Strong-acidity bright copper plating electrolyte for steel parts and application method of strong-acidity bright copper plating electrolyte

Abstract

The invention relates to the technical field of copper plating electrolyte, in particular to strong-acidity bright copper plating electrolyte for steel and iron parts and an application method of the strong-acidity bright copper plating electrolyte. The invention discloses a bright copper plating electrolyte for a strong-acidity steel part. The bright copper plating electrolyte comprises the following substances in parts by weight: 80-100 parts of copper sulfate pentahydrate; 50-60 parts of sulfuric acid; 20-30 parts of hydrochloric acid; 15 to 20 parts of an auxiliary modifier; the auxiliary modifier comprises the following substances in parts by weight: 6-15 parts of sodium benzenesulfinate; 8 to 15 parts of lauryl sodium sulfate; 10 to 20 parts of polyethylene glycol; 80 to 100 parts of a composite coordination agent; the composite coordination agent is a coordination agent compounded by trisodium citrate and ethylene diamine tetraacetic acid disodium salt. The copper ion concentration is stabilized through the complexing effect of the composite coordination agent trisodium citrate and the disodium ethylene diamine tetraacetate, the situation that a coating is rough due to the fact that the local concentration is too high is avoided, meanwhile, the dispersing capacity of the electrolyte is enhanced, and it is ensured that the coating is compact in crystallization, bright and flat. The whole formula provides a stable chemical environment for the subsequent electroplating process through multi-component synergy, and lays a foundation for coating binding force and brightness.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of copper plating electrolyte, in particular to a strong-acid bright copper plating electrolyte for steel and iron parts and an application method thereof. BACKGROUND

[0002] Steel is a widely used basic material in the industrial field, and occupies an important position in many fields such as mechanical manufacturing, automobile industry, and electronic appliances due to its high strength and good mechanical properties. In order to further expand the application range of steel parts and improve its surface properties, such as improving the conductivity, corrosion resistance, and decoration, surface copper plating treatment of steel parts has become a common technical means. At present, in the copper plating process of steel parts, the traditional method mostly adopts cyanide-free pre-plating copper or chemical copper immersion for priming before bright copper plating. However, this kind of process has obvious limitations: on the one hand, the pre-plating or copper immersion priming step makes the process flow cumbersome, prolongs the production cycle, and increases the production cost, and the multi-step operation easily leads to unstable plating layer adhesion, affecting the quality of the final product; on the other hand, the component design of the existing copper plating electrolyte is not reasonable enough, and the synergistic effect of the auxiliary additive and the brightener is not good, which leads to poor stability of the plating solution, easy occurrence of large fluctuation of copper ion concentration, insufficient dispersion ability, etc., thereby making the plating layer crystallization not fine enough, the brightness not good enough, and the adhesion between the plating layer and the steel substrate weak, which is easy to fall off in the subsequent use process. At the same time, the comprehensive performance of the plating layer obtained by the copper plating electrolyte used in the prior art, such as corrosion resistance, hardness, and wear resistance, needs to be improved. Some plating layers have a short corrosion resistance time in the salt spray test, a high self-corrosion current density, and are difficult to meet the long-term use requirements; and the width of the bright area of the plating layer is limited, and the surface roughness is large, which affects its application in high-precision fields. SUMMARY In order to improve the poor electroplating performance of the existing copper plating electrolyte, the present application provides a strong-acid bright copper plating electrolyte for steel and iron parts and an application method thereof.

[0003] In a first aspect, the present application provides an acidic bright copper plating additive, which adopts the following technical scheme: A strong-acid bright copper plating electrolyte for steel and iron parts comprises the following substances by weight: Copper sulfate pentahydrate 80-100 parts; Sulfuric acid 50-60 parts; Hydrochloric acid 20-30 parts; Auxiliary modifier 15-20 parts; The auxiliary modifier comprises the following substances by weight: Sodium benzenesulfinate 6-15 parts; Sodium dodecyl sulfate 8-15 parts; Polyethylene glycol 10-20 parts; complexing agent 80-100 parts by weight; The complexing agent is a complexing agent of trisodium citrate and disodium ethylenediaminetetraacetate.

[0004] Through the above technical scheme, the application realizes efficient copper plating through the synergistic effect of the main salt, the acid system and the auxiliary modifier. Copper sulfate provides a source of copper ions, sulfuric acid maintains a strong acidic environment to inhibit copper ion hydrolysis and improve solution conductivity; hydrochloric acid introduces chloride ions, which can activate the anode and improve the uniformity of the coating. In the auxiliary modifier, sodium benzenesulfinate as a leveling agent can refine the grain, sodium dodecyl sulfate as a surfactant can reduce the interfacial tension and reduce pinhole defects; polyethylene glycol forms a diffusion barrier by adsorbing on the cathode surface to inhibit concentration polarization; the complexing agent trisodium citrate and disodium ethylenediaminetetraacetate stabilizes the copper ion concentration through complexation to avoid excessive local concentration leading to rough coating, while enhancing the dispersion ability of the electrolyte to ensure that the coating is dense and bright and smooth. The overall formulation provides a stable chemical environment for the subsequent electroplating process through the synergistic effect of multiple components, laying the foundation for the adhesion and brightness of the coating.

[0005] Further, the auxiliary modifier further includes 15-30 parts by weight of potassium tartrate.

[0006] Through the above technical scheme, the application introduces potassium tartrate into the auxiliary modifier, which enhances the coordination ability and buffering performance of the electrolyte. As a polyhydroxy carboxylate, potassium tartrate can form a stable complex with copper ions, further regulate the concentration of free copper ions, slow down the deposition rate, and promote grain refinement of the coating. At the same time, the hydroxyl structure of potassium tartrate can synergistically adsorb on the cathode surface with other additives, optimizing the interfacial behavior during electrodeposition, reducing dendrite growth, and improving the uniformity and brightness of the coating.

[0007] Further, the strong acidic bright copper plating electrolyte for steel parts further includes 2-5 parts by weight of a brightener, the brightener including the following parts by weight of substances: Sodium polydithiopropanesulfonate 1-5 parts; 2-mercaptobenzimidazole 0.5-2 parts; Thiazolinyl dithiopropanesulfonic acid sodium 5-15 parts; Aliphatic amine ethoxysulfonate 3-8 parts; Nanometer aluminum oxide particles 1-5 parts.

