Electroplating solution, electroplating method and application thereof

Abstract

The embodiment of the invention provides electroplating liquid, an electroplating method and application of the electroplating liquid, and relates to the technical field of materials. The electroplating liquid comprises nickel salt, a grain refiner, a buffering agent, an auxiliary brightener and a main brightener, the main brightener comprises an onium salt structure, the onium salt structure comprises an imidazole ring, the imidazole ring comprises onium ions, the onium ions are positively charged organic ions and are composed of a nitrogen atom and three carbon atoms, and hydrogen on the nitrogen atom can be substituted by alkyl. The electroplating liquid has a relatively high leveling effect, and can be powerfully adsorbed on the uneven surface of a substrate to be electroplated, so that convex parts in the surface are covered and concave parts in the surface are filled and leveled up, and a uniform and bright plating layer with relatively low roughness is formed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of materials, in particular to a plating solution, a plating method and application thereof. BACKGROUND

[0002] Nickel is a silver-white metal with good ductility, plasticity and magnetism, can be highly polished and has good corrosion resistance. Therefore, nickel has excellent decorative and functional properties, and is one of the currently used plating materials.

[0003] Generally, a nickel plating solution is prepared from nickel sulfate, nickel chloride and boric acid. In addition, in order to achieve a bright and shiny appearance of the nickel plating solution deposition, a certain amount of organic brightener and inorganic brightener can also be added. In the process of adding organic brightener and inorganic brightener, the addition is usually carried out in a compounded manner, so that the nickel plating solution forms a nickel plating layer with a certain brightness. However, in the scenario where the substrate to be plated is a metal with a rough surface, such as die-cast aluminum, the use of the above-mentioned nickel plating solution cannot form a uniform and bright nickel plating layer under limited plating thickness, and the leveling ability is weak. SUMMARY

[0004] The embodiments of the present application provide a plating solution, a plating method and application thereof, and the leveling effect of the plating solution is high, which can strongly adsorb on the uneven surface of the substrate to be plated, cover the protruding part of the surface and fill the surface depression part, and form a uniform, low roughness and bright plating layer.

[0005] To achieve the above-mentioned purpose, the embodiments of the present application adopt the following technical solutions:

[0006] In a first aspect, the embodiments of the present application provide a plating solution, which comprises: a nickel salt, a grain refiner, a buffer, an auxiliary brightener and a main brightener.

[0007] The main brightener comprises an onium salt [A] x [B] y ;

[0008] Wherein, the structural general formula of A is as follows formula (1):

[0009]

[0010] x and n are positive integers, and y is a natural number;

[0011] R1 is selected from C1-C4 alkyl;

[0012] When y=0, R2 is selected from one of a hydrogen atom, an unsaturated alkyl containing a double bond, an aromatic hydrocarbon group and a heteroatom group.

[0013] When y≥1, R2 is selected from an unsaturated alkyl containing a double bond.

[0014] B is selected from at least one unsaturated monomer of an alkyl group.

[0015] Thus, the main brightener in the electroplating solution provided by the embodiments of the present application comprises a onium salt, on the one hand, the onium salt structure comprises an imidazole ring, the imidazole ring comprises a onium ion, the onium ion is a positively charged organic ion, which is composed of one nitrogen atom and three carbon atoms, the hydrogen on the nitrogen atom can be replaced by an alkyl group. In this way, the onium ion structure after alkylation has strong adsorption capacity, so that the main brightener also has strong adsorption capacity. Therefore, one or more main brighteners can be subsequently compounded with auxiliary brighteners to prepare a corresponding electroplating solution, and when electroplating a substrate with high roughness, the electroplating solution can strongly adsorb on the uneven surface of the substrate to be electroplated, covering the protruding part of the surface and filling the recessed part of the surface. In turn, the leveling effect of the electroplating solution can be improved, and a uniform, low-roughness and bright plating layer can be formed.

[0016] On the other hand, the onium salt structure also comprises R2 connected to the imidazole ring, R2 is selected from one of a hydrogen atom, an unsaturated alkyl group containing a double bond, an aromatic hydrocarbon group and a heteroatom group, R2 can undergo an addition polymerization reaction with at least one unsaturated monomer of an alkyl group, which can improve the stability of the main brightener. At the same time, it can also promote the main brightener to react with nickel salt, grain refiner, buffer, auxiliary brightener, and improve the dispersibility of the main brightener in the electroplating solution.

[0017] In an implementable manner, the unsaturated alkyl group containing a double bond comprises one of a methylene group, an ethylene group and a propylene group; the aromatic hydrocarbon group comprises one of a phenyl group, a phenol group, a halogenated phenyl group and a toluene group; and the heteroatom group comprises one of a hydroxyl group, an amino group, a mercapto group, a carboxyl group and an amide group.

[0018] In this way, R2 provided by the embodiments of the present application can be selected from the above-mentioned groups, and can undergo an addition polymerization reaction with at least one unsaturated monomer of an alkyl group selected from the structure of B, which can form a more stable onium salt structure and improve the stability of the main brightener.

[0019] In an implementable manner, the unsaturated monomer of at least one alkyl group comprises one of acrylamide, acryloyl glycine, methyl acrylamide, N,N-dimethyl acrylamide, acrylic acid, vinyl formamide, vinyl acetamide, vinyl caprolactam, vinyl pyrrolidone, vinyl imidazole, vinyl pyridine, vinyl benzoic acid, allyl amine, N,N-dimethyl allyl amine, vinyl acetate, isopropylene acetate, aminoethyl methacrylate and dimethylaminoethyl methacrylate.

[0020] Therefore, the unsaturated monomer with at least one alkyl group in the embodiment of the present application can be selected from the above-mentioned groups. The selected group can be added to the polymerization reaction of R2 in the main brightener structure, and can form an onium salt structure with certain stability and dispersibility, thereby improving the stability of the main brightener. Meanwhile, in the process of applying the main brightener to the electroplating solution, the onium salt structure can more easily react with nickel salt, grain refiner, buffer, and auxiliary brightener, thereby improving the chemical properties of the electroplating solution.

[0021] In an implementable manner, the onium salt further comprises an anion, and the anion is selected from one of a halogen-containing ion, a hydrogen sulfate ion, and a nitrate ion. The halogen-containing ion includes a chloride ion, a bromide ion, an iodide ion, a tetrafluoroborate ion, and a hexafluorophosphate ion.

