Chemical nickel plating solution with controllable plating speed and phosphorus content and preparation method of chemical nickel plating solution

Abstract

The invention provides a chemical nickel plating solution with controllable plating speed and phosphorus content. The chemical nickel plating solution comprises the following components in concentration content: 13-28 g / L of main salt, 12-25 g / L of a reducing agent, 3-80 g / L of a composite complexing agent, 4-15 mg / L of a stabilizing agent, 10-30 g / L of a buffering agent and 10-40 mg / L of a wetting agent, the composite complexing agent contains 1-40g / L of amine complexing agent. According to the chemical nickel-plating solution disclosed by the invention, the chemical nickel-plating rate can be controlled and the requirements of different phosphorus contents in a nickel-plating layer can be met by only adopting one basic chemical nickel-plating solution formula by only changing the content of the amine complexing agent, cooperating with the combined action of other substances and simultaneously adaptively adjusting the plating conditions, so that the production process is simplified, and the production cost is reduced. The production cost is reduced, and the application prospect is wide.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical nickel plating, and in particular relates to a chemical nickel plating solution with controllable plating speed and phosphorus content and a preparation method thereof. Background Art

[0002] Chemical plating is a surface treatment technology commonly used in the field of high-end electronic information. Among them, chemical nickel plating is the fastest growing type of chemical plating. The coating is usually Ni-P alloy, and its coating shows excellent performance in uniformity, corrosion resistance, hardness, weldability, magnetism, and decorativeness. Nickel coatings with different phosphorus contents can show different properties. According to the different phosphorus contents in the nickel coating, chemical nickel can be divided into low-phosphorus nickel (phosphorus content below 4wt%), medium-phosphorus nickel (5-8wt%) and high-phosphorus nickel (9-12wt%). The low-phosphorus content chemical nickel layer has high hardness, wear resistance, and is especially resistant to alkali corrosion. The obtained coating is dark in color and has strong weldability. Many light metal components can use low-phosphorus chemical nickel to improve weldability, so it is widely used in the electronics field. The coating obtained by low-phosphorus chemical nickel is also often used for wear parts, such as mechanical parts, because of its particularly good wear resistance. High phosphorus content chemical nickel layer belongs to amorphous structure and has excellent corrosion resistance. Some coatings have better corrosion resistance than stainless steel. High phosphorus chemical nickel coating is non-magnetic, so it is widely used in computer industry. High phosphorus content chemical nickel layer is brighter and whiter. The hardness, wear resistance and corrosion resistance of the coating are moderate, and it is widely used in various fields.

[0003] In actual production, different application scenarios have different requirements for the phosphorus content in the chemical nickel plating layer, and thus different chemical nickel plating solutions need to be selected; however, replacing different chemical nickel plating solutions requires a lot of manpower and material resources, which increases production costs, and the production process is more complicated. Therefore, how to control the deposition rate of the nickel plating layer has become an issue that needs to be studied and paid attention to in the current chemical nickel plating process. Summary of the invention

[0004] The main purpose of the present invention is to provide a chemical nickel plating solution with controllable plating speed and phosphorus content and a preparation method thereof, which solves the problems in the prior art that the deposition rate of the nickel coating in chemical nickel plating is uncontrollable, and when chemical nickel coatings with different phosphorus contents are required in actual production, the corresponding chemical nickel plating solution needs to be replaced, thereby increasing production costs and making the process complicated.

[0005] To achieve the above object, the technical solution adopted by the present invention is: A chemical nickel plating solution with controllable plating speed and phosphorus content, comprising the following components in concentration: 13-28 g / L of main salt, 12-25 g / L of reducing agent, 3-80 g / L of composite complexing agent, 4-15 mg / L of stabilizer, 10-30 g / L of buffer and 10-40 mg / L of wetting agent.

[0006] Furthermore, the main salt is one or more of nickel sulfate hexahydrate, nickel chloride, nickel sulfamate or nickel acetate.

[0007] Furthermore, the reducing agent is one or more of sodium hypophosphite monohydrate, potassium hypophosphite or ammonium hypophosphite.

