阅读说明：本技术 一种无氰镀铜锌合金晶粒细化剂及其应用 (Cyanide-free copper-zinc plated alloy grain refiner and application thereof ) 是由 胡国辉 段潇 李明刚 肖灵 肖春艳 刘阳 刘军 黄彬 于 2021-07-28 设计创作，主要内容包括：本发明涉及一种无氰镀铜锌合金晶粒细化剂,所述晶粒细化剂包括氨基乙醛缩二甲醇、N-甲基二乙醇胺、N,N’-硫羰基二咪唑；且三者在晶粒细化剂中的质量浓度分别为30-50g/L、3-5g/L和0.3～0.5g/L。本发明所述的晶粒细化剂简单、无毒,用量浓度较低,成本小等特点,适合于大量工业化生产。添加了本发明所述一种无氰镀铜锌合金晶粒细化剂的电镀液中可以在不改变原有镀层性能以及镀液的稳定性的基础上,大幅度提高镀层晶粒粒度,使镀层结晶更加细致,光亮,同时提高合金含量的均匀性,获得色泽均匀细致的金黄色镀层。(The invention relates to a cyanide-free copper-zinc alloy grain refiner, which comprises aminoacetaldehyde dimethyl acetal, N-methyldiethanolamine and N, N' -thiocarbonyl diimidazole; and the mass concentrations of the three components in the grain refiner are respectively 30-50g/L, 3-5g/L and 0.3-0.5 g/L. The grain refiner of the invention has the characteristics of simplicity, no toxicity, lower dosage concentration, low cost and the like, and is suitable for mass industrial production. The electroplating solution added with the cyanide-free copper-zinc alloy grain refiner can greatly improve the grain size of the plating layer on the basis of not changing the performance of the original plating layer and the stability of the electroplating solution, so that the plating layer is more delicate and bright in crystallization, the uniformity of the alloy content is improved, and a golden yellow plating layer with uniform and delicate color is obtained.)

1. The grain refiner for the cyanide-free copper-zinc alloy is characterized by consisting of aminoacetaldehyde dimethyl acetal, N-methyldiethanolamine and N, N' -thiocarbonyl diimidazole.

2. The grain refiner of claim 1, wherein the grain refiner comprises the following components by mass concentration: 30-50g/L, N-methyldiethanolamine 3-5g/L, N g/L aminoacetaldehyde dimethyl acetal, and 0.3-0.5 g/L N' -thiocarbonyldiimidazole.

3. A grain refiner according to claim 2, characterized in that the ratio of aminoacetaldehyde dimethyl acetal, N-methyldiethanolamine, N' -thiocarbonyldiimidazole is 100:10:1 by mass.

4. Use of a grain refiner as claimed in any one of claims 1 to 3 for the preparation of cyanide-free copper-zinc plated alloys.

5. The use as claimed in claim 4, wherein the grain refiner is added as a component of a cyanide-free copper-zinc alloy plating solution, and the concentration of each component of the grain refiner in the plating solution is as follows: 0.3-0.5 g/L, N g/L, N g/0.03-0.05 g/L, N g/L aminoacetaldehyde dimethyl acetal, and 0.003-0.005 g/L N' -thiocarbonyldiimidazole.

6. A cyanide-free copper-zinc alloy plating bath containing the grain refiner according to any one of claims 1 to 3, characterized in that the bath comprises the following components by mass:

7. the cyanide-free copper-zinc alloy plating solution according to claim 6, wherein the pH value of the plating solution is 11.2 to 11.6.

8. The cyanide-free copper-zinc alloy plating solution according to claim 6, wherein the plating process of the plating solution is as follows:

the electroplating temperature is 35-45 ℃, the electroplating time is 3-30 min, and the electroplating cathode current density is 0.3-1.0A/dm²The anode used for electroplating is a brass plate.

9. The cyanide-free copper-zinc alloy plating solution according to claim 8, wherein the mass ratio of copper to zinc in the brass plate is 68-70: 30-32.

