Electroplating blackening process

Abstract

The invention relates to the technical field of steel blackening, in particular to an electroplating blackening process. The invention relates to an electroplating blackening process, which comprises the following working procedures of oil removal, two times of water washing, acid pickling, two times of water washing, nickel electroplating, two times of water washing, blackening treatment, two times of water washing, silane spraying and drying, the concentration of tungsten ions is 2-6 g / L, the concentration of manganese ions is 26 g / L, the concentration of zinc ions is 26 g / L, yttrium oxide is 0.5-0.8 g / L, boric acid is 40-45 g / L, and an auxiliary blackening agent is 0.2-0.3 g / L. The electroplating blackening process provided by the invention not only solves the problems of high hydrogen embrittlement risk, unstable blackened film quality and the like in the prior art, but also shows remarkable advantages in the aspects of improving the product quality, reducing the cost, protecting the environment and the like.

Description

Technical Field

[0001] The present application relates to the technical field of steel blackening, and in particular to an electroplating blackening process. Background Art

[0002] Some small steel parts such as high-strength steel and carbon steel, such as the hinges for folding mobile phones, use ordinary electroplating technology. In some special parts, the hardness, corrosion resistance and color uniformity do not meet the requirements. For some frequently used parts, if the hardness does not meet the standard, wear and cracks will appear during use, which will affect the overall function of the product.

[0003] In addition, the traditional nickel electroplating process will infiltrate a large amount of hydrogen, which is particularly unsuitable for electronic components that require hydrogen embrittlement. The existing nickel layer blackening process can reduce the hydrogen content by heating and dehydrogenation, but it will cause the black surface effect to decrease or even disappear. Summary of the invention

[0004] The purpose of this application is to provide an electroplating blackening process to address the shortcomings of current technology. After being treated by the electroplating blackening process of this application, the surface of the steel product has a blackened film with uniform color. At the same time, the blackened film has high hardness, excellent corrosion resistance, and high peeling strength. The hydrogen content in the film layer is less than 5ppm, which greatly reduces the problem of hydrogen embrittlement. It is suitable for steel electronic products such as high-strength steel and carbon steel that require impact testing or drop testing.

[0005] The present application provides an electroplating blackening process, which adopts the following technical solutions: An electroplating blackening process comprises the following steps: degreasing → 2 water washings → pickling → 2 water washings → nickel electroplating → 2 water washings → blackening treatment → 2 water washings → silane spraying → drying, wherein the blackening liquid for the blackening treatment comprises the following components: 75-80 g / L nitric acid, 2-6 g / L tungsten ion concentration, 2-6 g / L manganese ion concentration, 2-6 g / L zinc ion concentration, 0.5-0.8 g / L yttrium oxide, 40-45 g / L boric acid, and 0.2-0.3 g / L auxiliary blackening agent.

[0006] By adopting the above technical solutions, degreasing: remove grease and other contaminants on the surface of steel parts to provide a clean surface for subsequent treatment. Water washing: to remove residual chemicals and ensure the surface is clean. Pickling: use acidic solution to remove oxides and other impurities on the surface of steel parts to improve the adhesion of the coating. Electroplating nickel: a layer of nickel is plated on the surface of steel parts as a base layer, which helps to improve the adhesion and corrosion resistance of the blackened film. Blackening treatment: use a blackening liquid containing specific metal ions and auxiliary agents to form a uniform blackened film. Silane spraying: spray silane on the blackened film to further improve corrosion resistance and wear resistance. Drying: remove moisture by heating to solidify the coating. Nitric acid: as an oxidant, it helps to form a blackened film. Tungsten ions, zinc ions, and manganese ions: these metal ions play a key role in the blackening liquid. They react with the surface of steel parts to form a uniform blackened film with high hardness and corrosion resistance. Yttrium oxide: used to adjust the properties of the blackened film and improve its corrosion resistance. Boric acid: acts as a buffer to maintain the pH value of the blackening liquid stable. Auxiliary blackening agent: enhances the complexation and blackening effects, making the color of the blackened layer more uniform and beautiful. In summary, the electroplating blackening process in this application achieves a uniform blackened film on the surface of steel products such as high-strength steel by precisely controlling the concentration of each component and using specific process steps, while improving the hardness, corrosion resistance and peeling resistance of the film layer, reducing the risk of hydrogen embrittlement, and is suitable for electronic products that require high durability and reliability.