[0008] By the technical scheme, the brightener system is gradually introduced, and a multi-level plating layer quality regulation mechanism is constructed. In the basic brightener component, sulfur-containing compounds such as sodium polydithiopropanesulfonate are adsorbed on the cathode surface to inhibit the crystal nucleus growth rate, promote the preferred orientation of the crystal grain, and improve the brightness of the plating layer; heterocyclic compounds such as sodium thiazoline dithiopropane sulfonate can improve the coverage ability in the low current density area and reduce the plating layer defects. Nano-aluminum oxide particles as inorganic additives are embedded in the plating layer through dispersion strengthening to improve the hardness and wear resistance.

[0009] Further, the brightener further includes the following weight parts of substances: 3-mercapto-1,2,4-triazole 0.1-0.5 parts; N-dodecyl alanine 0.1-0.5 parts; Nano-silicon dioxide 0.1-0.5 parts; Diphenyl guanidine 0.05-0.10 parts.

[0010] Through the above technical scheme, the organic molecules such as 3-mercapto-1,2,4-triazole added by the application can form a protective film through chelation with the metal surface to inhibit the hydrogen evolution reaction and reduce pinholes; N-dodecyl alanine as an amphoteric surfactant can reduce the interfacial tension and enhance the adsorption stability of the brightener; the synergy of nano-silicon dioxide and diphenyl guanidine further optimizes the density of the plating layer and improves the corrosion resistance. The overall brightener system realizes the comprehensive improvement of the plating layer from macro-brightness to micro-structural stability through organic-inorganic complexation.

[0011] In a second aspect, the application provides a method for acid bright copper plating of a strong acid steel part, comprising the following preparation steps: (1) Pre-treatment: oil removal treatment of the steel part, collection of the pretreated steel part; (2) Activation treatment: placing the pretreated steel part in an activation solution for 45-80s of immersion activation treatment; (3) Electroplating: placing the steel part after immersion activation treatment in an electroplating tank, adding a strong acid steel part bright copper electrolyte, and electroplating treatment for 10-15min; (4) Post-plating treatment: after three-stage countercurrent rinsing treatment of the electroplated steel part, placing it in a benzotriazole sealing treatment solution for 30-60s of treatment, and hot air circulation drying, the acid bright copper plating step is completed.

[0012] Through the technical scheme, the complete process flow of the acid bright copper plating is established, and the plating layer quality is ensured through the synergistic control of pre-plating treatment, activation, electroplating and post-plating treatment. The pre-plating oil removal treatment removes the oil stains and impurities on the surface of the steel part, avoiding the decrease of the plating adhesion; the activation treatment removes the oxide film through an acid solution to expose the fresh metal surface, providing active sites for copper ion deposition. In the electroplating stage, the aforementioned electrolyte is used to realize the uniform reduction and crystallization of copper ions under the action of an electric field. The post-plating three-stage counter-flow rinsing gradually reduces the water temperature, efficiently removes the residual electrolyte and avoids secondary pollution in the subsequent treatment; the benzotriazole sealing treatment forms a dense protective film on the surface of the plating layer to inhibit the penetration of corrosive media; and the hot air drying quickly removes the moisture to prevent oxidation and discoloration. The precise connection of each step in the whole process ensures the quality stability of the plating layer from deposition to finished product, and improves the corrosion resistance and appearance effect.

[0013] Further, the activation solution includes cerium nitrate and sulfuric acid solution mixed in a mass ratio of 1:10-15.

[0014] Through the technical scheme, the activation solution used by the application selects a specific ratio of cerium nitrate and sulfuric acid. The core principle is to use the synergistic effect of the redox property of cerium ions and the acidity of sulfuric acid to achieve efficient activation of the steel surface. As a strong oxidizing agent, cerium nitrate can preferentially react with the oxide film on the surface of the steel to generate soluble cerium salt and Ce 3+ , which is reduced to Ce 3+ itself, forming a micro-etching effect, increasing the surface roughness and improving the mechanical adhesion of the plating layer. Sulfuric acid provides an acidic environment to promote the dissolution of the oxide film and inhibit the hydrolysis and precipitation of cerium ions. The mass ratio of the two ensures a moderate activation rate, avoiding excessive etching that damages the substrate, while forming an activation layer rich in Ce 3+ on the surface, which can act as a catalytic site for copper deposition, promoting the uniform formation of copper nuclei and reducing the problem of loose plating layer caused by displacement reaction, laying a good surface foundation for the subsequent electroplating process.

[0015] Further, the electroplating treatment parameters include: The cathode current density is 2-5 A / dm 2 , the temperature is 25-35℃, and the electroplating time is 10-15 min.

[0016] Through the technical scheme, the application regulates the structure and performance of the plating layer by limiting the electroplating parameters. The cathode current density determines the reduction rate of copper ions, and the cathode current density is 2-5 A / dm 2The range of the temperature ensures the balance of the deposition rate and the crystallization quality: too low may cause the plating layer to grow slowly and the brightness to be insufficient, and too high may cause the concentration polarization to intensify and produce dendrites and pinholes. The temperature is controlled at 25-35 DEG C, the activity of each component in the electrolyte can be maintained, the balance of the additive adsorption-desorption is ensured, and decomposition of the additive caused by high temperature or increase of the viscosity caused by low temperature is avoided. The plating time of 10-15 min is set according to the thickness requirement of the plating layer, and the target thickness is uniformly deposited by the current density. The three work together to ensure that the plating layer has good compactness and bonding force while having high brightness, so as to meet the protection and decoration requirements of the steel parts Further, the water temperature of the three-stage countercurrent rinsing process comprises 40-50 DEG C, 30-40 DEG C and 20-30 DEG C in sequence.

[0017] Through the above technical scheme, the application gradually reduces the water temperature through the three-stage countercurrent rinsing process, and the core principle is to realize efficient cleaning and resource saving through temperature gradient. The first-stage high-temperature water can quickly dissolve the soluble salt in the residual electrolyte, and accelerate molecular diffusion through thermal motion; the second-stage medium-temperature water further removes the cleaning liquid attached to the surface, reducing the pollutants brought into the next stage; the third-stage low-temperature water realizes deep rinsing and reduces the residual ion concentration. The countercurrent design makes the cleaning water circulate from the low-temperature stage to the high-temperature stage, improves the water resource utilization rate, and at the same time avoids the energy loss caused by direct discharge of high-temperature water. The process not only can effectively remove the electrolyte residue on the surface of the plating layer to prevent white spots or corrosion points after drying, but also can reduce the pollution risk of the subsequent sealing solution to ensure the integrity of the sealing film and finally improve the corrosion resistance and appearance quality of the plating layer.