10. The cyanide-free copper-zinc alloy plating solution according to claim 8, wherein the stirring mode during electroplating is cathode movement, and the movement speed is 3-10 m/min.

Technical Field

The invention belongs to the technical field of metal surface treatment, and relates to a cyanide-free copper-zinc alloy grain refiner and application thereof.

Background

The appearance of the copper-zinc alloy is bright and delicate golden yellow, is similar to gold and is gorgeous, the copper-zinc alloy electroplating is one of the plating species with larger consumption in the electroplating industry, the annual output value in the whole country is about 200 million yuan, and the copper-zinc alloy electroplating is widely applied to the industries of electronics, aviation, aerospace, light industry, rail transit, mechanical manufacturing and the like. The traditional copper-zinc alloy adopts a cyaniding electroplating process, and the total amount of cyanide consumed each year is up to 40 tons; cyanide is a highly toxic substance, has great safety risk in the links of transportation, storage, use, wastewater treatment and the like, is very easy to cause major safety accidents and severe environmental pollution accidents, and has great potential safety hazards and environmental protection pressure. In recent decades, cyanide-free copper-zinc plated alloys have been studied, but there are still several problems, such as coarse crystal appearance of the plating layer, dark color and luster, etc., which cannot reach the level of cyanide copper-zinc plated alloy plating layer, and thus cannot satisfy the large-scale application of industrial production, so we must greatly improve the grain size of the plating layer on the basis of not changing the original plating layer performance and the stability of the plating solution, so that the plating layer is more fine and bright in crystal, and meanwhile, the uniformity of the alloy content is improved, and a uniform and fine golden yellow plating layer is obtained. To meet the requirements in actual production.

Disclosure of Invention

In view of the above, the present invention aims to provide a grain refiner for simply and effectively refining cyanide-free copper-zinc plated alloy, which can improve the fineness of the plated grains, and also to provide applications thereof and a cyanide-free copper-zinc plated alloy plating solution containing the grain refiner.

In order to achieve the purpose, the invention provides the following technical scheme:

1. a grain refiner for cyanide-free copper-zinc alloy plating consists of aminoacetaldehyde dimethyl acetal, N-methyldiethanolamine and N, N' -thiocarbonyl diimidazole.

Further, the grain refiner comprises the following components in concentration by mass: 30-50g/L, N-methyldiethanolamine 3-5g/L, N g/L aminoacetaldehyde dimethyl acetal, and 0.3-0.5 g/L N' -thiocarbonyldiimidazole.

Further, the ratio of aminoacetaldehyde dimethyl acetal, N-methyldiethanolamine and N, N' -thiocarbonyl diimidazole in the grain refiner is 100:10:1 by mass ratio.

2. The application of the grain refiner in the preparation of cyanide-free copper-zinc plated alloy.

Further, the grain refiner is added as a component of the cyanide-free copper-zinc alloy electroplating solution, and the concentration of each component in the grain refiner is as follows: 0.3-0.5 g/L, N g/L, N g/0.03-0.05 g/L, N g/L aminoacetaldehyde dimethyl acetal, and 0.003-0.005 g/L N' -thiocarbonyldiimidazole.

3. The cyanide-free copper-zinc alloy plating solution containing a grain refiner comprises the following components in percentage by mass:

further, the pH value of the plating solution is 11.2-11.6.

Further, the electroplating process of the plating solution comprises the following steps:

the electroplating temperature is 35-45 ℃, the electroplating time is 3-30 min, and the electroplating cathode current density is 0.3-1.0A/dm²The anode used for electroplating is a brass plate.

Further, the mass ratio of copper to zinc in the brass plate is 60-70: 30-32.

Furthermore, the stirring mode during electroplating is cathode movement, and the moving speed is 3-10 m/min.

