Cyanide-free cupronickel-tin electroplating solution and electroplating method

Abstract

The invention provides a cyanide-free cupronickel-tin electroplating solution and an electroplating method, and relates to the technical field of electroplating. The cyanide-free cupronickel tin electroplating solution comprises the following components: 20 to 50 g / L of copper sulfate, 10 to 30 g / L of stannous mono-sulphate, 90 to 110 g / L of sulfuric acid, 90 to 120 g / L of 3-mercapto-1-sodium propane sulfonate, 50 to 80 g / L of ammonium citrate, 10 to 20 g / L of carboxyethyl thiosuccinic acid, 0.02 to 0.05 g / L of polyepoxysuccinic acid, 0.1 to 0.3 g / L of thiomalic acid, 0.2 to 0.5 g / L of polyaspartic acid, 2 to 4 mL / L of PEG-5 disodium lauryl citrate sulfosuccinate and 1 to 2 mL / L of L-64 propylene glycol block polyether. By adding ammonium citrate, the plating solution can be clarified, by using carboxyethyl thiosuccinic acid, a plating layer can be finer, by using polyepoxysuccinic acid, plating solution precipitation and plating layer impurities can be reduced, by using the dispersion effect of L-64 propylene glycol block polyether, the surface tension is reduced, the plating layer is more uniform and smoother, and wetting of the plating solution on a complex workpiece is promoted.

Description

Technical Field

[0001] The invention relates to the technical field of electroplating, in particular to a cyanide-free white copper-tin electroplating solution and an electroplating method. Background Art

[0002] Electroplating is a technology that uses the principle of electrolysis to deposit a metal or alloy layer on a solid surface. It is mainly used to enhance the corrosion resistance, wear resistance, conductivity, and aesthetics of the material. During the electroplating process, redox reactions are mainly used to achieve electroplating. Among them, cyanide-free white copper-tin electroplating is mainly used to obtain silver-white or antique white copper-tin alloy coatings, which have excellent corrosion resistance, decorativeness and solderability.

[0003] The copper and tin salts currently used in electroplating solutions often incorporate a complexing agent, also known as a reducing agent, during the electroplating process. This agent reduces divalent copper to monovalent copper during dissolution, while also stabilizing monovalent copper and divalent tin ions. Insufficient complexing agent results in poor coating, yellowing, and turbidity in the plating solution. Excessive complexing agent results in slow deposition, thin coatings, and low current efficiency. Summary of the Invention

[0004] Technical problems solved In view of the deficiencies in the prior art, the present invention provides a cyanide-free white copper-tin electroplating solution and an electroplating method, which solve the problems raised in the background art.

[0005] Technical Solution To achieve the above objectives, the present invention is implemented through the following technical scheme: a cyanide-free white copper tin electroplating solution, comprising the following components: 20-50 g / L of copper sulfate, 10-30 g / L of stannous sulfate, 90-110 g / L of sulfuric acid, 90-120 g / L of sodium 3-mercapto-1-propanesulfonate, 50-80 g / L of ammonium citrate, 10-20 g / L of carboxyethyl thiosuccinic acid, 0.02-0.05 g / L of polyepoxysuccinic acid, 0.1-0.3 g / L of thiomalic acid, 0.2-0.5 g / L of polyaspartic acid, 2-4 mL / L of disodium PEG-5 lauryl citrate sulfosuccinate, and 1-2 mL / L of L-64 propylene glycol block polyether.

[0006] A cyanide-free copper-white tin electroplating method comprises the following specific steps: S1. First, sulfuric acid, complexing agent ammonium citrate, carboxyethyl thiosuccinic acid, and sodium 3-mercapto-1-propane sulfonate are dissolved in water in sequence, and then copper sulfate and stannous sulfate are added. Finally, additives such as polyepoxysuccinic acid, thiomalic acid, polyaspartic acid, PEG-5 lauryl citrate sulfosuccinate disodium, and L-64 propylene glycol block polyether are added and stirred evenly to obtain an electroplating solution, which is then placed in an electroplating tank. S2. Pre-treating the workpiece to be electroplated, the pre-treatment including degreasing-water washing-pickling-water washing-activation; S3, the workpiece to be electroplated is used as a cathode and the carbon plate is used as an anode, and then the cathode and anode are placed in the electroplating solution and energized to achieve electroplating, and the electroplating solution is always stirred during the electroplating process; S4. After the electroplating is completed, the electroplated workpiece is post-processed, and the post-processing includes water washing, purification, drying and inspection.

[0007] Preferably, after the electroplating solution is prepared in S1, the pH value of the electrolysis can be detected, and the pH value can be adjusted using sodium hydroxide and sulfuric acid to a pH value less than 1.

[0008] Preferably, the temperature of the electroplating solution during the electroplating process is 15-20°C.

[0009] Preferably, the cathode current density in S3 is 0.1-1.5A / dm 2 The electroplating method is barrel plating, the barrel plating speed is 6-10 revolutions per minute, and the electroplating time is 5-30 minutes.

