Ruthenium plating solution and preparation method thereof, ruthenium plating method, ruthenium plating layer and device containing the same

Abstract

The present invention discloses a ruthenium plating solution and a preparation method thereof, a ruthenium plating method, a ruthenium coating and a device containing the same. The ruthenium plating solution includes: a ruthenium main salt, a pH stabilizer, a conductive salt and an antioxidant. Among them, the ruthenium main salt has the function of stabilizing the ruthenium coordination substance, the pH stabilizer can adjust the pH value of the ruthenium plating solution to a preset value or a preset range; the conductive salt can effectively reduce the tank pressure, thereby preventing metal oxidation; and the antioxidant can inhibit anodic oxidation from an electrochemical perspective and enhance the stability of the ruthenium electroplating system. Under the joint action of the ruthenium main salt, the pH stabilizer, the conductive salt and the antioxidant, the ruthenium plating solution system is stable, has weak corrosion to the equipment, has low requirements on the ambient temperature during preparation, has good positioning and plating efficiency during electroplating, can adapt to processes such as hanging plating, rolling plating or shaking plating, and the surface quality of the obtained ruthenium coating meets the requirements of industrialization.

Description

Technical Field

[0001] The present invention belongs to the field of electroplating chemical industry and its application, and in particular, relates to a ruthenium plating solution and a preparation method thereof, a ruthenium plating method, a ruthenium plating layer and a device containing the same. Background Art

[0002] Platinum electroplating is a commonly used electroplating process in the field of precision electroplating. However, in practice, it is found that the related platinum electroplating in precision electroplating has the following defects: (1) Q salt alkaline platinum plating requires a high temperature of 90-95 degrees Celsius, and Q salt is expensive and difficult to buy; (2) P salt acidic platinum plating requires a medium-high temperature of 60-80 degrees Celsius; (3) DNS salt platinum plating The pH of the platinum plating solution is ≤1.2, and is actually often controlled at 0.2-1.0. It is highly corrosive, and it is necessary to consider thickening the underlying gold plating or platinum plating to prevent corrosion and thermal diffusion phase change.

[0003] With the development of electroplating, especially precision electroplating, it is found that ruthenium coating can be used as a platinum coating, especially under nickel-free technology. However, there are still some problems with the related ruthenium coating technology, such as the instability of ruthenium ions, which are easy to decompose during the electroplating process, produce fine powder suspension or precipitate, and co-deposit to make the surface of the electroplated layer rough, which cannot meet production requirements; or the ruthenium ions in the plating solution form oxide or hydroxide precipitation on the anode; or the deposition rate is low during continuous operation.

[0004] Therefore, the existing ruthenium plating technology needs to be further improved. Summary of the invention

[0005] The present invention aims to solve one of the technical problems in the related art to at least a certain extent. To this end, one object of the present invention is to provide a ruthenium plating solution and a preparation method thereof, a ruthenium plating method, a ruthenium coating and a device containing the same, wherein the ruthenium plating solution system is stable, has weak corrosion to equipment, has low requirements on ambient temperature during preparation, has good positioning and plating efficiency during electroplating, and the surface quality of the obtained ruthenium coating meets industrial requirements.

[0006] In one aspect of the present invention, a ruthenium plating solution is proposed. According to an embodiment of the present invention, the ruthenium plating solution includes: a ruthenium main salt, a pH stabilizer, a conductive salt and an antioxidant. According to the ruthenium plating solution of the embodiment of the present invention, the ruthenium main salt has the function of stabilizing the ruthenium coordination substance, and the pH stabilizer can adjust the pH value of the ruthenium plating solution to a preset value or a preset range; the conductive salt can effectively reduce the tank pressure, thereby preventing metal oxidation; and the antioxidant can inhibit anodic oxidation from an electrochemical perspective and enhance the stability of the ruthenium electroplating system. Under the joint action of the ruthenium main salt, the pH stabilizer, the conductive salt and the antioxidant, the ruthenium plating solution system is stable, has weak corrosion to the equipment, has low requirements for the ambient temperature during preparation, has good positioning and plating efficiency during electroplating, can adapt to processes such as hanging plating, rolling plating or shaking plating, and the surface quality of the resulting ruthenium coating meets the requirements of industrialization.

[0007] In addition, the ruthenium plating solution according to the above embodiment of the present invention may also have the following additional technical features:

[0008] In some embodiments of the present invention, the ruthenium main salt is u-nitrogen-bis(tetrachloro)ruthenate monohydrate potassium.

[0009] In some embodiments of the present invention, the pH stabilizer is selected from at least one of boric acid, acetate, potassium dihydrogen phosphate and phosphoric acid.

[0010] In some embodiments of the present invention, the conductive salt is selected from at least one of potassium sulfate, potassium chloride, and potassium phosphate.

[0011] In some embodiments of the present invention, the antioxidant is selected from at least one of formaldehyde, vitamin C, hydroxylamine sulfate, hydroxylammonium hydrochloride and formates.

[0012] In some embodiments of the present invention, the concentration ratio of the ruthenium main salt, the conductive salt and the antioxidant is (10-25): (40-80): (20-100).

[0013] In some embodiments of the present invention, the concentration of ruthenium in the ruthenium main salt is 3-6 g / L.

[0014] In some embodiments of the present invention, the concentration of the ruthenium main salt is 10-25 g / L.

[0015] In some embodiments of the present invention, the concentration of the conductive salt is 40-80 g / L.