[0008] Further preferably, the main salt is nickel sulfate hexahydrate, and the reducing agent is sodium hypophosphite monohydrate.

[0009] Furthermore, the buffer is one or more of sodium acetate, borax, potassium pyrophosphate, anhydrous sodium dihydrogen phosphate, and anhydrous disodium hydrogen phosphate.

[0010] Furthermore, the stabilizer is one or more of potassium iodate, thiourea or their derivatives.

[0011] Further preferably, the stabilizer comprises 3-10 mg / L potassium iodate, 1-5 mg / L thiourea or its derivatives.

[0012] Furthermore, the wetting agent is one or more of sodium dodecylbenzene sulfonate, sodium methane sulfonate, PEG-400, and OP-10.

[0013] Furthermore, the composite complexing agent includes 2-40 g / L of trisodium citrate dihydrate and malic acid, and 1-40 g / L of an amine complexing agent.

[0014] More preferably, the composite complexing agent is 15-30 g / L of trisodium citrate dihydrate, 4-10 g / L of malic acid and 1-40 g / L of an amine complexing agent.

[0015] Furthermore, the amine complexing agent is one or more of ethylenediamine, disodium ethylenediaminetetraacetate, hydroxyethylethylenediaminetriacetic acid, diethylenetriaminepentaacetic acid, triethylenetetramine, ethylenediaminetrimethylenephosphonic acid, diethylenetriaminepentamethylenephosphonic acid, and aminotrimethylenephosphonic acid.

[0016] Another aspect of the present invention provides a method for preparing the electroless nickel plating solution with controllable plating speed and phosphorus content, comprising the following steps: (1) adding the complexing agent, buffer and main salt to ultrapure water in sequence, stirring until completely dissolved, to obtain a first mixed solution; (2) adding a stabilizer and a wetting agent to the first mixed solution, stirring until completely dissolved, to obtain a second mixed solution; (3) Adding a reducing agent to the second mixed solution, stirring until completely dissolved, and adding a sodium hydroxide solution to adjust the pH of the plating solution to 4.0-6.0, thereby preparing the chemical nickel plating solution.

[0017] Another aspect of the present invention provides application of the chemical nickel plating solution in chemical nickel plating of workpieces.

[0018] Furthermore, when the plating temperature of the chemical nickel plating solution is 70-90° C. and the plating time is 10-30 min, the deposition rate of the workpiece coating is 0.10-0.36 μm / min.

[0019] More preferably, when the plating temperature of the chemical nickel plating solution is 80-85° C. and the plating time is 10-30 min, the deposition rate of the workpiece coating is 0.10-0.36 μm / min.

[0020] Furthermore, when the amount of amine complexing agent added to the chemical nickel plating solution is 1-8 g / L, the pH of the plating solution is adjusted to 4.0-4.4, the plating temperature is 80-85°C, and the phosphorus content in the chemical nickel plating layer is high phosphorus content (9-12wt%), then the deposition rate of the chemical plating layer is 0.10-0.19μm / min.

[0021] Furthermore, when the amount of amine complexing agent added to the chemical nickel plating solution is 10-25 g / L, the pH of the plating solution is adjusted to 4.5-5.2, the plating temperature is 80-85°C, and the phosphorus content in the chemical nickel plating layer is a medium phosphorus content (6-8wt%). At this time, the deposition rate of the chemical plating layer is 0.20-0.27μm / min.

[0022] Furthermore, when the amount of amine complexing agent added to the chemical nickel plating solution is 30-40 g / L, the pH of the plating solution is adjusted to 5.3-6.0, the plating temperature is 80-85°C, and the phosphorus content in the chemical nickel plating layer is low phosphorus content (2-3wt%), at this time, the deposition rate of the chemical plating layer is 0.29-0.36μm / min.

