Accelerator for alkaline platinum plating

Abstract

The invention belongs to the technical field of electroplating, and discloses an accelerant for alkaline platinum plating, the accelerant consists of N-methyl o-phenylenediamine hydrochloride and 1H-indazole-3-carboxylic acid, and the mass ratio of the N-methyl o-phenylenediamine hydrochloride to the 1H-indazole-3-carboxylic acid is 1: (1-2). And the concentration of the N-methyl o-phenylenediamine hydrochloride in the alkaline platinum plating solution is 0.01-0.1 g / L according to the mass concentration. And the concentration of the 1H-indazole-3-carboxylic acid in the alkaline platinum plating solution is 0.01-0.2 g / L according to the mass concentration of the 1H-indazole-3-carboxylic acid. When the accelerant is added into the alkaline platinum plating solution for use, the plating solution can reach the same current efficiency of 95-100 DEG C at the medium temperature of 60-80 DEG C, and meanwhile, an obtained platinum plating layer is uniform, fine and compact. And the consumption of high-temperature energy can be effectively reduced, and a severe working environment caused by volatilization of high-temperature ammonia water can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of electroplating, and in particular to an accelerator for alkaline platinum plating. Background Art

[0002] Alkaline platinum plating is a platinum plating process that uses "P salt" as the main salt, ammonium nitrate as the conductive salt, sodium nitrite as the stabilizer, and ammonia water to stabilize the pH value. The coating obtained by this process has the characteristics of high hardness, low resistance, high purity, uniform distribution of the coating, and weldability. It can be used for platinum plating on the surfaces of electronic components, corrosion-resistant devices, electrochemical devices, turbine blades, etc.

[0003] However, there are some problems in the actual use of alkaline platinum plating. The main problems are: 1. Low current efficiency. The current efficiency of alkaline platinum plating is usually 15-25%; 2. The temperature of the plating solution is high. The process temperature is generally controlled at 95℃~100℃. When the temperature drops from 90℃ to 80℃, the current efficiency will drop sharply, from the original 20% to about 10%, and the coating will appear black and rough. 3. A large amount of ammonia water is needed during the electroplating process to maintain the pH value of the plating solution between 9 and 10. Because the temperature of the plating solution is high, the ammonia water is easy to volatilize, resulting in a large amount of pungent odor in the environment. The existence of the above problems has also limited the use of alkaline platinum plating to a certain extent. Compared with alkaline platinum plating, acid platinum plating has a low working temperature, high current efficiency, and a very bright and dense coating. It is widely used in jewelry electroplating or some electronic devices. However, the high temperature resistance and dispersion ability of the acid platinum plating layer are worse than those of the alkaline platinum plating layer. The coating contains impurity elements such as sulfur, and some aspects do not meet the performance requirements of the platinum plating layer. Therefore, people hope to obtain an alkaline platinum plating process with high current efficiency and good coating state under medium temperature conditions. Summary of the invention

[0004] Based on the problems existing in the background technology, the present invention provides an accelerator for alkaline platinum plating to improve the current efficiency of alkaline platinum plating.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] An accelerator for alkaline platinum plating comprises N-methyl o-phenylenediamine hydrochloride and 1H-indazole-3-carboxylic acid.

[0007] Furthermore, the accelerator has a mass ratio of N-methyl o-phenylenediamine hydrochloride to 1H-indazole-3-carboxylic acid of 1:1-2.

[0008] Furthermore, the concentration of N-methyl-o-phenylenediamine hydrochloride in a conventional alkaline platinum plating solution is 0.01 to 0.1 g / L in terms of mass concentration.

[0009] Furthermore, the concentration of 1H-indazole-3-carboxylic acid in a conventional alkaline platinum plating solution is 0.01 to 0.2 g / L by mass concentration.

[0010] Any of the above alkaline platinum plating accelerators is used in an alkaline platinum plating solution.

