Nickel plating solution and surface treatment method of aluminum-based material

Abstract

The embodiment of the invention provides a nickel plating solution and a surface treatment method of an aluminum-based material. The nickel plating solution comprises soluble nickel salt, a complexing agent, a styrene polymer and ammonia water. The complexing agent comprises a compound as shown in a formula (I), and in the formula (I), X is an ether bond-containing alkyl chain, a phenyl-containing alkyl chain or a polyenol chain; r1 and R2 are respectively and independently selected from hydrogen, substituted or non-substituted alkyl, substituted or non-substituted cycloalkyl, substituted or non-substituted alkenyl, substituted or non-substituted alkynyl, substituted or non-substituted ester, substituted or non-substituted aryl, substituted or non-substituted heteroaryl or substituted or non-substituted alicyclic group, and R1 and R2 are independently selected from hydrogen, substituted or non-substituted alkyl, substituted or non-substituted cycloalkyl, substituted or non-substituted alkenyl, substituted or non-substituted alkynyl, substituted or non-substituted ester, substituted or non-substituted aryl, substituted or non-substituted heteroaryl or substituted or non-substituted alicyclic group; r1 and R2 are not heteroaryl containing sulfur atoms at the same time. The nickel plating solution is high in stability, does not need to add a reducing agent additionally, can be used for surface treatment of the aluminum-based material, enables the surface of the aluminum-based material to form a nickel film layer which is single in component, flat and uniform at room temperature, and further facilitates proceeding of a subsequent plating process.

Description

Technical Field

[0001] This application relates to the field of metal surface treatment technology, and in particular to a method for surface treatment of nickel plating solution and aluminum-based materials. Background Technology

[0002] Due to its special sandblasting process and complex alloy composition, die-cast aluminum alloys have high surface roughness and many inert sites. During the process of coating a thin film on its surface, problems such as film voids, uneven coating, and corrosion before coating in strongly acidic plating solutions are prone to occur, which increases the difficulty of surface treatment.

[0003] Currently, the industry uses a nickel plating bath to pre-plat nickel onto aluminum alloy substrates to achieve surface activation. The principle is that aluminum displaces nickel from the nickel plating bath, forming a base nickel layer on the aluminum alloy substrate surface. This base layer provides acid resistance, uniform surface potential, and improved adhesion between subsequent plating layers and the aluminum alloy substrate. To control the rate and equilibrium of the nickel-aluminum displacement reaction, ligands and / or complexing agents need to be added to the nickel plating bath to adjust the nickel ion concentration. However, existing ligands and complexing agents typically only achieve ideal results under specific conditions, such as high temperature, high pH environments, or the addition of additional reducing agents to assist nickel displacement. These specific conditions increase the cost and difficulty of aluminum substrate surface treatment processes. Therefore, it is necessary to provide a nickel plating bath formulation that is highly stable, requires no additional reducing agents, and can perform surface treatment on aluminum-based materials at room temperature to form a highly uniform pre-plated nickel film. Summary of the Invention

[0004] Therefore, this application provides a nickel plating solution and a surface treatment method for aluminum-based materials. The nickel plating solution itself has high stability and does not require the addition of a reducing agent. It can be used for surface treatment of aluminum-based materials, forming a uniform and flat nickel film layer with a single component on the surface of the aluminum-based material at room temperature, which is beneficial to the subsequent plating process.

[0005] In a first aspect, embodiments of this application provide a nickel plating solution comprising a soluble nickel salt, a complexing agent, a styrene-based polymer, and ammonia; the complexing agent comprises a compound as shown in formula (I).

[0006]

[0007] In formula (I), X is a hydrocarbon chain containing an ether bond, a hydrocarbon chain containing a phenylene group, or a polyenol chain; R1 and R2 are independently selected from hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted ester, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, or substituted or unsubstituted alicyclic group, and R1 and R2 are not simultaneously heteroaryl containing sulfur atoms.

[0008] The nickel plating solution provided in this application embodiment, under the synergistic effect of the complexing agent including the compound shown in formula (I) and the styrene polymer, can maintain high stability at a system pH of 9-10, without needing to adjust the system pH to greater than 10, which helps to avoid the adverse effects of high alkalinity of the solution on aluminum-based materials. The nickel plating solution provided in this application embodiment also contains soluble nickel salt, a complexing agent including the compound shown in formula (I), styrene polymer and ammonia, which can be used for surface treatment of aluminum-based materials. It can achieve one-time autocatalytic deposition of metallic nickel on the surface of aluminum-based materials at room temperature without the need for additional reducing agents, so that a single-component, flat and uniform nickel film layer is formed on the surface of aluminum-based materials, which is used to resist acid and uniform surface potential, thereby facilitating the subsequent plating process and improving the adhesion between the subsequent nickel plating layer and the surface of aluminum-based materials. Compared with the existing surface activation process, the nickel plating solution provided in this application embodiment can simplify the pre-nickel plating process of aluminum-based materials, that is, simplify the surface activation process and save process time.

[0009] Soluble nickel salts provide the nickel ions required for the nickel-aluminum substitution reaction. The compound shown in formula (I) (hereinafter referred to as XPT) acts as a complexing agent to complex nickel ions, forming a water-soluble dicyclic compound. On the one hand, this reduces the electrochemical reaction potential of nickel substitution on the aluminum surface, allowing nickel ions to be adsorbed and deposited on the aluminum-based material surface and undergo a substitution reaction with aluminum to form a nickel film. On the other hand, it reduces the number of active nickel ions that can participate in the substitution reaction, thereby enabling controllable adjustment of the ratio of active nickel ions to dicyclic compounds in the nickel plating solution. This allows for control of the rate of the nickel-aluminum substitution reaction, maintaining equilibrium and improving the uniformity, density, and adhesion of the nickel film. Furthermore, the dicyclic compound has a stable macrocyclic structure and is not easily decomposed in the nickel plating solution, which helps improve the stability of the system. Styrene polymers can also reduce the number of active nickel ions that can participate in the substitution reaction, forming a competitive constraint with XPT. The two work together to reduce the kinetic constant of the nickel substitution reaction, controlling the equilibrium of the nickel-aluminum substitution reaction to obtain a high-quality base nickel film.

[0010] In the embodiments of this application, the substituent groups in the substituted alkyl, substituted cycloalkyl, substituted alkenyl, substituted alkynyl, substituted ester, substituted aryl, substituted heteroaryl, or substituted aliphatic-heterocyclic groups include one or more of halogen atoms, alkyl, haloalkyl, cycloalkyl, alkyl-substituted cycloalkyl, alkoxy, haloalkoxy, and alkoxy-substituted alkyl. The introduction of substituents can adjust the properties of the compound to better meet the needs of the plating solution system.