[0018] In summary, the application has the following beneficial effects: First, the technology realizes the overall optimization of the brightness, compactness and corrosion resistance of the plating layer through the multi-component collaborative design. The composite complexing agent and the auxiliary modifier in the electrolyte cooperatively control the copper ion concentration and the deposition rate, and the dispersion strengthening effect of the organic-inorganic additives in the brightener system can refine the plating layer grains and inhibit the dendrite growth, so that the plating layer surface is bright and uniform and the crystallization is compact. At the same time, the embedding of the nanoparticles improves the hardness and wear resistance of the plating layer, and the benzotriazole sealing treatment forms a protective film to further enhance the corrosion resistance. Precise control of the plating parameters (such as current density and temperature) ensures uniform growth of the plating layer in different areas, avoids defects such as pinholes and peeling, and meets the dual requirements of decoration and functionality of the steel parts.

[0019] Second, the whole process design of the application realizes efficient connection from pretreatment to post-plating treatment. The pre-plating activation solution removes the oxide film quickly and forms active sites through the synergistic effect of cerium nitrate and sulfuric acid, thereby improving the adhesion of the plated layer. The high-stability electrolyte is used in the electroplating stage, and the deposition can be completed within 10-15 minutes at a current density of 2-5 A / dm2, thereby shortening the production cycle. The three-stage countercurrent rinsing efficiently removes the residual electrolyte through temperature gradient design, thereby reducing the risk of subsequent pollution. The quick operation (total time <2 minutes) of hot air drying and closed treatment reduces the process waiting time. The overall process has a wide process window and strong equipment compatibility, can adapt to the demand of large-scale production, and reduces the waste rate caused by parameter fluctuation.

[0020] Third, the process design of the application considers resource saving and environmental friendliness. The three-stage countercurrent rinsing adopts a countercurrent circulation mode with water temperature decreasing step by step, which can save more than 30% of water compared with the traditional single-stage rinsing, thereby reducing water consumption. The activation solution and the electrolyte formula avoid toxic ingredients, and the amount of benzotriazole blocking agent is small, thereby reducing chemical agent emissions. In addition, the efficient synergy of the auxiliary modifier and the brightener can reduce the main salt concentration, thereby prolonging the service life of the electrolyte; the quick drying process of the post-plating treatment reduces energy consumption. In summary, the technology reduces the unit production cost while ensuring the quality of the plated layer through material utilization rate improvement and energy consumption optimization, which conforms to the green manufacturing trend. DETAILED DESCRIPTION

[0021] The application will be further described below in combination with examples.

[0022] Preparation Example 1 Brightener 1 Take 1 g of polydithiobispropane sulfonic acid sodium, 0.5 g of 2-mercaptobenzimidazole, 5 g of thiazoline disulfide propane sulfonic acid sodium, 3 g of aliphatic amine ethoxysulfonate, 1 g of nano alumina particles and 1 L of deionized water, stir and mix to prepare brightener 1.

[0023] Preparation Example 2 Brightener 2 Take 3 g of polydithiobispropane sulfonic acid sodium, 1.2 g of 2-mercaptobenzimidazole, 10 g of thiazoline disulfide propane sulfonic acid sodium, 5 g of aliphatic amine ethoxysulfonate, 3 g of nano alumina particles and 1 L of deionized water, stir and mix to prepare brightener 2.

[0024] Preparation Example 3 Brightener 3 Take 5 g of polydithiobispropane sulfonic acid sodium, 2 g of 2-mercaptobenzimidazole, 15 g of thiazoline disulfide propane sulfonic acid sodium, 8 g of aliphatic amine ethoxysulfonate, 5 g of nano alumina particles and 1 L of deionized water, stir and mix to prepare brightener 3.

[0025] Preparation Example 4 Brightener 4 Take 3g of sodium polydithiopropyl sulfone, 1.2g of 2-mercaptobenzimidazole, 10g of sodium thiazolinyl dithiopropyl sulfone, 5g of fatty amine ethoxysulfonate, 3g of nano-alumina particles, 1g of 3-mercapto-1,2,4-triazole, 1g of N-dodecylalanine, 1g of nano-silica, 0.5g of diphenyl guanidine and 1L of deionized water, stir and mix to prepare brightener 4.

[0026] Preparation Example 5 Brightener 5 Take 3g of sodium polydithiopropyl sulfone, 1.2g of 2-mercaptobenzimidazole, 10g of sodium thiazolinyl dithiopropyl sulfone, 5g of fatty amine ethoxysulfonate, 3g of nano-alumina particles, 3g of 3-mercapto-1,2,4-triazole, 3g of N-dodecylalanine, 3g of nano-silica, 0.8g of diphenyl guanidine and 1L of deionized water, stir and mix to prepare brightener 5.

[0027] Preparation Example 6 Brightener 6 Take 3g of sodium polydithiopropyl sulfone, 1.2g of 2-mercaptobenzimidazole, 10g of sodium thiazolinyl dithiopropyl sulfone, 5g of fatty amine ethoxysulfonate, 3g of nano-alumina particles, 5g of 3-mercapto-1,2,4-triazole, 5g of N-dodecylalanine, 5g of nano-silica, 1.0g of diphenyl guanidine and 1L of deionized water, stir and mix to prepare brightener 6.

[0028] Preparation Example 7 Auxiliary modifier 1 Take 6g of sodium benzenesulfinate, 8g of sodium dodecyl sulfate, 10g of polyethylene glycol, 80g of a complexing agent of trisodium citrate and disodium ethylenediaminetetraacetate, stir and mix and 1L of deionized water, stir and mix to prepare auxiliary modifier 1.

[0029] Preparation Example 8 Auxiliary modifier 2 Take 10g of sodium benzenesulfinate, 10g of sodium dodecyl sulfate, 15g of polyethylene glycol, 90g of a complexing agent of trisodium citrate and disodium ethylenediaminetetraacetate, stir and mix and 1L of deionized water, stir and mix to prepare auxiliary modifier 2.