[0011] Principle and beneficial effects of the technical solution: The alkaline platinum plating accelerator of the present invention can effectively improve the current efficiency of alkaline platinum plating and improve the state of the coating. When the plating solution is at 60-80°C, after adding the accelerator, the current efficiency can be increased to 20-30%, and the coating is uniform, fine and dense, without blackening and coarseness, which fully meets the use requirements. Since the rich electron cloud on the benzene ring in N-methyl o-phenylenediamine hydrochloride is more easily adsorbed on the electrode, and the structure of the amine can attract platinum ions to form coordination, it is easier for platinum ions to reach the electrode surface for discharge. The special heterocyclic chemical structure of 1H-indazole-3-carboxylic acid can make the hydrogen evolution potential of platinum more negative, effectively inhibiting the generation of hydrogen evolution, thereby achieving the purpose of improving the current efficiency. Because of the influence of the heterocyclic ring on the electrode surface, platinum can be arranged in a directional manner during discharge deposition, so that the coating is uniform, fine and dense. DETAILED DESCRIPTION

[0012] The present invention will be further described in detail below in conjunction with specific embodiments, which is helpful for a better understanding of the present invention and its advantages and effects, but the embodiments are only used to illustrate the present invention rather than to limit the present invention.

[0013] The following are the methods for testing coating performance:

[0014] 1. Appearance inspection: The appearance should be inspected visually under a natural scattered light source or white projection light without reflected light. The test piece should be placed under a 40W fluorescent lamp at a distance of 1.2 to 1.5 meters from the object, and the eyes should be observed at a distance of 35±5cm from the part. The overall appearance of the test piece should be uniform and consistent, and the coating crystals should be fine, uniform and continuous without blackening or roughness.

[0015] 2. Deposition speed test: Use X-ray diffractometer to measure thickness. Place the fluorescent film thickness tester at the center of the test piece to test the thickness of the coating after 1 hour of plating, which is the deposition speed (μm / h).

[0016] Example 1

[0017] The mass concentration ratio of each component of the alkaline platinum plating accelerator in this embodiment is as follows:

[0018] Methyl o-phenylenediamine hydrochloride 0.02g / L

[0019] 1H-Indazole-3-carboxylic acid 0.02 g / L

[0020] The alkaline platinum plating accelerator of this embodiment can be obtained by mixing the above components.

[0021] Platinum plating is performed by adding an accelerator to a conventional alkaline platinum plating solution at medium temperature. The concentration of the conventional alkaline platinum plating solution is as follows: 15 g / L nitrosodiamine platinum (P salt), 100 g / L ammonium nitrate, 100 g / L sodium nitrite, 50 mL / L ammonia water (28%); the above alkaline platinum plating accelerator is added to the conventional alkaline platinum plating solution. Process parameters: current density 1 A / dm 2 , temperature 75℃, pH value 9.5, anode to cathode area ratio greater than 2:1, electroplating time 1 hour. A nickel-based alloy specimen with a length of 50×10×1mm was selected for plating, and the coating was tested.

[0022] The specific test data results are shown in Table 1. The test results show that the coating of the entire test piece is uniform and delicate in a semi-bright state, without any blackening or roughness. The thickness of the coating deposited in 1 hour can reach about 4.1μm.

[0023] Table 1 Results of platinum plating solution with accelerator added in Example 1

[0024] Appearance Deposition rate (μm / h) Sample 1 Uniform and delicate semi-gloss state 4.11 Sample 2 Uniform and delicate semi-gloss state 4.12 Sample 3 Uniform and delicate semi-gloss state 4.06

[0025] Platinum was plated in a conventional alkaline platinum plating solution at medium temperature. The conventional alkaline platinum plating solution was used for electroplating under the same medium temperature process conditions (15 g / L nitrosodiamine platinum (P salt), 100 g / L ammonium nitrate, 100 g / L sodium nitrite, 50 mL / L ammonia water (28%)) and the same process parameter conditions: current density 1 A / dm 2 , temperature 75℃, pH value 9.5, the ratio of anode to cathode area is greater than 2:1, the electroplating time is 1 hour, a 50×10×1mm nickel-based alloy test piece is selected for plating, and the coating is tested.

[0026] The specific test data results are shown in Table 2. The test results show that the coating of the entire test piece is unevenly black and rough. The thickness of the coating deposited in 1 hour can reach about 1.2μm.