[0011] In this embodiment, the substituted or unsubstituted heteroaryl group is a substituted or unsubstituted heteroaryl group containing 1-3 heteroatoms; the substituted or unsubstituted alicyclic group is a substituted or unsubstituted alicyclic group containing 1-3 heteroatoms; the heteroatoms are selected from one or more of nitrogen, oxygen, and sulfur. The introduction of the heterocycle can work together with the triazole structure in the compound shown in formula (I) to improve the stability of the complex obtained after complexing nickel ions.

[0012] In this embodiment of the application, the concentration of the compound represented by formula (I) in the nickel plating solution is 0.05 g / L-0.8 g / L. Adding an appropriate amount to the nickel plating solution system can better improve the stability of the nickel plating solution system and better utilize its complexing ability to regulate the nickel-aluminum displacement reaction, thereby improving the quality of the pre-plated nickel film.

[0013] In this embodiment, the styrene-based polymer includes one or more of linear polystyrene, cross-linked polystyrene, or styrene copolymers. The styrene-based polymer can synergistically work with the complexing agent in the system to improve the quality of the nickel film obtained from pre-plating nickel, thereby enhancing the adhesion of subsequent nickel plating layers.

[0014] In this embodiment, the weight-average molecular weight of the styrene polymer is 5K-50K. A suitable weight-average molecular weight is beneficial for the nickel plating solution system to maintain a suitable viscosity, exhibiting high stability, improving the quality of the pre-plated nickel film, and thus enhancing the adhesion of the nickel plating layer to the aluminum-based material surface.

[0015] In this embodiment, the particle size of the styrene-based polymer is 50 nm to 2.5 μm. Suitable particle size control of the styrene-based polymer is beneficial for its uniform dispersion in the nickel plating solution and for maintaining the overall uniformity of the plating solution.

[0016] In this embodiment, the concentration of styrene-based polymer in the nickel plating solution is 3 g / L-30 g / L. A suitable concentration of styrene-based polymer can improve the stability of the solution system, extend the service life of the nickel plating solution, better control the nickel-aluminum displacement reaction, and improve the quality of the pre-plated nickel film. It can also reduce the number of active nickel ions and the kinetic constant of the nickel displacement reaction.

[0017] In this embodiment, the complexing agent further includes other complexing agent molecules, the concentration of which is 3 g / L-30 g / L. The addition of appropriate amounts of these other complexing agent molecules can better control the nickel-aluminum displacement reaction and improve the quality of the pre-plated nickel film.

[0018] In this embodiment of the application, the mass ratio of the complexing agent to the styrene polymer in the nickel plating solution is (1-30):1. Controlling the mass ratio of the complexing agent and the styrene polymer within a suitable range is beneficial for better utilizing their synergistic effect, improving the performance of the nickel plating solution system, and regulating the rate of the nickel-aluminum replacement reaction, so as to deposit a smoother, more uniform, and denser nickel film layer on the surface of the aluminum-based material, thereby improving the adhesion of the nickel plating layer to the surface of the aluminum-based material.

[0019] In this embodiment, the soluble nickel salt includes one or more of nickel sulfate, nickel oxide, nickel chloride, nickel ammonium sulfate, nickel acetate, nickel nitrate, nickel carbonate, nickel aminosulfonate, organic sulfonate nickel salts, and carboxylate nickel salts. The soluble nickel salt can provide the required nickel ions for the nickel-aluminum substitution reaction.

[0020] In this embodiment of the application, the concentration of soluble nickel salt in the nickel plating solution is 10 g / L-30 g / L. Maintaining the soluble nickel salt at a suitable concentration is beneficial for the smooth progress of the nickel-aluminum replacement reaction, and at the same time, it can better control the reaction rate and promote the formation of a high-quality pre-plated nickel film.

[0021] In this embodiment, the nickel plating solution further includes a surfactant. The addition of the surfactant facilitates the dissolution of the components and improves the uniformity of the nickel plating solution.

[0022] In this application embodiment, the surfactant includes a nonionic surfactant, which includes at least one of polyoxyethylene surfactant and polyether surfactant.

[0023] In this embodiment of the application, the concentration of the surfactant in the nickel plating solution is 0.1 g / L to 10 g / L. An appropriate surfactant concentration is beneficial for improving the uniformity of the nickel plating solution.

[0024] In this embodiment of the application, the nickel plating solution further includes a silane coupling agent.

[0025] In this embodiment, the silane coupling agent includes one or more functional groups selected from acryloyl, epoxy, vinyl, amino, mercapto, and isocyanate groups. The addition of the silane coupling agent can fill the gaps in the pre-plated nickel film, making the nickel film more uniform, dense, smooth, and thus better improving the adhesion of the final nickel plating layer.

[0026] In this embodiment of the application, the concentration of the silane coupling agent in the nickel plating solution is 3 g / L-6 g / L. An appropriate amount of silane coupling agent is beneficial for filling gaps in the pre-plated nickel film without affecting the normal deposition of nickel.

[0027] In this embodiment, the pH value of the nickel plating solution is 9-10; the nickel plating process temperature is room temperature; and the nickel plating process time is 5-20 minutes. A suitable pH value provides the necessary alkaline environment for the nickel displacement reaction, while also ensuring the complete dissolution of the oxide film on the surface of the aluminum-based material to expose the aluminum layer, and preventing excessive alkalinity from etching the aluminum substrate.

[0028] In this embodiment of the application, the nickel plating solution does not contain a reducing agent.

[0029] The second aspect of this application provides a surface treatment method for aluminum-based materials, including:

[0030] The aluminum-based material is brought into contact with the nickel plating solution described in the first aspect of the present application to form a nickel film layer on the surface of the aluminum-based material.

[0031] In this embodiment of the application, the contact is carried out at room temperature; the contact time is 5 min to 20 min.

[0032] In this embodiment of the application, after the nickel film layer is formed, nickel is electroplated and / or electroless nickel plating is performed on the nickel film layer to form a nickel plating layer.

[0033] This application also provides an aluminum-based structural component, wherein a nickel film layer is formed on the surface of the aluminum-based material using the nickel plating solution described in the first aspect of this application. Detailed Implementation

[0034] The embodiments of this application will now be described in conjunction with the accompanying drawings.

[0035] Nickel plating is an ideal surface treatment technology for aluminum and aluminum alloys. Surface nickel plating can improve the corrosion resistance, wear resistance, weldability, and electrical contact properties of aluminum and aluminum alloys. However, aluminum is a difficult substrate to plate, especially for die-cast aluminum alloys. Due to their special sandblasting process and complex alloy composition, direct nickel plating presents the following problems: First, aluminum alloys have a strong affinity for oxygen, and their surfaces easily form uneven and discontinuous oxide films. The presence of these oxide films reduces the adhesion between the subsequent plating layer and the aluminum alloy substrate, leading to peeling and other defects. Second, die-cast aluminum alloys have a high surface roughness, and the presence of voids after the plating film makes them prone to galvanic corrosion, which in turn affects the adhesion of the plating layer and the reliability of the device. Among them, Giavian corrosion, also known as electrolytic corrosion, refers to the electrochemical reaction that occurs when two metals with different reactivity generate current through a medium due to a potential difference. The more active metal atoms lose electrons and are oxidized (corroded). Essentially, it is the oxidation of the more active metal. Third, trace components in aluminum alloys have a higher oxidation potential than the main aluminum material, which easily forms inert sites, resulting in uneven plating. Fourth, most plating solutions are strongly acidic, and aluminum, as an amphoteric metal, is sensitive to the pH of the plating solution used, often resulting in "corrosion before plating".