[0016] In some embodiments of the present invention, the concentration of the antioxidant is 20-100 g / L.

[0017] In some embodiments of the present invention, the concentration of the antioxidant is 20-50 g / L, 40-60 g / L or 55-75 g / L.

[0018] In some embodiments of the present invention, the pH value of the ruthenium plating solution is 1.4-4.5. Optionally, the pH value of the ruthenium plating solution is 1.4-1.6.

[0019] In some embodiments of the present invention, the ruthenium plating solution is a silver-grey bright ruthenium plating solution or a gunmetal black bright ruthenium plating solution.

[0020] In some embodiments of the present invention, compared with Pantone color card version C, the color of the ruthenium plating solution is Pantone 414C, Pantone 415C, Pantone 416C, Pantone 417C, Pantone 419C, Pantone 420C or Pantone 447C.

[0021] In yet another aspect of the present invention, the present invention provides a method for preparing the above-mentioned ruthenium plating solution. According to an embodiment of the present invention, the method comprises:

[0022] Prepare a first pH stabilizer to obtain a first solution;

[0023] Mixing the conductive salt, the second pH stabilizer, the first antioxidant and the first solution to obtain a second solution;

[0024] The ruthenium main salt is mixed with the second solution and subjected to heat treatment to obtain a third solution;

[0025] The second antioxidant is mixed with the third solution, and a third pH stabilizer is selected as needed to adjust the pH of the solution and stabilize it to a predetermined value, to obtain the ruthenium plating solution;

[0026] The first pH stabilizer, the second pH stabilizer and the third pH stabilizer are selected from the pH stabilizers; the first antioxidant and the second antioxidant are selected from the antioxidants.

[0027] According to the method for preparing the above-mentioned ruthenium plating solution in an embodiment of the present invention, after the first pH stabilizer is prepared to obtain the first solution, the conductive salt, the second pH stabilizer, and the first antioxidant are mixed therewith, which can improve the mixing uniformity of the components and is beneficial to improving the system stability of the ruthenium plating solution; by mixing the ruthenium main salt with the second solution and performing a heat treatment, the ruthenium main salt itself is a complex and is relatively stable, and the second solution provides an environment for the coupling of the ruthenium main salt, and the heat treatment can improve the coupling efficiency of the ruthenium main salt and the second solution; finally, the second antioxidant is mixed with the third solution, and the third pH stabilizer is selected as needed to adjust the pH of the solution and stabilize it to a predetermined value, so that the pH value of the solution can be conveniently controlled, and under the joint action of the first pH stabilizer, the second pH stabilizer and the optional third pH stabilizer, the ruthenium plating solution can form a pH stable system. It can be seen from this that the ruthenium plating solution system is stable and has low corrosion to equipment. It has low requirements for ambient temperature during preparation, has excellent positioning and plating efficiency during electroplating, can adapt to processes such as rack plating, roller plating or rocking plating, and the surface quality of the resulting ruthenium coating meets industrial requirements.

[0028] In some embodiments of the present invention, the temperature of the first solution is 50-60 degrees Celsius.

[0029] In some embodiments of the present invention, the heat treatment includes heating first and then cooling down.

[0030] In another aspect of the present invention, a ruthenium plating method is provided. According to an embodiment of the present invention, the ruthenium plating method uses the above-mentioned ruthenium plating solution or the ruthenium plating solution prepared by the above-mentioned method for preparing the ruthenium plating solution to plate ruthenium.

[0031] According to the ruthenium plating method of the embodiment of the present invention, the method adopts the above-mentioned ruthenium plating solution or the ruthenium plating solution prepared by the above-mentioned method for preparing the ruthenium plating solution to plate ruthenium. The ruthenium plating solution system is stable and has weak corrosion to equipment. It has low requirements for the ambient temperature during preparation, has good positioning and plating efficiency during electroplating, can adapt to processes such as hanging plating, roller plating or shaking plating, and the surface quality of the obtained ruthenium coating meets the needs of industrialization. A ruthenium coating that meets the requirements of appearance and surface quality can be obtained, and even the production and application of white ruthenium, which has been difficult to break through in the industry, can be realized.

[0032] In some embodiments of the present invention, the current scale Dk during ruthenium plating is 0-6A / dm 2 .

[0033] In some embodiments of the present invention, the ruthenium plating method has a ruthenium efficiency of 60-90%.

[0034] In another aspect of the present invention, the present invention proposes a ruthenium coating. According to an embodiment of the present invention, the ruthenium coating is a ruthenium coating prepared by the above-mentioned ruthenium plating method. The ruthenium coating has extremely high stability and reliability, does not have a rough grain appearance, has fine crystals, and has no gold layer corrosion phase. It is a bright and flat coating with good decorativeness, corrosion resistance and hardness. At the same time, it has black ruthenium, gun-colored ruthenium, white ruthenium and other chromaticities to choose from, which is conducive to expanding the application field of ruthenium coating. Precision industry (especially the hub centerpieces of electronic products such as connectors) parts have requirements for reliability, conductivity, uniformity, hardness and weldability of the coating; the production of the corresponding product must be dead angle, so roller plating is often used for manufacturing; the plating solution of the coating has high requirements, the plating solution must be excellent, and a small current range is required to meet the movement, and the obtained coating color is full and uniform. According to a large number of experiments in the present application, it is found that the ruthenium coating of the present application can well meet the above requirements.