[0010] Beneficial effects The present invention provides a cyanide-free copper-tin electroplating solution and electroplating method. It has the following beneficial effects: The present invention can clarify the plating solution by adding ammonium citrate, make the coating more delicate by using carboxyethyl thiosuccinic acid, reduce the precipitation of the plating solution and reduce the impurities in the coating, and reduce the surface tension by the dispersion effect of L-64 propylene glycol block polyether, so as to make the coating more uniform and smooth, and promote the wetting of the plating solution on complex workpieces. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a picture of the slider product after electroplating of the present invention; Figure 2 This is a scanning electron microscope image of the coating of the present invention; Figure 3 for Figure 2 Spectrum of mesoregion 25. DETAILED DESCRIPTION

[0012] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0013] Example 1: The embodiment of the present invention provides a cyanide-free white copper tin electroplating solution, comprising the following components: 20 g / L copper sulfate, 10 g / L stannous sulfate, 90 g / L sulfuric acid, 90 g / L sodium 3-mercapto-1-propanesulfonate, 50 g / L ammonium citrate, 10 g / L carboxyethyl sulfosuccinic acid, 0.02 g / L polyepoxysuccinic acid, 0.1 g / L thiomalic acid, 0.2 g / L polyaspartic acid, 2 mL / L disodium PEG-5 lauryl citrate sulfosuccinate, and 1 mL / L L-64 propylene glycol block polyether; The addition of ammonium citrate can clarify the plating solution, the use of carboxyethyl thiosuccinic acid can make the coating more delicate, the use of polyepoxysuccinic acid can reduce the precipitation of the plating solution and reduce the impurities in the coating, and the use of L-64 propylene glycol block polyether can disperse and reduce the surface tension, making the coating more uniform and smooth, and promoting the wetting of the plating solution on complex workpieces.

[0014] A cyanide-free copper-white tin electroplating method comprises the following specific steps: S1. First, sulfuric acid, complexing agent ammonium citrate, carboxyethyl thiosuccinic acid, and sodium 3-mercapto-1-propane sulfonate are dissolved in water in sequence, and then copper sulfate and stannous sulfate are added. Finally, additives such as polyepoxysuccinic acid, thiomalic acid, polyaspartic acid, PEG-5 lauryl citrate sulfosuccinate disodium, and L-64 propylene glycol block polyether are added and stirred evenly to obtain an electroplating solution, which is then placed in an electroplating tank. S2. Pre-treating the workpiece to be electroplated, the pre-treatment including degreasing-water washing-pickling-water washing-activation; S3, the workpiece to be electroplated is used as a cathode and the carbon plate is used as an anode, and then the cathode and anode are placed in the electroplating solution and energized to achieve electroplating, and the electroplating solution is always stirred during the electroplating process; S4. After the electroplating is completed, the electroplated workpiece is post-processed, and the post-processing includes water washing, purification, drying and inspection.

[0015] The pre-processing and post-processing in S2 and S4 are existing technologies and will not be described in detail here. They are mainly used to clean the electroplated workpiece.

[0016] After the plating solution in S1 is prepared, the pH value of the electrolysis can be tested, and sodium hydroxide and sulfuric acid are used to adjust the pH value to 0.8. The temperature of the plating solution during the electroplating process is 20°C, and the cathode current density in S3 is 1.5A / dm 2 The electroplating method is barrel plating, the barrel plating speed is 10 revolutions per minute, and the electroplating time is 25 minutes.

[0017] Example 2: The embodiment of the present invention provides a cyanide-free copper-white tin electroplating solution. Each liter of the cyanide-free copper-white tin electroplating solution includes the following components: 30 g / L of copper sulfate, 20 g / L of stannous sulfate, 100 g / L of sulfuric acid, 105 g / L of sodium 3-mercapto-1-propanesulfonate, 60 g / L of ammonium citrate, 15 g / L of carboxyethyl sulfosuccinic acid, 0.03 g / L of polyepoxysuccinic acid, 0.2 g / L of thiomalic acid, 0.4 g / L of polyaspartic acid, 3 mL / L of disodium PEG-5 lauryl citrate sulfosuccinate, and 1 mL / L of L-64 propylene glycol block polyether. A cyanide-free copper-white tin electroplating method comprises the following specific steps: S1. First, sulfuric acid, complexing agent ammonium citrate, carboxyethyl thiosuccinic acid, and sodium 3-mercapto-1-propane sulfonate are dissolved in water in sequence, and then copper sulfate and stannous sulfate are added. Finally, additives such as polyepoxysuccinic acid, thiomalic acid, polyaspartic acid, PEG-5 lauryl citrate sulfosuccinate disodium, and L-64 propylene glycol block polyether are added and stirred evenly to obtain an electroplating solution, which is then placed in an electroplating tank. S2. Pre-treating the workpiece to be electroplated, the pre-treatment including degreasing-water washing-pickling-water washing-activation; S3, the workpiece to be electroplated is used as a cathode and the carbon plate is used as an anode, and then the cathode and anode are placed in the electroplating solution and energized to achieve electroplating, and the electroplating solution is always stirred during the electroplating process; S4. After the electroplating is completed, the electroplated workpiece is post-processed, and the post-processing includes water washing, purification, drying and inspection.