[0022] Therefore, the main brightener in the embodiment of the present application can further comprise an anion, and the anion can be selected from the above-mentioned halogen-containing ion or halogen-free ion. The anion can react with the positively charged onium ion, and the two can combine to form an onium salt structure with certain stability and dispersibility, thereby improving the stability of the main brightener.

[0023] In an implementable manner, n is 1-5, x is 1-1000, and y is 0-1000.

[0024] Therefore, by controlling the values of n, x, and y, the onium ion structure with strong adsorption capacity, stability, and dispersibility can be formed, and the main brightener also has strong adsorption capacity, stability, and dispersibility. Therefore, the main brightener can be applied to the electroplating solution in the subsequent process, and the leveling effect of the electroplating solution can be improved, and a uniform, low-roughness, and bright plating layer can be formed on the surface of the electroplated substrate.

[0025] In an implementable manner, the concentration of the nickel salt in the electroplating solution is 1 g / L-500 g / L, the concentration of the grain refiner is 0.1 g / L-10 g / L, the concentration of the buffer is 1 g / L-100 g / L, the concentration of the auxiliary brightener is 10 ppm-1000 ppm, and the concentration of the at least one main brightener is 0.5 ppm-50 ppm.

[0026] Therefore, the concentration of the nickel salt, the concentration of the grain refiner, the concentration of the buffer, the concentration of the auxiliary brightener, and the concentration of the main brightener can be controlled in the embodiment of the present application, and the four can be maintained at a suitable concentration, so that the electroplating solution with strong adsorption capacity, stability, and dispersibility can be formed, and a uniform, low-roughness, and bright plating layer can be formed on the surface of the electroplated substrate.

[0027] In an implementable manner, the structural general formula of A includes at least one of the following structures:

[0028]

[0029]

[0030] Thus, the structure of the onium salt provided by the embodiments of the present application can include one of the structures of the above-mentioned formula (2) to formula (8). The structure includes the onium ion structure after alkylation, which can enable the main brightener to have strong adsorption capacity. At the same time, the above-mentioned structure can be added to the unsaturated monomer of at least one alkyl group to perform addition polymerization reaction, which is convenient for subsequent improvement of the stability of the main brightener. Thus, the leveling effect and stability of the electroplating solution are improved, so as to form a uniform, low-roughness and bright plating layer on the surface of the to-be-electroplated substrate.

[0031] In an implementable manner, the pH of the electroplating solution is 3-6.

[0032] In an implementable manner, the nickel salt includes at least one of nickel sulfamate, nickel chloride, nickel sulfate and nickel acetate, the grain refiner includes one of sodium saccharin, thiourea and derivatives thereof, and coumarin and derivatives thereof, the buffer includes one of boric acid, citric acid and acetic acid, and the auxiliary brightener includes one of hydroxypropane sulfonic acid pyridine salt, propane sulfonic acid pyridine salt, 1.4-butynediol, propargyl sulfonic acid sodium, allyl sulfonic acid sodium, ethoxylated butynediol and propoxylated propargyl alcohol.

[0033] In a second aspect, the embodiments of the present application further provide an electroplating method of the electroplating solution. The method includes: immersing a to-be-electroplated substrate into the electroplating solution of the first aspect, and applying an electric current to the electroplating solution at a preset temperature, so as to form an electroplating layer on the surface of the to-be-electroplated substrate.

[0034] Thus, by using the electroplating method provided by the embodiments of the present application, a thin and smooth bright electroplating layer can be formed, so as to realize smooth and bright finishing and provide a large amount of corrosion protection. Even if the to-be-electroplated substrate has high roughness, a mirror-like bright electroplating layer can still be formed.

[0035] In an implementable manner, the current density is 0.1 ASD-10 ASD, the preset temperature is 40℃-65℃, and the thickness of the electroplating layer is less than 15μm.

[0036] In a third aspect, the embodiments of the present application further provide the application of the electroplating solution of the first aspect in electroplating metal shells, electroplating electronic device shells and chip packaging. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 FIG. 1 is a schematic diagram of the appearance of the plating layer of Example 1 provided by the embodiments of the present application;

[0038] Figure 2An appearance schematic diagram of a plated layer of Example 2 is provided for the embodiments of the present application.

[0039] Figure 3 An appearance schematic diagram of a plated layer of Comparative Example 4 is provided for the embodiments of the present application.

[0040] Figure 4 An appearance schematic diagram of a plated layer of Comparative Example 5 is provided for the embodiments of the present application. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application. In the description of the present application, unless otherwise specified, “ / ” represents an “or” relationship between the objects before and after the “ / ”, for example, A / B can represent A or B; “and / or” in the present application is only a description of the relationship between the associated objects, which means that there can be three relationships, for example, A and / or B, which means that there are three cases of A alone, A and B together, and B alone, where A and B can be singular or plural. In addition, in the description of the present application, unless otherwise specified, “multiple” means two or more than two. “At least one of the following” or similar expressions means any combination of these items, including any combination of single item or multiple items. For example, at least one of a, b, or c can mean a, b, c, a-b, a-c, b-c, or a-b-c, where a, b, and c can be single or multiple. In addition, in order to clearly describe the technical solutions of the embodiments of the present application, in the embodiments of the present application, the same items or similar items with basically the same function and role are distinguished by using “first”, “second”, etc.

[0042] Those skilled in the art can understand that the “first”, “second”, etc. do not limit the quantity and execution order, and the “first”, “second”, etc. do not necessarily mean different. At the same time, in some embodiments of the present application, the words “exemplary” or “for example” are used to represent an example, illustration or description. Any embodiment or design scheme described as “exemplary” or “for example” in the embodiments of the present application should not be interpreted as more preferred or more advantageous than other embodiments or design schemes. Rather, the use of “exemplary” or “for example” is intended to present the relevant concept in a specific manner, for ease of understanding.

[0043] For ease of understanding, some descriptions of concepts related to the embodiments of the present application are given for reference. As shown below:

[0044] Roughness Average (Ra): refers to the average roughness of the surface, which is the arithmetic mean of the absolute values of the height deviations from the central plane in the area under consideration.

[0045] Leveling ability: also known as micro-dispersing ability, refers to the ability of the plating solution to make the micro profile of the plating layer smoother than the substrate surface when forming the plating layer on the metal surface.

