Cyanide-free copper plating electroplating solution as well as preparation method and application thereof

Abstract

The invention discloses cyanide-free copper plating electroplating liquid as well as a preparation method and application thereof, and belongs to the technical field of electroplating. The cyanide-free copper plating electroplating liquid is good in stability and high in electroplating current efficiency, an obtained plating layer is bright and flat, the binding force is good, the formula is simple, the cost is low, and the cyanide-free copper plating electroplating liquid is suitable for industrial production.

Description

Technical Field

[0001] The present application relates to a cyanide-free copper plating solution and a preparation method and application thereof, belonging to the technical field of electroplating. Background Art

[0002] In the traditional copper plating process, cyanide is often used as an additive. Although it can improve the bonding strength and glossiness of the coating, cyanide is a highly toxic substance and has environmental hazards. Therefore, the development of cyanide-free copper plating additives has gradually become the focus of research and application.

[0003] However, the existing cyanide-free copper plating solution has the following problems: the generated coating has poor brightness and low flatness; it will corrode the equipment during long-term use, increasing maintenance and replacement costs; the formula is relatively complex, requiring precise control of the proportion and concentration of each component, resulting in increased difficulty and cost in operation; the current efficiency is low and the electroplating speed is slow; the raw material cost and production process are relatively expensive, etc.

[0004] Therefore, there is an urgent need to develop a cyanide-free copper plating solution that can effectively improve the brightness and flatness of the copper plating layer, will not corrode the equipment, has a simple formula, low cost and high current efficiency. Summary of the invention

[0005] In view of the defects existing in the above-mentioned prior art, the present application provides a cyanide-free copper plating solution and a preparation method and application thereof. The cyanide-free copper plating solution has good stability, high electroplating current efficiency, the obtained coating is bright and smooth, has good bonding strength, and has a simple formula and low cost, and is suitable for industrial production.

[0006] According to one aspect of the present application, a cyanide-free copper plating solution is provided, wherein the cyanide-free copper plating solution comprises the following components by mass concentration:

[0007]

[0008]

[0009] Optionally, the mass concentration of cupric chloride is independently selected from any value among 10 g / L, 20 g / L, 30 g / L, 40 g / L, 50 g / L or a range value between any two of the above points.

[0010] Optionally, the mass concentration of p-methoxybenzaldehyde is independently selected from any value among 0.5g / L, 0.75g / L, 1g / L, 1.25g / L, 1.5g / L, 1.75g / L, 2g / L, 2.25g / L, 2.5g / L, 2.75g / L, 3g / L, or a range value between any two of the above points.

[0011] Optionally, the mass concentration of potassium salt is independently selected from any value among 2g / L, 3g / L, 4g / L, 5g / L, 6g / L or a range value between any two of the above points.

[0012] Optionally, the mass concentration of boric acid is independently selected from any value among 10g / L, 11g / L, 12g / L, 13g / L, 14g / L, 15g / L or a range value between any two of the above points.

[0013] Optionally, the mass concentration of the brightener is independently selected from any value among 0.5 g / L, 1 g / L, 1.5 g / L, 2 g / L or a range between any two of the above points.

[0014] Optionally, the mass concentration of the complexing agent is independently selected from any value of 40g / L, 50g / L, 60g / L, 70g / L, 80g / L, 90g / L, 100g / L, 110g / L, 120g / L, 130g / L, 140g / L or a range value between any two of the above points.

[0015] Optionally, the mass concentration of the leveling agent is independently selected from any value among 0.5 g / L, 1 g / L, 1.5 g / L, 2 g / L, or a range between any two of the above points.

[0016] Optionally, the potassium salt is selected from at least one of potassium chloride and potassium nitrate.

[0017] Optionally, the brightener is selected from at least one of thiourea, sodium methylenebisnaphthalene sulfonate, sodium benzene disulfonate, sodium polydisulfide propane sulfonate, and sodium phenyl disulfide propane sulfonate.

[0018] Optionally, the complexing agent is selected from at least one of potassium citrate, sodium citrate, potassium sodium tartrate, and disodium ethylenediaminetetraacetate.

[0019] Optionally, the leveling agent is selected from at least one of polyoxyethylene ether, polyethylene glycol, and sodium polyacrylate.

[0020] Optionally, the pH value of the cyanide-free copper plating solution is 9-10.

[0021] According to another aspect of the present application, a method for preparing a cyanide-free copper plating solution is provided, comprising the following steps:

[0022] S1: Add p-methoxybenzaldehyde, boric acid and a complexing agent to water and stir Ⅰ to prepare solution A;

[0023] S2: adding copper chloride, potassium salt, brightener and leveler to solution A, stirring Ⅱ, adjusting pH value, and preparing the cyanide-free copper plating solution.

[0024] Optionally, the temperature of the stirring I is 20-40°C.

[0025] Optionally, the stirring time I is 0.5 to 5 hours.

[0026] Optionally, the rotation speed of the stirring I is 100 to 300 r / min.