[0035] In some embodiments of the present invention, the surface roughness Ra of the ruthenium coating can be as low as 0.05 mm or less.

[0036] In some embodiments of the present invention, the ruthenium coating is used to replace the platinum coating.

[0037] In yet another aspect of the present invention, the present invention provides a device. According to an embodiment of the present invention, the device has the ruthenium coating layer.

[0038] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0040] Figure 1 The figure is a schematic flow chart of a method for preparing a ruthenium plating solution according to an embodiment of the present invention. DETAILED DESCRIPTION

[0041] The embodiments of the present invention are described in detail below. The terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features.

[0042] In one aspect of the present invention, the present invention provides a ruthenium plating solution. According to an embodiment of the present invention, the ruthenium plating solution includes: a ruthenium main salt, a pH stabilizer, a conductive salt and an antioxidant.

[0043] According to some embodiments of the present invention, the ruthenium main salt can be u-nitrogen-bis-tetrachloro-monohydrate potassium ruthenate. The inventors found that when the ruthenium main salt is in a crystalline state, it is a dark red crystal, soluble in water, and has a regular and orderly spatial structure. Every four chlorine atoms coordinate with ruthenium to form two planes centered on ruthenium. The nitrogen atoms bond with ruthenium and then connect the two planes. The solution stability is very good, and the ruthenium ions will not decompose or spontaneously reduce. Therefore, the above-mentioned ruthenium main salt has the function of stabilizing the ruthenium coordination substance, which is beneficial to improving the system stability of the ruthenium plating solution, and then it is beneficial to improve the ruthenium plating performance of the ruthenium plating solution and improve the quality of the ruthenium coating. According to some further embodiments of the present invention, the concentration of ruthenium in the ruthenium main salt can be 3-6g / L, such as 4.5-5.5g / L, specifically, such as 3g / L, 3.5g / L, 4g / L, 4.5g / L, 5g / L, 5.5g / L, 6g / L, etc., wherein the concentration of ruthenium refers to the concentration of the metal element ruthenium in the ruthenium plating solution. Further, the concentration of the ruthenium main salt can be 10-25g / L, such as 10.0g / L, 11g / L, 12g / L, 13g / L, 14g / L, 15g / L, 16g / L, 17g / L, 18g / L, 19g / L, 20g / L, 21g / L, 22g / L, 23g / L, 24g / L, 25g / L, etc. The inventors have found that when the concentration of ruthenium and / or the concentration of the ruthenium main salt is within the above range, the quality of the ruthenium plating layer can be significantly improved.

[0044] According to another embodiment of the present invention, the pH stabilizer can be selected from at least one of boric acid, acetate, potassium dihydrogen phosphate and phosphoric acid, preferably a pH stabilizer composed of boric acid, acetate, potassium dihydrogen phosphate and phosphoric acid. The inventors found that the pH stabilizer can adjust the pH value of the ruthenium plating solution so that it is within a preset value or a preset range. According to some specific examples of the present invention, when the pH stabilizer is composed of boric acid, acetate, potassium dihydrogen phosphate and phosphoric acid, after boric acid, acetate and phosphoric acid are configured in a certain proportion, potassium dihydrogen phosphate can make the solution steadily reach the optimal pH value.

[0045] According to another embodiment of the present invention, the conductive salt can be selected from at least one of potassium sulfate, potassium chloride, and potassium phosphate. The inventors have found that due to the use of an insoluble anode for electroplating, the conductivity of the conductive salt can be improved under the same current.

[0046] According to another embodiment of the present invention, the antioxidant can be selected from at least one of formaldehyde, vitamin C, hydroxylamine sulfate, hydroxylammonium hydrochloride and formates. The inventors found that the antioxidants in the present application are reducing agents, which can be oxidized first in terms of electrode reaction activity, thereby preventing oxidation (destruction) of the metal ions to be plated, that is, the antioxidants in the present application can inhibit anodic oxidation from an electrochemical perspective and enhance the stability of the ruthenium electroplating system. Further, the concentration of the antioxidant can be 20-100 g / L, such as 20-50 g / L, 40-60 g / L or 55-75 g / L, specifically, 20 g / L, 25 g / L, 30 g / L, 35 g / L, 40 g / L, 45 g / L, 50 g / L, 55 g / L, 60 g / L, 65 g / L, 70 g / L, 75 g / L, 80 g / L, 85 g / L, 90 g / L, 95 g / L, 100 g / L, etc.

[0047] According to another embodiment of the present invention, the concentration ratio of the ruthenium main salt, the conductive salt and the antioxidant can be (10-25): (40-80): (20-100), specifically, it can be (10 / 11 / 12 / 13 / 14 / 15 / 16 / 17 / 18 / 19 / 20 / 21 / 22 / 23 / 24 / 25): (40 / 45 / 50 / 55 / 60 / 65 / 70 / 75 / 80): (20 / 30 / 40 / 50 / 60 / 70 / 80 / 90 / 100). The inventors have found that when the concentration ratio of the ruthenium main salt, the conductive salt and the antioxidant is within the above range, it is beneficial to improve the quality of the ruthenium plating solution, thereby improving the ruthenium plating performance of the ruthenium plating solution and improving the quality of the ruthenium coating. Furthermore, the inventors have also found that within the above range, the more conductive salt there is, the more white ruthenium the color of the resulting ruthenium coating will be.