[0030] Preparation Example 9 Auxiliary modifier 3 Take 15g of sodium benzenesulfinate, 15g of sodium dodecyl sulfate, 20g of polyethylene glycol, 100g of a complexing agent of trisodium citrate and disodium ethylenediaminetetraacetate, stir and mix and 1L of deionized water, stir and mix to prepare auxiliary modifier 3.

[0031] Preparation Example 10 Auxiliary modifier 4 Take 15g sodium benzenesulfinate, 15g sodium dodecyl sulfate, 20g polyethylene glycol, 15g potassium tartrate, 100g trisodium citrate and ethylenediaminetetraacetic acid disodium complexing agent, stirring and mixing with 1L of deionized water, stirring and mixing, prepared auxiliary modifier 4.

[0032] Preparation Example 11 Auxiliary modifier 5 Take 15g sodium benzenesulfinate, 15g sodium dodecyl sulfate, 20g polyethylene glycol, 22g potassium tartrate, 100g trisodium citrate and ethylenediaminetetraacetic acid disodium complexing agent, stirring and mixing with 1L of deionized water, stirring and mixing, prepared auxiliary modifier 5.

[0033] Preparation Example 12 Auxiliary modifier 6 Take 15g sodium benzenesulfinate, 15g sodium dodecyl sulfate, 20g polyethylene glycol, 30g potassium tartrate, 100g trisodium citrate and ethylenediaminetetraacetic acid disodium complexing agent, stirring and mixing with 1L of deionized water, stirring and mixing, prepared auxiliary modifier 6.

[0034] Example 1 A strong acidic steel bright copper plating electrolyte, comprising the following substances: 160g copper sulfate pentahydrate, 100g sulfuric acid, 40g mass fraction 0.13% hydrochloric acid, 30g auxiliary modifier 1 and 1L deionized water.

[0035] A method for acidic bright copper plating of a strong acidic steel bright copper plating electrolyte, comprising the following preparation steps: (1) Pretreatment: the surface of the steel part is sequentially immersed in 60℃ NaOH solution with a concentration of 50g / L for 10min, 5A / dm 2 Cathode electrolysis oil removal 5min, 300W ultrasonic oil removal 8min, deionized water washing, collection of pretreated steel parts; (2) Activation treatment: the pretreated steel part is placed in a mixed solution of cerium nitrate and 0.5mol / L sulfuric acid with a mass ratio of 1:10, and immersed for 45-80s; (3) Electroplating: the steel part after immersion and activation treatment is placed in an electroplating tank, and a strong acidic steel bright copper plating electrolyte is added, with a cathode current density of 2A / dm 2 , temperature is 25℃, electroplating time is 10min; (4) post-plating treatment: after the steel and iron parts after plating are placed in water at 40℃, 30℃ and 20℃ respectively for three-stage countercurrent rinsing treatment, they are placed in a benzotriazole sealing treatment solution for 30s, and hot air circulation drying is performed, so that the acid bright copper plating step is completed.

[0036] Example 2 A strong-acid steel and iron part bright copper plating electrolyte comprises the following substances: 180g of copper sulfate pentahydrate, 110g of sulfuric acid, 50g of hydrochloric acid with a mass fraction of 0.13%, 35g of auxiliary modifier 1 and 1L of deionized water.

[0037] A method for acid bright copper plating of a strong-acid steel and iron part bright copper plating electrolyte, comprising the following preparation steps: (1) pre-plating treatment: the surface of the steel and iron part is sequentially immersed in a NaOH solution with a concentration of 50g / L at 60℃ for 10min, 5A / dm 2 cathode electrolysis oil removal for 5min, 300W ultrasonic oil removal for 8min, deionized water rinsing, and collection of the pretreated steel and iron part; (2) activation treatment: the pretreated steel and iron part is placed in a cerium nitrate and 0.5mol / L sulfuric acid solution mixed at a mass ratio of 1:12 for immersion activation treatment for 45-80s; (3) electroplating: the steel and iron part after immersion activation treatment is placed in an electroplating tank, and a strong-acid steel and iron part bright copper plating electrolyte is added, and the cathode current density is 3A / dm 2 , the temperature is 30℃, and the electroplating time is 12min; (4) post-plating treatment: after the steel and iron parts after plating are placed in water at 45℃, 35℃ and 25℃ respectively for three-stage countercurrent rinsing treatment, they are placed in a benzotriazole sealing treatment solution for 45s, and hot air circulation drying is performed, so that the acid bright copper plating step is completed.

[0038] Example 3 A strong-acid steel and iron part bright copper plating electrolyte comprises the following substances: 200g of copper sulfate pentahydrate, 120g of sulfuric acid, 60g of hydrochloric acid with a mass fraction of 0.13%, 40g of auxiliary modifier 1 and 1L of deionized water.

[0039] A method for acid bright copper plating of a strong-acid steel and iron part bright copper plating electrolyte, comprising the following preparation steps: (1) pre-plating treatment: the surface of the steel and iron part is sequentially immersed in a NaOH solution with a concentration of 50g / L at 60℃ for 10min, 5A / dm 2 cathode electrolysis oil removal for 5min, 300W ultrasonic oil removal for 8min, deionized water rinsing, and collection of the pretreated steel and iron part; (2) Activation treatment: the pretreated steel parts are immersed in a solution of cerium nitrate and 0.5 mol / L sulfuric acid mixed at a mass ratio of 1:15 for activation treatment for 45-80 s; (3) Electroplating: the steel parts after immersion activation treatment are placed in an electroplating tank, and a strong acid steel bright copper plating electrolyte is added, and the cathode current density is 5 A / dm 2 , the temperature is 35℃, and the electroplating time is 15 min; (4) Post-plating treatment: the steel parts after electroplating are placed in water at 50℃, 40℃ and 30℃ respectively for three-stage countercurrent rinsing treatment, and then placed in a benzotriazole sealing treatment solution for 60 s, and then hot air circulation drying is performed, thereby completing the acid bright copper plating step.

[0040] Example 4 A strong acid steel bright copper plating electrolyte, comprising the following substances: 180 g of copper sulfate pentahydrate, 110 g of sulfuric acid, 50 g of hydrochloric acid with a mass fraction of 0.13%, 35 g of auxiliary modifier 1, 4-10 g of brightener 1 and 1 L of deionized water.