[0046] The nickel plating method provided in the related art has a process flow including mechanical polishing, oil removal, chemical polishing, surface conditioning, zinc immersion, electroplating of base nickel, electroplating of pyrophoric copper, electroplating of acid copper, and electroplating of full bright nickel. Alternatively, the process flow includes stamping treatment, grinding, mechanical polishing, electroplating of nickel, and chemical plating of nickel. Alternatively, the process flow includes polishing pretreatment, electroplating of copper, plating of mist nickel, plating of semi-bright nickel, and post-treatment. The above-mentioned various process flows can first reduce the roughness of the electroplating substrate through mechanical polishing and chemical polishing, and then perform electroplating treatment once or multiple times. The process flow is relatively complicated, increases the electroplating cost, and reduces the product qualification rate in the electroplating process.

[0047] The related art also provides an electroplating solution, which can include a cationic polymer brightener of the reaction product of an imidazole compound and a bisepoxide. However, the electroplating solution can only obtain a plating layer in a wider current density range, such as an electroplating layer on an electrical connector and a lead frame. Thus, the electroplating solution has a low leveling ability when used for electroplating on a substrate with high roughness, and has certain use limitations.

[0048] The related art also provides another electroplating solution, which can provide a semi-bright nickel or nickel alloy electroplating bath without coumarin, and the leveling characteristics thereof are close to or even equal to those of a coumarin bath. However, the plating layer formed by the electroplating solution has low internal stress, that is, the bright plating layer can only be achieved in the case of low internal stress. Thus, the electroplating solution has a low leveling ability when used for electroplating on a substrate with high roughness, and has certain use limitations.

[0049] To solve the above technical problems, an electroplating solution is provided in the embodiments of the present application, which includes a nickel salt, a grain refiner, a buffer, an auxiliary brightener, and a main brightener. The main brightener includes an onium salt [A] x [B] y .

[0050] wherein the structural general formula of A is formula (1):

[0051]

[0052] x and n are positive integers, and y is a natural number;

[0053] R1 is selected from C1-C4 alkyl;

[0054] when y=0, R2 is selected from one of a hydrogen atom, an unsaturated alkyl group containing a double bond, an aromatic hydrocarbon group, and a heteroatom group;

[0055] R2is selected from the group consisting of an unsaturated alkyl group containing a double bond, when y > 1;

[0056] B is selected from at least one unsaturated monomer of an alkyl group.

[0057] Thus, the main brightener in the electroplating solution provided by the embodiments of the present application includes onium salt, on the one hand, the onium salt structure includes an imidazole ring, the imidazole ring includes onium ion, the onium ion is a positively charged organic ion, which is composed of one nitrogen atom and three carbon atoms, and the hydrogen on the nitrogen atom can be replaced by an alkyl group. In this way, the onium ion structure after alkylation has strong adsorption capacity, so that the main brightener also has strong adsorption capacity. Therefore, one or more main brighteners and auxiliary brighteners can be subsequently compounded to prepare a corresponding electroplating solution, which can strongly adsorb on the uneven surface of the electroplated substrate when electroplating a substrate with high roughness, covering the raised parts of the surface and filling the recessed parts of the surface. Further, the leveling effect of the electroplating solution can be improved, and a uniform, low-roughness and bright plating layer can be formed.

[0058] On the other hand, the onium salt structure also includes R2connected to the imidazole ring, R2is selected from one of a hydrogen atom, an unsaturated alkyl group containing a double bond, an aromatic hydrocarbon group and a heteroatom group, R2can undergo an addition polymerization reaction with at least one unsaturated monomer of an alkyl group, which can improve the stability of the main brightener. At the same time, it can also promote the main brightener to react with nickel salt, grain refiner, buffer, auxiliary brightener, and improve the dispersibility of the main brightener in the electroplating solution.

[0059] It should be noted that the main brightener of the electroplating solution in the embodiments of the present application can be one main brightener having the above structural general formula, of course, it can also be a plurality of different main brighteners having the above structural general formula, which is not limited in the embodiments of the present application.

[0060] In some embodiments of the present application, the unsaturated alkyl group containing a double bond includes one of a methylene group, an ethylene group and a propylene group, the aromatic hydrocarbon group includes one of a phenyl group, a phenol group, a halogenated phenyl group and a toluene group, and the heteroatom group includes one of a hydroxyl group, an amino group, a mercapto group, a carboxyl group and an amide group.

[0061] In some examples, the unsaturated alkyl group containing a double bond selected by R2may include one of a methylene group, an ethylene group and a propylene group. Of course, it can also include a butenyl group, a pentenyl group, a hexenyl group and a styrene group, etc. It should be noted that the embodiments of the present application do not specifically limit the groups selected by the unsaturated alkyl group containing a double bond.

[0062] In some examples, the aromatic hydrocarbon group selected by R2may include one of a phenyl group, a phenol group, a halogenated phenyl group, and a toluene group. Of course, a nitrophenyl group, an ethylbenzene group, a propylbenzene group, a butylbenzene group, and the like can also be included. It should be noted that embodiments of the present application do not specifically limit the group selected by the aromatic hydrocarbon group.

[0063] In some examples, the heteroatomic group selected by R2includes one of a hydroxyl group, an amino group, a mercapto group, a carboxyl group, and an amide group. Of course, an acid anhydride group, an ester group, and the like can also be included. It should be noted that embodiments of the present application do not specifically limit the group selected by the heteroatomic group.

[0064] Thus, R2provided by embodiments of the present application can be selected from the above-mentioned groups, can be subjected to an addition polymerization reaction with the at least one alkyl group selected by the unsaturated monomer of the B structure, and can form a more stable onium salt structure, thereby improving the stability of the main brightener.

[0065] In some embodiments of the present application, the at least one alkyl group of the unsaturated monomer can include one of an acrylamide, an acryloyl glycine, a methacrylamide, an N,N-dimethyl acrylamide, an acrylic acid, a vinyl formamide, a vinyl acetamide, a vinyl caprolactam, a vinyl pyrrolidone, a vinyl imidazole, a vinyl pyridine, a vinyl benzoic acid, an allyl amine, an N,N-dimethyl allyl amine, a vinyl acetate, an isopropenyl acetate, an aminoethyl methacrylate, and a dimethylaminoethyl methacrylate. It should be noted that embodiments of the present application do not specifically limit the group selected by the at least one alkyl group of the unsaturated monomer.

[0066] Thus, the at least one alkyl group of the unsaturated monomer provided by embodiments of the present application can be selected from the above-mentioned groups, and the above-mentioned groups can be selected to be subjected to an addition polymerization reaction with R2in the structure of the main brightener, thereby forming an onium salt structure having a certain stability and dispersibility, and thereby improving the stability of the main brightener. Meanwhile, in the process of applying the main brightener to the electroplating solution, the onium salt structure can more easily react with a nickel salt, a grain refiner, a buffer, and an auxiliary brightener, thereby improving the chemical properties of the electroplating solution.