[0048] According to another embodiment of the present invention, the pH value of the ruthenium plating solution may be 1.4-4.5, further, such as 1.4-1.6, specifically, such as 1.4, 1.5, 1.8, 2.0, 2.3, 2.6, 2.8, 3.0, 3.2, 3.5, 3.7, 4.0, 4.2, 4.5, etc. The inventors found that by using the pH adjusting agent of the present application, the pH value of the ruthenium plating solution can be conveniently adjusted to the above range, and the pH value of the ruthenium plating solution can be well maintained, which is very beneficial for the large-scale production of the ruthenium plating process. Furthermore, when the pH value of the ruthenium plating solution is within the above range, compared with the existing platinum plating process, especially the DNS platinum salt platinum plating process, its corrosiveness to the equipment is significantly reduced, which is beneficial to the quality control of the product.

[0049] According to another embodiment of the present invention, the ruthenium plating solution of the present application can be a silver-gray bright ruthenium plating solution or a gun-black bright ruthenium plating solution, that is, white ruthenium, gun-colored ruthenium, and black ruthenium in the art, that is, the present application creatively proposes a white ruthenium. The Baume degree of the silver-gray bright ruthenium plating solution is 28-28.5 Baume.

[0050] Furthermore, compared with the Pantone color card version C, the color of the ruthenium plating solution of the present application can be Pantone 414C, Pantone 415C, Pantone 416C, Pantone 417C, Pantone 419C, Pantone 420C or Pantone 447C, that is, the ruthenium plating solution of the present application has obvious characteristics of white ruthenium, gunmetal ruthenium and black ruthenium.

[0051] According to the ruthenium plating solution of the embodiment of the present invention, the ruthenium main salt has the function of stabilizing the ruthenium coordination substance, the pH stabilizer can adjust the pH value of the ruthenium plating solution to a preset value or a preset range; the conductive salt can effectively reduce the tank pressure, thereby preventing metal oxidation; and the antioxidant can inhibit anodic oxidation from an electrochemical perspective, thereby enhancing the stability of the ruthenium electroplating system. Under the joint action of the ruthenium main salt, the pH stabilizer, the conductive salt and the antioxidant, the ruthenium plating solution system is stable, has weak corrosion to the equipment, has low requirements for the ambient temperature during preparation, has good positioning and plating efficiency during electroplating, can adapt to processes such as hanging plating, roller plating or shaking plating, and the surface quality of the resulting ruthenium coating meets the requirements of industrialization.

[0052] In another aspect of the present invention, the present invention provides a method for preparing the above-mentioned ruthenium plating solution. According to an embodiment of the present invention, referring to Figure 1 , the method comprising:

[0053] S100: Prepare the first pH stabilizer

[0054] In this step, a first solution is obtained by preparing a first pH stabilizer, wherein the first pH stabilizer can be mixed with water for dissolution. Further, in order to improve the dissolution efficiency and facilitate the subsequent ruthenium plating solution for ruthenium plating, the water can be first heated to 50-60 degrees Celsius, such as 50-56 degrees Celsius, specifically, such as 50 degrees Celsius, 52 degrees Celsius, 54 degrees Celsius, 56 degrees Celsius, 58 degrees Celsius, 60 degrees Celsius, etc., and then the first pH stabilizer is added and dissolved. Further, the first pH stabilizer is selected from the above pH stabilizers.

[0055] S200: Mixing the conductive salt, the second pH stabilizer, the first antioxidant and the first solution

[0056] In this step, a conductive salt, a second pH stabilizer, and a first antioxidant are mixed with the aforementioned first solution to obtain a second solution. Specifically, the conductive salt, the second pH stabilizer, and the first antioxidant can be dissolved in the aforementioned first solution. When insufficient to dissolve, an appropriate amount of water can be added. The inventors have found that by mixing the conductive salt, the second pH stabilizer, and the first antioxidant with the aforementioned first solution, it is beneficial to improve the system stability of the ruthenium plating solution. It should be noted that the second pH stabilizer is selected from the aforementioned pH stabilizer, and the first antioxidant is selected from the aforementioned antioxidant.

[0057] S300: Mixing the ruthenium main salt with the second solution and performing heat treatment

[0058] In this step, the ruthenium main salt is mixed with the second solution and heat-treated to obtain a third solution. The inventors found that the ruthenium main salt itself is a complex and is relatively stable, and the second solution provides an environment for the coupling of the ruthenium main salt. Specifically, the ruthenium main salt can be first dissolved with the aforementioned second solution, then heated for a period of time, and then cooled, that is, the heat treatment can include heating first and then cooling treatment, or it can only be heated to a predetermined temperature. The inventors found that the above-mentioned heat treatment is beneficial to improving the coupling efficiency of the ruthenium main salt and the second solution. It should be noted that the heating temperature and time, as well as the cooling range can be selected by those skilled in the art according to actual process needs, such as the heating temperature can be 50-60 degrees Celsius, the time can be 10-20 minutes, and the cooling can be reduced by 5-15 degrees Celsius, etc.