[0041] A method for acid bright copper plating of a strong acid steel bright copper plating electrolyte, comprising the following preparation steps: (1) Pre-plating treatment: the surface of the steel parts is sequentially immersed in a 60℃ NaOH solution with a concentration of 50 g / L for 10 min, 5 A / dm 2 cathode electrolysis for 5 min, 300 W ultrasonic oil removal for 8 min, deionized water rinsing, and collection of pretreated steel parts; (2) Activation treatment: the pretreated steel parts are immersed in a solution of cerium nitrate and 0.5 mol / L sulfuric acid mixed at a mass ratio of 1:12 for activation treatment for 45-80 s; (3) Electroplating: the steel parts after immersion activation treatment are placed in an electroplating tank, and a strong acid steel bright copper plating electrolyte is added, and the cathode current density is 3 A / dm 2 , the temperature is 30℃, and the electroplating time is 12 min; (4) Post-plating treatment: the steel parts after electroplating are placed in water at 45℃, 35℃ and 25℃ respectively for three-stage countercurrent rinsing treatment, and then placed in a benzotriazole sealing treatment solution for 45 s, and then hot air circulation drying is performed, thereby completing the acid bright copper plating step.

[0042] Example 5 A strong acid steel bright copper plating electrolyte, comprising the following substances: 180 g of copper sulfate pentahydrate, 110 g of sulfuric acid, 50 g of hydrochloric acid with a mass fraction of 0.13%, 35 g of auxiliary modifier 1, 7 g of brightener 2 and 1 L of deionized water.

[0043] A method for acidic bright copper plating of a strong acidic steel part, comprising the following preparation steps: (1) Pre-plating treatment: immerse the surface of the steel part in a 60℃ NaOH solution with a concentration of 50g / L for 10min, 5A / dm 2 Cathode electrolysis for 5min, 300W ultrasonic oil removal for 8min, deionized water washing, and collection of pretreated steel parts; (2) Activation treatment: immerse the pretreated steel part in a cerium nitrate and 0.5mol / L sulfuric acid solution mixed at a mass ratio of 1:12 for 45-80s of immersion activation treatment; (3) Electroplating: place the steel part after immersion activation treatment in an electroplating tank, add a strong acidic steel part bright copper electrolyte, and electroplate at a cathode current density of 3A / dm 2 , a temperature of 30℃, and an electroplating time of 12min; (4) Post-plating treatment: after electroplating, place the steel part in water at 45℃, 35℃, and 25℃ for three-stage countercurrent rinsing treatment, then place it in a benzotriazole sealing treatment solution for 45s, and perform hot air circulation drying, thereby completing the acidic bright copper plating step.

[0044] Example 6 A strong acidic steel part bright copper electrolyte, comprising the following substances: 180g copper sulfate pentahydrate, 110g sulfuric acid, 50g hydrochloric acid with a mass fraction of 0.13%, 35g auxiliary modifier 1, 10g brightener 3, and 1L deionized water.

[0045] A method for acidic bright copper plating of a strong acidic steel part, comprising the following preparation steps: (1) Pre-plating treatment: immerse the surface of the steel part in a 60℃ NaOH solution with a concentration of 50g / L for 10min, 5A / dm 2 Cathode electrolysis for 5min, 300W ultrasonic oil removal for 8min, deionized water washing, and collection of pretreated steel parts; (2) Activation treatment: immerse the pretreated steel part in a cerium nitrate and 0.5mol / L sulfuric acid solution mixed at a mass ratio of 1:12 for 45-80s of immersion activation treatment; (3) Electroplating: place the steel part after immersion activation treatment in an electroplating tank, add a strong acidic steel part bright copper electrolyte, and electroplate at a cathode current density of 3A / dm 2 , a temperature of 30℃, and an electroplating time of 12min; (4) Post-plating treatment: after electroplating, place the steel part in water at 45℃, 35℃, and 25℃ for three-stage countercurrent rinsing treatment, then place it in a benzotriazole sealing treatment solution for 45s, and perform hot air circulation drying, thereby completing the acidic bright copper plating step.

[0046] Example 7 A strong acidic steel bright copper plating electrolyte, comprising the following substances: 180g copper sulfate pentahydrate, 110g sulfuric acid, 50g hydrochloric acid with a mass fraction of 0.13%, 35g auxiliary modifier 1, 7g brightener 4 and 1L deionized water.

[0047] A strong acidic steel bright copper plating electrolyte, comprising the following substances: 180g copper sulfate pentahydrate, 110g sulfuric acid, 50g hydrochloric acid with a mass fraction of 0.13%, 35g auxiliary modifier 1, 7g brightener 4 and 1L deionized water. (1) Pre-plating treatment: sequentially immerse the surface of the steel part in a 60℃ NaOH solution with a concentration of 50g / L for 10min, 5A / dm 2 Cathode electrolysis oil removal for 5min, 300W ultrasonic oil removal for 8min, deionized water washing, and collection of pretreated steel parts; (2) Activation treatment: immerse the pretreated steel part in a cerium nitrate and 0.5mol / L sulfuric acid solution mixed at a mass ratio of 1:12 for 45-80s of immersion activation treatment; (3) Electroplating: immerse the steel part after immersion activation treatment in an electroplating tank, add a strong acidic steel bright copper plating electrolyte, and perform electroplating at a cathode current density of 3A / dm 2 , a temperature of 30℃, and an electroplating time of 12min; (4) Post-plating treatment: sequentially immerse the electroplated steel part in water at 45℃, 35℃ and 25℃ for three-stage countercurrent rinsing treatment, then immerse it in a benzotriazole sealing treatment solution for 45s, and perform hot air circulation drying, thereby completing the acidic bright copper plating step.

[0048] Example 8 A strong acidic steel bright copper plating electrolyte, comprising the following substances: 180g copper sulfate pentahydrate, 110g sulfuric acid, 50g hydrochloric acid with a mass fraction of 0.13%, 35g auxiliary modifier 1, 7g brightener 4 and 1L deionized water.

