Ruthenium electroplating solution as well as preparation method and application thereof

Abstract

The invention discloses ruthenium electroplating liquid as well as a preparation method and application thereof. The ruthenium electroplating solution comprises ruthenium with the concentration of 0.25 g / L to 4.0 g / L provided by K2 [Ru2Cl8 (H2O) 2 (mu-N)], platinum with the concentration of 3.0 g / L to 5.0 g / L provided by [Pt (NH3) 2 (NO2) 2], 25 g / L to 40 g / L of 1, 2-cyclohexanediamine tetraacetic acid, 80 g / L to 150 g / L of ammonium sulfate, 0.2 g / L to 0.6 g / L of polyether block amide, 0.5 g / L to 1.2 g / L of ascorbyl palmitate and 5.0 g / L to 10 g / L of pyridine-3-sulfonic acid. According to the ruthenium electroplating solution, ruthenium and platinum can stably exist, a combined electroplating layer obtained after electroplating is simple in structure, nickel, nickel-tungsten alloy and rhodium-ruthenium alloy do not need to be used, the electroplating cost is reduced, and meanwhile the combined electroplating layer further has good anode electrolytic corrosion resistance.

Description

Technical Field

[0001] The present invention belongs to the technical field of electroplating, and in particular relates to a ruthenium electroplating solution and a preparation method and application thereof. Background Art

[0002] The main challenge in ruthenium plating stems from its many valence states, which form different complexes during electroplating, making the electrochemical reaction complex. Consequently, existing ruthenium plating processes require very thick coatings, resulting in low process efficiency. Furthermore, the ruthenium plating solution cannot stably coexist with the platinum plating solution to form a ruthenium-platinum composite coating.

[0003] Therefore, the existing technology needs to be further improved. Summary of the Invention

[0004] In response to the above-mentioned problems, the present invention aims to provide a ruthenium electroplating solution, a preparation method and an application, aiming to solve the problem that the ruthenium-platinum plating solution has poor stability and cannot form a ruthenium-platinum composite coating.

[0005] The technical solutions adopted by the present invention to solve the above technical problems are as follows:

[0006] A ruthenium electroplating solution, comprising: ruthenium provided by K2[Ru2Cl8(H2O)2(μ-N)] with a concentration of 0.25-4.0 g / L, platinum provided by [Pt(NH3)2(NO2)2] with a concentration of 3.0-5.0 g / L, and 1,2-cyclohexanediaminetetraacetic acid (1,2-cyclohexanediaminetetraacetic acid) (25-40 g / L);

[0007] The pH value of the ruthenium electroplating solution is 2.5-3.5.

[0008] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[0009] As a preferred technical solution, the ruthenium electroplating solution further comprises: 80-150 g / L of ammonium sulfate, 0.2-0.6 g / L of polyether block amide, and 0.5-1.2 g / L of ascorbyl palmitate.

[0010] As a preferred technical solution, the ruthenium electroplating solution further comprises: 5.0-10 g / L of pyridine-3-sulfonic acid.

[0011] A method for preparing the ruthenium electroplating solution as described above, comprising:

[0012] Weigh 1,2-cyclohexanediaminetetraacetic acid in proportion and disperse it in deionized water to obtain a base solution;

[0013] Weigh K2[Ru2Cl8(H2O)2(μ-N)] in proportion and add it to the base liquid in batches, and then add a predetermined proportion of [Pt(NH3)2(NO2)2] powder to the base liquid to obtain a mixed solution;

[0014] Adding sulfamic acid into the mixed solution to adjust the pH value of the mixed solution to 2.5-3.5 to obtain a ruthenium electroplating solution.

[0015] As a preferred technical solution, the method for preparing the ruthenium electroplating solution further comprises: adding a predetermined proportion of pyridine-3-sulfonic acid, ammonium sulfate, polyether block amide and ascorbyl palmitate to the base solution.

[0016] As a preferred technical solution, the method for preparing the ruthenium electroplating solution is as follows, wherein the D50 of the [Pt(NH3)2(NO2)2] powder is less than 5μm.

[0017] As a preferred technical solution, in the method for preparing a ruthenium electroplating solution, the molecular weight of the hydrophilic portion of the polyether block amide is 8000±500, and the hydrophilic-lipophilic balance is 12-14.

[0018] An application of a ruthenium electroplating solution, wherein the ruthenium electroplating solution is used for electroplating on the surface of a metal substrate or a metal coating.