[0067] In some embodiments of the present application, the onium salt further includes an anion selected from one of a halogen-containing ion, a hydrogen sulfate ion, and a nitrate ion, and the halogen-containing ion includes a chloride ion, a bromide ion, an iodide ion, a tetrafluoroborate ion, and a hexafluorophosphate ion.

[0068] In some examples, the primary brightener can further include an anion selected from a group consisting of halogen-containing ions such as one of chloride ion, bromide ion, iodide ion, tetrafluoroborate ion, and hexafluorophosphate ion. The anion can also be selected from bisulfate ion and nitrate ion. Of course, the anion can also be selected from hydroxide ion, permanganate ion, chlorate ion, iodate ion, formate ion, and the like. It is to be noted that the anion selected is not limited in the embodiments of the present application.

[0069] Thus, the embodiments of the present application provide that the primary brightener can further include an anion, which can be selected from the above-mentioned halogen-containing ions or halogen-free ions. The anion can react with the positively charged onium ion, and the two combine to form an onium salt structure with certain stability and dispersibility. Thus, the stability of the primary brightener is improved.

[0070] In some embodiments of the present application, n is 1-5, x is 1-1000, and y is 0-1000.

[0071] In some examples, n can typically but not limitingly be, for example, 1, 2, 3, 4, and 5.

[0072] In some examples, x can typically but not limitingly be, for example, 1, 3, 10, 50, 200, 300, 650, 800, 1000, and a number between any two of the above values, all of which are acceptable range values. For example, the number can be taken from a value between 1 and 100, or from a value between 100 and 500, or from a value between 500 and 700, or from a value between 700 and 1000, or from a number between any two of the other values.

[0073] In some examples, y can typically but not limitingly be, for example, 0, 1, 5, 15, 55, 250, 350, 650, 850, 1000, and a number between any two of the above values, all of which are acceptable range values. For example, the number can be taken from a value between 0 and 50, or from a value between 50 and 200, or from a value between 200 and 500, or from a value between 500 and 1000, or from a number between any two of the other values.

[0074] Thus, the embodiments of the present application control the values of n, x, and y to form an onium ion structure with strong adsorption capacity, stability, and dispersibility, so that the primary brightener also has strong adsorption capacity, stability, and dispersibility. Thus, the subsequent application of the primary brightener in the electroplating solution can improve the leveling effect of the electroplating solution, and a uniform, low-roughness, and bright plating layer can be formed on the surface of the electroplating substrate.

[0075] In some embodiments of the present application, the concentration of the nickel salt in the electroplating solution is 1 g / L to 500 g / L, the concentration of the grain refiner is 0.1 g / L to 10 g / L, the concentration of the buffer is 1 g / L to 100 g / L, the concentration of the auxiliary brightener is 10 ppm to 1000 ppm, and the concentration of the at least one primary brightener is 0.5 ppm to 50 ppm.

[0076] In some examples, the concentration of the nickel salt in the electroplating solution can typically but not exclusively be, for example, 1 g / L, 5 g / L, 15 g / L, 35 g / L, 100 g / L, 150 g / L, 250 g / L, 350 g / L, 500 g / L, and a number between any two of the above values, all of which are desirable range values, for example, a value can be desirable between 1 g / L and 100 g / L, also desirable between 100 g / L and 150 g / L, also desirable between 150 g / L and 350 g / L, also desirable between 350 g / L and 500 g / L, and also desirable between any two of the other values.

[0077] In some examples, the concentration of the grain refiner in the electroplating solution can typically but not exclusively be, for example, 0.1 g / L, 0.5 g / L, 1.5 g / L, 3.5 g / L, 5.5 g / L, 6.5 g / L, 7.5 g / L, 8.5 g / L, 10 g / L, and a number between any two of the above values, all of which are desirable range values, for example, a value can be desirable between 0.1 g / L and 3.5 g / L, also desirable between 3.5 g / L and 5.5 g / L, also desirable between 5.5 g / L and 8.5 g / L, also desirable between 8.5 g / L and 10 g / L, and also desirable between any two of the other values.

[0078] In some examples, the concentration of the buffer in the electroplating solution can typically but not exclusively be, for example, 1 g / L, 5 g / L, 15 g / L, 35 g / L, 100 g / L, and a number between any two of the above values, all of which are desirable range values, for example, a value can be desirable between 1 g / L and 10 g / L, also desirable between 10 g / L and 25 g / L, also desirable between 25 g / L and 50 g / L, also desirable between 50 g / L and 100 g / L, and also desirable between any two of the other values.

[0079] In some examples, the concentration of the auxiliary brightener in the electroplating solution can typically but not limitatively be, for example, 10 ppm, 20 ppm, 50 ppm, 100 ppm, 500 ppm, 750 ppm, 850 ppm, 1000 ppm, and a number between any two of the above values, all of which are desirable range values, for example, the value can be desirable between 10 ppm and 100 ppm, also desirable between 100 ppm and 200 ppm, also desirable between 200 ppm and 500 ppm, also desirable between 500 ppm and 1000 ppm, and also desirable between any two of the other values.

[0080] In some examples, the concentration of the at least one primary brightener in the electroplating solution can typically but not limitatively be, for example, 0.5 ppm, 1 ppm, 2 ppm, 10 ppm, 20 ppm, 30 ppm, 35 ppm, 50 ppm, and a number between any two of the above values, all of which are desirable range values, for example, the value can be desirable between 0.5 ppm and 1 ppm, also desirable between 1 ppm and 2 ppm, also desirable between 10 ppm and 30 ppm, also desirable between 30 ppm and 50 ppm, and also desirable between any two of the other values.

[0081] Thus, the embodiments of the present application can control the concentration of nickel salt, the concentration of grain refiner, the concentration of buffer, the concentration of auxiliary brightener, and the concentration of primary brightener, so that the four are maintained at a suitable concentration, and an electroplating solution with strong adsorption capacity, stability and dispersion capacity can be formed to form a uniform, low roughness and bright plating layer on the surface of the substrate to be electroplated.

[0082] It should be noted that the electroplating solution provided by the embodiments of the present application can also contain other unavoidable trace impurities, which are not limited by the embodiments of the present application.

[0083] In some embodiments of the present application, the structural general formula of A includes at least one of the following structures:

[0084]

[0085]

[0086] In formula (6), the proportion of a in the entire structure is 5%-80%, in formula (7), the proportion of a in the entire structure is 5%-80%, and in formula (8), the proportion of a in the entire structure is 5%-80%.

