A hydrophilic type electroplating nickel liquid and a copper-based heat dissipation component nickel plating method using the same

Abstract

The application belongs to the technical field of radiator corrosion prevention, and relates to a hydrophilic electroplating nickel liquid and a nickel plating method for a copper-based heat dissipation component using the same. The hydrophilic electroplating nickel liquid comprises a nickel source, a pH stabilizer, a grain refiner, a polarity regulator and a corrosion inhibitor. The pH of the hydrophilic electroplating nickel liquid is 3.8-4.2. The binding strength of the plating layer obtained by electroplating using the hydrophilic electroplating liquid is preferably as high as 60 MPa or more, the porosity is preferably as low as 0.35% or less, the hydrophilic performance is long-acting and stable, the initial water contact angle is 25-35°, the water contact angle is still lower than 55° after the natural environment is placed for 360 h, and the demand of long-term stable operation of the copper-based heat dissipation component under cold and hot working conditions is met.

Description

Technical Field

[0001] This invention relates to the field of radiator corrosion protection technology, and in particular to a hydrophilic electroplating nickel solution and a method for nickel plating copper-based heat dissipation components using the same. Background Technology

[0002] Copper and its alloys are widely used in heat sinks for electronic devices due to their excellent thermal conductivity and processing properties. However, copper is prone to oxidation and corrosion in humid environments, forming an oxide film mainly composed of Cu2O and CuO on its surface. This oxide film has a much lower thermal conductivity than metallic copper, resulting in significant thermal resistance and severely impacting heat dissipation efficiency. Current technologies often use electroless or electroplated nickel as a protective layer. While the nickel layer can effectively block corrosive media, its high surface energy leads to poor surface wettability and a large water contact angle (typically greater than 70°). Under temperature-driven condensation conditions, the high surface energy makes it easy for water vapor to condense and spread on the surface, forming a large-area continuous water film. This water film not only exacerbates the risk of substrate corrosion but can also cause electromigration and other faults due to electrolytic effects, severely restricting the long-term stable operation of electronic devices in humid and hot environments.

[0003] While traditional nickel plating technology can provide basic protection through a dense nickel layer, its plating structure is relatively simple. Its long-term protective effect is limited against condensation corrosion or repeated wet-dry cycles in high-humidity environments. Furthermore, incomplete pretreatment in traditional processes can leave oxide films or organic matter at the copper-nickel interface, resulting in insufficient interfacial bonding strength. Under thermal cycling stress, this easily leads to plating peeling and flaking. This protective failure not only causes a sharp increase in thermal resistance but also makes the device more prone to localized overheating and failure.

[0004] For example, CN101705481A discloses a chemical nickel-phosphorus alloy plating process for radiators. This process proposes to chemically plating nickel-phosphorus alloy onto steel, aluminum, and copper radiators to improve corrosion resistance and eliminate residual welding stress. However, it does not modify the surface wettability, and the problem of forming a continuous water film under hot and cold conditions still exists, which leads to increased corrosion. Moreover, its interfacial bonding is still insufficient, which easily produces microcracks and even peeling.

[0005] For example, CN205789937U discloses a foamed nickel-copper alloy heat sink, whose plating structure is a sandwich structure of chemical nickel plating layer, electroplated copper layer and electroplated nickel layer. This will generate contact thermal resistance at each interface, resulting in weakened heat dissipation performance. Moreover, the problem of high surface energy of nickel layer has not been solved, which makes it unsuitable for hot and cold working conditions, accelerates copper layer corrosion, and may even cause electromigration short circuit.

[0006] In addition, nickel plating technology for copper-based heat dissipation devices faces many challenges in delayed water droplet angle testing, mainly in the following aspects: (1) The surface energy increases significantly, leading to deterioration of wettability. Studies have shown that the surface energy of copper increases by about 30% after nickel plating, and the contact angle of water droplets on the nickel-plated surface is 60°~80°, which is significantly greater than the contact angle of pure copper surface (40°~60°), meaning that the surface is more difficult to wet with water after nickel plating. This deterioration of wettability directly affects the heat exchange efficiency between the heat sink and the coolant; (2) The microstructure of the plating layer leads to uncontrollable wettability; In the field of electronic packaging, the wetting angle rating standard is: ≤60° is acceptable, 60°~70° is poor, and >70° is unacceptable. The wetting angle of the plating obtained by the existing nickel plating process is often in a poor or unacceptable range. As the current density increases, the wetting angle of the nickel plating becomes larger and the wettability gradually deteriorates. (3) The contradiction between thermal conductivity and surface wettability. Although the existing nickel plating process has solved the problem of oxidation and corrosion of copper substrate, the nickel plating layer will reduce the overall thermal conductivity. The thicker the plating layer, the more obvious the decrease in thermal conductivity. At the same time, the deterioration of surface wettability further reduces the heat dissipation efficiency.

[0007] Therefore, for the special working conditions of alternating hot and cold temperatures of copper-based heat dissipation components, how to provide a new nickel plating solution and nickel plating method so that the resulting composite coating has excellent corrosion resistance, high interfacial bonding strength and low wettability, thereby improving the reliability of copper-based heat dissipation devices in humid and hot environments, has become an urgent technical problem to be solved in this field. Summary of the Invention

[0008] To solve the above-mentioned technical problems, the present invention provides a hydrophilic electroplating nickel solution and a nickel plating method for copper-based heat dissipation components using the same, which improves the adhesion of the obtained plating layer and the stability of the hydrophilic properties, and solves the problem that the existing nickel plating process cannot achieve long-term stable operation of copper-based heat dissipation components under hot and cold conditions due to insufficient adhesion of the nickel layer and unstable hydrophilic properties.