[0027] Table 2 Results obtained under conventional alkaline platinum plating solution medium temperature conditions

[0028] Appearance Deposition rate (μm / h) Sample 1 Uneven black, rough state 1.12 Sample 2 Uneven black, rough state 1.15 Sample 3 Uneven black, rough state 1.21

[0029] Conventional alkaline platinum plating solution (15 g / L nitrosodiamine platinum (P salt), 100 g / L ammonium nitrate, 100 g / L sodium nitrite, 50 mL / L ammonia water (28%)) is used for plating under high temperature process conditions: current density 1 A / dm 2 , temperature 95℃, pH value 9.5, the ratio of anode to cathode area is greater than 2:1, the electroplating time is 1 hour, a 50×10×1mm nickel-based alloy test piece is selected for plating, and the coating is tested.

[0030] The specific test data results are shown in Table 3. The test results show that the coating of the entire test piece is uniform and delicate in a semi-bright state, without any blackening or roughness. The thickness of the coating deposited in 1 hour can reach about 4.3μm.

[0031] Table 3 Results obtained under conventional alkaline platinum plating solution high temperature conditions

[0032] Appearance Deposition rate (μm / h) Sample 1 Uniform and delicate semi-gloss state 4.33 Sample 2 Uniform and delicate semi-gloss state 4.17 Sample 3 Uniform and delicate semi-gloss state 4.52

[0033] Example 2

[0034] The mass concentration ratio of each component of the alkaline platinum plating accelerator in this embodiment is as follows:

[0035] N-Methyl-o-phenylenediamine hydrochloride 0.02g / L

[0036] 1H-Indazole-3-carboxylic acid 0.04 g / L

[0037] The above components are mixed to obtain the alkaline platinum plating accelerator of this embodiment.

[0038] Platinum plating is performed by adding an accelerator to a conventional alkaline platinum plating solution at medium temperature. The concentration of the conventional alkaline platinum plating solution is as follows: 15 g / L nitrosodiamine platinum (P salt), 100 g / L ammonium nitrate, 100 g / L sodium nitrite, 50 mL / L ammonia water (28%); the above alkaline platinum plating accelerator is added to the conventional alkaline platinum plating solution. Process parameters: current density 1 A / dm 2 , temperature 75℃, pH value 9.5, anode to cathode area ratio greater than 2:1, electroplating time 1 hour. A 50×10×1mm nickel-based alloy test piece was selected for plating, and the coating was tested.

[0039] The specific test data results are shown in Table 4. The test results show that the coating of the entire test piece is uniform and delicate in a semi-bright state, without any blackening or roughness. The thickness of the coating deposited in 1 hour can reach about 4.7μm.

[0040] Table 4 Results of platinum plating solution with accelerator added in Example 2

[0041]

[0042]

[0043] Example 3

[0044] The mass concentration ratio of each component of the alkaline platinum plating accelerator in this embodiment is as follows:

[0045] N-Methyl-o-phenylenediamine hydrochloride 0.04g / L

[0046] 1H-Indazole-3-carboxylic acid 0.04 g / L

[0047] The above components are mixed to obtain the alkaline platinum plating accelerator of this embodiment.

[0048] Platinum plating is performed by adding an accelerator to a conventional alkaline platinum plating solution at medium temperature. The concentration of the conventional alkaline platinum plating solution is as follows: 15 g / L nitrosodiamine platinum (P salt), 100 g / L ammonium nitrate, 100 g / L sodium nitrite, 50 mL / L ammonia water (28%); the above alkaline platinum plating accelerator is added to the conventional alkaline platinum plating solution. Process parameters: current density 1 A / dm 2 , temperature 75℃, pH value 9.5, anode to cathode area ratio greater than 2:1, electroplating time 1 hour. A 50×10×1mm nickel-based alloy test piece was selected for plating, and the coating was tested.

[0049] The specific test data results are shown in Table 5. The test results show that the coating of the entire test piece is uniform and delicate in a semi-bright state, without any blackening or roughness. The thickness of the coating deposited in 1 hour can reach about 4.7μm.

[0050] Table 5 Results of platinum plating solution with accelerator added in Example 3

[0051] Appearance Deposition rate (μm / h) Sample 1 Uniform and delicate semi-gloss state 4.87 Sample 2 Uniform and delicate semi-gloss state 4.39 Sample 3 Uniform and delicate semi-gloss state 4.73

[0052] Example 4

[0053] The mass concentration ratio of each component of the alkaline platinum plating accelerator in this embodiment is as follows:

[0054] N-Methyl-o-phenylenediamine hydrochloride 0.1g / L

[0055] 1H-Indazole-3-carboxylic acid 0.1g / L

[0056] The above components are mixed to obtain the alkaline platinum plating accelerator of this embodiment.