[0087] In some examples, the proportion of a in the above-mentioned formula (6) to formula (8) and corresponds to a value, typically but not limited to, for example, 5%, 15%, 25%, 35%, 45%, 55%, 65%, 75%, 85%, and any two numerical values between the above-mentioned values, all of which are acceptable range values, for example, the numerical value can be taken from a value between 5% and 20%, can also be taken from a value between 20% and 35%, can also be taken from a value between 35% and 50%, can also be taken from a value between 50% and 86%, and can also be taken from a value between any two numerical values.

[0088] Thus, the onium salt provided by the embodiments of the present application corresponds to the structural general formula of A in the structure. One of the above-mentioned formula (2) to formula (8) structures can be included. The structure includes an onium ion structure after alkylation, which can enable the main brightener to have a strong adsorption capacity. At the same time, the above-mentioned structure can be subjected to an addition polymerization reaction with at least one unsaturated monomer of the alkyl group, which is convenient for subsequent improvement of the stability of the main brightener. Thus, the leveling effect and stability of the electroplating solution are improved, so as to form a uniform, low-roughness and bright plating layer on the surface of the electroplated substrate.

[0089] In some embodiments of the present application, the pH of the electroplating solution provided by the embodiments of the present application can be 3-6.

[0090] In some embodiments of the present application, the nickel salt provided by the embodiments of the present application can include at least one of nickel sulfamate, nickel chloride, nickel sulfate and nickel acetate. It should be noted that the specific implementation of the nickel salt is not limited by the embodiments of the present application.

[0091] In some embodiments of the present application, the grain refiner provided by the embodiments of the present application can include one of sodium saccharin, thiourea and its derivatives, and coumarin and its derivatives. It should be noted that the specific implementation of the grain refiner is not limited by the embodiments of the present application.

[0092] In some embodiments of the present application, the buffer provided by the embodiments of the present application can include one of boric acid, citric acid and acetic acid. It should be noted that the specific implementation of the buffer is not limited by the embodiments of the present application.

[0093] In some embodiments of the present application, the auxiliary brightener provided by the embodiments of the present application can include one of hydroxypropane sulfonic acid pyridine salt, propane sulfonic acid pyridine salt, 1.4-butynediol, propargyl sulfonic acid sodium, allyl sulfonic acid sodium, ethoxylated butynediol and propoxylated propargyl alcohol. It should be noted that the specific implementation of the auxiliary brightener is not limited by the embodiments of the present application.

[0094] The application further provides a preparation method of the electroplating solution, which comprises: taking appropriate amounts of nickel salt, buffer and water to prepare a mixed solution, and then adding a grain refiner, an auxiliary brightener and a main brightener into the mixed solution in sequence and mixing uniformly after complete dissolution, so that the concentrations of the grain refiner, the auxiliary brightener and the main brightener reach the above-mentioned concentration ranges, and the electroplating solution is prepared.

[0095] It can be understood that, in the process of preparing the electroplating solution by using the nickel salt, the grain refiner, the buffer, the auxiliary brightener and the main brightener, there can be a certain measurement error, and the values within the error range can be understood as the ranges defined in the application.

[0096] The application further provides an electroplating method of the electroplating solution, which comprises: immersing a substrate to be electroplated into the prepared electroplating solution. A current is applied to the electroplating solution at a preset temperature to form an electroplating layer on the surface of the substrate to be electroplated. The current density is 0.1 ASD-10 ASD, the preset temperature is 40-65°C, and the thickness of the electroplating layer is less than 15 μm. Further, the thickness of the electroplating layer is less than 12 μm.

[0097] In some embodiments, the substrate to be electroplated can include aluminum or aluminum alloy, copper or copper alloy, magnesium or magnesium alloy. It should be noted that the application does not limit the material corresponding to the substrate to be electroplated.

[0098] In this way, by using the prepared electroplating solution in the electroplating method of the application, a thin and smooth bright electroplating layer can be formed to achieve a smooth and bright finish and provide a large amount of corrosion protection.

[0099] The electroplating solution can be introduced by specific embodiments with reference to Table 1, and the prepared electroplating solution in the embodiments is used to electroplate the substrate to be electroplated, and the performance of the substrate before and after electroplating is tested.

[0100] In some embodiments of the application, appropriate amounts of nickel sulfamate, nickel chloride and boric acid are mixed with water to prepare a mixed solution of 300 g / L of nickel sulfamate, 20 g / L of nickel chloride and 45 g / L of boric acid. After complete dissolution, sodium saccharin is added to the mixed solution to make the concentration reach 0.5 g / L, the first onium chloride salt is added to the mixed solution to make the concentration reach 5 ppm, and the pyridine salt of hydroxypropane sulfonic acid is added to the mixed solution to make the concentration reach 100 ppm, and the solution is continuously stirred for 10 min to mix uniformly, and the electroplating solution (referred to as Example 1) is prepared. In the first onium chloride salt, the structure A is 1-(2-hydroxyethyl)-3-methylimidazolium (the above-mentioned formula 2).

[0101] Then, the prepared plating solution is transferred to a 1.5L Haring tank by adjusting pH to 4.2 with ammonia water. The substrate to be plated is immersed in the plating solution in the Haring tank. The plating solution is heated to 55 degrees, and a titanium plate is used as an anode and an aluminum plate is used as a cathode to apply a current of 1.0 ASD to the plating solution for plating for 70 minutes to form a plating layer on the surface of the substrate to be plated.

[0102] Thus, after the above plating is completed, the thickness of the plating layer can be measured by a film thickness meter to be 9.8 μm. The roughness Ra of the aluminum plate before plating can also be measured by a roughness detector to be 1.752 μm, and the Ra after plating can be measured to be 0.309 μm, the flattening effect is 82.36%, and the appearance of the plating layer presents a mirror-like brightness.

[0103] In some embodiments of the present application, a mixed solution of nickel sulfamate 300 g / L, nickel chloride 20 g / L, and boric acid 45 g / L is prepared by mixing suitable quality of nickel sulfamate, nickel chloride, and boric acid with water. After being fully dissolved, sodium saccharin is added to the mixed solution to make its concentration reach 0.5 g / L, and a second chloronium salt is added to make its concentration reach 5 ppm, and hydroxypropane sulfonic acid pyridine salt is added to make its concentration reach 100 ppm, and the solution is continuously stirred for 10 minutes to make the solution uniformly mixed, thereby preparing a plating solution (referred to as Example 2). In the second chloronium salt, the structure A is 1-allyl-3-methyl imidazolium chloride (the above formula 3).