[0036] To ensure the successful nickel plating of die-cast aluminum alloys, the industry commonly employs a "zinc catalysis" method for surface activation. Zinc catalysis, also known as zinc displacement, utilizes the potential difference between zinc hydroxide anions and aluminum to induce a zinc-aluminum displacement reaction, forming a thin zinc film on the aluminum alloy surface. Zinc has a high oxidation potential and is not easily corroded, allowing for successful subsequent nickel plating. Typically, this process involves two zinc catalysis steps before nickel plating, with a nitric acid stripping step between the two steps. This cumbersome process is also environmentally unfriendly.

[0037] Currently, some methods utilize "nickel catalysis" for surface activation. "Nickel catalysis," also known as pre-plating or nickel displacement, involves a substitution reaction between nickel ions in a nickel plating bath and aluminum under alkaline conditions, forming a base nickel film on the aluminum alloy surface. This process typically requires the addition of ligands and / or complexing agents to the nickel plating bath to adjust the nickel ion concentration and thus regulate the electrochemical reaction potential of nickel displacement on the aluminum surface, maintaining the equilibrium of the displacement reaction. However, existing ligands and complexing agents often require specific conditions to achieve ideal results. For example, the nickel plating bath temperature must be maintained at around 50°C, the pH of the nickel plating bath must be greater than 10, additional reducing agents must be added to assist nickel displacement, or heavy metal ions must be added for buffering. These specific conditions increase the cost and difficulty of aluminum alloy surface treatment, and some may even introduce other metallic impurities during nickel displacement.

[0038] Therefore, this application provides a nickel plating solution with high stability, which does not require the addition of a reducing agent and can be used for surface treatment of aluminum-based materials. At room temperature, it forms a uniform nickel film layer with a single component on the surface of the aluminum-based material, which is beneficial to the subsequent plating process.

[0039] In the embodiments of this application, the aluminum-based material may include aluminum, aluminum alloys, aluminum-containing composite materials, etc.

[0040] The nickel plating solution provided in this application includes a soluble nickel salt, a complexing agent, a styrene polymer, and ammonia; wherein the complexing agent includes a compound as shown in formula (I).

[0041]

[0042] In formula (I), X is a hydrocarbon chain containing an ether bond, a hydrocarbon chain containing a phenylene group, or a polyenol chain; R1 and R2 are independently selected from hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted ester, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, or substituted or unsubstituted alicyclic group, and R1 and R2 are not simultaneously heteroaryl containing sulfur atoms.

[0043] The nickel plating solution provided in this application embodiment maintains high stability at a system pH of 9-10, eliminating the need to adjust the system pH to greater than 10, which helps avoid the adverse effects of high alkalinity on aluminum-based materials. The nickel plating solution provided in this application embodiment can be used for surface treatment of aluminum-based materials, achieving one-time autocatalytic deposition of metallic nickel on the aluminum-based material surface at room temperature without the need for additional reducing agents. This results in a single-component, smooth, and uniform nickel film layer on the aluminum-based material surface, providing acid resistance and uniform surface potential, thus facilitating subsequent plating processes and enhancing the adhesion between the subsequent nickel plating layer and the aluminum-based material surface. Compared to existing surface activation processes, the nickel plating solution provided in this application embodiment simplifies the pre-nickel plating process for aluminum-based materials, i.e., simplifies the surface activation process and saves process time.

[0044] Soluble nickel salts provide the nickel ions required for the nickel-aluminum substitution reaction. The compound shown in formula (I) (hereinafter referred to as XPT) acts as a complexing agent to complex nickel ions, forming a water-soluble dicyclic compound. On the one hand, this reduces the electrochemical reaction potential of nickel substitution on the aluminum surface, allowing nickel ions to be adsorbed and deposited on the aluminum-based material surface and undergo a substitution reaction with aluminum to form a nickel film. On the other hand, it reduces the number of active nickel ions that can participate in the substitution reaction, thereby enabling controllable adjustment of the ratio of active nickel ions to dicyclic compounds in the nickel plating solution. This allows for control of the rate of the nickel-aluminum substitution reaction, maintaining equilibrium and improving the uniformity, density, and adhesion of the nickel film. Furthermore, the dicyclic compound has a stable macrocyclic structure and is not easily decomposed in the nickel plating solution, which helps improve the stability of the system. Styrene polymers can also reduce the number of active nickel ions that can participate in the substitution reaction, forming a competitive constraint with XPT. The two work together to reduce the kinetic constant of the nickel substitution reaction, controlling the equilibrium of the nickel-aluminum substitution reaction to obtain a high-quality base nickel film.

[0045] In this article, active nickel ions refer to nickel ions that can participate in displacement reactions.

[0046] In this embodiment, the water-soluble dicyclic macrocyclic compound formed by the complexation of XPT with nickel ions can be represented as Ni2XPT2M2. M in Ni2XPT2M2 is a coordinating ion capable of coordinating with nickel ions, which can be any one or two of ammonium ions, halide ions, or hydrated hydrogen ions, depending specifically on the composition of the nickel plating solution system, such as the type of soluble nickel salt. For example, if the soluble nickel salt is nickel sulfamate, M may be an ammonium ion; if the soluble nickel salt is another nickel salt, M may be a hydrated hydrogen ion; if sodium chloride is added to the nickel plating solution system to improve the charge stability and structural stability of the macrocyclic compound, then M may be a chloride ion or a hydrated hydrogen ion.

[0047] In formula (I), X is a hydrocarbon chain containing an ether bond (COC), a hydrocarbon chain containing a phenylene group (-ph-), or a polyenol chain. The hydrocarbon chain containing an ether bond (COC) can be -R1-O-R2-, where R1 and R2 can be C1-C10 alkylene groups respectively; the hydrocarbon chain containing a phenylene group can be -R3-O-R4-, where R3 and R4 can be C1-C10 alkylene groups respectively; the polyenol chain can be -(R5-CH(OH)). n- R5 can be a C1-C6 alkylene group, and n is an integer greater than or equal to 1, for example, 1-20. Specifically, the aforementioned C1-C10 alkylene groups can be C1, C2, C3, C4, C5, C6, C7, C8, C9, or C10 alkylene groups, and can be alkylene groups. Specifically, the aforementioned C1-C6 alkylene groups can be C1, C2, C3, C4, C5, or C6 alkylene groups, and can be alkylene groups. In some embodiments, the alkyl chain containing phenylene (-ph-) is -CH2-ph-CH2-, and the two CH2 groups can be at the meta or para positions on the benzene ring.