[0023] Compared with the prior art, the present invention has at least the following beneficial effects: The present invention optimizes the composition of chemical nickel plating solution, and on this basis, adds amine complexes. Since the amine complexing agent can adjust the pH value of the plating solution system, the stability of the nickel plating solution is improved, and the nitrogen atom in the amine acts as a bridging ligand and has a depolarizing effect, it can accelerate electron transfer, thereby improving the deposition rate of nickel, and the addition of the amine complexing agent does not affect the performance and appearance of the nickel-phosphorus layer. The chemical nickel plating solution of the present invention, by only changing the content of the amine complexing agent, and coordinating with other substances to act together, and adaptively adjusting the plating conditions, so that the nickel plating solution of the present invention can control the chemical nickel plating rate and meet the requirements of different phosphorus contents in the nickel plating layer, simplifying the production process, reducing the production cost, and having broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be further described below in conjunction with the accompanying drawings: Figure 1is a FIB image of the nickel-plated part of Example 2 of the present invention; Figure 2 is an EDS image of the nickel-plated part of Example 2 of the present invention; Figure 3 is a FIB image of the nickel-plated part of Example 5 of the present invention; Figure 4 is an EDS image of the nickel-plated part of Example 5 of the present invention; Figure 5 is a FIB image of the nickel-plated part of Example 8 of the present invention; Figure 6 This is the EDS image of the nickel-plated part in Example 8 of the present invention. DETAILED DESCRIPTION

[0025] In the chemical nickel plating solution of the present invention, since the complexing agent can react with Ni 2+ The formation of a stable complex to maintain the stability of the plating solution and extend the life of the plating solution. At the same time, some complexing agents can also increase the deposition rate of nickel, thereby increasing the rate of chemical nickel plating. For example, the nitrogen atom in the amine complexing agent can act as a bridging ligand and an electron bridge to accelerate electron transfer, which is beneficial to Ni 2+ The nickel is reduced, thereby increasing the deposition rate of nickel and accelerating the speed of chemical nickel plating. In addition, the pH of the plating solution is an important factor affecting the phosphorus content in the chemical nickel plating layer. Generally, the higher the pH of the plating solution, the lower the phosphorus content in the nickel plating layer. Therefore, the nickel plating solution of the present invention can simultaneously achieve controllability of the chemical nickel plating rate and the phosphorus content in the nickel plating layer.

[0026] The invention provides a chemical nickel plating solution, which contains 13-28 g / L of main salt, 12-25 g / L of reducing agent, 3-80 g / L of complexing agent, 4-15 mg / L of stabilizer, 10-30 g / L of buffer and 10-40 mg / L of wetting agent.

[0027] In the present invention, the main salt is nickel sulfate hexahydrate, and the reducing agent is sodium hypophosphite monohydrate. The inventors adjust the ratio of the main salt and the reducing agent in the chemical nickel plating solution to make the surface of the plated chemical nickel layer bright and uniform.

[0028] In the present invention, the composite complexing agent is trisodium citrate dihydrate, malic acid and an amine complexing agent. By changing the amount of the amine complexing agent added in the chemical nickel plating solution, the deposition speed of the nickel coating and the phosphorus content in the nickel coating are adjusted. Among them, trisodium citrate dihydrate has a stronger complexing ability and is used as the main complexing agent. Under preferred conditions, the complexing agent is: trisodium citrate dihydrate 15-30g / L and malic acid 4-10g / L.

[0029] In the present invention, the amine complexing agent is selected from one or more of ethylenediamine, disodium ethylenediaminetetraacetate, hydroxyethylethylenediaminetriacetic acid, diethylenetriaminepentaacetic acid, triethylenetetramine, ethylenediaminetrimethylenephosphonic acid, diethylenetriaminepentamethylphosphonic acid, and aminotrimethylenephosphonic acid. The addition of the amine complexing agent can not only adjust the pH value of the plating solution system, but also the nitrogen atom in the amine acts as a bridging ligand, has a depolarizing effect, can accelerate electron transfer, and thus improve the deposition rate of nickel. Therefore, the present invention can control the chemical nickel plating rate of the surface of the workpiece to be plated and the phosphorus content in the chemical nickel coating by changing the content of the amine complexing agent in the chemical nickel plating solution. Under preferred conditions, the content of the amine complexing agent is 1-40g / L.

[0030] In the present invention, the stabilizer is 3-10 mg / L potassium iodate and 1-5 mg / L thiourea. The addition of the stabilizer can inhibit the autocatalytic decomposition of the plating solution, maintain the stability of the chemical nickel plating solution, and avoid economic losses.