[0104] Then, the prepared plating solution is transferred to a 1.5L Haring tank by adjusting pH to 4.2 with ammonia water. The substrate to be plated is immersed in the plating solution in the Haring tank. The plating solution is heated to 55 degrees, and a titanium plate is used as an anode and an aluminum plate is used as a cathode to apply a current of 1.0 ASD to the plating solution for plating for 70 minutes to form a plating layer on the surface of the substrate to be plated.

[0105] Thus, after the above plating is completed, the thickness of the plating layer can be measured by a film thickness meter to be 11.0 μm. The roughness Ra of the aluminum plate before plating can also be measured by a roughness detector to be 1.336 μm, and the Ra after plating can be measured to be 0.468 μm, the flattening effect is 64.97%, and the appearance of the plating layer presents a mirror-like brightness.

[0106] In some embodiments of the present application, nickel sulfamate, nickel chloride and boric acid of suitable mass are mixed with water to prepare a mixed solution of 300 g / L nickel sulfamate, 20 g / L nickel chloride and 45 g / L boric acid. After being fully dissolved, saccharin sodium is added to the mixed solution to reach a concentration of 0.5 g / L, and then a third onium chloride salt is added thereto to reach a concentration of 10 ppm, and hydroxypropane sulfonic acid pyridinium salt is added thereto to reach a concentration of 100 ppm, and continuous stirring for 10 min is continued to mix the solution evenly, and an electroplating solution (abbreviated as Example 3) can be prepared. Wherein, the A structure in the third onium chloride salt is a copolymer of quaternized vinyl imidazole and vinyl pyrrolidone (the above formula 6).

[0107] The prepared electroplating solution was then adjusted to a pH of 4.2 using ammonia and transferred to a 1.5L Haring tank. The substrate to be plated was then immersed in the plating solution in the Haring tank. The plating solution was heated to 55°C and electroplated for 70 minutes at a current of 1.0 ASD using a titanium plate as the anode and an aluminum plate as the cathode to form a plating layer on the substrate.

[0108] After the electroplating is complete, the thickness of the electroplated layer can be measured using a film thickness meter to be 13.5 μm. A roughness tester can also be used to measure the roughness of the aluminum plate, which is 1.472 μm before electroplating and 0.377 μm after electroplating. The leveling effect is 74.39%, and the electroplated layer has a mirror-like finish.

[0109] In some embodiments of the present application, nickel sulfamate, nickel chloride and boric acid of suitable mass are mixed with water to prepare a mixed solution of 300 g / L nickel sulfamate, 20 g / L nickel chloride and 45 g / L boric acid. After being fully dissolved, saccharin sodium is added to the mixed solution to make its concentration reach 0.5 g / L, and then a fourth onium chloride salt is added thereto to make its concentration reach 5 ppm, and hydroxypropane sulfonic acid pyridinium salt is added thereto to make its concentration reach 100 ppm, and continuous stirring for 10 min is continued to mix the solution evenly, and an electroplating solution (abbreviated as Example 4) can be prepared. Wherein, the A structure in the fourth onium chloride salt is 1-benzyl-3-methylimidazolium to make its concentration (above formula 5).

[0110] The prepared electroplating solution was then adjusted to a pH of 4.2 using ammonia and transferred to a 1.5L Haring tank. The substrate to be plated was then immersed in the plating solution in the Haring tank. The plating solution was heated to 55°C and electroplated for 70 minutes at a current of 1.0 ASD using a titanium plate as the anode and an aluminum plate as the cathode to form a plating layer on the substrate.

[0111] Thus, after the above plating is completed, the thickness of the plating layer can be measured by a film thickness meter to be 10.4 μm. The roughness Ra of the aluminum plate before plating can also be measured by a roughness detector to be 1.225 μm, and the roughness Ra after plating can be measured to be 0.245 μm, the leveling effect is 80.00%, and the appearance of the plating layer presents mirror bright.

[0112] In some embodiments of the present application, a mixed solution of nickel sulfamate 300 g / L, nickel chloride 20 g / L and boric acid 45 g / L is prepared by mixing appropriate amounts of nickel sulfamate, nickel chloride and boric acid with water. After being fully dissolved, sodium saccharin is added to the mixed solution to make its concentration reach 0.5 g / L, and then the fifth onium chloride salt is added to make its concentration reach 10 ppm, and then the pyridine hydroxypropane sulfonate salt is added to make its concentration reach 100 ppm, and the solution is continuously stirred for 10 min to make the solution uniformly mixed, thereby obtaining the plating solution (referred to as Example 5). In the fifth onium chloride salt, the structure A is 1-butyl-3-methylimidazolium (the above formula 4).

[0113] Then, the prepared plating solution is transferred to a 1.5 L Haring tank by adjusting the pH to 4.2 with ammonia water. The substrate to be plated is immersed in the plating solution in the Haring tank. The temperature of the plating solution is heated to 55 degrees, and a titanium plate is used as the anode and an aluminum plate is used as the cathode to apply a current of 1.0 ASD to the plating solution for plating for 70 min, so as to form a plating layer on the surface of the substrate to be plated.

[0114] Thus, after the above plating is completed, the thickness of the plating layer can be measured by a film thickness meter to be 10.4 μm. The roughness Ra of the aluminum plate before plating can also be measured by a roughness detector to be 1.225 μm, and the roughness Ra after plating can be measured to be 0.245 μm, the leveling effect is 80.00%, and the appearance of the plating layer presents mirror bright.

[0115] In some embodiments of the present application, a mixed solution of nickel sulfamate 300 g / L, nickel chloride 20 g / L and boric acid 45 g / L is prepared by mixing appropriate amounts of nickel sulfamate, nickel chloride and boric acid with water. After being fully dissolved, sodium saccharin is added to the mixed solution to make its concentration reach 0.5 g / L, and then the fifth onium chloride salt is added to make its concentration reach 10 ppm, and then the pyridine hydroxypropane sulfonate salt is added to make its concentration reach 100 ppm, and the solution is continuously stirred for 10 min to make the solution uniformly mixed, thereby obtaining the plating solution (referred to as Example 5). In the fifth onium chloride salt, the structure A is 1-butyl-3-methylimidazolium (the above formula 4).