The invention has the beneficial effects that: the grain refiner is added into cyanide-free copper-zinc alloy electroplating solution, so that the grain size of a plating layer can be further greatly improved on the basis of not changing the performance of the original plating layer and the stability of the electroplating solution, the crystallization of the plating layer is finer and brighter, the level of a cyanide electroplating plating layer is reached, the cyanide copper-zinc alloy electroplating process can be completely replaced, and the purpose of protecting the environment is achieved. And furthermore, in the same time of electroplating, the electroplating speed is accelerated, the thickness of a coating is increased, and the electroplating efficiency is improved. So that the color of the gold-imitating plating layer is more vivid and bright. The grain refiner has the characteristics of environmental protection, no toxicity, lower dosage concentration, low use cost and the like, and is suitable for industrial production of electroplating. The N, N '-thiocarbonyl diimidazole can obviously improve the brightness of a cyanide-free copper-zinc plated layer, the aminoacetaldehyde dimethyl acetal can effectively improve the dissolution of the N, N' -thiocarbonyl diimidazole and simultaneously play a role in refining grains and improving the thickness of the plated layer, the N-methyldiethanolamine can improve the uniformity of the alloy content of the cyanide-free copper-zinc plated layer in a large radian, and the three components are compounded under proper concentration to ensure that an electroplated workpiece finally obtains a golden yellow plated layer with uniform and fine color.

Drawings

In order to make the object, technical scheme and beneficial effect of the invention more clear, the invention provides the following drawings for explanation:

FIG. 1 is a test chart of a sample of example 1, wherein A is an appearance chart of a cyanide-free copper-zinc alloy plated layer without adding a grain refiner of the present invention; b is an appearance diagram of the cyanide-free copper-zinc alloy plating layer added with the grain refiner.

FIG. 2 is a test chart of a sample of example 2, wherein A is an appearance chart of a cyanide-free copper-zinc alloy plated layer without the addition of the grain refiner of the present invention; b is an appearance diagram of the cyanide-free copper-zinc alloy plating layer added with the grain refiner.

FIG. 3 is a test chart of a sample of example 3, wherein A is an appearance chart of a cyanide-free copper-zinc alloy plated layer without the addition of the grain refiner of the present invention; b is an appearance diagram of the cyanide-free copper-zinc alloy plating layer added with the grain refiner.

FIG. 4 is a test chart of a sample of example 4, wherein A is an appearance chart of a cyanide-free copper-zinc alloy plated layer without the addition of the grain refiner of the present invention; b is an appearance diagram of the cyanide-free copper-zinc alloy plating layer added with the grain refiner.

FIG. 5 is the surface micro-topography of the sample of example 1, wherein A is the surface micro-topography of the non-cyanide copper-zinc alloy plating layer without the addition of the grain refiner of the present invention; b is the surface micro-morphology of the cyanide-free copper-zinc alloy plating layer added with the grain refiner.

FIG. 6 is the surface micro-topography of the sample of example 2, wherein A is the surface micro-topography of the non-cyanide copper-zinc alloy plating layer without the addition of the grain refiner of the present invention; b is the surface micro-morphology of the cyanide-free copper-zinc alloy plating layer added with the grain refiner.

FIG. 7 is the surface micro-topography of the sample of example 3, wherein A is the surface micro-topography of the non-cyanide copper-zinc alloy plating layer without the addition of the grain refiner of the present invention; b is the surface micro-morphology of the cyanide-free copper-zinc alloy plating layer added with the grain refiner.

FIG. 8 is the surface micro-topography of the sample of example 4, wherein A is the surface micro-topography of the non-cyanide copper-zinc alloy plating layer without the addition of the grain refiner of the present invention; b is the surface micro-morphology of the cyanide-free copper-zinc alloy plating layer added with the grain refiner.

Detailed Description

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The experimental procedures, in which specific conditions are not specified in the examples, are generally carried out under conventional conditions or under conditions recommended by the manufacturers.

A grain refiner, which comprises the following components by mass concentration:

30-50g/L, N-methyldiethanolamine 3-5g/L, N g/L aminoacetaldehyde dimethyl acetal, and 0.3-0.5 g/L N' -thiocarbonyldiimidazole.