[0009] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a hydrophilic nickel plating solution, the hydrophilic nickel plating solution comprising a nickel source, a pH stabilizer, a grain refiner, a polarity adjuster, and a corrosion inhibitor; The pH of the hydrophilic nickel plating solution is 3.8 to 4.2, for example, it can be 3.8, 3.9, 4.0, 4.1 or 4.2.

[0010] The hydrophilic nickel plating solution of this invention, by synergistically adding a pH stabilizer and a polarity adjuster, can enhance the surface polarity of the plating layer while controlling its pH to 3.8~4.2. The synergistic effect of the two enhances the adhesion between the obtained nickel layer and the workpiece to be plated and improves the long-term stability of its hydrophilic properties. Therefore, when applied to nickel plating of copper-based heat dissipation components, it improves the boiling heat transfer performance, and has an earlier boiling onset time, a higher heating rate, a higher heat flux density, a higher interfacial thermal conductivity, and a lower interfacial thermal resistance, thereby improving the heat dissipation performance and heat dissipation stability of copper-based heat dissipation components.

[0011] If the pH of the hydrophilic nickel plating solution is less than 3.8, it will intensify the hydrogen evolution side reaction, making the plating layer prone to pinholes and reducing adhesion. If the pH of the hydrophilic nickel plating solution is greater than 4.2, it will increase the tendency of nickel ion hydrolysis, easily generating nickel hydroxide colloid, making the plating layer rough and increasing internal stress. If the polarity regulator is not added, the resulting plating layer will have a low hydroxyl content, resulting in poor hydrophilicity and instability.

[0012] The pH stabilizer is used to stabilize the pH of the hydrophilic nickel plating solution, preventing a sudden increase in local pH that could lead to nickel hydroxide precipitation and affect the plating process. The grain refiner is used to refine the grains of the resulting plating layer and reduce its porosity. The polarity regulator is used to increase the hydroxyl content on the surface of the resulting plating layer, thereby increasing its surface energy and maintaining its hydrophilic properties. The corrosion inhibitor is used to inhibit the chemical reaction between the copper substrate and the plating solution, preventing defects such as pinholes or pitting from appearing in the plating layer.

[0013] Preferably, the hydrophilic nickel plating solution comprises 350~440g / L nickel source, 35~40g / L pH stabilizer, 3~5g / L grain refiner, 8~12g / L polarity adjuster and 1~2g / L corrosion inhibitor.

[0014] Among them, the nickel source is 350~440 g / L, for example, it can be 350 g / L, 360 g / L, 370 g / L, 380 g / L, 390 g / L, 400 g / L, 410 g / L, 420 g / L, 430 g / L or 440 g / L, etc.; 35~40 g / L pH stabilizers, for example, can be 35 g / L, 36 g / L, 37 g / L, 38 g / L, 39 g / L, or 40 g / L; grain refiners, for example, can be 3 g / L, 3.5 g / L, 4 g / L, 4.5 g / L, or 5 g / L; polarity modifiers, for example, can be 8 g / L, 8.5 g / L, 9 g / L, 9.5 g / L, 10 g / L, 10.5 g / L, 11 g / L, 11.5 g / L, or 12 g / L; corrosion inhibitors, for example, can be 1 g / L, 1.2 g / L, 1.5 g / L, 1.8 g / L, or 2 g / L.

[0015] Preferably, the mass ratio of the pH stabilizer to the polarity regulator is (3.5~4.5):1, for example, it can be 3.5:1, 3.6:1, 3.7:1, 3.8:1, 3.9:1, 4:1, 4.1:1, 4.2:1, 4.3:1, 4.4:1 or 4.5:1, etc.

[0016] This invention further optimizes the mass ratio of the pH stabilizer to the polarity regulator to be (3.5~4.5):1, which is beneficial for maximizing the adsorption of the polarity regulator at the cathode interface while maintaining the pH stability of the plating solution, thereby synergistically optimizing the density and hydrophilicity of the coating. If the mass ratio of the pH stabilizer to the polarity regulator is too low, that is, the amount of pH stabilizer added is too small and the amount of polarity regulator added is too large, it will lead to insufficient pH stability and easily cause coating defects. If the mass ratio of the pH stabilizer to the polarity regulator is too high, that is, the amount of pH stabilizer added is too large and the amount of polarity regulator added is too small, it will lead to a weakening of the effect of the polarity regulator and an insignificant improvement in hydrophilicity.

[0017] Preferably, the pH stabilizer comprises any one or a combination of at least two of boric acid, citric acid, tartaric acid, acetic acid, or propionic acid, wherein typical but non-limiting combinations include combinations of boric acid and tartaric acid, combinations of citric acid and acetic acid, and combinations of tartaric acid and propionic acid, etc.

[0018] It is worth noting that the pH stabilizer described in this invention can also be an alkali metal salt of the corresponding acid, such as sodium citrate, sodium acetate, or sodium borate.