[0116] Then, the prepared plating solution is transferred to a 1.5 L Haring tank by adjusting the pH to 4.2 with ammonia water. The substrate to be plated is immersed in the plating solution in the Haring tank. The temperature of the plating solution is heated to 55 degrees, and a titanium plate is used as the anode and an aluminum plate is used as the cathode to apply a current of 1.0 ASD to the plating solution for plating for 70 min, so as to form a plating layer on the surface of the substrate to be plated.

[0117] Thus, after the above plating is completed, the thickness of the plating layer can be measured by a film thickness meter to be 12.0 μm. The roughness Ra of the aluminum plate before plating can also be measured by a roughness detector to be 1.318 μm, and the roughness Ra after plating can be measured to be 0.719 μm, the leveling effect is 45.45%, and the appearance of the plating layer presents a matte finish.

[0118] In some embodiments of the present application, a mixed solution of nickel sulfamate 300 g / L, nickel chloride 20 g / L and boric acid 45 g / L is prepared by mixing appropriate amounts of nickel sulfamate, nickel chloride and boric acid with water. After being fully dissolved, sodium saccharin is added to the mixed solution to make its concentration reach 0.5 g / L, and then 1-(2-hydroxyethyl)-3-methylimidazolium is added to make its concentration reach 5 ppm. The solution is stirred for 10 min to make it uniformly mixed, and then the electroplating solution (referred to as Comparative Example 2) is prepared.

[0119] Then, the prepared electroplating solution is transferred to a 1.5 L Haring tank by adjusting the pH to 4.2 with ammonia water. The substrate to be electroplated is immersed in the electroplating solution in the Haring tank. The temperature of the electroplating solution is heated to 55 degrees, and a titanium plate is used as the anode and an aluminum plate is used as the cathode to apply a current of 1.0 ASD to the electroplating solution for electroplating for 70 min to form a plating layer on the surface of the substrate to be electroplated.

[0120] Thus, after the above plating is completed, the thickness of the plating layer can be measured by a film thickness meter to be 12.0 μm. The roughness Ra of the aluminum plate before plating can also be measured by a roughness detector to be 1.318 μm, and the roughness Ra after plating can be measured to be 0.719 μm, the leveling effect is 45.45%, and the appearance of the plating layer presents a matte finish.

[0121] In some embodiments of the present application, a mixed solution of nickel sulfamate 300 g / L, nickel chloride 20 g / L and boric acid 45 g / L is prepared by mixing appropriate amounts of nickel sulfamate, nickel chloride and boric acid with water. After being fully dissolved, sodium saccharin is added to the mixed solution to make its concentration reach 0.5 g / L, and then 1-(2-hydroxyethyl)-3-methylimidazolium is added to make its concentration reach 5 ppm. The solution is stirred for 10 min to make it uniformly mixed, and then the electroplating solution (referred to as Comparative Example 2) is prepared.

[0122] Then, the prepared electroplating solution is transferred to a 1.5 L Haring tank by adjusting the pH to 4.2 with ammonia water. The substrate to be electroplated is immersed in the electroplating solution in the Haring tank. The temperature of the electroplating solution is heated to 55 degrees, and a titanium plate is used as the anode and an aluminum plate is used as the cathode to apply a current of 1.0 ASD to the electroplating solution for electroplating for 70 min to form a plating layer on the surface of the substrate to be electroplated.

[0123] After the electroplating is complete, the thickness of the electroplated layer can be measured using a film thickness meter to be 12.2 μm. A roughness tester can also be used to measure the roughness of the aluminum plate, which is 1.531 μm before electroplating and 0.934 μm after electroplating. The leveling effect is 38.99%, and the electroplated layer appears rough and matte.

[0124] In some examples of the present application, suitable quantities of nickel sulfamate, nickel chloride, and boric acid were mixed with water to prepare a mixed solution of 300 g / L nickel sulfamate, 20 g / L nickel chloride, and 45 g / L boric acid. After sufficient dissolution, sodium saccharin was added to the mixed solution to a concentration of 0.5 g / L, and then imidazole-epichlorohydrin copolymer was added to a concentration of 10 ppm. Hydroxypropanesulfonic acid pyridinium salt was added to a concentration of 100 ppm. The solution was stirred for 10 minutes to uniformly mix, thereby preparing an electroplating solution (referred to as Comparative Example 4).

[0125] The prepared electroplating solution was then adjusted to a pH of 4.2 using ammonia and transferred to a 1.5L Haring tank. The substrate to be plated was then immersed in the plating solution in the Haring tank. The plating solution was heated to 55°C and electroplated for 70 minutes at a current of 1.0 ASD using a titanium plate as the anode and an aluminum plate as the cathode to form a plating layer on the substrate.

[0126] After the electroplating is complete, the thickness of the electroplated layer can be measured using a film thickness meter to be 10.3 μm. A roughness tester can also be used to measure the roughness of the aluminum plate, which is 1.369 μm before electroplating and 0.804 μm after electroplating. The leveling effect is 41.27%, and the electroplated layer has a matte appearance.

[0127] In some examples of the present application, suitable quantities of nickel sulfamate, nickel chloride, and boric acid were mixed with water to prepare a mixed solution of 300 g / L nickel sulfamate, 20 g / L nickel chloride, and 45 g / L boric acid. After sufficient dissolution, sodium saccharin was added to the mixed solution to a concentration of 0.5 g / L, 1-benzylpyridine-3-carboxylate was added to the solution to a concentration of 5 ppm, and hydroxypropanesulfonic acid pyridinium salt was added to the solution to a concentration of 100 ppm. The solution was stirred for 10 minutes to mix uniformly, thereby preparing an electroplating solution (referred to as Comparative Example 4).

[0128] The prepared electroplating solution was then adjusted to a pH of 4.2 using ammonia and transferred to a 1.5L Haring tank. The substrate to be plated was then immersed in the plating solution in the Haring tank. The plating solution was heated to 55°C and electroplated for 70 minutes at a current of 1.0 ASD using a titanium plate as the anode and an aluminum plate as the cathode to form a plating layer on the substrate.

[0129] Thus, after the above plating is completed, the plating layer thickness can be measured by a film thickness meter to be 10.6 μm. The roughness of the aluminum plate before plating can also be measured by a roughness detector to be Ra 1.575 μm, and the roughness after plating can be measured to be Ra 0.705 μm, the leveling effect is 55.24%, and the appearance of the plating layer is matt.