[0007] Preferably, the tungsten ion concentration is 4.5 g / L, the manganese ion concentration is 4.2 g / L, the zinc ion concentration is 2.5 g / L, and the yttrium oxide concentration is 0.7 g / L.

[0008] By adopting the above technical scheme, the concentrations of tungsten ions, manganese ions, zinc ions and yttrium oxide are 4.5g / L, 4.2g / L, 2.5g / L and 0.7g / L respectively. The effects and synergistic effects of these components in the blackening liquid are as follows: Tungsten ions (concentration 4.5g / L): Tungsten ions play a role in improving the hardness of the blackening film in the blackening liquid. It can react chemically with the surface of the substrate to form a dense tungsten compound layer, thereby improving the hardness and wear resistance of the film layer. At the same time, tungsten ions also have certain corrosion resistance and can enhance the corrosion resistance of the blackening film. Manganese ions (concentration 4.2g / L): Manganese ions mainly play a role in improving the corrosion resistance of the blackening film in the blackening liquid. It can react chemically with the surface of the substrate to form a dense manganese compound layer, thereby preventing oxygen and other corrosive substances from corroding the substrate. In addition, manganese ions can also improve the adhesion of the blackening film and enhance its anti-stripping performance. Zinc ions (concentration 2.5g / L): Zinc ions in the blackening liquid mainly play the role of improving the anti-stripping performance of the blackened film. It can react chemically with the surface of the substrate to form a dense zinc compound layer, thereby improving the adhesion of the film layer and preventing the blackened film from falling off during use. Yttrium oxide (concentration 0.7g / L): Yttrium oxide in the blackening liquid mainly plays the role of improving the color uniformity of the blackened film. It can react chemically with the surface of the substrate to form a dense yttrium oxide compound layer, thereby making the color of the blackened film more uniform. In addition, yttrium oxide can also improve the gloss and corrosion resistance of the blackened film, making its appearance more beautiful. In summary, the synergistic effect of tungsten ions, manganese ions, zinc ions and yttrium oxide in this application is mainly reflected in improving the hardness, corrosion resistance, stripping resistance and color uniformity of the blackened film. By precisely controlling the concentration of these components, efficient and high-quality electroplating blackening treatment of the surface of electronic products made of steel such as high-strength steel and carbon steel can be achieved.

[0009] Preferably, the auxiliary blackening agent is composed of sodium ethylenediaminetetramethylenephosphate, 5-(3-aminophenyl)tetrazole and hydroxyethylidene diphosphonic acid in a mass ratio of 3:2:3.

[0010] By adopting the above technical scheme, ethylenediaminetetramethylene phosphate (EDTA): EDTA is a commonly used chelating agent that can form a stable complex with metal ions. In the blackening liquid, EDTA can react with metal ions such as tungsten ions, zinc ions and manganese ions to control the concentration of these metal ions and keep them within a suitable range. This can improve the hardness, corrosion resistance and peeling resistance of the blackened film. 2.5-(3-aminophenyl)tetrazole (5-APT): 5-APT is an organic compound with good complexing properties. In the blackening liquid, 5-APT can react with metal ions to further stabilize the concentration of metal ions. In addition, 5-APT can also promote the blackening reaction and improve the blackening effect. Hydroxyethyl diphosphonic acid (HEDP): HEDP is an organic phosphonate with strong chelating ability and antioxidant properties. In the blackening liquid, HEDP can react with metal ions to stabilize the concentration of metal ions. At the same time, HEDP can also improve the corrosion resistance of the blackening film and extend its service life. In summary, ethylenediaminetetramethylenephosphate sodium, 5-(3-aminophenyl)tetrazole and hydroxyethylidene diphosphonic acid in the blackening liquid synergistically regulate the concentration of metal ions and improve the hardness, corrosion resistance and peeling resistance of the blackened film. At the same time, these auxiliary blackening agents can also promote the blackening reaction, improve the blackening effect, and make the obtained blackened layer have better color and uniformity.

[0011] Preferably, the degreasing process conditions are: sodium carbonate 20-25 g / L, sodium hydroxide 20-25 g / L, dioxyethylene octylphenol ether 0.2-0.5 g / L, triethanolamine 0.3-0.5 g / L, temperature 50-60°C, degreasing time 3-5 minutes, ultrasonic power 3-5 kW.

