Alkali copper electroplating solution and preparation method

Abstract

The invention discloses a novel alkaline copper electroplating solution and a preparation method, and the novel alkaline copper electroplating solution comprises the following components: 40-380g / L of copper sulfate, 50-410g / L of organic acid containing multiple-COOH groups and salts thereof, 65-380g / L of ammonium sulfate, 55-180ml / L of ammonia water, 2-20g / L of a surfactant and the balance of water. The electroplating solution has the following advantages: 1, the electroplating solution is prepared from non-toxic chemical materials, belongs to a cyanide-free electroplating formula, and is a clean production electroplating process; 2, the problem that pure iron and steel parts cannot be directly electroplated with copper is solved; 3, the solution is high in stability and durable; the solution composition is simple, and maintenance in the production process is convenient; and 5, the cost is low.

Description

Technical Field

[0001] The invention relates to the technical field of copper electroplating, in particular to an alkaline copper electroplating solution and a preparation method thereof. Background Art

[0002] The copper electroplating process is one of the widely used surface treatment processes. It is mostly used for pre-plating or intermediate layers. It can improve the bonding strength, corrosion resistance and appearance quality of the plating. It is an important component of the protective decorative copper / nickel / chromium system. Copper plating is also used as anti-carburizing plating, through-hole plating of printed circuit boards PCB, intermediate layers of plastic electroplating and other metallization treatments. In addition, the bright copper plating layer can be treated with other finishing treatments after chemical treatment to obtain a beautiful appearance for surface decoration. At present, the copper electroplating process is widely used in aerospace, electronics, automobiles, instrumentation, medical equipment and other industries, and the copper electroplating solution is the key to the copper electroplating process, which directly affects whether the process can be successfully implemented. Existing copper electroplating solutions and processes mainly include cyanide copper plating process, acid copper plating process and other copper electroplating processes. These copper electroplating processes have the following shortcomings:

[0003] 1. The cyanide copper electroplating process uses high concentrations of cyanide: cuprous cyanide CuCN and sodium cyanide NaCN, which are extremely toxic and difficult to manage. At the same time, the wastewater discharged during the production process is extremely polluting to the environment. The cyanide copper electroplating process is an obsolete process;

[0004] 2. Acid copper electroplating process is not suitable for direct copper electroplating of steel parts and pure iron parts, and requires pre-treatment - pre-plating;

[0005] 3. Other electroplating copper processes, such as organic phosphonic acid aminotri(methylenephosphonic acid) (ATMP), hydroxyethyldiphosphonic acid (HEDP), ethylenediaminetetra(methylenephosphonic acid) (DMP) and other electroplating copper processes, have problems such as poor solution stability and complex formula leading to unstable quality of electroplating copper process. Summary of the invention

[0006] The object of the present invention is to provide an alkaline copper electroplating solution and a preparation method thereof. The solution has a simple formula and high stability and can be used for directly electroplating metallic copper on the surface of steel parts, using organic acids containing multiple -COOH groups and their salts as complexes.

[0007] The technical solution of the present invention is an alkaline copper electroplating solution, which comprises the following components: 40-380 g / L of copper sulfate, 50-410 g / L of an organic acid containing multiple-COOH groups and its salt, 65-380 g / L of ammonium sulfate, 55-180 ml / L of ammonia water and 2-20 g / L of a surfactant, and the balance is water.

[0008] The invention comprises the following components: 140-280 g / L of copper sulfate, 150-310 g / L of organic acid containing multiple-COOH groups and its salt, 160-300 g / L of ammonium sulfate, 85-150 ml / L of ammonia water and 5-17 g / L of surfactant, and the balance is water.

[0009] The invention comprises the following components: 200-230 g / L of copper sulfate, 220-240 g / L of organic acid containing multiple-COOH groups and its salt, 225-255 g / L of ammonium sulfate, 130-140 ml / L of ammonia water and 10-12 g / L of surfactant, and the balance is water.

[0010] The surfactant is polyethylene glycol or triethanolamine.

[0011] The organic acid containing multiple -COOH groups and its salts are iminodiacetic acid, nitrilotriacetic acid or citric acid and its salts.

[0012] The organic acid containing multiple -COOH groups and its salt is iminodiacetic acid.