Preferably, the composition comprises the following components in percentage by mass: 30-40 g/L, N g/3-4 g/L, N g/3-4 g/3-0.5 g/L aminoacetaldehyde dimethyl acetal.

Preferably, the ratio of aminoacetaldehyde dimethyl acetal, N-methyldiethanolamine and N, N' -thiocarbonyl diimidazole is 100:10:1 by mass ratio.

Example 1

1. The mass concentration ratio of each component of the grain refiner described in this embodiment is as follows:

aminoacetaldehyde dimethyl acetal 30g/L

N-methyldiethanolamine 3g/L

N, N' -Thiocarbonyldiimidazole 0.3g/L

2. The preparation method of the grain refiner described in this embodiment is as follows:

1) preparation of aminoacetaldehyde dimethyl acetal solution: weighing 30g of aminoacetaldehyde dimethyl acetal, adding into 500ml of deionized water, and stirring to obtain a uniform solution for later use;

2) weighing N-methyldiethanolamine: weighing 3g N-methyldiethanolamine for later use by using an analytical balance;

3) weighing N, N' -thiocarbonyl diimidazole: weighing 0.3g N-methyldiethanolamine by using an analytical balance for later use;

4) preparing a grain refiner: and (3) adding the N-methyldiethanolamine weighed in the step (2) into the aminoacetaldehyde dimethyl acetal solution prepared in the step (1), fully stirring to completely mix the solution, slowly adding the N, N' -thiocarbonyl diimidazole weighed in the step (3), fixing the volume to 1L by using deionized water, and continuously stirring to uniformly mix the solution.

3. Performance detection

10ml of the grain refiner prepared in example 1 was added to 1L of a cyanide-free copper-zinc alloy plating solution (tartrate system cyanide-free copper-zinc alloy plating solution is acceptable), the work piece was placed in the prepared plating solution to be plated, after plating, the work piece was taken out, the thickness and zinc content of the plating layer were measured, and the appearance of the plating layer was observed. The workpiece is typically a copper part.

The cyanide-free copper-zinc alloy plating solution used in this example was:

the electroplating process conditions in this example are as follows:

the workpiece was plated under the same conditions with the same cyanide-free copper-zinc alloy plating solution without adding the above-mentioned grain refiner, and the thickness and zinc content of the copper-zinc plating layer and the appearance state of the plating layer were measured using fisher (fisheri).

4. The result of the detection

FIG. 1 is a test chart of a sample of this embodiment, wherein A is an appearance chart of a non-cyanide copper-zinc alloy plated layer without the grain refiner of the present invention; b is an appearance diagram of the cyanide-free copper-zinc alloy plating layer added with the grain refiner. FIG. 5 shows the surface micro-topography of the sample of this example, wherein A is the surface micro-topography of the non-cyanide copper-zinc alloy plating layer without the grain refiner of the present invention; b is the surface micro-morphology of the cyanide-free copper-zinc alloy plating layer added with the grain refiner.

The thickness of the plating layer of the electroplating workpiece added with the grain refiner is 2.53 mu m, the zinc content is 32.14 percent, the appearance of the plating layer is fine and bright, the plating layer has luster, and the plating layer is golden yellow with uniform luster, as shown in B in figure 1. The thicker the coating thickness, the better the corrosion resistance of the coating, the different zinc content in the copper-zinc alloy, and the different appearance colors of the coating, therefore, the proportion of copper and zinc in the coating needs to be strictly controlled, the sample of the invention needs to prepare the imitation gold coating, and the zinc content is preferably 32-38%. The grain refinement and the compactness of the non-cyanide copper-zinc alloy plating layer added with the grain refiner can be seen from B in FIG. 5.

The thickness of the plating layer of the electroplating workpiece without the grain refiner is 1.12 mu m, the zinc content is 31.21 percent, the appearance color of the plating layer is dim and uneven, and the plating layer has no brightness and coarse crystals.