[0049] A strong acidic steel bright copper plating electrolyte, comprising the following substances: 180g copper sulfate pentahydrate, 110g sulfuric acid, 50g hydrochloric acid with a mass fraction of 0.13%, 35g auxiliary modifier 1, 7g brightener 4 and 1L deionized water. (1) Pre-plating treatment: sequentially immerse the surface of the steel part in a 60℃ NaOH solution with a concentration of 50g / L for 10min, 5A / dm 2 Cathode electrolysis oil removal for 5min, 300W ultrasonic oil removal for 8min, deionized water washing, and collection of pretreated steel parts; (2) Activation treatment: immerse the pretreated steel part in a cerium nitrate and 0.5mol / L sulfuric acid solution mixed at a mass ratio of 1:12 for 45-80s of immersion activation treatment; (3) Electroplating: placing the steel piece after immersion and activation treatment in an electroplating tank, adding a strong acid steel piece bright copper plating electrolyte, and electroplating at a cathode current density of 3 A / dm 2 , a temperature of 30°C, and an electroplating time of 12 min; (4) Post-plating treatment: placing the electroplated steel piece in water at 45°C, 35°C, and 25°C for three-stage countercurrent rinsing treatment, and then placing it in a benzotriazole sealing treatment solution for 45 s and hot air circulation drying to complete the acid bright copper plating step.

[0050] Example 9 A strong acid steel piece bright copper plating electrolyte includes the following substances: 180 g of copper sulfate pentahydrate, 110 g of sulfuric acid, 50 g of hydrochloric acid with a mass fraction of 0.13%, 35 g of auxiliary modifier 1, 7 g of brightener 6, and 1 L of deionized water.

[0051] A method for acid bright copper plating of a strong acid steel piece bright copper plating electrolyte includes the following preparation steps: (1) Pre-plating treatment: sequentially immersing the surface of the steel piece in a 60°C NaOH solution with a concentration of 50 g / L for 10 min, a 5 A / dm 2 cathode electrolysis for 5 min, 300 W ultrasonic oil removal for 8 min, deionized water rinsing, and collecting the pretreated steel piece; (2) Activation treatment: placing the pretreated steel piece in a cerium nitrate and 0.5 mol / L sulfuric acid solution mixed at a mass ratio of 1:12 for immersion and activation treatment for 45-80 s; (3) Electroplating: placing the steel piece after immersion and activation treatment in an electroplating tank, adding a strong acid steel piece bright copper plating electrolyte, and electroplating at a cathode current density of 3 A / dm 2 , a temperature of 30°C, and an electroplating time of 12 min; (4) Post-plating treatment: placing the electroplated steel piece in water at 45°C, 35°C, and 25°C for three-stage countercurrent rinsing treatment, and then placing it in a benzotriazole sealing treatment solution for 45 s and hot air circulation drying to complete the acid bright copper plating step.

[0052] Example 10 A strong acid steel piece bright copper plating electrolyte includes the following substances: 180 g of copper sulfate pentahydrate, 110 g of sulfuric acid, 50 g of hydrochloric acid with a mass fraction of 0.13%, 35 g of auxiliary modifier 2, 7 g of brightener 5, and 1 L of deionized water.

[0053] A method for acid bright copper plating of a strong acid steel piece bright copper plating electrolyte includes the following preparation steps: (1) Pre-plating treatment: the surface of the steel part is sequentially immersed in a 60℃ NaOH solution with a concentration of 50g / L for 10min, 5A / dm 2 cathode electrolysis oil removal for 5min, 300W ultrasonic oil removal for 8min, deionized water washing, and collection of pretreated steel parts; (2) Activation treatment: the pretreated steel part is placed in a cerium nitrate and 0.5mol / L sulfuric acid solution mixed at a mass ratio of 1:12 for immersion activation treatment for 45-80s; (3) Electroplating: the steel part after immersion activation treatment is placed in an electroplating tank, and a strong acid steel part bright copper plating electrolyte is added, with a cathode current density of 3A / dm 2 , a temperature of 30℃, and an electroplating time of 12min; (4) Post-plating treatment: the steel part after electroplating is placed in water at 45℃, 35℃ and 25℃ respectively for three-stage countercurrent rinsing treatment, and then placed in a benzotriazole sealing treatment solution for 45s, and hot air circulation drying, thereby completing the acid bright copper plating step.

[0054] Example 11 A strong acid steel part bright copper plating electrolyte, comprising the following substances: 180g copper sulfate pentahydrate, 110g sulfuric acid, 50g hydrochloric acid with a mass fraction of 0.13%, 35g auxiliary modifier 3, 7g brightener 5, and 1L deionized water.

[0055] A method for acid bright copper plating of a strong acid steel part bright copper plating electrolyte, comprising the following preparation steps: (1) Pre-plating treatment: the surface of the steel part is sequentially immersed in a 60℃ NaOH solution with a concentration of 50g / L for 10min, 5A / dm 2 cathode electrolysis oil removal for 5min, 300W ultrasonic oil removal for 8min, deionized water washing, and collection of pretreated steel parts; (2) Activation treatment: the pretreated steel part is placed in a cerium nitrate and 0.5mol / L sulfuric acid solution mixed at a mass ratio of 1:12 for immersion activation treatment for 45-80s; (3) Electroplating: the steel part after immersion activation treatment is placed in an electroplating tank, and a strong acid steel part bright copper plating electrolyte is added, with a cathode current density of 3A / dm 2 , a temperature of 30℃, and an electroplating time of 12min; (4) Post-plating treatment: the steel part after electroplating is placed in water at 45℃, 35℃ and 25℃ respectively for three-stage countercurrent rinsing treatment, and then placed in a benzotriazole sealing treatment solution for 45s, and hot air circulation drying, thereby completing the acid bright copper plating step.

[0056] Example 12 A strong acidic steel bright copper plating electrolyte, comprising the following substances: 180g copper sulfate pentahydrate, 110g sulfuric acid, 50g hydrochloric acid with a mass fraction of 0.13%, 35g auxiliary modifier 4, 7g brightener 5 and 1L deionized water.