[0019] As a preferred technical solution, the application of the ruthenium electroplating solution, wherein the electroplating parameters are: current density 0.3 ~ 6A / dm 2 , temperature 30-40℃, time 5-45min.

[0020] Beneficial effects: The ruthenium electroplating solution of the present invention can stably contain ruthenium and platinum, and the combined plating layer obtained after electroplating has a simple structure, without the need to use nickel, nickel-tungsten alloy, and rhodium-ruthenium alloy, thereby reducing the electroplating cost. At the same time, the combined electroplating layer also has good resistance to anodic electrolytic corrosion. DETAILED DESCRIPTION

[0021] The present invention will be described in further detail below with reference to specific examples, but the embodiments of the present invention are not limited thereto. For process parameters not particularly noted, conventional techniques may be used.

[0022] Unless otherwise specified, technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to which this invention belongs; all units expressing raw material content are expressed in parts by mass. All other raw materials and reagents used in this invention, unless otherwise specified, are those commonly used in the art.

[0023] The inventors have found that the existing electroplating of platinum and ruthenium needs to be electroplated separately, and the ruthenium plating process requires a thicker coating, and the platinum layer and the ruthenium layer are prone to falling off, affecting the overall performance of the coating.

[0024] To address the above-mentioned issues, the inventors of the present invention provide a ruthenium electroplating solution comprising: 0.25-4.0 g / L of ruthenium provided by K2[Ru2Cl8(H2O)2(μ-N)], 3.0-5.0 g / L of platinum provided by [Pt(NH3)2(NO2)2], and 25-40 g / L of 1,2-cyclohexanediaminetetraacetic acid; the pH of the ruthenium electroplating solution is 2.5-3.5. Because the K2[Ru2Cl8(H2O)2(μ-N)] used has excellent water solubility and a regular and ordered spatial structure, with potassium atoms and chlorine atoms coordinated with ruthenium to form a stable structure centered on ruthenium, the solution exhibits excellent stability, preventing ruthenium ions from decomposing or spontaneously reducing and allowing for easy precipitation. It enables it to form a stable platinum-ruthenium composite plating solution with [Pt(NH3)2(NO2)2] and form a synergistic deposition path. 1,2-cyclohexanediaminetetraacetic acid (CDTA) tetradentate chelates the open coordination sites of binuclear ruthenium to form a [Ru2-CDTA] supramolecular network, which improves the electroplating efficiency. The resulting platinum-ruthenium alloy coating has higher hardness and electrolysis resistance.

[0025] In one embodiment of the present invention, the provided ruthenium electroplating solution further contains 80-150 g / L of ammonium sulfate, such as 80 g / L to 90 g / L, 90 g / L to 100 g / L, 100 g / L to 110 g / L, 110 g / L to 120 g / L, 120 g / L to 130 g / L, 130 g / L to 140 g / L, 140 g / L to 150 g / L; 0.2-0.6 g / L of polyether block amide, such as 0.2 g / L to 0.3 g / L, 0.3 g / L to 0.4 g / L, 0.4 g / L to 0.5 g / L, 0.5 g / L to 0.6 g / L; 0.5-1.2 g / L of ascorbyl palmitate, such as 0.5 g / L to 0.6 g / L; 0g / L, 7.0g / L to 8.0g / L, 8.0g / L to 9.0g / L, 9.0g / L to 10g / L; wherein pyridine-3-sulfonic acid acts as a dynamic coordination regulator, is adsorbed on the platinum surface to regulate the deposition orientation, and forms a π-π stacking stable interface with the Ru-μ-N bridge. Ammonium sulfate reduces concentration polarization, while polyether block amide encapsulates the dinuclear ruthenium salt in nano-sized micelles, increasing mass transfer rates. Ascorbyl palmitate acts as a fat-soluble antioxidant, extending the life of the plating solution.

[0026] In the present invention, the pH regulator used to adjust the pH value is aminosulfonic acid. Controlling the pH value of the ruthenium electroplating solution at 2.5-3.5 is beneficial to stabilizing the μ-N bridge bond.

[0027] Based on the same inventive concept, the present invention also provides a method for preparing a ruthenium electroplating solution, comprising: weighing 1,2-cyclohexanediaminetetraacetic acid in proportion, adding it to deionized water, and magnetically stirring until it is completely dissolved to obtain a base solution.

[0028] Weigh pyridine-3-sulfonic acid and slowly add it to the base solution. Maintain the temperature of the base solution at 50±2°C and stir for 30 minutes to form a yellow-green transparent solution.