Example 2

1. The concentration ratio of each component of the grain refiner described in this embodiment is as follows:

aminoacetaldehyde dimethyl acetal 40g/L

N-methyldiethanolamine 4g/L

N, N' -Thiocarbonyldiimidazole 0.4g/L

2. The preparation method of the grain refiner described in this example is the same as that of example 1, except that the contents of the components are calculated according to the above mixture ratio.

3. Performance detection

10ml of the grain refiner prepared in example 2 was added to 1L of a cyanide-free copper-zinc alloy plating solution (tartrate system cyanide-free copper-zinc alloy plating solution), and the work was plated in the prepared plating solution, after which the work was taken out, the thickness and zinc content of the plating layer were measured, and the appearance of the plating layer was observed.

Similarly, the workpiece is electroplated by using cyanide-free copper-zinc alloy electroplating solution without the grain refiner under the same condition, and the workpiece is detected.

4. The result of the detection

FIG. 2 is a test chart of a sample of the present embodiment, wherein A is an appearance chart of a non-cyanide copper-zinc alloy plated layer without the grain refiner of the present invention; b is an appearance diagram of the cyanide-free copper-zinc alloy plating layer added with the grain refiner. FIG. 6 shows the surface micro-topography of the sample of this example, wherein A is the surface micro-topography of the non-cyanide copper-zinc alloy plating layer without the grain refiner of the present invention; b is the surface micro-morphology of the cyanide-free copper-zinc alloy plating layer added with the grain refiner.

The thickness of the plating layer of the electroplating workpiece added with the grain refiner is 2.64 mu m, the zinc content is 32.12 percent, the appearance of the plating layer is fine and bright, the plating layer is glossy and is golden yellow with uniform color, and the color of the gold-imitating plating layer is more vivid and bright. The grain refinement and the compactness of the cyanide-free copper-zinc alloy plating layer added with the grain refiner can be seen from the surface micro-topography picture. In the same time of electroplating, the electroplating speed is accelerated, the thickness of the coating is increased, and the electroplating efficiency is improved.

The thickness of the plating layer of the electroplating workpiece without the grain refiner is 1.09 mu m, the zinc content is 25.85 percent, and the plating layer has rough appearance, dull and lusterless color and uneven color.

Example 3

1. The concentration ratio of each component of the grain refiner described in this embodiment is as follows:

aminoacetaldehyde dimethyl acetal 50g/L

N-methyldiethanolamine 5g/L

N, N' -Thiocarbonyldiimidazole 0.5g/L

2. The preparation method of the grain refiner described in this example is the same as that of example 1, except that the amount of each component is calculated according to the above mixture ratio.

3. Performance detection

10ml of the grain refiner prepared in example 3 was added to 1L of a cyanide-free copper-zinc alloy plating solution (tartrate system cyanide-free copper-zinc alloy plating solution) and the work was plated in the prepared plating solution under the same conditions as in example 1.

Similarly, the cyanide-free copper-zinc alloy plating solution without the grain refiner is used for parallel comparison of the plated workpieces under the same conditions, and the detection is carried out.

4. The result of the detection

FIG. 3 is a test chart of a sample of the present embodiment, wherein A is an appearance chart of a non-cyanide copper-zinc alloy plated layer without the grain refiner of the present invention; b is an appearance diagram of the cyanide-free copper-zinc alloy plating layer added with the grain refiner. FIG. 7 is the surface micro-topography of the sample of this example, wherein A is the surface micro-topography of the non-cyanide copper-zinc alloy plating layer without the grain refiner of the present invention; b is the surface micro-morphology of the cyanide-free copper-zinc alloy plating layer added with the grain refiner.

The thickness of the plating layer of the electroplating workpiece added with the grain refiner is 2.69 mu m, the zinc content is 32.09 percent, the appearance of the plating layer is fine and bright, and the plating layer has luster and is golden yellow with uniform luster. The grain refinement and the compactness of the cyanide-free copper-zinc alloy plating layer added with the grain refiner can be seen from the surface micro-topography picture.

The thickness of the plating layer of the electroplating workpiece without the grain refiner is 1.04 mu m, the zinc content is 25.94 percent, and the plating layer has rough appearance, dull and dull color and uneven color. The grains are also relatively coarse as can be seen from the surface micro-topography.