[0059] S400: Mix the second antioxidant with the third solution, and select a third pH stabilizer as needed to adjust the pH of the solution and stabilize it to a predetermined value

[0060] In this step, the second antioxidant is mixed with the third solution, and the third pH stabilizer is selected as needed to adjust the pH of the solution and stabilize it to a predetermined value to obtain a ruthenium plating solution. The inventors found that the process of adding the third pH stabilizer to adjust the pH of the solution to a predetermined value as needed makes it very convenient to adjust the pH value, and the pH value of the solution can be easily controlled, and under the joint action of the first pH stabilizer, the second pH stabilizer and the optional third pH stabilizer, the ruthenium plating solution can form a pH stabilization system. It should be noted that the second antioxidant selects the aforementioned antioxidant. When the third pH stabilizer is selected to adjust the pH of the solution, a portable precision acidometer can be used for adjustment, such as the Shanghai Sanxin brand PHB-3 acidometer. The pH value is first calibrated to 7.0 before use, and then calibrated with a pH4.0 standard solution.

[0061] According to the method for preparing the above-mentioned ruthenium plating solution in an embodiment of the present invention, after the first pH stabilizer is prepared to obtain the first solution, the conductive salt, the second pH stabilizer, and the first antioxidant are mixed therewith, which can improve the mixing uniformity of the components and is beneficial to improving the system stability of the ruthenium plating solution; by mixing the ruthenium main salt with the second solution and performing a heat treatment, the ruthenium main salt itself is a complex and is relatively stable, and the second solution provides an environment for the coupling of the ruthenium main salt, and the heat treatment can improve the coupling efficiency of the ruthenium main salt and the second solution; finally, the second antioxidant is mixed with the third solution, and the third pH stabilizer is selected as needed to adjust the pH of the solution and stabilize it to a predetermined value, so that the pH value of the solution can be conveniently controlled, and under the joint action of the first pH stabilizer, the second pH stabilizer and the optional third pH stabilizer, the ruthenium plating solution can form a pH stable system. It can be seen that the ruthenium plating solution system is stable, has low corrosion to equipment, has low requirements for ambient temperature during preparation, has good positioning and plating efficiency during electroplating, can adapt to processes such as rack plating, barrel plating or rocking plating, and the surface quality of the obtained ruthenium coating meets industrial requirements.

[0062] In another aspect of the present invention, the present invention proposes a ruthenium plating method. According to an embodiment of the present invention, the ruthenium plating method adopts the above-mentioned ruthenium plating solution or the ruthenium plating solution prepared by the above-mentioned method for preparing the ruthenium plating solution to plate ruthenium. According to the ruthenium plating method of the embodiment of the present invention, the method adopts the above-mentioned ruthenium plating solution or the ruthenium plating solution prepared by the above-mentioned method for preparing the ruthenium plating solution to plate ruthenium. The ruthenium plating solution system is stable and has weak corrosion to the equipment. The environmental temperature requirement during preparation is low. It has good positioning and plating efficiency during electroplating, can adapt to processes such as hanging plating, roller plating or shaking plating, and the surface quality of the obtained ruthenium coating meets the requirements of industrialization. A ruthenium coating that meets the requirements of appearance and surface quality can be obtained, and even the production and application of white ruthenium, which has been unable to be broken through in the industry, can be realized.

[0063] According to one embodiment of the present invention, the current scale Dk during ruthenium plating can be 0-6A / dm 2 , such as 0.05-2.5A / dm 2 , or 1.5-6A / dm 2 , or 0.3-3A / dm 2 , or 0.6-4A / dm 2 The inventors found that by adjusting the current scale during ruthenium plating, ruthenium coatings with different color (measured by Pantone color card) can be obtained. For example, when plating white ruthenium (i.e. silver-gray bright ruthenium), the current scale Dk can be adjusted to 0.05-2.5A / dm 2 When plated with gunmetal ruthenium and black ruthenium, i.e. gunmetal black bright ruthenium, the current scale Dk can be adjusted to 1.5-6A / dm 2It is found in practice that after pre-plating nickel, gold and platinum on the Hastelloy slot, ruthenium is plated, according to a specific example of the present invention, Dk is 0-0.6A / dm 2 When a uniform light silver gray (yellow-white halo) ruthenium coating is obtained; according to another specific example of the present invention, Dk is 0.6-4A / dm 2 When the ruthenium plating layer is light silver gray (yellow-white halo)-light yellow-yellow-yellow-brown-yellow-brown, a ruthenium plating layer can be obtained; according to another specific example of the present invention, Dk is not less than 2A / dm 2 When the ruthenium coating is full and uniform, a gun black ruthenium coating can be obtained; according to another specific example of the present invention, Dk is 0.05-2.5A / dm 2 When , a silver-grey bright ruthenium coating can be obtained.

[0064] According to another embodiment of the present invention, the temperature of the ruthenium plating solution during ruthenium plating can be 50-60 degrees Celsius, the pH value can be 1.4-4.5, preferably 1.4-1.6, and the anode can be an insoluble electrode plate, such as ruthenium iridium mesh, platinum-coated titanium mesh, high-density graphite plate (PP filter cloth bag wrapped graphite), etc.

[0065] According to another embodiment of the present invention, the ruthenium plating method has a ruthenium efficiency of 60-90%. The inventors found that when the ruthenium plating solution of the present application or the ruthenium plating solution prepared by the method for preparing the ruthenium plating solution of the present application is used for ruthenium plating, the ruthenium plating efficiency is high and the economy is significant. In particular, compared with the platinum plating efficiency of DNS platinum salt plating of 28% in the platinum plating process, the ruthenium plating efficiency is significantly improved.