[0019] Preferably, the polarity modifier comprises any one or a combination of at least two of aminosulfonic acid, p-toluenesulfonic acid, sodium dodecyl sulfate, sulfosalicylic acid, or glycine, wherein typical but non-limiting combinations include combinations of aminosulfonic acid and p-toluenesulfonic acid, combinations of aminosulfonic acid and sulfosalicylic acid, and combinations of aminosulfonic acid and sodium dodecyl sulfate, etc.

[0020] Preferably, the nickel source includes nickel sulfate, nickel aminosulfonate, and nickel chloride.

[0021] Preferably, the hydrophilic nickel plating solution comprises 220-250 g / L nickel sulfate, 100-150 g / L nickel sulfamate, and 30-40 g / L nickel chloride.

[0022] Among them, nickel sulfate with a concentration of 220~250 g / L can be, for example, 220 g / L, 225 g / L, 230 g / L, 235 g / L, 240 g / L, 245 g / L or 250 g / L; nickel aminosulfonate with a concentration of 100~150 g / L can be, for example, 100 g / L, 110 g / L, 120 g / L, 130 g / L, 140 g / L or 150 g / L; and nickel chloride with a concentration of 30~40 g / L can be, for example, 30 g / L, 32 g / L, 35 g / L, 38 g / L or 40 g / L.

[0023] The nickel sulfate provides the main source of nickel ions to ensure the thickness of the coating; the aminosulfonic acid solution provides the main source of nickel ions to improve the conductivity of the plating solution and ensure the thickness of the nickel layer; the nickel chloride is used to improve the conductivity of the plating solution and acts as an anode activator to inhibit the burning of the coating.

[0024] Preferably, the grain refiner comprises silicon dioxide nanoparticles.

[0025] Preferably, the particle size D50 of the silica nanoparticles is 5~20nm, for example, it can be 5nm, 8nm, 10nm, 12nm, 15nm, 18nm or 20nm, etc.

[0026] This invention further optimizes the particle size D50 of the silica nanoparticles to 5-20 nm, which helps to refine the grain structure of the resulting coating to a particle size of 1-2 μm, thereby reducing the porosity of the coating. If the particle size D50 of the silica nanoparticles is too low, it will lead to a serious tendency for particle agglomeration and make it difficult to disperse evenly; if the particle size D50 of the silica nanoparticles is too high, it will be difficult to embed into the coating, or even become an inclusion, which will increase the porosity.

[0027] Preferably, the corrosion inhibitor comprises a benzotriazole derivative.

[0028] Preferably, the benzotriazole derivative includes any one or a combination of at least two of benzotriazole, methylbenzotriazole, carboxybenzotriazole or nitrobenzazole, wherein typical but non-limiting combinations include combinations of benzotriazole and methylbenzotriazole, combinations of benzotriazole and carboxybenzotriazole, and combinations of methylbenzotriazole and nitrobenzazole, etc.

[0029] The present invention does not limit the preparation method of the hydrophilic nickel plating solution. As long as the above formula is followed and the particles are uniformly dispersed without agglomeration, the preparation method is acceptable. For example, deionized water can be heated to 40-45°C, and then pH stabilizer, nickel sulfate, nickel chloride and nickel sulfamate can be added in sequence. The mixture can be stirred until completely dissolved, cooled to room temperature, and then polarity regulator and corrosion inhibitor can be added and ultrasonically dispersed for 5-15 minutes. Finally, grain refiner can be added and ultrasonically dispersed for 15-25 minutes with an ultrasonic power of 450-550W to obtain the hydrophilic nickel plating solution.

[0030] In a second aspect, the present invention provides a method for nickel plating of a copper-based heat dissipation component, wherein the nickel plating method is performed in the hydrophilic nickel plating solution described in the first aspect.

[0031] The nickel plating method for the copper-based heat dissipation component of the present invention is carried out by electroplating in the hydrophilic nickel plating solution described in the first aspect. The resulting plating layer has strong adhesion, low porosity, and excellent hydrophilic stability, and can adapt to hot and cold working conditions.

[0032] Preferably, the nickel plating method includes the following steps: The copper-based heat dissipation component is pretreated to obtain the part to be plated; the part to be plated is then electroplated in the hydrophilic nickel plating solution in stages to obtain the copper-based heat dissipation component with a nickel plating layer. During the segmented electroplating process, the pH of the hydrophilic nickel plating solution is adjusted in real time to maintain it at 3.8~4.2, for example, it can be 3.8, 3.9, 4.0, 4.1 or 4.2, etc.

[0033] Preferably, the segmented electroplating includes a first electroplating, a second electroplating, and a third electroplating performed sequentially.

[0034] Preferably, the temperature of the first electroplating is less than the temperature of the third electroplating and less than the temperature of the second electroplating.

[0035] Preferably, the current density of the first electroplating is less than the current density of the third electroplating and less than the current density of the second electroplating.

[0036] Preferably, the time for the first electroplating is less than or equal to the time for the second electroplating and less than or equal to the time for the third electroplating.

[0037] This invention further optimizes the use of a segmented electroplating process. First, nickel ions are slowly deposited at low temperature and low current, allowing the nickel layer to bond tightly with the workpiece. Then, the temperature is appropriately increased and the current is raised to accelerate the growth of the plating layer. At the same time, the grain refiner in the hydrophilic nickel plating solution is embedded in the plating layer. Subsequently, the temperature and current are lowered to repair minor defects on the plating surface and reduce internal stress. Combined with the hydrophilic nickel plating solution with the above-mentioned specific composition, the plating layer with higher bonding strength, lower porosity, and better hydrophilic stability is formed.