[0029] Weigh a certain amount of K2[Ru2Cl8(H2O)2(μ-N)] and add it to the above solution in multiple batches. The water temperature should be ≤35℃ during the whole process to prevent the μ-N bridge from breaking.

[0030] Weigh a certain amount of [Pt(NH3)2(NO2)2], premix it with deionized water to form a turbid liquid, add it dropwise into the above solution in the form of a turbid liquid, and simultaneously disperse it by ultrasonication (such as 40kHz) to obtain an electroplating solution.

[0031] Weigh PEBA mother liquor (10%), slowly inject it into the plating solution with a syringe, and mechanically stir (200 rpm) for 1 hour to form a uniform colloidal system; weigh a certain amount of ascorbyl palmitate ethanol solution (5%) and add it to the system in the dark, and stir under nitrogen protection for 15 minutes.

[0032] The pH value is adjusted to 2.5-3.5 with 10% sulfamic acid solution, and a certain amount of ammonium sulfate is added and stirred until the ammonium is completely dissolved to obtain a ruthenium electroplating solution.

[0033] The following is a further explanation of the ruthenium electroplating solution and electroplating method provided by the present invention through specific preparation examples.

[0034] Example 1

[0035] Weigh 50 g of 1,2-cyclohexanediaminetetraacetic acid and add it to 60°C deionized water. Stir magnetically (500 rpm) until it is completely dissolved to obtain a CDTA solution. Slowly add 10 g of pyridine-3-sulfonic acid to the CDTA solution to obtain a base solution.

[0036] Weigh 0.5g K2[Ru2Cl8(H2O)2(μ-N)] and add it to the above solution in 5 batches. The water temperature is ≤35℃ throughout the process to prevent the μ-N bridge from breaking. Premix 6g of [Pt(NH3)2(NO2)2] with 50ml of deionized water into a suspension, add it dropwise to the main solution at a rate of 1mL / min through a peristaltic pump, and perform simultaneous ultrasonic dispersion (40kHz); take 0.4g PEBA mother liquor (10%) and slowly inject it into the plating solution with a syringe. Mechanically stir (200rpm) for 1 hour to form a uniform colloidal system. Add 1.0g ascorbyl palmitate ethanol solution (5%) to the system in the dark and stir under nitrogen for 15 minutes. Adjust the pH to 2.5 with 10% aminosulfonic acid solution, add 160g ammonium sulfate, and stir until completely dissolved to obtain a ruthenium electroplating solution.

[0037] A workpiece to be plated is provided. From the inside out, the surface of the workpiece to be plated has been plated with a nickel-phosphorus layer (2μm), a gold layer (0.5μm), and a platinum layer (0.75μm). The workpiece to be plated is now electroplated with a ruthenium-platinum alloy layer (0.375μm) on the surface of the platinum layer using the above-mentioned ruthenium electroplating solution. The electroplating parameters are as follows:

[0038] Current density 5A / dm 2 , temperature 90℃, time 60min.

[0039] After deposition, the sample was rinsed with deionized water → ultrasonically cleaned with anhydrous ethanol → vacuum dried at room temperature to obtain the sample.

[0040] The hardness and corrosion resistance of the coating on the surface of the obtained sample were tested, wherein the hardness test was carried out using a micro Vickers hardness tester equipped with an optical microscope, and 10 test areas were randomly selected on the coating surface; 3 effective indentation tests were performed on each area; the diagonal length was measured using an optical microscope (1000×); the average value was calculated and converted into a Vickers hardness value, and the calculated hardness value was 715Hv.

[0041] Corrosion resistance testing was conducted under the following saltwater anodic electrolytic corrosion test conditions: 5% sodium chloride by weight; temperature: 40°C; electromagnetic stirring: 200 RPM; cathode: platinum titanium sheet; anode: the sample being tested, with the functional test area exposed and other areas sealed with nail polish or epoxy resin; cathode-cathode spacing: 10-20mm; a constant anodic voltage of 5V. The test was considered a failure when the first corrosion point exceeding 0.05mm was observed on the functional area of the sample. The test result was an electrolysis time of more than 70 minutes.

[0042] Example 2

[0043] Weigh 60 g of 1,2-cyclohexanediaminetetraacetic acid and add it to 60°C deionized water. Stir magnetically (600 rpm) until it is completely dissolved to obtain a CDTA solution. Slowly add 12 g of pyridine-3-sulfonic acid to the CDTA solution to obtain a base solution.