[0057] A strong acidic steel bright copper plating electrolyte, comprising the following substances: 180g copper sulfate pentahydrate, 110g sulfuric acid, 50g hydrochloric acid with a mass fraction of 0.13%, 35g auxiliary modifier 4, 7g brightener 5 and 1L deionized water. (1) Pre-plating treatment: the surface of the steel part is sequentially immersed in a 60℃ NaOH solution with a concentration of 50g / L for 10min, 5A / dm 2 Cathode electrolysis oil removal for 5min, 300W ultrasonic oil removal for 8min, deionized water washing, and collection of pretreated steel parts; (2) Activation treatment: the pretreated steel part is placed in a cerium nitrate and 0.5mol / L sulfuric acid solution mixed at a mass ratio of 1:12 for immersion activation treatment for 45-80s; (3) Electroplating: the steel part after immersion activation treatment is placed in an electroplating tank, and a strong acidic steel bright copper plating electrolyte is added, with a cathode current density of 3A / dm 2 , a temperature of 30℃, and an electroplating time of 12min; (4) Post-plating treatment: the electroplated steel part is placed in water at 45℃, 35℃ and 25℃ respectively for three-stage countercurrent rinsing treatment, then it is placed in a benzotriazole sealing treatment solution for 45s, and hot air circulation drying is performed, thereby completing the acid bright copper plating step.

[0058] Example 13 A strong acidic steel bright copper plating electrolyte, comprising the following substances: 180g copper sulfate pentahydrate, 110g sulfuric acid, 50g hydrochloric acid with a mass fraction of 0.13%, 35g auxiliary modifier 4, 7g brightener 5 and 1L deionized water.

[0059] A strong acidic steel bright copper plating electrolyte, comprising the following substances: 180g copper sulfate pentahydrate, 110g sulfuric acid, 50g hydrochloric acid with a mass fraction of 0.13%, 35g auxiliary modifier 4, 7g brightener 5 and 1L deionized water. (1) Pre-plating treatment: the surface of the steel part is sequentially immersed in a 60℃ NaOH solution with a concentration of 50g / L for 10min, 5A / dm 2 Cathode electrolysis oil removal for 5min, 300W ultrasonic oil removal for 8min, deionized water washing, and collection of pretreated steel parts; (2) Activation treatment: the pretreated steel part is placed in a cerium nitrate and 0.5mol / L sulfuric acid solution mixed at a mass ratio of 1:12 for immersion activation treatment for 45-80s; (3) Electroplating: the steel part after immersion activation treatment is placed in an electroplating tank, and a strong acidic steel bright copper plating electrolyte is added, with a cathode current density of 3A / dm 2 , a temperature of 30℃, and an electroplating time of 12min; (4) Post-plating treatment: after the steel and iron parts are plated, they are placed in water at 45°C, 35°C and 25°C respectively for three-stage countercurrent rinsing treatment, and then placed in a benzotriazole sealing treatment solution for 45s, and hot air circulation drying, so that the acid bright copper plating step is completed.

[0060] Example 14 A strong acid bright copper plating electrolyte for steel and iron parts, comprising the following substances: 180g of copper sulfate pentahydrate, 110g of sulfuric acid, 50g of hydrochloric acid with a mass fraction of 0.13%, 35g of auxiliary modifier 6, 7g of brightener 5 and 1L of deionized water.

[0061] A method for acid bright copper plating of a strong acid bright copper plating electrolyte for steel and iron parts, comprising the following preparation steps: (1) Pre-plating treatment: the surface of the steel and iron parts is sequentially immersed in a 60°C NaOH solution with a concentration of 50g / L for 10min, 5A / dm 2 Cathode electrolysis for 5min, 300W ultrasonic oil removal for 8min, deionized water rinsing, and collection of pretreated steel and iron parts; (2) Activation treatment: the pretreated steel and iron parts are placed in a cerium nitrate and 0.5mol / L sulfuric acid solution mixed at a mass ratio of 1:12 for 45-80s of immersion activation treatment; (3) Electroplating: the steel and iron parts after immersion activation treatment are placed in an electroplating tank, and a strong acid bright copper plating electrolyte for steel and iron parts is added, with a cathode current density of 3A / dm 2 , a temperature of 30°C, and an electroplating time of 12min; (4) Post-plating treatment: after the steel and iron parts after electroplating are placed in water at 45°C, 35°C and 25°C respectively for three-stage countercurrent rinsing treatment, they are placed in a benzotriazole sealing treatment solution for 45s, and hot air circulation drying, so that the acid bright copper plating step is completed.

[0062] Comparative Example 1 Compared with Example 1, no auxiliary modifier material is added in Comparative Example 1, and the remaining preparation steps and parameters are the same as those of Example 1.

[0063] Performance detection The copper plating layer prepared in Examples 1-14 and Comparative Example 1 is detected, and the detection standards are as follows: ① Bending test: the test piece is repeatedly bent along an axis with a diameter equal to the thickness by 180° until it breaks, and the plating layer is qualified if there is no peeling off; ② Hundred grid test: a hard tool is vertically intersected to form a 10x10 grid, the cutting depth needs to penetrate the plating layer to the substrate, the grid area is covered with adhesive tape, and the rubber eraser is pressed (pressure about 5N / cm²), and after standing for 60 seconds, it is quickly torn off at 180°, and the copper plating layer has no peeling off.

[0064] ③Lightness test: Hall groove test was used, 267 ml standard tank was used, at 25℃, 3A current, the full light area width of the test piece was observed, and the light area was tested by gloss meter.

[0065] ④Porosity test: filter paper soaked with corrosive test solution was attached to the surface of the plated layer, the test solution penetrated into the pores and reacted with the base metal to form characteristic color spots, and the porosity was evaluated by the number of spots.

[0066] ⑤Corrosion resistance test: 1. Salt spray test: according to GB / T 10125-2012 standard, neutral salt spray test (NSS) was carried out, the plated parts were placed in 5% NaCl atomized environment at 35±1℃, and continuous spraying mode was used. The test period is divided into four stages of 24h, 48h, 72h and 96h 2. Tafel polarization: the polarization curve of the plated layer in 3.5% NaCl solution was measured by electrochemical workstation, and the self-corrosion current density was obtained by Tafel extrapolation method. Test parameters: scan rate 1mV / s, potential range-0.25V~+0.25V (vs. SCE). The results show that the self-corrosion current density of copper plated layer ⑥Hardness test: the hardness value of the cross section of the plated layer was measured by microhardness tester (HV scale, load 25g). 10 parallel tests were carried out.

[0067] ⑦Surface roughness: the surface roughness of the copper plated layer under the same current density was detected by surface roughness meter, and the value of Ra was used to represent it.

[0068] ⑧Conductivity: metal conductivity tester was used for conductivity test.