[0012] Preferably, the water for the second water washing in the two water washings is RO water, the conductivity is 0.5-3 μS / cm, and the water washing time is 0.5-1 min.

[0013] Preferably, the pickling process conditions are: 5-7 g / L sulfuric acid with a density of 1.84 g / mL, room temperature, and a time of 20-30 s.

[0014] Preferably, the process conditions for the nickel electroplating are: nickel chloride 10-20 g / L, nickel sulfamate 400-450 g / L, nickel sulfate 10-20 g / L, sodium citrate 20-25 g / L, sodium propargyl sulfonate 0.1-0.2 g / L, sodium dodecyl sulfate 0.03-0.05 g / L, stress reliever 0.03-0.05 g / L, temperature 50-55 ° C, cathode current density 1-3 A / dm 2 , pH 4.3-4.8, the plating time is 20-40 minutes, and the plating current is applied in the constant current mode of a DC power supply.

[0015] Preferably, the stress reliever is composed of sodium o-benzoylsulfonyl imide and sodium propylene sulfonate in a mass ratio of 3:2.

[0016] By adopting the above technical scheme, the stress reliever is composed of sodium o-benzoylsulfonyl imide and sodium propylene sulfonate in a mass ratio of 3:2. The role in this application and the synergistic effect between sodium o-benzoylsulfonyl imide and sodium propylene sulfonate are mainly reflected in the following aspects: the synergistic effect of sodium o-benzoylsulfonyl imide and sodium propylene sulfonate can significantly reduce the internal stress in the electroplated nickel layer. The reduction of this stress helps to improve the adhesion and overall mechanical properties of the coating and reduce the risk of cracking and peeling of the coating. In the process of electroplating nickel, hydrogen atoms easily penetrate into the coating, resulting in hydrogen embrittlement. The combined use of sodium o-benzoylsulfonyl imide and sodium propylene sulfonate can effectively inhibit the absorption of hydrogen, thereby reducing the hydrogen content in the coating and reducing the occurrence of hydrogen embrittlement problems. The use of the stress reliever not only reduces the stress of the coating, but also improves the microstructure of the coating, making it more dense and uniform. This structural optimization helps to improve the corrosion resistance of the coating and extend the service life of the product. By reducing the stress of the coating and optimizing the structure of the coating, the stress reliever can also enhance the anti-peeling performance of the coating. This means that the coating is less likely to peel off from the substrate when subjected to mechanical shock or environmental changes, maintaining its integrity and functionality. The synergistic effect of sodium o-benzoylsulfonimide and sodium propylene sulfonate helps to achieve uniform deposition of metal ions during the electroplating process, forming a smooth and uniform coating. This helps to improve the appearance quality and performance consistency of the final product. In summary, the combined use of sodium o-benzoylsulfonimide and sodium propylene sulfonate as stress relievers plays multiple positive roles in the nickel electroplating process, not only solving the hydrogen embrittlement problem, but also improving the overall performance of the coating, meeting the high standards for surface treatment technology of electronic products made of high-strength steel, carbon steel and other steel materials.

[0017] Preferably, the process conditions of the silane spraying are: temperature 25-35° C., organic film coupling agent concentration 4.5-5.5 g / L, and the model of the organic film coupling agent is KBM-403.

[0018] By adopting the above technical solution, by spraying silane after the nickel electroplating process, a dense organic film can be formed on the surface of the blackened film. This organic film can effectively block moisture and oxygen in the air from contacting the blackened film, thereby slowing down the corrosion process.

[0019] Preferably, the drying process adopts a temperature of 120-150° C. and a time of 10-20 minutes.

[0020] In summary, the beneficial technical effects of this application are: 1. Improve the quality of the surface blackening film: By precisely controlling the concentration of each component in the blackening liquid, including the amount of tungsten ions, zinc ions, manganese ions and yttrium oxide, the blackening film formed on the surface of the treated high-strength steel products has uniform color, high hardness, and significantly improved corrosion resistance and peeling resistance. This high-quality blackening film is not only more beautiful in appearance, but also can better protect the substrate from corrosion and damage during use.

[0021] 2. Reduce the risk of hydrogen embrittlement: Adding stress relievers to the nickel plating process can significantly reduce the stress and hydrogen content in the nickel layer, thereby effectively reducing the occurrence of hydrogen embrittlement. This is especially important for electronic products made of high-strength steel, carbon steel, and other steel materials that need to withstand impact tests or drop tests, as they may be subject to greater impact or pressure during use.