[0013] The preparation method of alkaline copper electroplating solution comprises the following specific steps:

[0014] S1. Clean the plating tank, add 1 / 3 to 1 / 2 volume of pure water, then add measured copper sulfate, and stir to completely dissolve it;

[0015] S2 Take another clean bucket, add an appropriate amount of pure water, then add a measured amount of organic acid containing multiple -COOH groups and its salt, stir to completely dissolve, and pour the solution into the plating tank;

[0016] S3 measures the amount of ammonium sulfate according to the operation method of S2, and after the ammonium sulfate is completely dissolved, the solution is poured into the plating tank;

[0017] S4 adds the measured surfactant into the plating tank solution and stirs;

[0018] S5 adds the measured ammonia water into the plating tank solution, replenishes the purified water according to the measured amount of the raw materials, and stirs evenly.

[0019] In S1, copper sulfate is dissolved by heating.

[0020] Beneficial effects of the present invention: In the present invention, the main functions of the components of the electroplating copper solution are: copper sulfate: the main salt of the electroplating copper solution, mainly providing Cu 2+ Ions; iminodiacetic acid: main complexing agent; ammonia water: auxiliary complexing agent; ammonium sulfate: conductive salt; polyethylene glycol: wetting agent. Compared with the prior art, the present invention has the following advantages:

[0021] 1. The new alkaline copper electroplating solution is made of non-toxic chemical materials and belongs to a cyanide-free electroplating formula, which is a clean production electroplating process;

[0022] 2. Solve the problem that pure iron and steel parts cannot be directly electroplated with copper;

[0023] 3. The solution is highly stable and durable;

[0024] 4. The solution composition is simple, which is convenient for production process maintenance;

[0025] 5. Low cost. DETAILED DESCRIPTION

[0026] The present invention will be further described below in conjunction with the embodiments, but they are not intended to limit the present invention.

[0027] Example 1. An alkaline copper electroplating solution comprises the following components: 40-380 g / L copper sulfate, 50-410 g / L poly-COOH group organic acid and its salt, 65-380 g / L ammonium sulfate, 55-180 ml / L ammonia water and 2-20 g / L surfactant, and the balance is water.

[0028] Better yet, it includes the following components: 140-280 g / L of copper sulfate, 150-310 g / L of poly-COOH group organic acid and its salt, 160-300 g / L of ammonium sulfate, 85-150 ml / L of ammonia water and 5-17 g / L of surfactant, with the balance being water.

[0029] Better yet, it includes the following components: 200-230 g / L of copper sulfate, 220-240 g / L of poly-COOH group organic acid and its salt, 225-255 g / L of ammonium sulfate, 130-140 ml / L of ammonia water and 10-12 g / L of surfactant, with the balance being water.

[0030] The surfactant is polyethylene glycol or triethanolamine.

[0031] The organic acid containing multiple -COOH groups and its salts are iminodiacetic acid, nitrilotriacetic acid or citric acid and its salts.

[0032] The preparation method of alkaline copper electroplating solution comprises the following specific steps:

[0033] S1. Clean the plating tank, add 1 / 3 to 1 / 2 volume of pure water, then add measured copper sulfate, and stir to completely dissolve it;

[0034] S2 Take another clean bucket, add an appropriate amount of pure water, then add a measured amount of organic acid containing multiple -COOH groups and its salt, stir to completely dissolve, and pour the solution into the plating tank;

[0035] S3 measures the amount of ammonium sulfate according to the operation method of S2, and after the ammonium sulfate is completely dissolved, the solution is poured into the plating tank;

[0036] S4 adds the measured surfactant into the plating tank solution and stirs;

[0037] S5 adds the measured ammonia water into the plating tank solution, replenishes the purified water according to the measured amount of the raw materials, and stirs evenly.

[0038] More preferably, in S1, copper sulfate is quickly dissolved by heating.

[0039] Example 2. An alkaline copper electroplating solution comprises the following components: 215 g / L copper sulfate, 230 g / L iminodiacetic acid, 240 g / L ammonium sulfate, 135 ml / L ammonia water and 11 g / L polyethylene glycol, with the balance being water.

[0040] Example 3. An alkaline copper electroplating solution comprises the following components: 255 g / L copper sulfate, 280 g / L nitrilotriacetic acid and its salt, 270 g / L ammonium sulfate, 145 ml / L ammonia water and 13 g / L polyethylene glycol, with the balance being water.

[0041] Example 4. An alkaline copper electroplating solution comprises the following components: 160 g / L copper sulfate, 120 g / L citric acid and its salt, 130 g / L ammonium sulfate, 80 ml / L ammonia water and 5 g / L polyethylene glycol, with the balance being water.

[0042] Example 5. An alkaline copper electroplating solution comprises the following components: 210 g / L copper sulfate, 220 g / L sodium iminodiacetic acid, 250 g / L ammonium sulfate, 125 ml / L ammonia water and 10 g / L polyethylene glycol, with the balance being water.