[0066] In another aspect of the present invention, the present invention proposes a ruthenium coating. According to an embodiment of the present invention, the ruthenium coating is a ruthenium coating prepared by the above-mentioned ruthenium plating method. The ruthenium coating has extremely high stability and reliability, does not have a rough grain appearance, has fine crystals, and has no gold layer corrosion phase. It is a bright and flat coating with good decorativeness, corrosion resistance and hardness. At the same time, it has black ruthenium, gun-colored ruthenium, white ruthenium and other chromaticities to choose from, which is conducive to expanding the application field of ruthenium coating. Precision industry (especially the hub centerpieces of electronic products such as connectors) parts have requirements for reliability, conductivity, uniformity, hardness and weldability of the coating; the production of the corresponding product must be dead angle, so roller plating is often used for manufacturing; the plating solution of the coating has high requirements, the plating solution must be excellent, and a small current range is required to meet the movement, and the obtained coating color is full and uniform. According to a large number of experiments in the present application, it is found that the ruthenium coating of the present application can well meet the above requirements.

[0067] According to one embodiment of the present invention, the surface roughness Ra of the ruthenium coating can be as low as 0.05 mm or less.

[0068] According to another embodiment of the present invention, the ruthenium coating can be used to replace the platinum coating. The inventors found that the ruthenium coating of the present application can replace the precious metal platinum electroplating layer used for corrosion protection in precision industrial fields (such as connecting terminals, etc.) or its fields, the HV of ruthenium ≥ 600, and the HV of platinum = 400; and platinum is more expensive than ruthenium (on December 27, 2021, the price of platinum is 210; the price of ruthenium is 110); further, as described in the background technology section, the platinum coating and its preparation process also have various problems, so the research on the ruthenium coating that can replace the platinum coating has good economy and applicability. The ruthenium coating is developed along with the nickel-free process. The ruthenium coating in the present application itself is nickel-free and can be well used in the field of nickel-free process, but it is not limited to the application to the nickel-free process, and can also be used in nickel-containing processes. For example, the common design process of smart wearable nickel-free product technology is "base copper plating-white copper tin plating / silver plating-gold plating-platinum plating" or "base copper plating-white copper tin plating / silver plating-gold plating-ruthenium plating". The ruthenium process without considering nickel release can be: nickel plating-gold plating-ruthenium plating / / nickel plating-PNP plating-pre-gold plating-ruthenium plating. At the same time, the ruthenium plating can achieve platinum replacement and quality assurance that is conducive to industrialization (scale).

[0069] It should be noted that the Q salt in the present application is a hydrogen phosphate (complex) platinum salt, and the P salt is a platinum-containing salt commonly used in the jewelry platinum plating industry.

[0070] In another aspect of the present invention, the present invention provides a device, and according to an embodiment of the present invention, the device has the above-mentioned ruthenium coating. The inventors have found that the above-mentioned device can be a decorative part, a precision device (such as a connecting terminal), an anti-corrosion part, an industrial bottleneck part, etc., and if there are requirements for appearance, anti-corrosion performance or processing technology, the ruthenium plating solution of the present application can be considered, or the method of plating ruthenium using the ruthenium plating solution of the present application can be used to add the above-mentioned ruthenium coating of the present application to the device.

[0071] The present invention is described below with reference to specific embodiments. It should be noted that these embodiments are merely illustrative and do not limit the present invention in any way.

[0072] Example 1 Ruthenium plating test of Hastelloy slot sheet 1 (after pre-plating nickel-gold-platinum)

[0073] A Hastelloy slot sheet that has been pre-plated with nickel, gold, and platinum is taken. The entire sheet is bright and white, and the bonding strength between the layers is excellent. After activation with 10% V / v sulfuric acid and washing with water, ruthenium plating is performed on the platinum layer. The formula of the ruthenium plating solution used is:

[0074] Ruthenium main salt: u-nitrogen-bis(tetrachloro)-ruthenate potassium monohydrate (selected from Kunming Guiyan Platinum Research Institute) 15.0-15.8 g / L (including 4.8-5 g / L of ruthenium metal);

[0075] pH stabilizer: boric acid 30-32g / L, ammonium acetate 24g / L, KH 2 PO 4 100g / L and appropriate amount of phosphoric acid;

[0076] Conductive salt: potassium sulfate 60g / L;

[0077] Antioxidant: sodium formate 12g / L, hydroxylamine sulfate 10g / L;

[0078] The method for preparing a ruthenium plating solution is as follows: 50% volume of pure water is heated to 50 degrees Celsius, and the boric acid is dissolved; potassium sulfate, potassium dihydrogen phosphate, ammonium acetate, and sodium formate are then dissolved in the boric acid solution (a small amount of pure water is added when the solution is insufficient); the ruthenium main salt (red powder) is then dissolved; the solution is then heated at 50 degrees Celsius for about 15 minutes to form a uniform solution, and then the solution is cooled appropriately; hydroxylamine sulfate is then added to dissolve, and finally the pH value of the solution is adjusted to 1.5 using pure phosphoric acid (density d=1.69).

[0079] The ruthenium plating conditions are: the ruthenium plating solution temperature is 55 degrees Celsius, and the electroplating is carried out for 3 minutes at a current intensity of 1A.

[0080] Result: Current scale Dk is 0-0.6A / dm 2 The ruthenium coating in the area is light silver gray (yellow-white halo; uniform) and reaches the color of Pantone 420C; at 0.6-4A / dm 2 The regional ruthenium plating is light silver gray (yellow-white) - light yellow - yellow - yellow-brown - yellow-brown, the appearance test is excellent, and the bonding strength of the ruthenium-plated test piece is qualified.