[0018] After the plating solution in S1 is prepared, the pH value of the electrolysis can be tested, and sodium hydroxide and sulfuric acid are used to adjust the pH value to 0.8. The temperature of the plating solution during the electroplating process is 20°C, and the cathode current density in S3 is 1.5A / dm 2 The electroplating method is barrel plating, the barrel plating speed is 10 revolutions per minute, and the electroplating time is 25 minutes.

[0019] Example 3: The embodiment of the present invention provides a cyanide-free white copper tin electroplating solution, comprising the following components: 50 g / L copper sulfate, 30 g / L stannous sulfate, 110 g / L sulfuric acid, 120 g / L sodium 3-mercapto-1-propanesulfonate, 80 g / L ammonium citrate, 20 g / L carboxyethyl sulfosuccinic acid, 0.05 g / L polyepoxysuccinic acid, 0.3 g / L thiomalic acid, 0.5 g / L polyaspartic acid, 4 mL / L disodium PEG-5 lauryl citrate sulfosuccinate, and 2 mL / L L-64 propylene glycol block polyether; A cyanide-free copper-white tin electroplating method comprises the following specific steps: S1. First, sulfuric acid, complexing agent ammonium citrate, carboxyethyl thiosuccinic acid, and sodium 3-mercapto-1-propane sulfonate are dissolved in water in sequence, and then copper sulfate and stannous sulfate are added. Finally, additives such as polyepoxysuccinic acid, thiomalic acid, polyaspartic acid, PEG-5 lauryl citrate sulfosuccinate disodium, and L-64 propylene glycol block polyether are added and stirred evenly to obtain an electroplating solution, which is then placed in an electroplating tank. S2. Pre-treating the workpiece to be electroplated, the pre-treatment including degreasing-water washing-pickling-water washing-activation; S3, the workpiece to be electroplated is used as a cathode and the carbon plate is used as an anode, and then the cathode and anode are placed in the electroplating solution and energized to achieve electroplating, and the electroplating solution is always stirred during the electroplating process; S4. After the electroplating is completed, the electroplated workpiece is post-processed, and the post-processing includes water washing, purification, drying and inspection.

[0020] After the plating solution in S1 is prepared, the pH value of the electrolysis can be tested, and sodium hydroxide and sulfuric acid are used to adjust the pH value to 0.8. The temperature of the plating solution during the electroplating process is 20°C, and the cathode current density in S3 is 1.5A / dm 2 The electroplating method is barrel plating, the barrel plating speed is 10 revolutions per minute, and the electroplating time is 25 minutes.

[0021] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A cyanide-free copper-white tin electroplating solution, characterized in that: The invention comprises the following components: 20-50 g / L of copper sulfate, 10-30 g / L of stannous sulfate, 90-110 g / L of sulfuric acid, 90-120 g / L of sodium 3-mercapto-1-propane sulfonate, 50-80 g / L of ammonium citrate, 10-20 g / L of carboxyethyl sulfosuccinic acid, 0.02-0.05 g / L of polyepoxysuccinic acid, 0.1-0.3 g / L of thiomalic acid, 0.2-0.5 g / L of polyaspartic acid, 2-4 mL / L of disodium PEG-5 lauryl citrate sulfosuccinate and 1-2 mL / L of L-64 propylene glycol block polyether.

2. A cyanide-free copper-white tin electroplating method, comprising the cyanide-free copper-white tin electroplating solution according to claim 1, characterized in that: The specific steps include: S1. First, sulfuric acid, complexing agent ammonium citrate, carboxyethyl thiosuccinic acid, and sodium 3-mercapto-1-propane sulfonate are dissolved in water in sequence, and then copper sulfate and stannous sulfate are added. Finally, additives such as polyepoxysuccinic acid, thiomalic acid, polyaspartic acid, PEG-5 lauryl citrate sulfosuccinate disodium, and L-64 propylene glycol block polyether are added and stirred evenly to obtain an electroplating solution, which is then placed in an electroplating tank. S2. Pre-treating the workpiece to be electroplated, the pre-treatment including degreasing-water washing-pickling-water washing-activation; S3, the workpiece to be electroplated is used as a cathode and the carbon plate is used as an anode, and then the cathode and anode are placed in the electroplating solution and energized to achieve electroplating, and the electroplating solution is always stirred during the electroplating process; S4. After the electroplating is completed, the electroplated workpiece is post-processed, and the post-processing includes water washing, purification, drying and inspection.

3. A cyanide-free copper-white tin electroplating method according to claim 2, characterized in that: After the electroplating solution in S1 is prepared, the pH value of the electrolysis can be detected, and the pH value can be adjusted using sodium hydroxide and sulfuric acid to be less than 1.

4. A cyanide-free copper-white tin electroplating method according to claim 2, characterized in that: The temperature of the electroplating solution during the electroplating process is 15-20°C.

5. A cyanide-free copper-white tin electroplating method according to claim 2, characterized in that: The cathode current density in S3 is 0.1-1.5A / dm 2 The electroplating method is barrel plating, the barrel plating speed is 6-10 revolutions per minute, and the electroplating time is 5-30 minutes.

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