[0048] In formula (I), R1 and R2 can be the same group or different groups.

[0049] In some embodiments, the substituted or unsubstituted alkyl group can be a substituted or unsubstituted C1-C6 alkyl group, and can be a straight-chain or branched alkyl group. For example, the substituted or unsubstituted alkyl group is a substituted or unsubstituted C1, C2, C3, C4, C5, or C6 alkyl group. Exemplarily, the substituted or unsubstituted alkyl group is substituted or unsubstituted methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, 2-methylbutyl, n-hexyl, 2,2-dimethylpropyl, 2-ethylpropyl, 2-methylpentyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, or 2-ethylbutyl.

[0050] The substituted or unsubstituted cycloalkyl group can be a substituted or unsubstituted C3-C8 cycloalkyl group. For example, the substituted or unsubstituted cycloalkyl group is substituted or unsubstituted cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, or cyclooctyl.

[0051] The substituted or unsubstituted alkenyl group can be a substituted or unsubstituted C2-C6 alkenyl group, and can be a straight-chain or branched alkenyl group. For example, the substituted or unsubstituted alkenyl group is a substituted or unsubstituted C2, C3, C4, C5, or C6 alkenyl group. Exemplarily, the substituted or unsubstituted alkenyl group is a substituted or unsubstituted vinyl, propenyl, butenyl, pentenyl, or hexenyl group.

[0052] The substituted or unsubstituted alkynyl group can be a substituted or unsubstituted C2-C6 alkynyl group, and can be a straight-chain or branched alkynyl group. For example, the substituted or unsubstituted alkynyl group is a substituted or unsubstituted C2, C3, C4, C5, or C6 alkynyl group. Exemplarily, the substituted or unsubstituted alkynyl group is substituted or unsubstituted ethynyl, propynyl, butynyl, penynyl, or hexynyl.

[0053] The substituted or unsubstituted ester group can be a substituted or unsubstituted C2-C6 ester group, for example, a substituted or unsubstituted C2, C3, C4, C5, or C6 ester group. The substituted or unsubstituted ester group can be represented as -COOR, where R can be a substituted or unsubstituted alkyl group of C1-C5.

[0054] The substituted or unsubstituted aryl group can be a substituted or unsubstituted C6-C12 aryl group, such as a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, etc.

[0055] The substituted or unsubstituted heteroaryl group can be a substituted or unsubstituted five-membered heteroaryl group, a substituted or unsubstituted six-membered heteroaryl group, or a fused-ring heteroaryl group. The substituted or unsubstituted heteroaryl group can be an unsubstituted or unsubstituted heteroaryl group containing 1-3 heteroatoms; the heteroatoms can be selected from one or more of nitrogen, oxygen, and sulfur. In some embodiments, the heteroatoms in the substituted or unsubstituted heteroaryl group include nitrogen atoms. Exemplarily, a five-membered heteroaryl group can be, for example, furan, pyrrole, pyrazole, imidazole, oxazole, isoxazole, oxadiazole, thiophene, thiazole, isothiazole, thiadiazole, or triazole. A six-membered heteroaryl group can be, for example, pyridine, pyridazine, pyrazine, or triazine. A fused-ring heteroaryl group can be a benzo[a]hexacyclic aryl group, for example, a quinoline.

[0056] When R1 and / or R2 are substituted or unsubstituted aryl groups or substituted or unsubstituted heteroaryl groups, they are more likely to complex with nickel ions, thereby adjusting the nickel plating solution system and improving the adhesion between the nickel plating layer and the aluminum-based material.

[0057] Substituted or unsubstituted alicyclic groups refer to heterocyclic compounds that lack aromatic characteristics. Substituted or unsubstituted alicyclic groups can be non-substituted or non-substituted alicyclic groups containing 1-3 heteroatoms. The heteroatoms can be selected from one or more of nitrogen, oxygen, and sulfur.

[0058] In this application, in R1 and R2, the substituent groups in the substituted alkyl, substituted cycloalkyl, substituted alkenyl, substituted alkynyl, substituted ester, substituted aryl, substituted heteroaryl, or substituted aliphatic-heterocyclic groups include one or more of halogen atoms, alkyl, haloalkyl, cycloalkyl, alkyl-substituted cycloalkyl, alkoxy, haloalkoxy, and alkoxy-substituted alkyl groups. The introduction of substituents can adjust the properties of the compound to better meet the needs of the plating solution system. The aforementioned substituent groups can include one or more substituent groups, each of which can be independently a halogen atom, alkyl, haloalkyl, cycloalkyl, alkyl-substituted cycloalkyl, alkoxy, haloalkoxy, or alkoxy-substituted alkyl. The halogen atom can be any one selected from fluorine, chlorine, bromine, and iodine atoms. The number of carbon atoms in the alkyl, haloalkyl, alkoxy, and haloalkoxy groups can be 1-6, specifically, for example, 1, 2, 3, 4, 5, or 6. The halogenation in the haloalkyl and haloalkoxy groups can be fluorinated, chlorinated, brominated, or iodinated. The cycloalkyl group can have 3-8 carbon atoms, specifically 3, 4, 5, 6, 7, or 8. Alkyl-substituted cycloalkyl groups can be C1-C6 alkyl-substituted C3-C8 cycloalkyl groups; for example, alkyl-substituted cycloalkyl groups can be methylcyclopropyl, ethylcyclobutyl, etc. Alkoxy-substituted alkyl groups can be C1-C6 alkoxy-substituted C1-C1 alkyl groups.

[0059] In some embodiments, R1 and R2 are independently selected from hydrogen atoms, substituted or unsubstituted pyridinyl groups, substituted or unsubstituted pyrazolyl groups, substituted or unsubstituted imidazoyl groups, substituted or unsubstituted pyrazinyl groups, etc.

[0060] In this application, the compound represented by formula (I) can form a water-soluble complex with nickel ions. The compound represented by formula (I) cannot be a substance that forms a precipitate with nickel ions. In order to avoid the formation of precipitates that would damage the performance of the nickel plating solution system and hinder the formation of a uniform nickel film on the surface of the aluminum-based material, R1 and R2 in formula (I) must satisfy the following: R1 and R2 are not simultaneously heteroaryl groups containing sulfur atoms.

[0061] In some embodiments of this application, the compound represented by formula (I) may be, for example, but is not limited to, compounds with the structures shown in formulas (I-1) to (I-8):

[0062]

[0063]

[0064] In this embodiment of the application, the concentration of the compound represented by formula (I) in the nickel plating solution can be 0.05 g / L to 0.8 g / L. Exemplarily, the concentration of the compound represented by formula (I) can be, but is not limited to, 0.05 g / L, 0.1 g / L, 0.2 g / L, 0.3 g / L, 0.4 g / L, 0.5 g / L, 0.6 g / L, 0.7 g / L, or 0.8 g / L. A suitable XPT concentration can better improve the stability of the nickel plating solution system and better utilize its complexing ability to control the nickel-aluminum displacement reaction, thereby improving the quality of the pre-plated nickel film.