[0081] Example 2 Ruthenium Plating Test on Hastelloy Groove Plate 2 (Pre-plated with Nickel-Gold-Platinum)

[0082] A Hastelloy slot sheet that has been pre-plated with nickel, gold, and platinum is taken. The entire sheet is bright and white, and the bonding strength between the layers is excellent. After activation with 10% V / v sulfuric acid and washing with water, ruthenium plating is performed on the platinum layer. The formula of the ruthenium plating solution used is:

[0083] Ruthenium main salt: u-nitrogen-bis(tetrachloro)-ruthenate potassium monohydrate (selected from Kunming Guiyan Platinum Research Institute) 15.0-15.8 g / L (including 4.8-5 g / L of ruthenium metal);

[0084] pH stabilizer: boric acid 30-32g / L, ammonium acetate 24g / L, KH 2 PO 4 100g / L and appropriate amount of phosphoric acid;

[0085] Conductive salt: potassium sulfate 60g / L;

[0086] Antioxidant: sodium formate 12g / L, hydroxylamine sulfate 20g / L;

[0087] The method for preparing ruthenium plating solution is as follows: 50% volume of pure water is heated to 50 degrees Celsius, and then boric acid is dissolved; potassium sulfate, potassium dihydrogen phosphate, ammonium acetate, and sodium formate are then dissolved in the boric acid solution (a small amount of pure water is added when the solution is insufficient); then the ruthenium main salt (red powder) is dissolved; then the solution is heated at 50 degrees Celsius for about 15 minutes to form a uniform solution; then hydroxylamine sulfate is added to dissolve, and finally the pH value of the solution is adjusted to 1.5 with pure phosphoric acid (density d=1.69).

[0088] The ruthenium plating conditions are: the ruthenium plating solution temperature is 55 degrees Celsius, and the electroplating is carried out for 3 minutes at a current intensity of 1A.

[0089] Result: Current diameter Dk is 1.5-6A / dm 2 The ruthenium coating in the area is gun black, and the color is full and uniform. Research has found that when the current scale is within this range, when the current scale is not less than 2A / dm 2 When the color is treated with ruthenium, it can reach the color of Pantone 447C, or even the darker Pantone 419C. The appearance test is excellent, and the bonding strength of the ruthenium-plated test piece is qualified.

[0090] Example 3 Ruthenium Plating Test on Hastelloy Groove Plate 3 (Pre-plated with Nickel-Gold-Platinum)

[0091] A Hastelloy slot sheet that has been pre-plated with nickel, gold, and platinum is taken. The entire sheet is bright and white, and the bonding strength between the layers is excellent. After activation with 10% V / v sulfuric acid and washing with water, ruthenium plating is performed on the platinum layer. The formula of the ruthenium plating solution used is:

[0092] Ruthenium main salt: u-nitrogen-bis(tetrachloro)-ruthenate potassium monohydrate (selected from Kunming Guiyan Platinum Research Institute) 15.0-15.8 g / L (including 4.8-5 g / L of ruthenium metal);

[0093] pH stabilizer: boric acid 30-32g / L, ammonium acetate 24g / L, KH 2 PO 4 100g / L and appropriate amount of phosphoric acid;

[0094] Conductive salt: potassium sulfate 60g / L;

[0095] Antioxidant: sodium formate 12g / L, hydroxylamine sulfate 30g / L;

[0096] The method for preparing a ruthenium plating solution is as follows: 50% volume of pure water is heated to 50 degrees Celsius, and the boric acid is dissolved; potassium sulfate, potassium dihydrogen phosphate, ammonium acetate, and sodium formate are then dissolved in the boric acid solution (a small amount of pure water is added when the solution is insufficient); the ruthenium main salt (red powder) is then dissolved; the solution is then heated at 50 degrees Celsius for about 15 minutes to form a uniform solution, and then the solution is cooled appropriately; hydroxylamine sulfate is then added to dissolve, and finally the pH value of the solution is adjusted to 1.5 using pure phosphoric acid (density d=1.69).

[0097] The ruthenium plating conditions are: the ruthenium plating solution temperature is 55 degrees Celsius, and the electroplating is carried out for 3 minutes at a current intensity of 1A.

[0098] Result: The current scale Dk is 0.5A / dm 2 The color of the ruthenium coating is Pantone 414C, and the current scale Dk is 1A / dm 2 The color of the ruthenium coating is Pantone 415C, and the current scale Dk is 1.5A / dm 2 The color of the ruthenium coating is Pantone 416C, and the current scale Dk is 2A / dm 2 The color of the ruthenium coating is Pantone 417C, the appearance test is excellent, and the bonding strength of the ruthenium-plated test piece is qualified.