[0027] Optionally, the temperature of the stirring II is 30-60°C.

[0028] Optionally, the stirring time II is 2 to 6 hours.

[0029] Optionally, the rotation speed of the stirring II is 100 to 300 r / min.

[0030] Optionally, the pH regulator is selected from at least one of ammonia water, potassium hydroxide and sodium hydroxide.

[0031] According to another aspect of the present application, there is provided an application of the above-mentioned cyanide-free copper plating solution and the cyanide-free copper plating solution prepared by the above-mentioned preparation method in cyanide-free copper plating of zinc alloy.

[0032] The beneficial effects of this application include:

[0033] (1) The cyanide-free copper plating solution provided by the present application effectively improves the brightness of the coating by adding p-methoxybenzaldehyde. It has high compatibility, good stability of the plating solution, and the coating after electroplating is bright and smooth.

[0034] (2) The cyanide-free copper plating solution provided in this application can simplify the formula, reduce the difficulty of operation, will not corrode the equipment, and reduce the cost of labor, raw materials, maintenance, etc.

[0035] (3) The cyanide-free copper plating solution provided in the present application has high current efficiency, fast electroplating speed, and the coating has high brightness, uniformity and strong adhesion.

[0036] (4) The cyanide-free copper plating solution provided in the present application is cyanide-free and phosphorus-free, and the waste liquid treatment is simple. It is an environmentally friendly product and is suitable for large-scale industrial production. DETAILED DESCRIPTION

[0037] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0038] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0039] In the embodiment of the present application, the analysis method of copper in the plating solution is as follows:

[0040] 1) Pipette 5 mL of plating solution into a 250 mL conical flask, add 25 mL of water, and shake well;

[0041] 2) Add ammonium persulfate (NH 4 ) 2 S 2 O 8 3g, shake for a while, add 10mL of 1:1 ammonia water, the solution is clear dark blue, add 60mL of water, shake well;

[0042] 3) Add 5-6 drops of PAN indicator, the solution turns purple-red;

[0043] 4) Titrate with 0.05M EDTA standard solution until the color changes from purple-red to yellow-green;

[0044] The calculation formula is Cu / g(1 / L)=0.635×V.

[0045] Example 1

[0046] S1: Add 2 g / L p-methoxybenzaldehyde, 15 g / L boric acid and 100 g / L complexing agent into water, stir at 150 r / min for 1 h at 20°C to prepare solution A;

[0047] S2: Add 10 g / L of copper chloride, 5 g / L of potassium salt, 0.5 g / L of brightener and 2 g / L of leveler to solution A, stir at 200 r / min at 30°C for 4 h, adjust the pH value to 9.5, and prepare a cyanide-free copper plating solution.

[0048] Example 2

[0049] S1: Add 0.5 g / L p-methoxybenzaldehyde, 15 g / L boric acid and 100 g / L complexing agent into water, stir at 150 r / min for 0.5 h at 25 °C to prepare solution A;

[0050] S2: Add 10 g / L of cupric chloride, 5 g / L of potassium salt, 0.5 g / L of brightener and 2 g / L of leveler to solution A, stir at 200 r / min at 30°C for 3 h, adjust the pH value to 9.5, and prepare a cyanide-free copper plating solution.

[0051] Example 3

[0052] S1: Add 3 g / L p-methoxybenzaldehyde, 15 g / L boric acid and 60 g / L complexing agent into water, stir at 150 r / min for 1 h at 20°C to prepare solution A;

[0053] S2: Add 10 g / L of copper chloride, 5 g / L of potassium salt, 1 g / L of brightener and 2 g / L of leveler to solution A, stir at 200 r / min at 30°C for 4 h, adjust the pH value to 9, and prepare a cyanide-free copper plating solution.

[0054] Example 4

[0055] S1: Add 1 g / L p-methoxybenzaldehyde, 15 g / L boric acid and 140 g / L complexing agent into water, stir at 100 r / min for 1 h at 30°C to prepare solution A;

[0056] S2: Add 12 g / L of copper chloride, 6 g / L of potassium salt, 2 g / L of brightener and 2 g / L of leveler to solution A, stir at 150 r / min at 35°C for 4 h, adjust the pH value to 10, and prepare a cyanide-free copper plating solution.

[0057] Comparative Example 1

[0058] S1: Add 15 g / L boric acid and 100 g / L complexing agent into water, stir at 150 r / min for 1 h at 20°C to prepare solution A;

[0059] S2: Add 10 g / L of copper chloride, 5 g / L of potassium salt, 0.5 g / L of brightener and 2 g / L of leveler to solution A, stir at 200 r / min at 30°C for 4 h, adjust the pH value to 9.5, and prepare a cyanide-free copper plating solution.