[0044] Weigh 0.6g K2[Ru2Cl8(H2O)2(μ-N)] and add it to the above solution in 5 batches. The water temperature is ≤35℃ throughout the process to prevent the μ-N bridge from breaking. Premix 8g of [Pt(NH3)2(NO2)2] with 60ml of deionized water into a suspension, add it dropwise to the main solution at a rate of 1mL / min through a peristaltic pump, and perform simultaneous ultrasonic dispersion (40kHz). Take 0.6g PEBA mother liquor (10%) and slowly inject it into the plating solution with a syringe. Mechanically stir (200rpm) for 1 hour to form a uniform colloidal system. Add 1.2g ascorbyl palmitate ethanol solution (5%) to the system in the dark and stir under nitrogen for 15 minutes. Adjust the pH to 3.0 with 10% aminosulfonic acid solution, add 200g ammonium sulfate, and stir until completely dissolved to obtain a ruthenium electroplating solution.

[0045] A workpiece to be plated is provided. From the inside out, the surface of the workpiece to be plated has been plated with a nickel-phosphorus layer (2μm), a gold layer (0.5μm), and a platinum layer (0.375μm). The workpiece to be plated is now electroplated with a ruthenium-platinum alloy layer (0.4μm) on the surface of the platinum layer using the above-mentioned ruthenium electroplating solution. The electroplating parameters are as follows:

[0046] Current density 5A / dm 2 , temperature 90℃, time 45min.

[0047] After deposition, the sample was rinsed with deionized water → ultrasonically cleaned with anhydrous ethanol → vacuum dried at room temperature to obtain the sample.

[0048] The hardness and corrosion resistance of the coating on the surface of the obtained sample were tested, wherein the hardness test was carried out using a micro Vickers hardness tester equipped with an optical microscope, and 10 test areas were randomly selected on the coating surface; 3 effective indentation tests were performed on each area; the diagonal length was measured using an optical microscope (1000×); the average value was calculated and converted into a Vickers hardness value, and the calculated hardness value was 745Hv.

[0049] Corrosion resistance testing was conducted under the following saltwater anodic electrolytic corrosion test conditions: 5% sodium chloride by weight; temperature: 40°C; electromagnetic stirring: 200 RPM; cathode: platinum titanium sheet; anode: the sample being tested, with the functional test area exposed and other areas sealed with nail polish or epoxy resin; cathode-cathode spacing: 10-20mm; a constant anodic voltage of 5V. The test was considered a failure when the first corrosion point exceeding 0.05mm was observed on the functional area of the sample. The test result was an electrolysis time of more than 70 minutes.

[0050] Example 3

[0051] 80 g of 1,2-cyclohexanediaminetetraacetic acid was weighed and added to 60°C deionized water, and magnetic stirring (600 rpm) was performed until it was completely dissolved to obtain a CDTA solution. 20 g of pyridine-3-sulfonic acid was slowly added to the CDTA solution to obtain a base solution.

[0052] Weigh 8g K2[Ru2Cl8(H2O)2(μ-N)] and add it to the above solution in 5 batches. The water temperature is ≤35°C throughout the process to prevent the μ-N bridge from breaking. Premix 10g of [Pt(NH3)2(NO2)2] with 70ml of deionized water into a suspension, add it dropwise to the main solution at a rate of 1mL / min through a peristaltic pump, and perform simultaneous ultrasonic dispersion (40kHz); take 1.2g PEBA mother liquor (10%), slowly inject it into the plating solution with a syringe, and stir mechanically (200rpm) for 1 hour to form a uniform colloidal system. Add 2.4g ascorbyl palmitate ethanol solution (5%) to the system in the dark, stir under nitrogen protection for 15 minutes, adjust the pH to 3.5 with 10% aminosulfonic acid solution, add 300g ammonium sulfate, and stir until completely dissolved to obtain a ruthenium electroplating solution.

[0053] A workpiece to be plated is provided. From the inside out, the surface of the workpiece to be plated has been plated with a nickel-phosphorus layer (2μm), a gold layer (0.5μm), and a platinum layer (0.75μm). The workpiece to be plated is now electroplated with a ruthenium-platinum alloy layer (0.45μm) on the surface of the platinum layer using the above-mentioned ruthenium electroplating solution. The electroplating parameters are as follows:

[0054] Current density 5A / dm2 , temperature 90℃, time 50min.

[0055] After deposition, the sample was rinsed with deionized water → ultrasonically cleaned with anhydrous ethanol → vacuum dried at room temperature to obtain the sample.