[0065] In this embodiment, the complexing agent in the nickel plating solution also includes other complexing agent molecules, the concentration of which can be 3 g / L-30 g / L. Exemplarily, the concentration of other complexing agent molecules can be, but is not limited to, 3 g / L, 5 g / L, 8 g / L, 10 g / L, 12 g / L, 15 g / L, 18 g / L, 20 g / L, 22 g / L, 25 g / L, 28 g / L, or 30 g / L. The addition of appropriate amounts of other complexing agent molecules can better control the nickel-aluminum displacement reaction and improve the quality of the pre-plated nickel film. These other complexing agent molecules can be various complexing agents capable of complexing with nickel ions, such as thiourea complexing agents, EDTA, etc. Among them, thiourea complexing agents can be, but are not limited to, N,N'-diisopropylthiourea and 1,3-diphenylthiourea.

[0066] In this embodiment, the styrene-based polymer is a polymer molecule with a solubility in water of not less than 5 mg / L; the polymer molecule does not decompose upon exposure to light and can be protonated in an acidic environment. Specifically, the styrene-based polymer can be one or more of linear polystyrene, cross-linked polystyrene, or styrene copolymers. The styrene copolymer can be, but is not limited to, copolymers of styrene with one or more of acrylonitrile and butadiene, such as styrene-acrylonitrile copolymers, styrene-butadiene copolymers, and styrene-acrylonitrile-butadiene copolymers. The styrene-based polymer can synergistically work with the complexing agent in the system to improve the quality of the nickel film layer obtained from pre-plating nickel, thereby improving the adhesion of the subsequent nickel plating layer.

[0067] In this embodiment, the weight-average molecular weight of the styrene-based polymer can be 5K-50K, i.e., 5000-50000. For example, the weight-average molecular weight of the styrene-based polymer can be 5K, 8K, 10K, 12K, 15K, 20K, 25K, 30K, 35K, 40K, 45K, or 50K. A suitable weight-average molecular weight helps the nickel plating solution system maintain a suitable viscosity, exhibits high stability, improves the quality of the pre-plated nickel film, and thus enhances the adhesion of the nickel plating layer to the aluminum-based material surface.

[0068] In this embodiment, the particle size of the styrene-based polymer can be 50 nm to 2.5 μm. Exemplarily, the particle size of the styrene-based polymer can be 50 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 1 μm, 1.5 μm, 2 μm, or 2.5 μm. Suitable particle size control of the styrene-based polymer is beneficial for its uniform dispersion in the nickel plating solution and for maintaining the overall uniformity of the plating solution.

[0069] In this embodiment of the application, the mass ratio of the complexing agent (including the compound shown in formula (I) and other complexing agent molecules) to the styrene polymer in the nickel plating solution is (1-30):1. Controlling the mass ratio of the complexing agent to the styrene polymer within a suitable range is beneficial for better utilizing their synergistic effect, improving the performance of the nickel plating solution system, and regulating the rate of the nickel-aluminum displacement reaction. This allows for the deposition of a smoother, more uniform, and denser nickel film layer on the aluminum-based material surface, thereby enhancing the adhesion of the nickel plating layer to the aluminum-based material surface. Exemplarily, the mass ratio of the complexing agent to the styrene polymer can be 1:1, 3:1, 5:1, 7:1, 9:1, 10:1, 12:1, 15:1, 18:1, 20:1, 22:1, 25:1, 27:1, or 30:1.

[0070] In this embodiment, the concentration of styrene-based polymer in the nickel plating solution is 3 g / L-30 g / L. Exemplarily, the concentration of styrene-based polymer can be, but is not limited to, 3 g / L, 5 g / L, 8 g / L, 10 g / L, 12 g / L, 15 g / L, 18 g / L, 20 g / L, 22 g / L, 25 g / L, 28 g / L, or 30 g / L. A suitable concentration of styrene-based polymer can give the solution system higher stability, extend the service life of the nickel plating solution, better control the nickel-aluminum displacement reaction, and improve the quality of the pre-plated nickel film. It can also reduce the number of active nickel ions and the kinetic constant of the nickel displacement reaction.

[0071] In this embodiment, the soluble nickel salt can specifically be a soluble divalent nickel salt, which may include one or more of nickel sulfate, nickel oxide, nickel chloride, nickel ammonium sulfate, nickel acetate, nickel nitrate, nickel carbonate, nickel aminosulfonate, organic sulfonate nickel salts, and carboxylate nickel salts. The organic sulfonate nickel salt may be, but is not limited to, one or more of benzenesulfonic acid, taurine, and linolenic acid.

[0072] In some embodiments of this application, the soluble nickel salt is nickel aminosulfonate (Ni(SO3NH2)2) or nickel sulfate, which has high solubility in water, facilitating the control of nickel ion concentration in the system. Nickel aminosulfonate can decompose into nickel ions and aminosulfonate ions. Aminosulfonate ions have a certain buffering effect and can competitively adsorb hydrogen ions, inhibiting hydrogen evolution. Stabilizing hydrogen and nickel ions in the nickel plating bath helps stabilize the pH value of the nickel plating bath and effectively controls the nickel deposition rate, thereby obtaining a nickel layer with fine grains, high surface gloss, and low porosity.

[0073] In this application, during the pre-plating of nickel, the nickel-aluminum substitution reaction process may include: divalent nickel ions Ni provided by soluble nickel salts. 2+ Under alkaline conditions (such as ammonia water NH3·H2O), hexaamminenickel ions are formed [Ni(NH3)6]. 2+ The process is shown in equation (1);

[0074] Furthermore, under alkaline conditions, hexaamminenickel ions (Ni(NH3)6) 2+ The nickel reacts with aluminum in a displacement reaction as shown in equation (2), and the resulting metallic nickel is deposited on the surface of the aluminum-based material to form a base nickel film.

[0075] Ni 2+ +6NH3·H2O=[Ni(NH3)6] 2+ +6H2O Equation (1);

[0076] 3Ni(NH3)6 2+ +2Al+8OH - →2Al(OH)4 - +3Ni+18NH3 (Formula 2).

[0077] In this embodiment of the application, the concentration of soluble nickel salt in the nickel plating solution is 10 g / L-30 g / L. Exemplarily, the concentration of soluble nickel salt can be, but is not limited to, 10 g / L, 12 g / L, 13 g / L, 15 g / L, 16 g / L, 18 g / L, 20 g / L, 22 g / L, 25 g / L, 28 g / L, or 30 g / L. Maintaining the soluble nickel salt at a suitable concentration is beneficial for the smooth progress of the nickel-aluminum substitution reaction, and also allows for better control of the reaction rate, promoting the formation of a high-quality pre-plated nickel film.