[0038] Preferably, the temperature of the first electroplating is 40~42℃, for example, it can be 40℃, 40.5℃, 41℃, 41.5℃ or 42℃, etc.

[0039] Preferably, the current density of the first electroplating is 1.0~1.2 A / dm². 3 For example, it could be 1.0A / dm 3 1.05A / dm 3 1.1A / dm 3 1.15A / dm 3 Or 1.2A / dm 3 wait.

[0040] Preferably, the first electroplating time is 10-15 minutes, for example, 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes or 15 minutes.

[0041] Preferably, the temperature of the second electroplating is 45~55℃, for example, it can be 45℃, 48℃, 50℃, 52℃ or 55℃, etc.

[0042] Preferably, the current density of the second electroplating is 1.5~1.8 A / dm². 3 For example, it could be 1.5A / dm 3 1.55A / dm 3 1.6A / dm 3 1.65A / dm 3 1.7A / dm 3 1.75A / dm 3 Or 1.8A / dm 3 wait.

[0043] Preferably, the second electroplating time is 15 to 20 minutes, for example, 15 minutes, 16 minutes, 17 minutes, 18 minutes, 19 minutes, or 20 minutes.

[0044] Preferably, the temperature of the third electroplating is 42~43℃, for example, it can be 42℃, 42.2℃, 42.5℃, 42.8℃ or 43℃, etc.

[0045] Preferably, the current density of the third electroplating is 1.2~1.5 A / dm². 3 For example, it could be 1.2A / dm 3 1.25A / dm 3 1.3A / dm 3 1.35A / dm 3 1.4A / dm 3 1.45A / dm3 Or 1.5A / dm 3 wait.

[0046] Preferably, the third electroplating time is 20-25 minutes, for example, it can be 20 minutes, 21 minutes, 22 minutes, 23 minutes, 24 minutes or 25 minutes.

[0047] Preferably, the pretreatment includes degreasing, pickling and activation treatment performed sequentially.

[0048] Preferably, the degreasing process includes ultrasonic cleaning in a degreasing agent.

[0049] Preferably, the degreasing treatment temperature is 60~80℃, for example, it can be 60℃, 65℃, 70℃, 75℃ or 80℃.

[0050] Preferably, the ultrasonic cleaning time is 4 to 6 minutes, for example, 4 minutes, 5 minutes or 6 minutes.

[0051] Preferably, the acid solution used for pickling includes hydrochloric acid solution and / or sulfuric acid solution.

[0052] Preferably, the acid solution used in the pickling process has a H2 content. + The concentration is 1.0~3.0 mol / L, for example, it can be 1.0 mol / L, 1.5 mol / L, 2.0 mol / L, 2.5 mol / L or 3.0 mol / L, etc.

[0053] Preferably, the pickling time is 40-80 seconds, for example, 40 seconds, 50 seconds, 60 seconds, 70 seconds or 80 seconds.

[0054] Preferably, the activation solution used in the activation treatment includes a combination of sulfuric acid and hydrogen peroxide.

[0055] Preferably, the concentration of the sulfuric acid is 5-15 wt%, for example, it can be 5 wt%, 8 wt%, 10 wt%, 12 wt%, or 15 wt%.

[0056] Preferably, the concentration of the hydrogen peroxide is 3 to 10 wt%, for example, it can be 3 wt%, 5 wt%, 8 wt%, or 10 wt%.

[0057] Preferably, the volume ratio of sulfuric acid to hydrogen peroxide in the activation solution is 1~3):1, for example, it can be 1:1, 1.5:1, 2:1, 2.5:1 or 3:1, etc.

[0058] Preferably, the activation treatment time is 40-80 seconds, for example, 40 seconds, 50 seconds, 60 seconds, 70 seconds or 80 seconds.

[0059] Preferably, the segmented electroplating process is accompanied by stirring.

[0060] Preferably, the stirring speed during the first electroplating, the second electroplating, and the third electroplating processes is independently 50~80 r / min, for example, it can be 50 r / min, 55 r / min, 60 r / min, 65 r / min, 70 r / min, 75 r / min, or 80 r / min, etc.