[0130] Table 1

[0131]

[0132]

[0133] According to the above test results, the leveling ability of Examples 1-5 is stronger, and the appearance effect of each is mirror bright. Specifically, referring to Figure 1 , the appearance of the plating layer of Example 1 is mirror bright. Referring to Figure 2 , the appearance of the plating layer of Example 2 is also mirror bright. The leveling effect after plating using the plating solution provided in the present application can reach more than 60%. In Comparative Example 1, no primary brightener is added, and the leveling ability of the plating solution is low, and the appearance effect of the plating layer is not matt. In Comparative Example 2, no auxiliary brightener is added, and the leveling ability of the plating solution is low, and the appearance effect of the plating layer is not lusterless. In Comparative Example 3, the concentration of the primary brightener added is high, and the leveling ability of the plating solution is low, and the appearance effect of the plating layer is not lusterless. In Comparative Examples 4 and 5, the brightener used is not the primary brightener provided in the present application, and the leveling ability of the plating solution is low. Specifically, referring to Figure 3 , the appearance of the plating layer of Comparative Example 4 is matt. Referring to Figure 4 , the appearance of the plating layer of Comparative Example 5 is also matt.

[0134] Thus, the plating solution provided in the present application has strong leveling ability, and after plating using the plating solution provided in the present application, the appearance can present good mirror bright effect.

[0135] The present application also provides applications of the above plating solution in plating metal housings, plating electronic device housings and chip packaging. For example, plating mobile phone metal housings, plating optical module housings, and plating computer metal housings, etc. Of course, the plating solution provided in the present application can also be used in automobiles, electrical appliances, hardware and other industries to achieve smooth bright finish and provide a large amount of corrosion protection. The plating solution provided in the present application is also suitable for deposition on a plurality of different types of substrates to be plated.

[0136] In some aspects, multiple embodiments of the present application can be combined, and the combined aspects can be implemented. Optionally, some operations in the flow of various method embodiments are combined, and / or the order of some operations is changed. Also, the order of execution or performance of the operations in each flow is not limited to the order given; nor is it necessary that all operations be performed, some operations can be optional, and / or a subset of some operations can be performed. Any of the operations can be performed in any order.

[0137] Those of ordinary skill in the art will realize and understand that there are many ways to reorder the operations described in the embodiments of the present application. In addition, it should be pointed out that the process details involved in some embodiments of the present application are also applicable in a similar manner to other embodiments, or can be used in combination between different embodiments.

[0138] In addition, some steps in the method embodiments can be equivalently replaced by other possible steps. Alternatively, some steps in the method embodiments can be optional and can be deleted in some use scenarios. Alternatively, other possible steps can be added to the method embodiments. Also, the method embodiments can be implemented individually or in combination. The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto, and any changes or replacements within the technical scope disclosed in the present application should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An electroplating solution, characterized by, The electroplating solution comprises a nickel salt, a grain refiner, a buffer, an auxiliary brightener and a main brightener. The primary brightener comprises a onium salt [A] x [B] y ; The general structure of A is as shown in formula (1): x and n are positive integers, and y is a natural number; R1 is selected from C1-C4 alkyl; when y=0, R2 is selected from one of a hydrogen atom, a double-bond-containing unsaturated alkyl group, an aromatic hydrocarbon group and a heteroatom group; when y≥1, R2 is selected from a double-bond-containing unsaturated alkyl group; B is selected from an unsaturated monomer of at least one alkyl group.

2. The electroplating solution of claim 1, wherein The double-bond-containing unsaturated alkyl group includes one of methylene, ethylene and propylene; the aromatic hydrocarbon group includes one of phenyl, phenol, halogenated phenyl and toluene; and the heteroatom group includes one of hydroxyl, amino, sulfhydryl, carboxyl and amide.

3. The electroplating solution according to claim 1 or 2, characterized in that, The unsaturated monomer of at least one alkyl group includes one of acrylamide, acryloyl glycine, methyl acrylamide, N,N-dimethyl acrylamide, acrylic acid, vinyl formamide, vinyl acetamide, vinyl caprolactam, vinyl pyrrolidone, vinyl imidazole, vinyl pyridine, vinyl benzoic acid, allyl amine, N,N-dimethyl allyl amine, vinyl acetate, isopropylene acetate, aminoethyl methacrylate and dimethylaminoethyl methacrylate.

4. The electroplating solution according to any one of claims 1 to 3, characterized in that, The onium salt further comprises an anion selected from one of a halogen-containing ion, a hydrogen sulfate ion and a nitrate ion, and the halogen-containing ion includes one of chloride ion, bromide ion, iodide ion, tetrafluoroborate ion and hexafluorophosphate ion.

5. The electroplating solution according to any one of claims 1 to 4, characterized in that, n is 1-5.

6. The electroplating solution according to any one of claims 1 to 5, characterized in that, x is 1-1000, and y is 0-1000.

7. The electroplating solution according to any one of claims 1 to 6, characterized in that, The concentration of the nickel salt in the electroplating solution is 1-500 g / L, the concentration of the grain refiner is 0.1-10 g / L, the concentration of the buffer is 1-100 g / L, the concentration of the auxiliary brightener is 10-1000 ppm, and the concentration of the at least one main brightener is 0.5-50 ppm.

8. The electroplating solution according to any one of claims 1 to 7, characterized in that, The general structure of A includes at least one of the following structures:

9. The electroplating solution according to any one of claims 1 to 8, characterized in that The pH of the electroplating solution is 3-6.

10. The electroplating solution according to any one of claims 1 to 9, characterized in that, The nickel salt includes at least one of nickel sulfamate, nickel chloride, nickel sulfate and nickel acetate, the grain refiner includes one of sodium saccharin, thiourea and its derivatives and coumarin and its derivatives, the buffer includes one of boric acid, citric acid and acetic acid, and the auxiliary brightener includes one of hydroxypropane sulfonic acid pyridine salt, propane sulfonic acid pyridine salt, 1.4-butynediol, propargyl sulfonic acid sodium, allyl sulfonic acid sodium, ethoxylated butynediol and propoxylated propargyl alcohol.

11. An electroplating method of an electroplating solution, characterized by, The method comprises: immersing a substrate to be electroplated in the electroplating solution according to any one of claims 1-10; applying a current to the electroplating solution at a preset temperature to form an electroplating layer on the surface of the substrate to be electroplated.

12. The electroplating method of claim 11, wherein, The current density is 0.1-10 ASD, the preset temperature is 40-65°C, and the thickness of the electroplating layer is less than 15 μm.

13. Use of the electroplating bath according to any one of claims 1 to 10 for electroplating metal housings, electroplating electronic device housings and chip packaging.

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