[0031] In the present invention, the buffer is sodium acetate. In the process of chemical nickel plating, hydrogen ions are generated, so that the pH value of the solution gradually decreases with the progress of plating. In order to stabilize the plating speed and ensure the quality of the coating and the phosphorus content therein, the chemical nickel plating system must have a buffering capacity to prevent the pH value of the system from changing significantly during the chemical plating process. The buffer can offset the effect of a small amount of external acid or alkali and dilution on the change of the pH value of the solution, so that it fluctuates within a small range to maintain the stability of the pH value of the chemical nickel plating solution.

[0032] In the present invention, the wetting agent is one or more of sodium dodecylbenzene sulfonate, sodium methane sulfonate, PEG-400 or OP-10. A small amount of wetting agent, i.e., surfactant, is added to the chemical nickel plating solution, which helps the gas to escape and reduces the porosity of the coating. In addition, since the surfactant used also acts as a foaming agent, a layer of white foam is formed on the surface of the plating solution under stirring conditions of a large amount of gas escaping during the plating process, which not only can keep warm, reduce the evaporation loss of the plating solution, and reduce the sour taste, but also makes many suspended impurities sandwiched in the foam and easy to remove, so as to keep the plated parts and the plating solution clean.

[0033] The method for preparing a chemical nickel plating solution with controllable plating speed and phosphorus content provided by the present invention comprises the following steps: (1) adding the complexing agent, buffer and main salt to ultrapure water in sequence, stirring until completely dissolved, to obtain a first mixed solution; (2) adding a stabilizer and a wetting agent to the first mixed solution, stirring until completely dissolved, to obtain a second mixed solution; (3) Adding a reducing agent to the second mixed solution, stirring until completely dissolved, and adding a sodium hydroxide solution to adjust the pH of the plating solution to 4.0-6.0, thereby preparing the chemical nickel plating solution.

[0034] In order to better understand the present invention, the present invention is further described in detail below in conjunction with the embodiments, but the scope of protection claimed in the present invention is not limited to the following embodiments.

[0035] Embodiment 1: The composition and content of the chemical nickel plating solution of this embodiment are shown in Table 1: Table 1 Chemical nickel plating solution components and contents

[0036] The preparation method of the chemical nickel plating solution comprises the following steps: (1) In 200 ml of ultrapure water, 2 g of trisodium citrate dihydrate, 1 g of malic acid, 0.2 g of ethylenediamine, 4 g of sodium acetate and 3 g of nickel sulfate hexahydrate were added in sequence and stirred until completely dissolved to obtain a first mixed solution; (2) adding 0.6 mg of potassium iodate, 1 mg of thiourea and 2 mg of sodium dodecylbenzene sulfonate to the first mixed solution, stirring until completely dissolved, to obtain a second mixed solution; (3) Sodium hypophosphite monohydrate is added to the second mixed solution, stirred until completely dissolved, and ultrapure water is added to make the volume to 200 ml. Then, sodium hydroxide solution is added to adjust the pH of the plating solution to 4.0, thereby preparing the chemical nickel plating solution.

[0037] Embodiment 2: The composition and content of the chemical nickel plating solution of this embodiment are shown in Table 2: Table 2 Chemical nickel plating solution components and contents

[0038] The preparation method is the same as that of Example 1, except that in step (3), a sodium hydroxide solution is used to adjust the pH of the plating solution to 4.2.

[0039] Embodiment 3: The composition and content of the chemical nickel plating solution of this embodiment are shown in Table 3: Table 3 Chemical nickel plating solution components and contents

[0040] The preparation method is the same as that of Example 1, except that in step (3), a sodium hydroxide solution is used to adjust the pH of the plating solution to 4.4.

[0041] Embodiment 4: The composition and content of the chemical nickel plating solution of this embodiment are shown in Table 4: Table 4 Chemical nickel plating solution components and contents

[0042] The preparation method is the same as that of Example 1, except that in step (3), a sodium hydroxide solution is used to adjust the pH of the plating solution to 4.5.