[0022] 3. Enhanced corrosion resistance: The application of silane spraying process further improves the corrosion resistance of the black film, so that the treated steel products can maintain stability and durability for a long time in harsh environments.

[0023] 4. Optimize electroplating process conditions: Through fine control of nickel electroplating process conditions, such as controlling the concentration of nickel chloride, nickel sulfamate, nickel sulfate, etc., as well as temperature, cathode current density, pH value and other parameters, a more efficient and stable electroplating process is achieved. This not only improves production efficiency, but also ensures the quality and performance of the coating.

[0024] 5. Environmental protection and cost-effectiveness: The electroplating blackening process of this application not only improves product quality, but also takes environmental protection and cost factors into consideration. Reasonable formula design and process optimization help reduce waste generation, energy consumption and raw material consumption, which is in line with the current trend of green manufacturing and sustainable development. DETAILED DESCRIPTION

[0025] The embodiments of the present application will be described in detail below in conjunction with the examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. In the examples, if specific conditions are not specified, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0026] In the following embodiments and comparative examples, a high-strength steel polished sheet with a size of 10 cmX10 cmX0.1 cm is used as the raw material to be blackened.

[0027] Example 1 An electroplating blackening process, comprising the following steps: degreasing → 2 water washings → acid washing → 2 water washings → nickel electroplating → 2 water washings → blackening treatment → 2 water washings → silane spraying → drying, wherein the blackening liquid for the blackening treatment comprises the following components: 75 g / L nitric acid, 2 g / L tungsten ion concentration, 6 g / L manganese ion concentration, 2 g / L zinc ion concentration, 0.5 g / L yttrium oxide, 40 g / L boric acid, and 0.2 g / L auxiliary blackening agent, wherein the auxiliary blackening agent is composed of sodium ethylenediaminetetramethylenephosphate, 5-(3-aminophenyl)tetrazole, and hydroxyethylidene diphosphonic acid in a mass ratio of 3:2:3; The degreasing process conditions are: 20 g / L sodium carbonate, 20 g / L sodium hydroxide, 0.2 g / L dimeroxy octylphenol ether, 0.3 g / L triethanolamine, temperature 50°C, degreasing time 5 minutes, ultrasonic power 3 KW; The water for the second water washing in the two water washings is RO water, the conductivity is 0.5 μS / cm, and the water washing time is 0.5 min; The pickling process conditions are: 5 g / L sulfuric acid with a density of 1.84 g / mL, room temperature, and a time of 20 s; The process conditions of the nickel electroplating are: nickel chloride 10g / L, nickel sulfamate 450g / L, nickel sulfate 10g / L, sodium citrate 20g / L, sodium propargyl sulfonate 0.1g / L, sodium dodecyl sulfate 0.03g / L, stress reliever 0.03g / L, temperature 50°C, cathode current density 1A / dm 2 , pH 4.3, the electroplating time is 40 minutes, the electroplating current is applied in a constant current mode of a DC power supply, and the stress reliever is composed of sodium o-benzoylsulfonyl imide and sodium propylene sulfonate in a mass ratio of 3:2; The process conditions of the silane spraying are: temperature 25° C., organic film coupling agent concentration 4.5 g / L, and the organic film coupling agent model is KBM-403.

[0028] Example 2 An electroplating blackening process, comprising the following steps: degreasing → 2 water washings → acid washing → 2 water washings → nickel electroplating → 2 water washings → blackening treatment → 2 water washings → silane spraying → drying, wherein the blackening liquid for the blackening treatment comprises the following components: 80 g / L nitric acid, 6 g / L tungsten ion concentration, 2 g / L manganese ion concentration, 6 g / L zinc ion concentration, 0.8 g / L yttrium oxide, 45 g / L boric acid, and 0.3 g / L auxiliary blackening agent, wherein the auxiliary blackening agent is composed of sodium ethylenediaminetetramethylenephosphate, 5-(3-aminophenyl)tetrazole, and hydroxyethylidene diphosphonic acid in a mass ratio of 3:2:3; The degreasing process conditions are: 25 g / L sodium carbonate, 25 g / L sodium hydroxide, 0.5 g / L dimeroxy octylphenol ether, 0.5 g / L triethanolamine, temperature 60°C, degreasing time 3 minutes, ultrasonic power 5 KW; The water for the second water washing in the two water washings is RO water, the conductivity is 3 μS / cm, and the water washing time is 1 minute; The pickling process conditions are: 7 g / L sulfuric acid with a density of 1.84 g / mL, room temperature, and a time of 30 s; The process conditions of the nickel electroplating are: nickel chloride 20g / L, nickel sulfamate 400g / L, nickel sulfate 20g / L, sodium citrate 25g / L, sodium propargyl sulfonate 0.2g / L, sodium dodecyl sulfate 0.05g / L, stress reliever 0.05g / L, temperature 55°C, cathode current density 3A / dm 2 , pH 4.8, the electroplating time is 20 minutes, the electroplating current is applied in a constant current mode of a DC power supply, and the stress reliever is composed of sodium o-benzoylsulfonyl imide and sodium propylene sulfonate in a mass ratio of 3:2; The process conditions of the silane spraying are: temperature 35° C., organic film coupling agent concentration 5.5 g / L, and the organic film coupling agent model is KBM-403.