[0061] As a further preferred technical solution of the present invention, the nickel plating method includes the following steps: First, the copper-based heat dissipation components are ultrasonically cleaned with a degreasing agent at 60-80℃ for 4-6 minutes to degrease them, then H... + The degreased copper-based heat dissipation component is pickled with an acid solution of 1.0~3.0 mol / L for 40~80 seconds, and then activated with an activation solution containing sulfuric acid and hydrogen peroxide for 40~80 seconds to obtain the part to be plated; wherein the mass concentration of sulfuric acid is 5wt%~15wt%, the mass concentration of hydrogen peroxide is 3wt%~10wt%, and the volume ratio of sulfuric acid to hydrogen peroxide is (1~3):1; subsequently, the part to be plated is subjected to segmented electroplating in a hydrophilic nickel plating solution, wherein the segmented electroplating includes first plating at 40~42℃ and a current density of 1.0~1.2 A / dm³. 3 The first electroplating is carried out for 10-15 minutes with a stirring speed of 50-80 r / min; then, the electroplating is carried out at 45-55℃ and a current density of 1.5-1.8 A / dm³. 3 The second electroplating was carried out for 15-20 minutes with a stirring speed of 50-80 r / min; finally, the plating was carried out at 42-43℃ and a current density of 1.2-1.5 A / dm³. 3 A third electroplating process was carried out for 20-25 minutes at a stirring speed of 50-80 r / min to obtain a copper-based heat dissipation component with a nickel plating layer. Furthermore, during the segmented electroplating process, the pH of the hydrophilic nickel plating solution is adjusted in real time to maintain it at 3.8~4.2. Compared with the prior art, the present invention has at least the following beneficial effects: (1) The hydrophilic nickel plating solution provided by the present invention optimizes the plating solution formula so that the bonding strength of the resulting plating layer is preferably as high as 60 MPa or more, which is more than 30% higher than the traditional process (≤45 MPa). It refines the plating layer grains, and the porosity is preferably as low as 0.35% or less. It improves the surface polarity of the plating layer, which is conducive to the formation of a hydrophilic sealing film. The initial water contact angle is 25~35°, which has excellent hydrophilic properties.

[0062] (2) The nickel plating method for copper-based heat dissipation components provided by the present invention uses a hydrophilic electroplating nickel solution with a specific composition and specific pH, and further combines it with a specific segmented electroplating process to achieve a test effect of delayed water contact angle of less than 60°. After being placed in a natural environment for 360 hours, the water contact angle is still less than 55°. At the same time, it maintains excellent anti-corrosion performance and thermal conductivity. It solves the problem that the surface wettability of the coating obtained by the existing nickel plating process is poor and it is difficult to meet the industry standard requirements. Moreover, the entire process is free of heavy metals such as chromates, which complies with the RoHS 2.0 standard. No additional equipment is required, and mass production is highly feasible. Detailed Implementation

[0063] The technical solution of the present invention will be further illustrated below through specific embodiments. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0064] Unless otherwise specified, the reagents involved in the following specific embodiments of the present invention are all conventional reagents in the art and can be purchased from commercially available products.

[0065] The preparation method of the hydrophilic nickel plating solution described in the following examples or comparative examples includes the following steps: first, deionized water is heated to 45°C, then pH stabilizer, nickel sulfate, nickel chloride and nickel aminosulfonate are added sequentially, stirred until completely dissolved, cooled to 25°C, then polarity regulator and corrosion inhibitor are added and ultrasonically dispersed at 500W for 10 minutes, and finally grain refiner is added and ultrasonically dispersed at 500W for 20 minutes to obtain the hydrophilic nickel plating solution.

[0066] In the following examples or comparative examples, the pH of the hydrophilic nickel plating solution is adjusted in real time to 3.8~4.2 during the nickel plating process. Wherein, if pH>4.2, 10wt% sulfuric acid solution is added for pH adjustment; if pH<3.8, 5wt% sodium hydroxide solution is added for pH adjustment.

[0067] The degreaser described in the following examples or comparative examples is BONDERITE C-AK 7036, an alkaline degreaser and oil remover from Henkel, Germany, which was purchased from Baobang Chemical (Shanghai) Co., Ltd.

[0068] I. Implementation Examples Example 1 This embodiment provides a hydrophilic nickel plating solution, which comprises 235 g / L nickel sulfate, 120 g / L nickel sulfamate, 35 g / L nickel chloride, 38 g / L boric acid, 4 g / L silica nanoparticles (particle size D50 of 15 nm), 10 g / L sulfamate, 1.5 g / L methylbenzotriazole, and water; the pH of the hydrophilic nickel plating solution is 4.

[0069] This embodiment also provides a method for nickel plating of a copper-based heat dissipation component, the nickel plating method comprising the following steps: First, the copper-based heat dissipation components are ultrasonically cleaned at 70℃ for 5 minutes using a degreasing agent, then subjected to H... + The degreased copper-based heat dissipation component was acid-washed for 60 seconds with a 2.0 mol / L sulfuric acid solution, and then activated for 60 seconds with an activation solution containing sulfuric acid (10 wt%) and hydrogen peroxide (8 wt%) to obtain the part to be plated; the volume ratio of sulfuric acid to hydrogen peroxide was 2:1; subsequently, the part to be plated was subjected to segmented electroplating in a hydrophilic nickel plating solution, the segmented electroplating including first plating at 41°C and a current density of 1.1 A / dm³. 3 The first electroplating was carried out for 12 minutes at a stirring speed of 50 r / min; then electroplating was performed at 50℃ and a current density of 1.7 A / dm³. 3 The second electroplating was carried out for 18 minutes at a stirring speed of 60 r / min; finally, the plating was carried out at 42.5℃ and a current density of 1.3 A / dm³. 3 A third electroplating process was performed for 22 minutes at a stirring speed of 80 r / min to obtain a copper-based heat dissipation component with a nickel plating layer. Furthermore, during the segmented electroplating process, the pH of the hydrophilic nickel plating solution is adjusted in real time to maintain it at 3.8~4.2.

[0070] Example 2 This embodiment provides a hydrophilic nickel plating solution, which comprises 220 g / L nickel sulfate, 100 g / L nickel sulfamate, 30 g / L nickel chloride, 37.3 g / L boric acid, 3 g / L silica nanoparticles (particle size D50 of 5 nm), 10.7 g / L sulfamate, 1 g / L benzotriazole, and water; the pH of the hydrophilic nickel plating solution is 3.8.