[0056] The hardness and corrosion resistance of the coating on the surface of the obtained sample were tested, wherein the hardness test was carried out using a micro Vickers hardness tester equipped with an optical microscope, and 10 test areas were randomly selected on the coating surface; 3 effective indentation tests were performed on each area; the diagonal length was measured using an optical microscope (1000×); the average value was calculated and converted into a Vickers hardness value, and the calculated hardness value was 787Hv.

[0057] Corrosion resistance testing was conducted under the following saltwater anodic electrolytic corrosion test conditions: 5% sodium chloride by weight; temperature: 40°C; electromagnetic stirring: 200 RPM; cathode: platinum titanium sheet; anode: the sample being tested, with the functional test area exposed and other areas sealed with nail polish or epoxy resin; cathode-cathode spacing: 10-20mm; a constant anodic voltage of 5V. The test was considered a failure when the first corrosion point exceeding 0.05mm was observed on the functional area of the sample. The test result was an electrolysis time of more than 70 minutes.

[0058] In summary, the present invention provides a ruthenium electroplating solution comprising: 0.25-4.0 g / L of ruthenium provided by K2[Ru2Cl8(H2O)2(μ-N)], 3.0-5.0 g / L of platinum provided by [Pt(NH3)2(NO2)2], 25-40 g / L of 1,2-cyclohexanediaminetetraacetic acid, 80-150 g / L of ammonium sulfate, 0.2-0.6 g / L of polyether block amide, 0.5-1.2 g / L of ascorbyl palmitate, and 5.0-10 g / L of pyridine-3-sulfonic acid. The ruthenium electroplating solution of the present invention has a simple combined plating layer structure, eliminates the need for nickel, nickel-tungsten alloy, and rhodium-ruthenium, reducing electroplating costs. Furthermore, the combined electroplating layer exhibits excellent resistance to anodic electrolytic corrosion.

[0059] The above description describes the basic principles, main features, and performance advantages of the present invention. It should be understood that the performance and application of the present invention are not limited to the above examples. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications are intended to fall within the scope of protection of the appended claims.

Claims

1. A ruthenium electroplating solution, characterized in that Contains: ruthenium provided by K2[Ru2Cl8(H2O)2(μ-N)] with a concentration of 0.25-4.0 g / L, platinum provided by [Pt(NH3)2(NO2)2] with a concentration of 3.0-5.0 g / L, and 1,2-cyclohexanediaminetetraacetic acid 25-40 g / L; The pH value of the ruthenium electroplating solution is 2.5-3.

5.

2. The ruthenium electroplating solution according to claim 1, characterized in that The ruthenium electroplating solution further comprises: 80-150 g / L of ammonium sulfate, 0.2-0.6 g / L of polyether block amide, and 0.5-1.2 g / L of ascorbyl palmitate.

3. The ruthenium electroplating solution according to claim 2, characterized in that The ruthenium electroplating solution also includes: 5.0-10 g / L of pyridine-3-sulfonic acid.

4. A method for preparing a ruthenium electroplating solution as claimed in claim 1, characterized in that: include: Weigh 1,2-cyclohexanediaminetetraacetic acid in proportion and disperse it in deionized water to obtain a base solution; Weigh K2[Ru2Cl8(H2O)2(μ-N)] in proportion and add it to the base liquid in batches, and then add a predetermined proportion of [Pt(NH3)2(NO2)2] powder to the base liquid to obtain a mixed solution; Adding sulfamic acid to the mixed solution, adjusting the pH value of the mixed solution to 2.5-3.5, and obtaining a ruthenium electroplating solution.

5. The method for preparing a ruthenium electroplating solution according to claim 4, wherein: The preparation method further comprises: adding a predetermined proportion of pyridine-3-sulfonic acid, ammonium sulfate, polyether block amide and ascorbyl palmitate to the base solution.

6. The method for preparing a ruthenium electroplating solution according to claim 4, wherein: The D50 of the [Pt(NH3)2(NO2)2] powder is less than 5 μm.

7. The method for preparing a ruthenium electroplating solution according to claim 5, wherein: The molecular weight of the hydrophilic part of the polyether block amide is 8000±500, and the hydrophilic-lipophilic balance is 12-14.

8. An application of a ruthenium electroplating solution, characterized in that: The ruthenium electroplating solution is used for electroplating on the surface of a metal substrate or a metal coating.

9. The use of the ruthenium electroplating solution according to claim 8, characterized in that: The electroplating parameters are: current density 0.3~6A / dm 2 , temperature 30-40℃, time 5-45min.