[0078] In some embodiments of this application, the nickel plating solution further includes a surfactant. Specifically, the surfactant may be a nonionic surfactant. The addition of a surfactant facilitates the dissolution of the components and improves the uniformity of the nickel plating solution.

[0079] Nonionic surfactants are surfactants whose molecules contain ether groups as the main hydrophilic groups that do not dissociate in aqueous solutions. In the embodiments of this application, nonionic surfactants include at least one of polyoxyethylene surfactants and polyether surfactants. Specifically, nonionic surfactants can be, for example, compounds polymerized from 2 mol-300 mol of ethylene oxide and / or propylene oxide with any one or more of C1-C20 alkanols, phenols, naphthols, bisphenols, (poly)C1-C25 alkylphenols, (poly)arylalkylphenols, C1-C25 alkylnaphthols, C1-C25 alkoxylated phosphates (salts), sorbitan esters, polyalkylene glycols, C1-C22 fatty amines, and C1-C22 fatty amides. In some embodiments, nonionic surfactants include one or more of block copolymers (EOPO) formed by alternating ethoxy (EO) and propoxy (PO) groups and alkylphenol polyoxyethylene ethers (APEO).

[0080] In this embodiment of the application, the concentration of the surfactant in the nickel plating solution is 0.1 g / L-10 g / L. Exemplarily, the surfactant concentration can be 0.1 g / L, 0.2 g / L, 0.3 g / L, 0.5 g / L, 0.8 g / L, 1 g / L, 1.5 g / L, 2 g / L, 3 g / L, 4 g / L, 5 g / L, 6 g / L, 7 g / L, 8 g / L, 9 g / L, or 10 g / L. An appropriate concentration of nonionic surfactant is beneficial for improving the uniformity of the nickel plating solution.

[0081] In some embodiments of this application, the nickel plating solution further includes a silane coupling agent. The silane coupling agent may be one or more functional groups selected from acryloyl, epoxy, vinyl, amino, mercapto, and isocyanate groups. In some embodiments of this application, the silane coupling agent may be, for example, one or more selected from isocyanate-propyltriethoxysilane, vinyltrimethoxysilane, 3-epoxypropoxypropyltrimethoxysilane, (2,3-epoxypropoxy)propyltrimethoxysilane, and 3-mercaptopropyltrimethoxysilane. The addition of the silane coupling agent can fill the gaps in the pre-plated nickel film layer, making the nickel film layer more uniform, dense, smooth, and thus better improving the adhesion of the final nickel plating layer.

[0082] In this embodiment of the application, the concentration of the silane coupling agent in the nickel plating solution is 3 g / L-6 g / L. Exemplarily, the concentration of the silane coupling agent can be 3 g / L, 4 g / L, 5 g / L, or 6 g / L. An appropriate amount of silane coupling agent is beneficial for filling gaps in the pre-plated nickel film without affecting the normal deposition of nickel.

[0083] In this embodiment, the pH value of the nickel plating solution is 9-10. The pH value of the nickel plating solution can be adjusted by using ammonia in the system. For example, the pH value of the nickel plating solution can be 9, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, or 10. A suitable pH value provides the necessary alkaline environment for the nickel displacement reaction, while allowing the oxide film on the surface of the aluminum-based material to completely dissolve and expose the aluminum layer, and also preventing excessive alkalinity from etching the aluminum substrate.

[0084] In this embodiment, the nickel plating process temperature of the nickel plating solution is room temperature, such as 15℃-40℃, specifically 15℃, 20℃, 25℃, 30℃, 35℃, and 40℃. The nickel plating solution of this application can complete the pre-plating of nickel to form an ideal base nickel film layer at room temperature, which is simple to operate and can reduce process costs.

[0085] In this embodiment, the nickel plating process time of the nickel plating solution is 5-20 minutes. Specifically, for example, 5 minutes, 8 minutes, 10 minutes, 12 minutes, 15 minutes, 18 minutes, and 20 minutes. The nickel plating solution of this application can complete the pre-plating of nickel to form an ideal base nickel film layer in a relatively short time, thus saving process time.

[0086] In this embodiment of the application, the nickel plating solution also includes a solvent, which may be water.

[0087] In this embodiment, the nickel plating solution does not contain a reducing agent. The nickel plating solution of this application forms a nickel film layer on the surface of the aluminum-based material through a displacement reaction. During the displacement process, aluminum itself acts as a reducing agent, eliminating the need for additional reducing agents. This facilitates the pre-plating of a nickel film layer with a single composition and free of other metallic impurities.

[0088] The nickel plating solution provided in this application embodiment can be used for surface activation treatment of aluminum-based materials. By simultaneously adding the complexing agent XPT and styrene-based polymers, the two synergistically reduce the kinetic constant of the nickel replacement reaction and regulate the rate of the replacement reaction. This facilitates the pre-plating of a dense, uniform, high-purity, and strongly bonded nickel film layer on the surface of the aluminum-based material, thereby improving the adhesion of subsequent plating layers. Using the nickel plating solution provided in this application embodiment for pre-plating nickel on aluminum-based materials, autocatalytic deposition of the nickel film layer on the aluminum-based material can be achieved at room temperature. Furthermore, no additional reducing agents or buffers are required to assist the nickel replacement reaction, avoiding the problem of other metal elements being replaced during nickel replacement, which would lead to the final deposited nickel plating layer containing other metal impurities and reducing the purity and adhesion of the nickel plating layer.

[0089] This application also provides a surface treatment method for aluminum-based materials, including:

[0090] Pre-plating nickel process: The aluminum-based material is brought into contact with the nickel plating solution described in the embodiments of this application so that a nickel film layer is formed on the surface of the aluminum-based material.

[0091] The specific method of contacting aluminum-based materials with nickel plating solutions can be to immerse the aluminum-based materials in the nickel plating solution. The pre-plated nickel film layer is the foundation of the entire plating system. It plays a role in priming and isolating between the aluminum-based materials and the nickel plating layer. It can fill gaps and smooth the surface, and also protect the surface of the fresh aluminum-based materials after the oxide film is removed, avoiding the situation of corrosion of the aluminum-based materials before plating. This provides a good substrate for the subsequent nickel plating and improves the adhesion of the nickel plating layer to the surface of the aluminum-based materials.

[0092] In this embodiment, the contact time, i.e., the pre-plating nickel time, is 5-20 minutes. For example, it can be 5 minutes, 8 minutes, 10 minutes, 12 minutes, 15 minutes, 18 minutes, or 20 minutes. A suitable pre-plating time ensures that the pre-plated nickel film has an appropriate thickness, avoiding a pre-plated nickel film that is too thin or does not cover the aluminum substrate surface, thus failing to achieve the desired effect.