[0071] This embodiment also provides a method for nickel plating of a copper-based heat dissipation component, the nickel plating method comprising the following steps: First, the copper-based heat sink components are ultrasonically cleaned at 60℃ for 6 minutes using a degreasing agent to remove grease, then H... +The degreased copper-based heat dissipation component was pickled for 40 seconds with a 1.0 mol / L hydrochloric acid solution, and then activated for 40 seconds with an activation solution containing sulfuric acid (5 wt%) and hydrogen peroxide (3 wt%) to obtain the part to be plated; the volume ratio of sulfuric acid and hydrogen peroxide was 1:1; subsequently, the part to be plated was subjected to segmented electroplating in a hydrophilic nickel plating solution, the segmented electroplating including first plating at 40°C and a current density of 1.0 A / dm³. 3 The first electroplating was carried out for 10 minutes with a stirring speed of 60 r / min; then electroplating was performed at 45℃ and a current density of 1.5 A / dm. 3 The second electroplating was carried out for 15 minutes at a stirring speed of 70 r / min; finally, the plating was carried out at 42℃ and a current density of 1.2 A / dm³. 3 A third electroplating process was performed for 20 minutes at a stirring speed of 75 r / min to obtain a copper-based heat dissipation component with a nickel plating layer. Furthermore, during the segmented electroplating process, the pH of the hydrophilic nickel plating solution is adjusted in real time to maintain it at 3.8~4.2.

[0072] Example 3 This embodiment provides a hydrophilic nickel plating solution, which comprises 250 g / L nickel sulfate, 150 g / L nickel sulfamate, 40 g / L nickel chloride, 39.3 g / L citric acid, 5 g / L silica nanoparticles (particle size D50 of 20 nm), 8.7 g / L p-toluenesulfonic acid, 2 g / L nitrobenzazole, and water; the pH of the hydrophilic nickel plating solution is 4.2.

[0073] This embodiment also provides a method for nickel plating of a copper-based heat dissipation component, the nickel plating method comprising the following steps: First, the copper-based heat dissipation components are ultrasonically cleaned at 80℃ for 4 minutes using a degreasing agent, then subjected to H... + The degreased copper-based heat dissipation component was pickled for 80 seconds with a 3.0 mol / L hydrochloric acid solution, and then activated for 80 seconds with an activation solution containing sulfuric acid (15 wt%) and hydrogen peroxide (10 wt%) to obtain the part to be plated; the volume ratio of sulfuric acid to hydrogen peroxide was 3:1; subsequently, the part to be plated was subjected to segmented electroplating in a hydrophilic nickel plating solution, the segmented electroplating including first plating at 42°C and a current density of 1.2 A / dm³. 3 The first electroplating was carried out for 15 minutes at a stirring speed of 55 r / min; then electroplating was performed at 55℃ and a current density of 1.8 A / dm. 3 The second electroplating was carried out for 20 minutes with a stirring speed of 65 r / min; finally, the plating was carried out at 43℃ and a current density of 1.5 A / dm³. 3A third electroplating process was performed for 25 minutes at a stirring speed of 80 r / min to obtain a copper-based heat dissipation component with a nickel plating layer. Furthermore, during the segmented electroplating process, the pH of the hydrophilic nickel plating solution is adjusted in real time to maintain it at 3.8~4.2.

[0074] Example 4 This embodiment provides a hydrophilic nickel plating solution. Except for the boric acid content of 36 g / L and the aminosulfonic acid content of 12 g / L (i.e., the mass ratio of boric acid to aminosulfonic acid is 3:1), the hydrophilic nickel plating solution is the same as that in Example 1.

[0075] This embodiment also provides a nickel plating method for copper-based heat dissipation components. Except for electroplating in the hydrophilic nickel plating solution described in this embodiment, the nickel plating method is the same as in Embodiment 1.

[0076] Example 5 This embodiment provides a hydrophilic nickel plating solution. Except for the boric acid content of 40 g / L and the aminosulfonic acid content of 8 g / L (i.e., the mass ratio of boric acid to aminosulfonic acid is 5:1), the hydrophilic nickel plating solution is the same as that in Example 1.

[0077] This embodiment also provides a nickel plating method for copper-based heat dissipation components. Except for electroplating in the hydrophilic nickel plating solution described in this embodiment, the nickel plating method is the same as in Embodiment 1.

[0078] Example 6 This embodiment provides a hydrophilic nickel plating solution, which is the same as that in Embodiment 1 except that the particle size D50 of the silica nanoparticles is 3 nm.

[0079] This embodiment also provides a nickel plating method for copper-based heat dissipation components. Except for electroplating in the hydrophilic nickel plating solution described in this embodiment, the nickel plating method is the same as in Embodiment 1.

[0080] Example 7 This embodiment provides a hydrophilic nickel plating solution, which is the same as that in Embodiment 1 except that the particle size D50 of the silica nanoparticles is 25 nm.

[0081] This embodiment also provides a nickel plating method for copper-based heat dissipation components. Except for electroplating in the hydrophilic nickel plating solution described in this embodiment, the nickel plating method is the same as in Embodiment 1.