[0057] Platinum plating is performed by adding an accelerator to a conventional alkaline platinum plating solution at medium temperature. The concentration of the conventional alkaline platinum plating solution is as follows: 15 g / L nitrosodiamine platinum (P salt), 100 g / L ammonium nitrate, 100 g / L sodium nitrite, 50 mL / L ammonia water (28%); the above alkaline platinum plating accelerator is added to the conventional alkaline platinum plating solution. Process parameters: current density 1 A / dm 2 , temperature 75℃, pH value 9.5, anode to cathode area ratio greater than 2:1, electroplating time 1 hour. A 50×10×1mm nickel-based alloy test piece was selected for plating, and the coating was tested.

[0058] The specific test data results are shown in Table 6. The test results show that the coating of the entire test piece is uniform and delicate in a semi-bright state, without any blackening or roughness. The thickness of the coating deposited in 1 hour can reach about 4.5μm.

[0059] Table 6 Results of platinum plating solution with accelerator added in Example 4

[0060] Appearance Deposition rate (μm / h) Sample 1 Uniform and delicate semi-gloss state 4.52 Sample 2 Uniform and delicate semi-gloss state 4.21 Sample 3 Uniform and delicate semi-gloss state 4.76

[0061] Example 5

[0062] The mass concentration ratio of each component of the alkaline platinum plating accelerator in this embodiment is as follows:

[0063] N-Methyl-o-phenylenediamine hydrochloride 0.1g / L

[0064] 1H-Indazole-3-carboxylic acid 0.15 g / L

[0065] The above components are mixed to obtain the alkaline platinum plating accelerator of this embodiment.

[0066] Platinum plating is performed by adding an accelerator to a conventional alkaline platinum plating solution at medium temperature. The concentration of the conventional alkaline platinum plating solution is as follows: 15 g / L nitrosodiamine platinum (P salt), 100 g / L ammonium nitrate, 100 g / L sodium nitrite, 50 mL / L ammonia water (28%); the above alkaline platinum plating accelerator is added to the conventional alkaline platinum plating solution. Process parameters: current density 1 A / dm 2 , temperature 75℃, pH value 9.5, anode to cathode area ratio greater than 2:1, electroplating time 1 hour. A 50×10×1mm nickel-based alloy test piece was selected for plating, and the coating was tested.

[0067] The specific test data results are shown in Table 7. The test results show that the coating of the entire test piece is uniform and delicate in a semi-bright state, without any blackening or roughness. The thickness of the coating deposited in 1 hour can reach about 4.6μm.

[0068] Table 7 Results of platinum plating solution with accelerator added in Example 5

[0069]

[0070]

[0071] The above five embodiments further demonstrate that the addition of the accelerator for alkaline platinum plating of the present invention can enable the alkaline plating solution to achieve the same current efficiency under medium temperature conditions as under high temperature conditions, and the coating of the test piece is in a uniform and delicate semi-bright state without any blackening or roughness. The platinum plating accelerator of the present invention can effectively improve the current efficiency of alkaline platinum plating.

[0072] The above is only an embodiment of the present invention, and the common knowledge such as the known specific technical solutions or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the technical solution of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. An accelerator for alkaline platinum plating, characterized in that: The accelerator includes N-methyl o-phenylenediamine hydrochloride and 1H-indazole-3-carboxylic acid.

2. The accelerator for alkaline platinum plating according to claim 1, characterized in that: In terms of mass ratio, the ratio of N-methyl-o-phenylenediamine hydrochloride to 1H-indazole-3-carboxylic acid is 1:1-2.

3. The accelerator for alkaline platinum plating according to claim 1, characterized in that: The concentration of the N-methyl-o-phenylenediamine hydrochloride in a conventional alkaline platinum plating solution is 0.01-0.1 g / L in terms of mass concentration.

4. The accelerator for alkaline platinum plating according to claim 1, characterized in that: The concentration of the 1H-indazole-3-carboxylic acid in a conventional alkaline platinum plating solution is 0.01 to 0.2 g / L in terms of mass concentration.

5. The accelerator for alkaline platinum plating according to any one of claims 1 to 4, characterized in that: The accelerator is used in conventional alkaline platinum plating solution.

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