[0099] Example 4 Ruthenium plating test of Hastelloy slot sheet 4 (after pre-plating nickel-gold-platinum)

[0100] A Hastelloy slot sheet that has been pre-plated with nickel, gold, and platinum is taken. The entire sheet is bright and white, and the bonding strength between the layers is excellent. After activation with 10% V / v sulfuric acid and washing with water, ruthenium plating is performed on the platinum layer. The formula of the ruthenium plating solution used is:

[0101] Ruthenium main salt: u-nitrogen-bis(tetrachloro)-ruthenate potassium monohydrate (selected from Kunming Guiyan Platinum Research Institute) 15.0-15.8 g / L (including 4.8-5 g / L of ruthenium metal);

[0102] pH stabilizer: boric acid 30-32g / L, ammonium acetate 24g / L, KH 2 PO 4 100g / L and appropriate amount of phosphoric acid;

[0103] Conductive salt: potassium sulfate 60g / L;

[0104] Antioxidant: sodium formate 12g / L, hydroxylamine sulfate 50g / L;

[0105] The method for preparing a ruthenium plating solution is as follows: 50% volume of pure water is heated to 50 degrees Celsius, and the boric acid is dissolved; potassium sulfate, potassium dihydrogen phosphate, ammonium acetate, and sodium formate are then dissolved in the boric acid solution (a small amount of pure water is added when the solution is insufficient); the ruthenium main salt (red powder) is then dissolved; the solution is then heated at 50 degrees Celsius for about 15 minutes to form a uniform solution, and then the solution is cooled appropriately; hydroxylamine sulfate is then added to dissolve, and finally the pH value of the solution is adjusted to 1.5 using pure phosphoric acid (density d=1.69).

[0106] The ruthenium plating conditions are: the ruthenium plating solution temperature is 55 degrees Celsius, and the electroplating is carried out for 3 minutes at a current intensity of 1A.

[0107] Results: Current scale Dk is 0.05-2.5A / dm 2 The color of the ruthenium coating is Pantone 420C, the color is silver-gray, the appearance test is excellent, and the bonding strength of the ruthenium-plated test piece is qualified.

[0108] Example 5: Ruthenium electroplating with ruthenium-iridium mesh as anode in a 5L test tank

[0109] A copper alloy Pogopin needle was selected, and after rolling nickel plating 70-110 marks + gold plating 2.5 marks, silver-gray bright ruthenium (instead of platinum) was plated ≤10 marks. The ruthenium plating solution formula, preparation method and ruthenium plating conditions were consistent with those in Example 4.

[0110] Results: The quality is qualified, the appearance test is excellent and the bonding strength is qualified. This fully demonstrates that the ruthenium plating solution formula, preparation method and ruthenium plating method of the present application are very suitable for industrial application.

[0111] Comparative Example 1: Add 5 g / L thiourea

[0112] The conditions were the same as those in Example 4, except that 5 g / L thiourea was added. Thiourea is an antioxidant and also a chelating agent.

[0113] Result: The 0-3.5cm area on the test piece is bright light titanium gold (light champagne yellow), half the chromaticity of Pantone 1205; the 4.4-6cm area is bright titanium gold (champagne yellow), the chromaticity is Pantone 1205C; the area larger than 6cm is titanium yellow with brown, and the entire test piece is of no use.

[0114] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0115] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for preparing a ruthenium plating solution, characterized in that: The ruthenium plating solution comprises: a ruthenium main salt, a pH stabilizer, a conductive salt and an antioxidant; The ruthenium main salt is u-nitrogen-bis(tetrachloro)ruthenate potassium monohydrate; The pH stabilizer is selected from at least one of boric acid, acetate, potassium dihydrogen phosphate and phosphoric acid; The conductive salt is selected from at least one of potassium sulfate, potassium chloride and potassium phosphate; The antioxidant is selected from at least one of formaldehyde, vitamin C, hydroxylamine sulfate, hydroxylammonium hydrochloride and formates; The concentration ratio of the ruthenium main salt, the conductive salt and the antioxidant is (10-25): (40-80): (20-100); The concentration of ruthenium in the ruthenium main salt is 3-6 g / L; The concentration of the ruthenium main salt is 10-25 g / L; The concentration of the conductive salt is 40-80 g / L; The concentration of the antioxidant is 20-100 g / L; The pH value of the ruthenium plating solution is 1.4-4.5; The ruthenium plating solution is a silver-grey bright ruthenium plating solution or a gunmetal black bright ruthenium plating solution; Compared with Pantone color card version C, the color of the ruthenium plating solution is Pantone 414C, Pantone 415C, Pantone 416C, Pantone 417C, Pantone 419C, Pantone 420C or Pantone 447C; A method for preparing a ruthenium plating solution, comprising: Prepare a first pH stabilizer to obtain a first solution; Mixing the conductive salt, the second pH stabilizer, the first antioxidant and the first solution to obtain a second solution; The ruthenium main salt is mixed with the second solution and subjected to heat treatment to obtain a third solution; The second antioxidant is mixed with the third solution, and a third pH stabilizer is selected as needed to adjust the pH value of the solution and stabilize it to a predetermined value, to obtain the ruthenium plating solution; wherein the first pH stabilizer, the second pH stabilizer and the third pH stabilizer are selected from the pH stabilizers; the first antioxidant and the second antioxidant are selected from the antioxidants; The temperature of the first solution is 50-60 degrees Celsius; The heat treatment includes heating first and then cooling down.

2. A ruthenium plating method, characterized in that: The ruthenium plating method adopts the ruthenium plating solution prepared by the method of claim 1 to carry out ruthenium plating.

3. The method according to claim 2, characterized in that The current scale Dk during ruthenium plating is 0.05-6A / dm 2 ; The ruthenium plating efficiency of the ruthenium plating method is 60-90%.

4. A ruthenium coating, characterized in that: The ruthenium plating layer is prepared by the method according to claim 1.

5. The ruthenium coating according to claim 4, characterized in that The surface roughness Ra of the ruthenium coating can reach 0.05 mm or less; the ruthenium coating is used to replace the platinum coating.

6. A device, characterized in that The device has the ruthenium coating layer according to claim 4 or 5.

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