[0082] Example 8 This embodiment provides a nickel plating method for a copper-based heat dissipation component. Except that the first electroplating, the second electroplating, and the third electroplating are all performed at the same temperature of 50°C, the nickel plating method is the same as that in Embodiment 1.

[0083] Example 9 This embodiment provides a nickel plating method for a copper-based heat dissipation component. Except for the fact that the second and third electroplating temperatures are the same (50°C), the nickel plating method is the same as in Embodiment 1.

[0084] Example 10 This embodiment provides a nickel plating method for a copper-based heat dissipation component. The nickel plating method uses the same current density (1.7 A / dm³) for the first, second, and third electroplating processes. 3 Except for the above, everything else is the same as in Example 1.

[0085] Example 11 This embodiment provides a nickel plating method for a copper-based heat dissipation component. The nickel plating method uses the same current density (1.7 A / dm²) for both the second and third electroplating processes. 3 Except for the above, everything else is the same as in Example 1.

[0086] Example 12 This embodiment provides a nickel plating method for copper-based heat dissipation components. The nickel plating method involves direct electroplating for 42 minutes under the conditions of the first electroplating step, i.e., the electroplating temperature is 41°C and the current density is 1.1 A / dm³. 3 Except for the stirring speed, which is 50 r / min, everything else is the same as in Example 1.

[0087] Example 13 This embodiment provides a nickel plating method for copper-based heat dissipation components. Except for the fact that the pH is not adjusted in real time during the segmented electroplating process, the nickel plating method is the same as that in Embodiment 1.

[0088] II. Comparative Example Comparative Example 1 This comparative example provides a hydrophilic nickel plating solution. Except for the absence of aminosulfonic acid and the addition of boric acid at a concentration of 48 g / L, which increases the pH of the nickel plating solution to 4.5, the hydrophilic nickel plating solution is the same as that in Example 1.

[0089] This comparative example also provides a nickel plating method for a copper-based heat dissipation component. The nickel plating method is the same as in Example 1, except that the hydrophilic nickel plating solution described in this comparative example is used for electroplating, and the pH of the hydrophilic nickel plating solution is not adjusted during the electroplating process.

[0090] Comparative Example 2 This comparative example provides a hydrophilic nickel plating solution. Except for the absence of boric acid and the addition of 48 g / L of aminosulfonic acid, which reduces the pH of the nickel plating solution to 2.8, the hydrophilic nickel plating solution is the same as that in Example 1.

[0091] This comparative example also provides a nickel plating method for a copper-based heat dissipation component. The nickel plating method is the same as in Example 1, except that the hydrophilic nickel plating solution described in this comparative example is used for electroplating, and the pH of the hydrophilic nickel plating solution is not adjusted during the electroplating process.

[0092] III. Tests and Results The bonding strength, porosity, initial water contact angle, and water contact angle of the nickel plating coatings obtained by the above embodiments or comparative examples were tested after being placed in a natural environment (20~30℃, humidity 40%~60%) for 360h. The results are shown in Table 1. Test methods and standards: Bond strength: The "tensile method" in GB / T 5270-2005 "Test method for adhesion strength of metallic coatings on metallic substrates" was adopted. The specific steps are as follows: A cylindrical pull-out head with a diameter of 10 mm (using high-strength epoxy adhesive) was bonded to the coating surface. After curing, a universal testing machine was used to vertically stretch the coating at a rate of 1 mm / min. The maximum load when the coating peeled off was recorded, and the bond strength (MPa) was calculated.

[0093] Porosity: The porosity test was performed using the potassium ferricyanide method (GB / T18590-2001 "Test of Porosity of Corrosion Coatings of Metals and Oxides"). The specific steps are as follows: The obtained coating was immersed in a solution containing potassium ferricyanide, sodium chloride, and hydrochloric acid (standard formulation: 10 g / L K3[Fe(CN)6], 20 g / L NaCl, and 10 mL / L HCl). After reacting for 10 minutes, the coating was removed, rinsed with deionized water, and dried. Blue spots (Cu) 2+ With [Fe(CN)6] 3- The location of pores is indicated by the formation of Tennant Blue (from the reaction). The unit area (cm²) is statistically analyzed using image analysis software. 2 The number of internal pores, converted into porosity (%).

[0094] Water contact angle: The static droplet method was used according to ISO 19403-2:2017 standard. The specific steps are as follows: Under constant temperature and humidity (23±1℃, RH 50±5%), a 3 μL droplet of ultrapure water was dropped onto the coating surface using a contact angle measuring instrument. A side view image was taken within 5 seconds. The contact angle was calculated by fitting the Young-Laplace equation. Five different locations were measured for each sample, and the average value was taken. The initial water contact angle was measured within 2 hours after electroplating. The water contact angle after 360 hours of natural environment placement refers to (20~30℃, humidity 40%~60%).

[0095] Table 1 The test results show that: (1) As can be seen from Examples 1 to 3, by optimizing the composition and ratio of the electroplating nickel solution and combining it with a specific segmented electroplating process, the present invention enables the nickel layer on the copper-based heat dissipation component to have a bonding strength of more than 60 MPa, a porosity of less than 0.35%, an initial water contact angle of 25~35°, and stable hydrophilic properties. After being placed in a natural environment for 360 hours, the water contact angle is still less than 55°, which solves the problems of insufficient nickel layer bonding and poor and unstable wetting performance in the existing nickel plating process.