[0029] Example 3 An electroplating blackening process, comprising the following steps: degreasing → 2 water washings → acid washing → 2 water washings → nickel electroplating → 2 water washings → blackening treatment → 2 water washings → silane spraying → drying, wherein the blackening liquid for the blackening treatment comprises the following components: 78 g / L nitric acid, 3 g / L tungsten ion concentration, 3 g / L manganese ion concentration, 4 g / L zinc ion concentration, 0.6 g / L yttrium oxide, 43 g / L boric acid, and 0.25 g / L auxiliary blackening agent, wherein the auxiliary blackening agent is composed of sodium ethylenediaminetetramethylenephosphate, 5-(3-aminophenyl)tetrazole, and hydroxyethylidene diphosphonic acid in a mass ratio of 3:2:3; The degreasing process conditions are: 23 g / L sodium carbonate, 22 g / L sodium hydroxide, 0.4 g / L diethylene glycol octylphenol ether, 0.4 g / L triethanolamine, temperature 55°C, degreasing time 4 minutes, ultrasonic power 4 KW; The water for the second water washing in the two water washings is RO water, the conductivity is 2 μS / cm, and the water washing time is 0.8 min; The pickling process conditions are: 6 g / L sulfuric acid with a density of 1.84 g / mL, room temperature, and a time of 25 s; The process conditions of the nickel electroplating are: nickel chloride 15g / L, nickel sulfamate 430g / L, nickel sulfate 15g / L, sodium citrate 22g / L, sodium propargyl sulfonate 0.15g / L, sodium dodecyl sulfate 0.04g / L, stress reliever 0.04g / L, temperature 53°C, cathode current density 2A / dm 2 , pH 4.5, the electroplating time is 30 minutes, the electroplating current is applied in a constant current mode of a DC power supply, and the stress reliever is composed of sodium o-benzoylsulfonyl imide and sodium propylene sulfonate in a mass ratio of 3:2; The process conditions of the silane spraying are: temperature 30° C., organic film coupling agent concentration 5 g / L, and the organic film coupling agent model is KBM-403.

[0030] Example 4 The same as Example 3, the differences are: the tungsten ion concentration is 4.5 g / L, the manganese ion concentration is 4.2 g / L, the zinc ion concentration is 2.5 g / L, and the yttrium oxide concentration is 0.7 g / L.

[0031] Comparative Example 1 The same as Example 4, the differences are: the tungsten ion concentration is 0 g / L, the manganese ion concentration is 0 g / L, the zinc ion concentration is 2.5 g / L, and the yttrium oxide concentration is 0.7 g / L.

[0032] Comparative Example 2 The same as Example 4, the differences are: the tungsten ion concentration is 0 g / L, the manganese ion concentration is 4.2 g / L, the zinc ion concentration is 2.5 g / L, and the yttrium oxide concentration is 0.7 g / L.

[0033] Comparative Example 3 The same as Example 4, the differences are: the tungsten ion concentration is 4.5 g / L, the manganese ion concentration is 4.2 g / L, the zinc ion concentration is 2.5 g / L, and the yttrium oxide concentration is 0 g / L.

[0034] Comparative Example 4 The same as Example 4, the difference is that the auxiliary blackening agent is sodium ethylenediaminetetramethylenephosphate.

[0035] Comparative Example 5 The same as Example 4, except that the auxiliary blackening agent is 5-(3-aminophenyl)tetrazole.