[0043] The applicant has conducted a large number of tests on the effect of the alkaline copper electroplating solution formulation, and some selected data are shown in Table 1.

[0044] The alkaline copper electroplating process and electroplating parameters of the experiment are as follows:

[0045] Chemical degreasing (45℃-60℃, 3min) → hot water rinsing → tap water rinsing → activation (room temperature, 0.5-1min) → tap water rinsing → primary pure water rinsing → secondary pure water rinsing → copper electroplating (25℃-50℃, 1.0A / dm 2 , electroplating time is set according to the copper plating thickness requirement) → recovery → tap water rinsing → first-level pure water rinsing → second-level pure water rinsing → passivation → tap water rinsing → pure water rinsing → drying (85℃-95℃, 10-20min) → inspection → storage.

[0046] If the parts are electroplated with copper as the base coating, the process flow is as follows:

[0047] Chemical degreasing (45℃-60℃, 3min) → hot water rinsing → tap water rinsing → activation (room temperature, 0.5-1min) → tap water rinsing → primary pure water rinsing → secondary pure water rinsing → copper electroplating (25℃-50℃, 1.0A / dm 2 , electroplating time is set according to the thickness requirement of copper plating layer) → recovery → tap water rinsing → activation → tap water rinsing → primary pure water rinsing → secondary pure water rinsing → electroplating other plating layers → ………

[0048] Table 1 Copper electroplating test results

[0049]

[0050] The alkaline copper electroplating effect of the present invention meets the production requirements, the plating solution has good stability, and the current density range is 0.5-1.5A / dm 2 , the best value is 1.0A / dm 2 .

[0051] The production effects obtained through the above experimental results show that pure iron and steel parts can be directly electroplated with copper without the need for pre-copper plating; the solution has high stability; the solution composition is simple; the solution composition materials are made of non-toxic chemical materials, which is cyanide-free electroplating and a clean production electroplating process.

Claims

1. An alkaline copper electroplating solution, characterized in that: The invention comprises the following components: 40-380 g / L of copper sulfate, 50-410 g / L of organic acid containing multiple-COOH groups and its salt, 65-380 g / L of ammonium sulfate, 55-180 ml / L of ammonia water and 2-20 g / L of surfactant, and the balance is water.

2. The alkaline copper electroplating solution according to claim 1, characterized in that: The invention comprises the following components: 140-280 g / L of copper sulfate, 150-310 g / L of organic acid containing multiple-COOH groups and its salt, 160-300 g / L of ammonium sulfate, 85-150 ml / L of ammonia water and 5-17 g / L of surfactant, and the balance is water.

3. The alkaline copper electroplating solution according to claim 2, characterized in that: The invention comprises the following components: 200-230 g / L of copper sulfate, 220-240 g / L of organic acid containing multiple-COOH groups and its salt, 225-255 g / L of ammonium sulfate, 130-140 ml / L of ammonia water and 10-12 g / L of surfactant, and the balance is water.

4. The alkaline copper electroplating solution according to any one of claims 1 to 3, characterized in that: The surfactant is polyethylene glycol or triethanolamine.

5. The alkaline copper electroplating solution according to any one of claims 1 to 3, characterized in that: The organic acid containing multiple -COOH groups and its salts are iminodiacetic acid, nitrilotriacetic acid or citric acid and its salts.

6. The alkaline copper electroplating solution according to claim 5, characterized in that: The organic acid containing multiple -COOH groups and its salt is iminodiacetic acid.

7. The method for preparing an alkaline copper electroplating solution according to any one of claims 1 to 6, characterized in that: The specific steps are as follows: S1. Clean the plating tank, add 1 / 3 to 1 / 2 volume of pure water, then add measured copper sulfate, and stir to completely dissolve it; S2 Take another clean bucket, add an appropriate amount of pure water, then add a measured amount of organic acid containing multiple -COOH groups and its salt, stir to completely dissolve, and pour the solution into the plating tank; S3 measures the amount of ammonium sulfate according to the operation method of S2, and after the ammonium sulfate is completely dissolved, the solution is poured into the plating tank; S4 adds the measured surfactant into the plating tank solution and stirs; S5 adds the measured ammonia water into the plating tank solution, replenishes the purified water according to the measured amount of the raw materials, and stirs evenly.

8. The method for preparing an alkaline copper electroplating solution according to claim 7, characterized in that: In S1, copper sulfate is dissolved by heating.

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