[0096] (2) As can be seen from the combined examples 1, 4 and 5, the present invention further improves the stability of the hydrophilic properties of the obtained coating by further optimizing the mass ratio of the pH stabilizer to the polarity regulator to (3.5~4.5):1.

[0097] (3) As can be seen from the combined examples 1, 6 and 7, the present invention further refines the grain structure of the obtained coating by optimizing the particle size D50 of the silica nanoparticles to 5~20nm, thereby further reducing its porosity and thus being more conducive to improving the long-term stability of hydrophilic properties.

[0098] (4) As can be seen from the combined examples 1 and 8 to 13, the present invention further improves the bonding strength and hydrophilic stability of the obtained coating by further optimizing the segmented electroplating process and strictly controlling the temperature, current density and pH parameters of each segment of the electroplating process.

[0099] (5) As can be seen from the combined example 1 and comparative examples 1 and 2, the present invention controls the pH of the hydrophilic nickel plating solution within the range of 3.8 to 4.2 by synergistically adding pH stabilizer and polarity regulator, thereby increasing the surface polarity and forming a hydrophilic sealing film, so that the hydrophilic properties of the resulting coating are stable for a long time, which meets the long-term stable operation requirements of copper-based heat dissipation components under hot and cold conditions.

[0100] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A hydrophilic nickel plating solution, characterized in that, The hydrophilic nickel plating solution includes a nickel source, a pH stabilizer, a grain refiner, a polarity adjuster, and a corrosion inhibitor; The pH of the hydrophilic nickel plating solution is 3.8~4.

2.

2. The hydrophilic nickel plating solution according to claim 1, characterized in that, The hydrophilic nickel plating solution includes 350~440g / L nickel source, 35~40g / L pH stabilizer, 3~5g / L grain refiner, 8~12g / L polarity adjuster and 1~2g / L corrosion inhibitor.

3. The hydrophilic nickel plating solution according to claim 2, characterized in that, The mass ratio of the pH stabilizer to the polarity regulator is (3.5~4.5):1; The pH stabilizer includes any one or a combination of at least two of boric acid, citric acid, tartaric acid, acetic acid, or propionic acid; The polarity modifier includes any one or a combination of at least two of aminosulfonic acid, p-toluenesulfonic acid, sodium dodecyl sulfate, sulfosalicylic acid, or glycine.

4. The hydrophilic nickel plating solution according to claim 1, characterized in that, The nickel source includes nickel sulfate, nickel aminosulfonate, and nickel chloride; The hydrophilic nickel plating solution comprises 220-250 g / L nickel sulfate, 100-150 g / L nickel aminosulfonate, and 30-40 g / L nickel chloride; The grain refiner includes silicon dioxide nanoparticles; The particle size D50 of the silica nanoparticles is 5~20nm; The corrosion inhibitor includes benzotriazole derivatives; The benzotriazole derivatives include any one or a combination of at least two of benzotriazole, methylbenzotriazole, carboxybenzotriazole, or nitrobenzazole.

5. A method for nickel plating a copper-based heat dissipation component, characterized in that, The nickel plating method is performed in the hydrophilic nickel plating solution according to any one of claims 1 to 4.

6. The nickel plating method according to claim 5, characterized in that, The nickel plating method includes the following steps: The copper-based heat dissipation component is pretreated to obtain the part to be plated; the part to be plated is then electroplated in the hydrophilic nickel plating solution in stages to obtain the copper-based heat dissipation component with a nickel plating layer. During the segmented electroplating process, the pH of the hydrophilic nickel plating solution is adjusted in real time to maintain it at 3.8~4.

2.

7. The nickel plating method according to claim 6, characterized in that, The segmented electroplating includes a first electroplating, a second electroplating, and a third electroplating performed sequentially. The temperature of the first electroplating is less than the temperature of the third electroplating and less than the temperature of the second electroplating. The current density of the first electroplating is less than the current density of the third electroplating and less than the current density of the second electroplating. The time for the first electroplating is less than or equal to the time for the second electroplating and less than or equal to the time for the third electroplating.

8. The nickel plating method according to claim 7, characterized in that, The temperature of the first electroplating is 40~42℃; The current density for the first electroplating is 1.0~1.2 A / dm². 3 ; The first electroplating time is 10~15 minutes; The second electroplating temperature is 45~55℃; The current density for the second electroplating is 1.5~1.8 A / dm². 3 ; The second electroplating time is 15-20 minutes; The temperature of the third electroplating is 42~43℃; The current density for the third electroplating is 1.2~1.5 A / dm². 3 ; The third electroplating time is 20-25 minutes.

9. The nickel plating method according to claim 6, characterized in that, The pretreatment includes sequential degreasing, pickling, and activation. The degreasing process includes ultrasonic cleaning in a degreasing agent; The degreasing treatment temperature is 60~80℃; The pickling process uses an acid solution with H₂... + The concentration is 1.0~3.0 mol / L; The activation solution used in the activation treatment includes a combination of sulfuric acid and hydrogen peroxide; The volume ratio of sulfuric acid to hydrogen peroxide in the activation solution is (1~3):

1.

10. The nickel plating method according to claim 7, characterized in that, The segmented electroplating process is accompanied by stirring; During the first electroplating, the second electroplating, and the third electroplating processes, the stirring speed is independently 50~80 r / min.

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