[0093] In some embodiments of this application, the thickness of the pre-plated nickel film can be 10nm-100nm. Exemplarily, the thickness of the pre-plated nickel film can be 10nm, 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, or 100nm. A suitable pre-plated nickel film thickness is beneficial for improving the quality of subsequent electroplating or electroless nickel plating.

[0094] In this embodiment of the application, the temperature during the contact process, that is, the temperature of the pre-plating nickel, is room temperature, such as 15℃-40℃, specifically 15℃, 20℃, 25℃, 30℃, 35℃, and 40℃.

[0095] In the embodiments of this application, the surface treatment method for aluminum-based materials further includes:

[0096] Nickel plating process: After forming a nickel film layer, electroplating and / or electroless nickel plating are performed on the nickel film layer to form a nickel plating layer.

[0097] In the embodiments of this application, the electroplating and electroless nickel plating solutions used, as well as the specific operating processes, are not limited; various formulations and process parameters capable of completing the plating can be used. In some specific embodiments of this application, nickel may be electroplated for 15-20 minutes, followed by electroless nickel plating for 25-35 minutes. The thickness of the nickel plating layer obtained by electroplating can be 8 μm-30 μm, and the thickness of the nickel plating layer obtained by electroless nickel plating can be 2 μm-5 μm. After the replating process, the total thickness of the nickel layer obtained on the surface of the aluminum-based material can be 10 μm-40 μm. Exemplarily, the total thickness of the nickel layer obtained on the surface of the aluminum-based material can be 10 μm-40 μm.

[0098] In some embodiments of this application, the surface treatment method for aluminum-based materials further includes:

[0099] Degreasing process: Before pre-plating the nickel film, the aluminum-based material undergoes degreasing treatment. The purpose of degreasing is to remove grease, stains, and other contaminants from the surface of the aluminum-based material. Degreasing can be alkaline, such as using a degreasing solution containing sodium silicate, or it can be ultrasonic degreasing. Specifically, for example, the aluminum-based material can be immersed in a degreasing solution at 30℃-60℃ for 5-10 minutes. After degreasing, it can be cleaned with deionized water, specifically using high-temperature water or room-temperature water.

[0100] In some embodiments of this application, the surface treatment method for aluminum-based materials further includes:

[0101] Etching Process: Before pre-plating the nickel film, the aluminum-based material undergoes an etching treatment. This etching process involves immersing the aluminum-based material in an etching solution. Etching can be acid etching or alkaline etching. Etching removes the oxide film and defects from the surface of the aluminum-based material, removes various alloying elements and impurities, and forms a uniform aluminum surface, providing a good substrate for subsequent processes and ensuring the quality of the subsequent plating layer. Alkaline etching is particularly beneficial for obtaining a smoother aluminum surface and for better removing burrs and sharp edges that are difficult to completely cover with electroless nickel plating. In some embodiments of this application, the etching time can be 2-3 minutes.

[0102] In this embodiment of the application, after the above-mentioned degreasing process, etching process, pre-nickel plating process, and re-nickel plating process are completed, a deionized water cleaning operation can be performed. On the one hand, this can remove the chemical degreasing solution, etching solution, and nickel plating solution remaining in the corners and crevices of the aluminum-based material, reducing the adverse effects of residual solution on the nickel-plated aluminum-based material, such as discoloration and corrosion. On the other hand, it can prevent residual solution from contaminating the treatment solution in subsequent processes, which helps to extend the service life of each treatment solution.

[0103] In this embodiment, after the nickel plating process is completed, a drying process is also included. The drying process may include baking in an oven at 130℃-150℃ for 1-1.5 hours. The drying process can remove nitrogen gas adsorbed on the surface of the aluminum base material during the electroless nickel plating process, and can also release stress in the coating, thereby improving the adhesion between the coating and the aluminum base material.

[0104] Compared to traditional aluminum-based material surface treatment methods, the surface treatment method provided in this application embodiment achieves autocatalytic deposition of nickel metal film on the aluminum-based material surface at room temperature through its activation process; moreover, the pre-plating nickel treatment only requires one immersion, achieving an effect comparable to the traditional two-stage zinc immersion process, significantly improving the efficiency of pre-plating nickel. In summary, the aluminum alloy substrate surface treatment process provided in this application embodiment not only ensures that the deposited pre-plated nickel film layer has good uniformity, density, and coating adhesion, but also simplifies the operation procedure of the pre-plating process, reduces heat energy consumption, and is suitable for industrial production.

[0105] This application also provides an aluminum-based structural component, which uses the nickel plating solution described in this application to form a nickel film layer on the surface of the aluminum-based material. Because the nickel plating solution described in this application is used for pre-plating, a high-quality surface nickel plating layer can be obtained, enhancing the hardness, corrosion resistance, and aesthetics of the aluminum-based material. It maintains surface smoothness and integrity while resisting wear and scratches, extending the service life of the aluminum-based material. This aluminum-based structural component can be used in various parts in the fields of electronic devices, communication equipment, and precision instruments. In some embodiments, the aluminum-based structural component is an optical module structural component.

[0106] The technical solution of this application will be further described below with reference to several embodiments.

[0107] Example 1

[0108] A surface treatment method for aluminum alloy structural parts, comprising:

[0109] (1) Degreasing process: Under 50℃ conditions, the aluminum alloy structural parts are immersed in chemical degreasing solution for 5 minutes and then cleaned with deionized water;

[0110] (2) Etching process: Under the condition of 25℃, the degreased aluminum alloy structural parts are immersed in the etching solution for 2 minutes and then cleaned with deionized water;

[0111] (3) Pre-plating nickel process: Under 30°C, the micro-etched aluminum alloy structural parts are immersed in nickel plating solution for 10 minutes and then rinsed with deionized water; the pH of the nickel plating solution is 9.5.

[0112] (4) Nickel plating process: First, electroplat the pre-nickel-plated aluminum alloy structural parts in the electroplating solution for 15 minutes, then immerse them in the chemical plating solution for 30 minutes for chemical nickel plating, and finally clean them with deionized water.

[0113] (5) Drying process: After the aluminum alloy structural parts are chemically nickel-plated, they are placed in an oven and baked at 130°C for 75 minutes. After baking, they are taken out and cooled naturally to obtain aluminum alloy structural parts with nickel plating on the surface.

[0114] Example 2-10

[0115] The only difference between Examples 2-10 and Example 1 is the nickel plating solution formulation used in the pre-nickel plating process. The specific differences are shown in Table 1.

[0116] Comparative Example 1

[0117] The only difference between Comparative Example 1 and Example 1 is the type and concentration of each component in the pre-plated nickel formulation. The specific differences are shown in Table 1.

[0118] Table 1. Formulation composition of nickel plating solutions in Examples 1-10 and Comparative Example 1

[0119]

[0120]

[0121] In Table 1, EOPO is a block copolymer formed by alternating ethoxy (EO) and propoxy (PO) groups.