[0036] Comparative Example 6 The same as Example 4, except that the auxiliary blackening agent is hydroxyethylidene diphosphonic acid.

[0037] Comparative Example 7 The same as Example 4, the difference is that the stress reliever is sodium o-benzoylsulfonimide.

[0038] Comparative Example 8 The same as Example 4, the difference is that the stress reliever is sodium o-benzoylsulfonimide.

[0039] Performance Testing The high-strength steel polishing sheets prepared in Examples 1 to 4 and Comparative Examples 1 to 8 were respectively subjected to the following performance tests. The test results are shown in Table 1.

[0040] Color and color difference detection: Observe the surface color of the copper foil with the naked eye, and use a colorimeter to detect the color difference ΔE; Hydrogen content: tested in accordance with GB / T 223.82-2018 standard; Neutral salt spray test: Test in accordance with GB / T10125-1997; in the salt spray corrosion test chamber, use a salt solution with a sodium chloride content of 5±1%: when the temperature is 35°C, the pH value of the collected liquid after spraying is 6.5-7.2, and the pH value can be adjusted with diluted hydrochloric acid or sodium hydroxide. The test space temperature is 35°C; the continuous spray test time is 72 hours; then return to normal atmospheric conditions in the chamber, and maintain for 2 hours after stabilization. Inspect the appearance of each plated part. Standard: No rust, discoloration, or coating shedding, record as OK, otherwise record as NG.

[0041] Table 1 Performance test Analyzing the data in Table 1, we can see that: 1) The high-strength steel fine polishing sheets prepared in Examples 1 to 4 have a uniformly colored blackened film on the surface of the product after being treated by the electroplating blackening process of the present application. The blackened film has excellent corrosion resistance, and the hydrogen content in the film layer is less than 5ppm, which greatly reduces the problem of hydrogen embrittlement. It is suitable for electronic products made of steel such as high-strength steel and carbon steel that require impact testing or drop testing.

[0042] 2) The performance comparison analysis of the high-strength steel fine polishing sheet prepared by Example 4 and Comparative Examples 1-3 shows that when the concentrations of tungsten ions, manganese ions, zinc ions and yttrium oxide are 4.5g / L, 4.2g / L, 2.5g / L and 0.7g / L respectively. The synergistic effect between tungsten ions, manganese ions, zinc ions and yttrium oxide can significantly improve the color uniformity and corrosion resistance of the blackened film. By accurately controlling the concentrations of these components, efficient and high-quality electroplating blackening treatment can be achieved on the surface of electronic products made of steel such as high-strength steel and carbon steel.

[0043] 3) The performance comparison analysis of the high-strength steel polishing sheet prepared by Example 4 and Comparative Examples 4-6 shows that the auxiliary blackening agent is composed of sodium ethylenediaminetetramethylene phosphate, 5-(3-aminophenyl)tetrazole and hydroxyethylidene diphosphonic acid in a mass ratio of 3:2:3. The synergistic effect between sodium ethylenediaminetetramethylene phosphate, 5-(3-aminophenyl)tetrazole and hydroxyethylidene diphosphonic acid is utilized to jointly regulate the concentration of metal ions and improve the color uniformity and corrosion resistance of the blackened film. At the same time, these auxiliary blackening agents can also promote the blackening reaction, improve the blackening effect, and make the obtained blackened layer have better color and uniformity.

[0044] 4) The performance comparison analysis of the high-strength steel polishing sheet prepared by Example 4 and Comparative Examples 7-8 shows that the stress reliever is composed of sodium o-benzoylsulfonyl imide and sodium propylene sulfonate in a mass ratio of 3:2. The synergistic effect between sodium o-benzoylsulfonyl imide and sodium propylene sulfonate is mainly reflected in the following aspects: the synergistic effect of sodium o-benzoylsulfonyl imide and sodium propylene sulfonate can significantly reduce the internal stress in the electroplated nickel layer. The reduction of this stress helps to improve the adhesion and overall mechanical properties of the coating and reduce the risk of cracking and peeling of the coating. During the nickel electroplating process, hydrogen atoms easily penetrate into the coating, resulting in hydrogen embrittlement. The combined use of sodium o-benzoylsulfonyl imide and sodium propylene sulfonate can effectively inhibit the absorption of hydrogen, thereby reducing the hydrogen content in the coating and reducing the occurrence of hydrogen embrittlement problems. The use of stress relievers not only reduces the stress of the coating, but also improves the microstructure of the coating, making it more dense and uniform. This structural optimization helps to improve the corrosion resistance of the coating and extend the service life of the product. By reducing coating stress and optimizing coating structure, stress relievers can also enhance the coating's resistance to peeling. This means that when subjected to mechanical shock or environmental changes, the coating is less likely to peel off from the substrate, maintaining its integrity and functionality. The synergistic effect of sodium o-benzoylsulfonyl imide and sodium propylene sulfonate helps to achieve uniform deposition of metal ions during the electroplating process, forming a smooth and uniform coating. This helps to improve the appearance quality and performance consistency of the final product. In summary, the combined use of sodium o-benzoylsulfonyl imide and sodium propylene sulfonate as stress relievers plays multiple positive roles in the nickel electroplating process, not only solving the hydrogen embrittlement problem, but also improving the overall performance of the coating, meeting the high standards for surface treatment technology of electronic products made of high-strength steel, carbon steel and other steel materials.