[0060] Comparative Example 2

[0061] S1: Add 10 g / L p-methoxybenzaldehyde, 15 g / L boric acid and 100 g / L complexing agent into water, stir at 150 r / min for 1 h at 20°C to prepare solution A;

[0062] S2: Add 10 g / L of copper chloride, 5 g / L of potassium salt, 0.5 g / L of brightener and 2 g / L of leveler to solution A, stir at 200 r / min at 30°C for 4 h, adjust the pH value to 9.5, and prepare a cyanide-free copper plating solution.

[0063] Test Example 1

[0064] The zinc alloy workpiece was subjected to cyanide-free copper plating using the cyanide-free copper plating solution prepared in Examples 1 to 4 and Comparative Examples 1 to 2. The electroplating conditions were as follows: the electroplating anode was oxygen-free electrolytic copper, the temperature was 30° C., the current density was 2 A / dm 2 The zinc alloy workpiece after electroplating was washed and dried to obtain a zinc alloy sample with cyanide-free copper plating.

[0065] Test Example 2

[0066] The quality evaluation test was conducted on the zinc alloy sample with cyanide-free copper plating prepared in Test Example 1. Under the same lighting conditions, the brightness of the coating was evaluated by visual brightness empirical evaluation method, and the morphology of the coating was detected under SEM electron microscope. The test results are shown in Table 1.

[0067] Among them, the reference standards for the classification of visual brightness experience evaluation method are as follows:

[0068] Level 1 (mirror finish): The coating surface is as bright as a mirror and can clearly reflect the facial features of the observer, including details such as facial features and eyebrows.

[0069] Level 2 (Bright): The surface is bright and the facial features can be clearly seen, but the details of the eyebrows may not be as clear as level 1.

[0070] Level 3 (semi-bright): The surface has a certain degree of brightness, but the outline of the face can still be recognized, but the details are not as obvious as the first two levels.

[0071] Level 4 (dull): The surface has almost no gloss, the facial contour cannot be seen through reflection, and it appears dull.

[0072] Table 1: Plating quality evaluation test results

[0073]

[0074] It can be seen from Table 1 that the coating obtained by electroplating with the cyanide-free copper plating solution provided by the present application has good brightness, a smooth and dense surface, and no pinholes or pits.

[0075] Test Example 3

[0076] The bonding strength test was performed on the cyanide-free copper-plated zinc alloy sample prepared in Test Example 1. The test results are shown in Table 2.

[0077] Table 2: Plating adhesion test results

[0078]

[0079] It can be seen from Table 2 that the coating obtained by electroplating with the cyanide-free copper plating solution provided by the present application has good bonding strength, and no peeling of the coating occurs after the bending test and the scratch test.

[0080] Unless otherwise specified, all numbers appearing in the specification and claims of this application, such as temperature and time values, should not be understood as absolutely precise values. Due to the standard deviation of the measurement technology, the measured values ​​inevitably have certain experimental errors.

[0081] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A cyanide-free copper plating solution, characterized in that The cyanide-free copper plating solution comprises the following components by mass concentration:

2. The cyanide-free copper plating solution according to claim 1, characterized in that The potassium salt is selected from at least one of potassium chloride and potassium nitrate.

3. The cyanide-free copper plating solution according to claim 1, characterized in that: The brightener is selected from at least one of thiourea, sodium methylene bisnaphthalene sulfonate, sodium benzene disulfonate, sodium polydisulfide propane sulfonate, and sodium phenyl disulfide propane sulfonate.

4. The cyanide-free copper plating solution according to claim 1, characterized in that The complexing agent is selected from at least one of potassium citrate, sodium citrate, potassium sodium tartrate, and disodium ethylenediaminetetraacetate.

5. The cyanide-free copper plating solution according to claim 1, characterized in that: The leveling agent is selected from at least one of polyoxyethylene ether, polyethylene glycol, and sodium polyacrylate.

6. The cyanide-free copper plating solution according to claim 1, characterized in that: The pH value of the cyanide-free copper plating solution is 9-10.

7. A method for preparing the cyanide-free copper plating solution according to any one of claims 1 to 6, characterized in that: include Follow these steps: S1: Add p-methoxybenzaldehyde, boric acid and a complexing agent to water and stir Ⅰ to prepare solution A; S2: adding copper chloride, potassium salt, brightener and leveler to solution A, stirring Ⅱ, adjusting pH value, and preparing the cyanide-free copper plating solution.

8. The preparation method according to claim 7, characterized in that: The temperature of the stirring I is 20 to 40°C; The stirring time of I is 0.5 to 5 hours; The rotation speed of the stirring I is 100-300 r / min; Preferably, the temperature of stirring II is 30-60°C; The stirring time of II is 2 to 6 hours; The rotation speed of the stirring II is 100-300 r / min.

9. The preparation method according to claim 7, characterized in that: The pH regulator is selected from at least one of ammonia water, potassium hydroxide and sodium hydroxide.

10. Use of the cyanide-free copper plating solution according to any one of claims 1 to 6 or the cyanide-free copper plating solution prepared by the preparation method according to any one of claims 7 to 9 in cyanide-free copper plating of zinc alloy.

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