[0122] APEO: Alkylphenol polyoxyethylene ether;

[0123] IPTS: Propyltriethoxysilane isocyanate;

[0124] KH-560: (2,3-epoxypropoxy)propyltrimethoxysilane;

[0125]

[0126] The total thickness of the nickel layer on the surface of the nickel-plated aluminum alloy structural parts obtained in Examples 1-10 and Comparative Example 1 was measured.

[0127] The adhesion of the nickel layer on the surface of the nickel-plated aluminum alloy structural parts obtained in Examples 1-10 and Comparative Example 1 was tested by cross-cut adhesion test.

[0128] The specific results are shown in Table 2:

[0129] Table 2 shows the nickel layer thickness and coating adhesion results for nickel-plated aluminum alloy structural parts in Examples 1-10 and Comparative Example 1.

[0130]

[0131] As shown in Table 2, the nickel layers obtained in Examples 1-10 of this application, due to the use of a nickel plating solution containing the compound of formula (I) and styrene-based polymers for pre-plating, exhibit good adhesion to the aluminum alloy structural parts and all pass the cross-cut adhesion test (4B). Comparing Example 1 and Comparative Example 1, the total thickness of the nickel layer obtained in Example 1 and Comparative Example 1 is the same. However, Comparative Example 1 passes the cross-cut adhesion test (4B) but fails, while Example 1 of this application passes it. This indicates that, compared to Comparative Example 1, Example 1 of this application, due to the use of a nickel plating solution containing the compound of formula (I) and styrene-based polymers for pre-plating, exhibits significantly improved adhesion to the aluminum alloy structural parts.

[0132] It should be understood that the use of the terms "first," "second," and various numerical designations in this document is merely for descriptive convenience and is not intended to limit the scope of this application.

[0133] In this application, "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone, where A and B can be singular or plural. The character " / " generally indicates that the related objects before and after it are in an "or" relationship.

[0134] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0135] In this application, "-" indicates a range value, including the endpoint values ​​at both ends. For example, the value of a can be 0.5-15, meaning that the value of a can be between 0.5 and 15, and includes the endpoint values ​​of 0.5 and 15.

[0136] It should be understood that in the various embodiments of this application, the order of the above processes does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

Claims

1. A nickel plating solution, characterized in that, The nickel plating solution comprises a soluble nickel salt, a complexing agent, a styrene polymer, and ammonia; the complexing agent comprises a compound as shown in formula (I). In formula (I), X is a hydrocarbon chain containing an ether bond, a hydrocarbon chain containing a phenylene group, or a polyenol chain; R1 and R2 are independently selected from hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted ester, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, or substituted or unsubstituted alicyclic group, and R1 and R2 are not simultaneously heteroaryl containing sulfur atoms.

2. The nickel plating solution as described in claim 1, characterized in that, The substituted groups in the substituted alkyl, substituted cycloalkyl, substituted alkenyl, substituted alkynyl, substituted ester, substituted aryl, substituted heteroaryl, or substituted aliphatic heterocyclic groups include one or more of halogen atoms, alkyl, haloalkyl, cycloalkyl, alkyl-substituted cycloalkyl, alkoxy, haloalkoxy, and alkoxy-substituted alkyl.

3. The nickel plating solution as described in claim 1 or 2, characterized in that, The substituted or unsubstituted heteroaryl group is a substituted or unsubstituted heteroaryl group containing 1-3 heteroatoms; the substituted or unsubstituted alicyclic group is a substituted or unsubstituted alicyclic group containing 1-3 heteroatoms; the heteroatoms are selected from one or more of nitrogen, oxygen and sulfur.

4. The nickel plating solution according to any one of claims 1-3, characterized in that, In the nickel plating solution, the concentration of the compound represented by formula (I) is 0.05 g / L to 0.8 g / L.

5. The nickel plating solution according to any one of claims 1-4, characterized in that, The styrene polymers include one or more of linear polystyrene, cross-linked polystyrene, or styrene copolymers.

6. The nickel plating solution according to any one of claims 1-5, characterized in that, The weight-average molecular weight of the styrene-based polymer is 5K-50K; the particle size of the styrene-based polymer is 50nm-2.5μm.

7. The nickel plating solution according to any one of claims 1-6, characterized in that, The concentration of styrene polymer in the nickel plating solution is 3 g / L-30 g / L.

8. The nickel plating solution according to any one of claims 1-7, characterized in that, The complexing agent also includes other complexing agent molecules, the concentration of which is 3g / L-30g / L.

9. The nickel plating solution according to any one of claims 1-8, characterized in that, In the nickel plating solution, the mass ratio of the complexing agent to the styrene polymer is (1-30):

1.

10. The nickel plating solution according to any one of claims 1-9, characterized in that, The soluble nickel salts include one or more of nickel sulfate, nickel oxide, nickel chloride, nickel ammonium sulfate, nickel acetate, nickel nitrate, nickel carbonate, nickel aminosulfonate, organic sulfonate nickel salts, and carboxylate nickel salts.

11. The nickel plating solution according to any one of claims 1-10, characterized in that, The concentration of soluble nickel salt in the nickel plating solution is 10 g / L-30 g / L.

12. The nickel plating solution according to any one of claims 1-11, characterized in that, The nickel plating solution also includes a surfactant.

13. The nickel plating solution as described in claim 12, characterized in that, The surfactant includes a nonionic surfactant, which includes at least one of a polyoxyethylene surfactant and a polyether surfactant.

14. The nickel plating solution as described in claim 12 or 13, characterized in that, The concentration of the surfactant in the nickel plating solution is 0.1 g / L-10 g / L.

15. The nickel plating solution according to any one of claims 1-14, characterized in that, The nickel plating solution also includes a silane coupling agent.

16. The nickel plating solution as described in claim 15, characterized in that, The silane coupling agent includes one or more functional groups selected from acryloyl, epoxy, vinyl, amino, mercapto, and isocyanate groups.

17. The nickel plating solution as described in claim 15 or 16, characterized in that, The concentration of the silane coupling agent in the nickel plating solution is 3 g / L-6 g / L.

18. The nickel plating solution according to any one of claims 1-17, characterized in that, The pH value of the nickel plating solution is 9-10.

19. A surface treatment method for aluminum-based materials, characterized in that, include: The aluminum-based material is contacted with the nickel plating solution according to any one of claims 1-18 to form a nickel film layer on the surface of the aluminum-based material.

20. The method as described in claim 19, characterized in that, The contact is performed at room temperature; the contact time is 5 min to 20 min.

21. The method as described in claim 19 or 20, characterized in that, After the nickel film layer is formed, nickel is electroplated and / or electroless nickel plating is performed on the nickel film layer to form a nickel plating layer.

22. A structural component made of aluminum-based material, characterized in that, A nickel film layer is formed on the surface of an aluminum-based material using the nickel plating solution described in any one of claims 1-18.

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