[0043] Embodiment 5: The composition and content of the chemical nickel plating solution of this embodiment are shown in Table 5: Table 5 Chemical nickel plating solution components and contents

[0044] The preparation method is the same as that of Example 1, except that in step (3), a sodium hydroxide solution is used to adjust the pH of the plating solution to 4.8.

[0045] Embodiment 6: The composition and content of the chemical nickel plating solution of this embodiment are shown in Table 6: Table 6 Chemical nickel plating solution components and contents

[0046] The preparation method is the same as that of Example 1, except that in step (3), a sodium hydroxide solution is used to adjust the pH of the plating solution to 5.2.

[0047] Embodiment 7: The composition and content of the chemical nickel plating solution of this embodiment are shown in Table 7: Table 7 Chemical nickel plating solution components and contents

[0048] The preparation method is the same as that of Example 1, except that in step (3), sodium hydroxide is used to adjust the pH of the plating solution to 5.3.

[0049] Embodiment 8: The composition and content of the chemical nickel plating solution of this embodiment are shown in Table 8: Table 8 Chemical nickel plating solution components and contents

[0050] The preparation method is the same as that of Example 1, except that in step (3), sodium hydroxide is used to adjust the pH of the plating solution to 5.5.

[0051] Embodiment 9: The composition and content of the chemical nickel plating solution of this embodiment are shown in Table 9: Table 9 Chemical nickel plating solution components and contents

[0052] The preparation method is the same as that of Example 1, except that in step (3), sodium hydroxide is used to adjust the pH of the plating solution to 6.0.

[0053] Comparative Example 1 The composition and content of the chemical nickel plating solution of this comparative example are shown in Table 10: Table 10 Chemical nickel plating solution components and contents

[0054] The preparation method is the same as that of Example 1, except that in step (3), a sodium hydroxide solution is used to adjust the pH of the plating solution to 4.8.

[0055] Comparative Example 2 The composition and content of the chemical nickel plating solution of this comparative example are shown in Table 11: Table 11 Chemical nickel plating solution components and contents

[0056] The preparation method is the same as that of Example 1, except that in step (3), a sodium hydroxide solution is used to adjust the pH of the plating solution to 4.8.

[0057] Comparative Example 3 The composition and content of the chemical nickel plating solution of this comparative example are shown in Table 12: Table 12 Chemical nickel plating solution components and contents

[0058] The preparation method is the same as that of Example 1, except that in step (3), sulfuric acid is used to adjust the pH of the plating solution to 3.0.

[0059] Comparative Example 4 The composition and content of the chemical nickel plating solution of this comparative example are shown in Table 13: Table 13 Chemical nickel plating solution components and contents

[0060] The preparation method is the same as that of Example 1, except that in step (3), a sodium hydroxide solution is used to adjust the pH of the plating solution to 6.5.

[0061] Effect example: The chemical nickel plating solutions of Examples 1-9 and Comparative Examples 1-4 are respectively used for chemical nickel-phosphorus plating of copper-plated silicon wafers by PVD method, specifically comprising the following steps: S1. Pretreatment of PVD copper-plated silicon wafers (size 2cm*2cm, copper thickness 500nm) by pickling, microetching and palladium activation in sequence; S2. The pretreated copper-plated silicon wafer is placed in the chemical nickel plating solution of the above embodiment and comparative example, and the plating is performed at 80°C for 20min; S3. Clean and dry the nickel-plated silicon wafer with ultrapure water to obtain a nickel-plated part.

[0062] S4. The nickel coating thickness and surface phosphorus content of the nickel-plated parts were analyzed by FIB (focused ion beam) and EDS (X-ray spectrometer). The results are shown in Table 14 and Figure 1-6 .