[0069] The test results are shown in the following table 1: Table 1 Performance test table

[0070] From the results of examples 1-14 and comparative example 1, it can be found that: Comparing examples 1-3 with comparative example 1, when no auxiliary modifier is added in comparative example 1, the absence of sodium benzenesulfinate leads to intensified displacement reaction of steel substrate, unqualified bonding force, porosity more than 2.0 / cm², and salt spray corrosion resistance time only 12h, which verifies the key role of auxiliary modifier in inhibiting displacement reaction and improving the quality of plated layer.

[0071] Compared with Examples 1-3 and Examples 4-6, with the increase of effective components in brightener 1-3, the full bright area width increases from 7.8 cm to 8.5 cm, the glossiness increases to 480 GU, the hardness reaches 110 HV, and the salt spray corrosion resistance time is prolonged to 60 h, which reflects the enhancement effect of the brightener on the brightness and wear resistance of the coating; Compared with Examples 4-6 and Examples 7-9, after adding 3-mercapto-1,2,4-triazole and other synergistic components in brightener 4-6, the full bright area width breaks through 9 cm, the glossiness exceeds 500 GU, the salt spray corrosion resistance time reaches 72-80 h, the Tafel polarization current decreases to 0.07 μA / cm 2 , the hardness increases to 120 HV, which verifies the synergistic leveling and strengthening effect of the new components and the basic brightener.

[0072] Compared with Examples 10-11 and Examples 7-9, by optimizing the ratio of sodium benzenesulfinate and polyethylene glycol, the adhesion stability of auxiliary modifier 2-3 is improved, the porosity is reduced to ≤0.4 pieces / cm 2 , and the salt spray corrosion resistance time is prolonged by 4-6 h compared with Example 5, which reflects the improvement of the auxiliary agent on the dispersion of the plating solution.

[0073] Compared with Examples 12-14 and Examples 10-11, after adding potassium tartrate in auxiliary modifier 4-6, a synergistic complex is formed with the composite complexing agent, the porosity is further reduced to ≤0.3 pieces / cm 2 , the salt spray corrosion resistance time reaches 72-80 h, and the hardness increases to 120 HV, which shows that potassium tartrate can enhance the compactness and adhesion of the coating.

[0074] The above detailed description of the present application is made in combination with the specific embodiments and exemplary examples, but these descriptions cannot be understood as limitations of the present application. Those skilled in the art understand that various equivalent substitutions, modifications or improvements can be made to the technical solutions and embodiments of the present application without departing from the spirit and scope of the present application, which all fall within the scope of the present application. The protection scope of the present application is subject to the appended claims.

[0075] All publications, patent applications, patents and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meaning commonly understood by one of ordinary skill in the art. In case of conflict, the definitions in this specification prevail.

[0076] When the specification derives material, substances, methods, steps, devices or components, etc. with the lead word "known to the person skilled in the art", "prior art" or similar, the objects derived with the lead word encompass those which are conventionally used in the art at the time of the present application, but also those which are not yet conventionally used, but will become generally recognized in the art as suitable for analogous purposes.

[0077] In the context of the present specification, any matter or item not mentioned in addition to the explicitly stated matters or items applies directly to those known in the art without any change, unless otherwise explicitly stated.

Claims

1. A bright copper plating electrolyte for strongly acidic steel parts, characterized in that, Includes the following substances by weight: 80-100 parts of copper sulfate pentahydrate; 50-60 parts of sulfuric acid; 20-30 parts hydrochloric acid; 15-20 parts of auxiliary modifier; The auxiliary modifier comprises the following substances in parts by weight: 6-15 parts of sodium benzenesulfinate; 8-15 parts of sodium dodecyl sulfate; 10-20 parts of polyethylene glycol; 80-100 parts of compound coordination agent; The composite ligand is a ligand composed of trisodium citrate and disodium ethylenediaminetetraacetate.

2. The strong acid bright copper plating electrolyte for steel parts according to claim 1, characterized in that, The auxiliary modifier also includes 15-30 parts by weight of potassium tartrate.

3. The strong acid bright copper plating electrolyte for steel parts according to claim 1, characterized in that, The strongly acidic bright copper plating electrolyte for steel parts also includes 2-5 parts by weight of a brightener comprising the following substances by weight: 1-5 parts of sodium polydisulfide dipropane sulfonate; 0.5-2 parts of 2-mercaptobenzimidazole; Sodium thiazolinyl dithiopropane sulfonate, 5-15 parts; 3-8 parts of aliphatic amine ethoxysulfonate; 1-5 parts of nano-alumina particles.

4. The strong acid bright copper plating electrolyte for steel parts according to claim 3, characterized in that, The brightening agent also includes the following substances in parts by weight: 0.1-0.5 parts of 3-mercapto-1,2,4-triazole; 0.1-0.5 parts of N-dodecylalanine; 0.1-0.5 parts of nano-silica; Diphenylguanidine 0.05-0.10 parts.

5. A method for acidic bright copper plating of steel parts using the strongly acidic bright copper plating electrolyte according to any one of claims 1-4, characterized in that, The preparation steps include the following: (1) Pre-plating treatment: Degrease the steel parts and collect the pre-treated steel parts; (2) Activation treatment: Place the pretreated steel parts in the activation solution and immerse them for 45-80 seconds; (3) Electroplating: Place the steel parts that have been immersed and activated into an electroplating tank, add a strong acidic bright copper plating electrolyte for steel parts, and electroplating for 10-15 minutes; (4) Post-plating treatment: After electroplating, the steel parts are rinsed in a three-stage countercurrent process, then placed in a benzotriazole sealing solution for 30-60 seconds and dried with hot air circulation to complete the acidic bright copper plating step.

6. The method for acidic bright copper plating of steel parts using a strongly acidic electrolyte as described in claim 5, characterized in that, The activation solution comprises a mixture of cerium nitrate and sulfuric acid in a mass ratio of 1:10-15.

7. The method for acidic bright copper plating of steel parts using a strongly acidic electrolyte as described in claim 5, characterized in that, The electroplating parameters include: The cathode current density is 2-5 A / dm. 2 The temperature is 25-35℃, and the electroplating time is 10-15 minutes.

8. The method for acidic bright copper plating of steel parts using a strongly acidic electrolyte as described in claim 5, characterized in that, The water temperatures for the three-stage countercurrent rinsing process are 40-50℃, 30-40℃, and 20-30℃, respectively.

Images