Example 4

1. The concentration ratio of each component of the grain refiner described in this embodiment is as follows:

aminoacetaldehyde dimethyl acetal 36g/L

N-methyldiethanolamine 3.6g/L

N, N' -thiocarbonyldiimidazole 0.36 g/L.

2. The preparation method of the grain refiner described in this example is the same as that of example 1, except that the amount of each component is calculated according to the above mixture ratio.

3. Performance detection

10ml of the grain refiner prepared in example 4 was added to 1L of a cyanide-free copper-zinc alloy plating solution (tartrate system cyanide-free copper-zinc alloy plating solution) and the work was plated in the prepared plating solution under the same conditions as in example 1.

Similarly, the workpiece is electroplated by using cyanide-free copper-zinc alloy electroplating solution without the grain refiner under the same condition, and the workpiece is detected.

The electroplating process conditions in this example are as follows:

4. the result of the detection

FIG. 4 is a test chart of a sample of this embodiment, wherein A is an appearance chart of a non-cyanide copper-zinc alloy plated layer without the grain refiner of the present invention; b is an appearance diagram of the cyanide-free copper-zinc alloy plating layer added with the grain refiner. FIG. 8 is the surface micro-topography of the sample of this example, wherein A is the surface micro-topography of the non-cyanide copper-zinc alloy plating layer without the grain refiner of the present invention; b is the surface micro-morphology of the cyanide-free copper-zinc alloy plating layer added with the grain refiner.

The thickness of the plating layer of the electroplating workpiece added with the grain refiner is 2.98 mu m, the zinc content is 32.65 percent, the appearance of the plating layer is fine and bright, and the color of the plating layer is uniform and golden yellow.

The thickness of the plating layer of the electroplating workpiece without the grain refiner is 1.28 mu m, the zinc content is 28.32 percent, the appearance of the plating layer is rough, dull and lusterless, and the color is not uniform.

Example 5

1. The concentration ratio of each component of the grain refiner described in this embodiment is as follows:

aminoacetaldehyde dimethyl acetal 45g/L

N-methyldiethanolamine 4.5g/L

N, N' -Thiocarbonyldiimidazole 0.45g/L

2. The preparation method of the grain refiner described in this example is the same as that of example 1, except that the amount of each component is calculated according to the above mixture ratio.

3. Performance detection

10ml of the grain refiner prepared in example 5 was added to 1L of a cyanide-free copper-zinc alloy plating solution (tartrate system cyanide-free copper-zinc alloy plating solution) and the work was plated in the prepared plating solution under the same conditions as in example 1.

Similarly, the workpiece is electroplated by using cyanide-free copper-zinc alloy electroplating solution without the grain refiner under the same condition, and the workpiece is detected.

The electroplating process conditions in this example are as follows:

4. the result of the detection

The thickness of the plating layer of the electroplating workpiece added with the grain refiner is 1.98 mu m, the zinc content is 32.98 percent, the appearance of the plating layer is fine and bright, and the color of the plating layer is uniform and golden yellow.

The thickness of the plating layer of the electroplating workpiece without the grain refiner is 0.92 mu m, the zinc content is 27.32 percent, the appearance of the plating layer is rough, dull and lusterless, and the color is not uniform.

The above examples further show that the method has no adverse effect on the original performance of the plating solution and the original performance of the plating layer, can greatly improve the grain size of the plating layer, enables the crystallization of the plating layer to be more delicate and bright, and simultaneously improves the uniformity of the alloy content to obtain a golden yellow plating layer which is uniform, delicate and bright in color. Under the same electroplating time and condition, the method has obvious effect on improving the thickness of the plating layer and can completely meet the requirements in the prior production application.

Finally, it is noted that the above-mentioned preferred embodiments illustrate rather than limit the invention, and that, although the invention has been described in detail with reference to the above-mentioned preferred embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the scope of the invention as defined by the appended claims.