[0045] The above embodiments are only used to explain the technical solutions of the present application rather than to limit them. Although the above embodiments provide a specific description of the present application, relevant technical personnel should understand that the specific implementation modes of the present invention can still be modified or replaced by equivalents, and any modifications and equivalent replacements that do not depart from the spirit and scope of the present application should be included in the scope of protection of the present application.

Claims

1. An electroplating blackening process, characterized in that: The method comprises the following steps: degreasing → 2 water washings → pickling → 2 water washings → nickel electroplating → 2 water washings → blackening treatment → 2 water washings → silane spraying → drying, wherein the blackening liquid for the blackening treatment comprises the following components: 75-80 g / L nitric acid, 2-6 g / L tungsten ion concentration, 2-6 g / L manganese ion concentration, 2-6 g / L zinc ion concentration, 0.5-0.8 g / L yttrium oxide, 40-45 g / L boric acid, and 0.2-0.3 g / L auxiliary blackening agent.

2. The electroplating blackening process according to claim 1, characterized in that: The tungsten ion concentration is 4.5 g / L, the manganese ion concentration is 4.2 g / L, the zinc ion concentration is 2.5 g / L, and the yttrium oxide concentration is 0.7 g / L.

3. The electroplating blackening process according to claim 1, characterized in that: The auxiliary blackening agent is composed of sodium ethylenediaminetetramethylenephosphate, 5-(3-aminophenyl)tetrazole and hydroxyethylidene diphosphonic acid in a mass ratio of 3:2:

3.

4. The electroplating blackening process according to claim 1, characterized in that: The degreasing process conditions are: 20-25 g / L sodium carbonate, 20-25 g / L sodium hydroxide, 0.2-0.5 g / L dimeroxy octylphenol ether, 0.3-0.5 g / L triethanolamine, temperature 50-60° C., degreasing time 3-5 minutes, and ultrasonic power 3-5 KW.

5. The electroplating blackening process according to claim 1, characterized in that: The water for the second water washing in the two water washings is RO water with a conductivity of 0.5-3 μS / cm and a washing time of 0.5-1 min.

6. The electroplating blackening process according to claim 1, characterized in that: The pickling process conditions are: 5-7 g / L sulfuric acid with a density of 1.84 g / mL, room temperature, and a time of 20-30 s.

7. The electroplating blackening process according to claim 1, characterized in that: The process conditions of the nickel electroplating are: nickel chloride 10-20g / L, nickel sulfamate 400-450g / L, nickel sulfate 10-20g / L, sodium citrate 20-25g / L, sodium propargyl sulfonate 0.1-0.2g / L, sodium dodecyl sulfate 0.03-0.05g / L, stress reliever 0.03-0.05g / L, temperature 50-55°C, cathode current density 1-3A / dm 2 , pH 4.3-4.8, the plating time is 20-40 minutes, and the plating current is applied in the constant current mode of a DC power supply.

8. The electroplating blackening process according to claim 7, characterized in that: The stress relieving agent is composed of sodium o-benzoylsulfonyl imide and sodium propylene sulfonate in a mass ratio of 3:

2.

9. The electroplating blackening process according to claim 1, characterized in that: The process conditions of the silane spraying are: temperature 25-35° C., organic film coupling agent concentration 4.5-5.5 g / L.

10. The electroplating blackening process according to claim 1, characterized in that: The temperature used in the drying process is 120-150° C. and the time is 10-20 minutes.

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