, sodium benzenesulfinate 0.4 g / L, and thiol-containing fused heterocyclic compound 0.015 g / L.

3. The electroplating process for improving the performance of automotive-grade LEDs according to claim 1, characterized in that, The mass ratio of benzotriazole to hydroxyethylethylenediaminetriacetic acid is 1:

4.

4. The electroplating process for improving the performance of automotive-grade LEDs according to claim 1, characterized in that, The selected nickel plating corresponds to a nickel plating thickness of 35-45 microinches.

5. The electroplating process for improving the performance of automotive-grade LEDs according to claim 1, characterized in that, The selected nickel plating current density is 6 amperes per square decimeter, and the electrodeposition time is 15 seconds.

6. The electroplating process for improving the performance of automotive-grade LEDs according to claim 1, characterized in that, The thickness of the copper plating layer corresponding to the alkaline copper plating is 25-35 microinches.

7. The electroplating process for improving the performance of automotive-grade LEDs according to claim 1, characterized in that, The pH of the alkaline copper plating solution is 10-12.