[0063] Table 14 Effect test and plating solution stability of nickel-plated parts of embodiments and comparative examples

[0064] As can be seen from the results of Examples 1-9, the surface of the copper-plated silicon wafer is electrolessly plated with nickel using the electroless nickel plating solution provided by the present invention. By only adjusting the amount of the amine complexing agent added in the electroless nickel plating solution and adaptively adjusting the plating conditions, the electroless nickel plating rate and the requirements for achieving different phosphorus contents in the nickel coating can be controlled, thereby simplifying the production process and reducing production costs. As can be seen from the results of Comparative Examples 1-4, when no amine complexing agent is added to the electroless nickel plating solution, the plating rate is significantly reduced and the phosphorus content in the nickel coating is significantly increased. When an excessive amount of amine complexing agent is added, the plating rate is significantly reduced and the phosphorus content in the nickel coating is significantly increased due to the excessively strong complexing ability. In addition, when the pH value of the electroless nickel plating solution is too low, the plating rate is also significantly reduced and the phosphorus content in the nickel coating is significantly increased. When the pH value of the electroless nickel plating solution is too high, the plating solution is unstable during the heating process and produces a large amount of precipitation. This shows that the electroless nickel plating solution within the composition and pH range of the present invention can simultaneously achieve the requirements for controlling the electroless nickel plating rate and achieving different phosphorus contents in the nickel coating.

[0065] The above embodiments are only preferred technical solutions of the present invention and should not be regarded as limiting the present invention. The protection scope of the present invention shall be the technical solutions recorded in the claims, including equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A chemical nickel plating solution with controllable plating speed and phosphorus content, characterized in that: The chemical nickel plating solution comprises the following components in concentration: 13-28 g / L of main salt, 12-25 g / L of reducing agent, 3-80 g / L of composite complexing agent, 4-15 mg / L of stabilizer, 10-30 g / L of buffer and 10-40 mg / L of wetting agent.

2. The chemical nickel plating solution according to claim 1, characterized in that The main salt is one or more of nickel sulfate hexahydrate, nickel chloride, nickel sulfamate or nickel acetate; The reducing agent is one or more of sodium hypophosphite monohydrate, potassium hypophosphite or ammonium hypophosphite; The buffer is one or more of sodium acetate, borax, potassium pyrophosphate, anhydrous sodium dihydrogen phosphate, and anhydrous disodium hydrogen phosphate; The stabilizer is one or more of potassium iodate, thiourea or their derivatives.

3. The chemical nickel plating solution according to claim 1, characterized in that The main salt is nickel sulfate hexahydrate, and the reducing agent is sodium hypophosphite monohydrate.

4. The chemical nickel plating solution according to claim 1, characterized in that The stabilizer comprises 3-10 mg / L potassium iodate and 1-5 mg / L thiourea.

5. The chemical nickel plating solution according to claim 1, characterized in that The wetting agent is one or more of sodium dodecylbenzene sulfonate, sodium methane sulfonate, PEG-400, and OP-10.

6. The chemical nickel plating solution according to claim 1, characterized in that The composite complexing agent is 2-40 g / L of trisodium citrate dihydrate and malic acid, and 1-40 g / L of an amine complexing agent.

7. The chemical nickel plating solution according to claim 6, characterized in that The amine complexing agent is one or more of ethylenediamine, disodium ethylenediaminetetraacetate, hydroxyethylethylenediaminetriacetic acid, diethylenetriaminepentaacetic acid, triethylenetetramine, ethylenediaminetrimethylenephosphonic acid, diethylenetriaminepentamethylenephosphonic acid, and aminotrimethylenephosphonic acid.

8. The method for preparing the chemical nickel plating solution according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) adding the complexing agent, buffer and main salt to ultrapure water in sequence, stirring until completely dissolved, to obtain a first mixed solution; (2) adding a stabilizer and a wetting agent to the first mixed solution, stirring until completely dissolved, to obtain a second mixed solution; (3) Adding a reducing agent to the second mixed solution, stirring until completely dissolved, and adding a sodium hydroxide solution to adjust the pH of the plating solution to 4.0-6.0, thereby preparing the chemical nickel plating solution.

9. Use of the chemical nickel plating solution with controllable plating speed and phosphorus content according to any one of claims 1 to 8 in chemical nickel plating of workpieces.

10. The use according to claim 9, characterized in that: When the plating temperature of the chemical nickel plating solution is 70-90° C. and the plating time is 10-30 min, the deposition rate of the workpiece coating is 0.10-0.36 μm / min.

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