Environment-friendly chemical nickel-plated layer yellow colorant and preparation method and coloring method thereof

Abstract

The invention discloses an environment-friendly yellow coloring agent for a chemical nickel-plated layer and a preparation method and a coloring method of the environment-friendly yellow coloring agent. The coloring agent comprises the following components: a main coloring agent, an auxiliary coloring agent, a pH buffering agent, a surfactant, a color fixing agent and the balance of deionized water. A continuous color system oxidation film from light yellow to golden yellow can be formed on the surface of a nickel plating layer by regulating and controlling technological parameters of pH value, temperature and time and adopting a treatment mode of soaking, spraying or brush coating and roller coating. The method has the following effects: (1) the method is green and environment-friendly, does not contain heavy metals such as Cr, Pb, Cd and the like, and meets the RoHS and REACH environmental protection standards; (2) the applicability is high: the method is suitable for chemical nickel-plating layers with different phosphorus contents, and has a very good coloring effect on low-phosphorus, medium-phosphorus and high-phosphorus chemical nickel-plating layers; (3) the performance is excellent: the obtained coating is uniform and stable in color and luster, and has good wear resistance and corrosion resistance; and (4) the color is rich: various hues from quietly elegant light yellow to luxury golden yellow can be realized by adjusting parameters.

Description

Technical Field

[0001] The invention relates to the technical field of chemical nickel plating coloring, and more particularly to an environmentally friendly yellow colorant for chemical nickel plating layers, a preparation method thereof, and a coloring method. Background Art

[0002] Electroless nickel-phosphorus alloy coatings offer excellent hardness, corrosion resistance, wear resistance, a certain degree of magnetism, and weldability, making them widely used in aerospace, military, petrochemical, automotive, marine, electronics, and communications. As people's living standards improve, they demand more diverse and personalized decorative features. Consequently, electroless nickel coatings in colors like black and yellow, which differ from the traditional silvery-white appearance, have become increasingly popular.

[0003] Traditional chemical nickel plating is silvery white. In recent years, two different processes have emerged: direct black chemical nickel plating technology and chemical nickel plating layer blackening technology, which meet the market demand for the appearance of black chemical nickel plating. At present, there are no applications, literature or patents for yellow chemical nickel plating technology. The coating produced after the chemical nickel plating solution is contaminated, or the coating that has been heat-treated in air above 300°C has yellow spots, but this type of yellow spot is an undesirable defect with uneven distribution, inconsistent color, and uncontrollable process, which cannot meet market demand. Chemical copper plating and chemical gold plating can produce a yellow appearance, but there are problems such as insufficient corrosion resistance and high production costs.

[0004] Therefore, it is currently necessary to develop a yellow coloring technology for chemical nickel plating that is clean, environmentally friendly, stable in performance, widely applicable, and has diverse and controllable colors. Summary of the Invention

[0005] In light of this, the present invention aims to provide an environmentally friendly yellow colorant for electroless nickel plating, its preparation method, and a controllable coloring method to meet market demand for a wide range of yellow electroless nickel-plated products, from elegant pale yellow to luxurious golden yellow. This technology is heavy metal-free, features a simple and controllable process, and is applicable to electroless nickel plating with various phosphorus contents. The resulting coatings exhibit uniform and stable color, combining aesthetics with practicality, making them particularly suitable for the manufacture of high-value-added products requiring both decorative and functional properties.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] An environmentally friendly yellow colorant for chemical nickel plating, characterized by comprising the following components:

[0008] Main colorant 50-100g / L, auxiliary colorant 10-20g / L, pH buffer 30-50g / L, surfactant 0.1-1g / L, color fixing agent 1-5g / L, and the balance is deionized water.

[0009] The primary colorant in this colorant is the primary substance that reacts with the electroless nickel layer to form the yellow oxide film, which determines the primary hue of the film. Auxiliary colorants also participate in the oxidation reaction, affecting the depth of the film's color. The active ingredients of the primary and auxiliary colorants must be within a certain pH range to achieve a stable oxidizing effect. A too low pH results in excessive hydrogen peroxide, resulting in excessively yellow or black color, and even corrosion of the coating. A too high pH impairs oxidizing properties, leading to poor coloration or even failure.

[0010] pH buffers can stabilize the pH of the colorant, keeping the degree of oxidation reaction within the desired range and maintaining a stable coloring effect. As the reaction proceeds, nickel ions are generated in the coloring liquid, affecting the coloring effect. pH buffers can also complex nickel ions. Therefore, pH buffers are key to maintaining the coloring effect of the colorant and extending the service life of the colorant. The addition of surfactants is to promote full contact between the colorant and the nickel plating layer, making the appearance of the colored coating more uniform and consistent; the addition of a fixing agent can quickly dehydrate the colored workpiece and form a thin organic film to isolate the water vapor and pollutants in the environment, protecting the colored film from secondary oxidation and discoloration, maintaining the stability of the film color, and also providing a certain degree of corrosion resistance.

[0011] Preferably, the primary colorant is chlorate.

[0012] More preferably, the main colorant is one or more of potassium chlorate, sodium chlorate, and magnesium chlorate.

[0013] Preferably, the auxiliary colorant is one or more of hydrogen peroxide, sodium nitrate, and sodium persulfate.

[0014] The primary colorant in the colorant is the main substance that reacts with the electroless nickel layer to form a yellow oxide film, which determines the main color of the color film. The auxiliary colorant also participates in the oxidation reaction and can affect the depth of the color of the color film.

[0015] Preferably, the pH buffer is one or more of acetic acid, citric acid, ammonia water, and sodium carbonate.

[0016] pH buffers maintain the coloring effect and extend the life of colorants. They stabilize the pH of the colorant, ensuring that the active ingredients are in the optimal oxidation state, preventing excessive yellowing and blackening of the color or even corrosion of the coating due to a low pH, or color degradation or failure due to a high pH. They also complex the nickel ions generated by the reaction, preventing the metal ions from affecting the coloring effect. Among them, a pH buffer formulated with acetic acid and ammonia water has the best stabilization effect, the best coloring effect, and the longest life.

[0017] Preferably, the surfactant includes anionic surfactant and nonionic surfactant;

[0018] Wherein, the anionic surfactant includes one or more of sodium lauryl sulfonate, sodium fatty alcohol ether sulfate, and alcohol ether phosphate;

[0019] The nonionic surfactant includes one or more of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether-10, and polyethylene glycol-400.

[0020] Preferably, the fixing agent includes one or more of oleic acid, triethanolamine oleate, and triethyl phosphate.

[0021] More preferably, the surfactant is polyethylene glycol-400, and the fixing agent is triethanolamine oleate.

[0022] The addition of a surfactant promotes uniform contact between the colorant's active ingredients and the coating, resulting in a more uniform and consistent coloration. Adding a color fixative quickly dehydrates the colored workpiece, keeping the surface dry and preventing adsorption of contaminants that can cause changes in appearance due to wear and tear, thereby maintaining a long-lasting color. Polyethylene glycol-400 and triethyl phosphate offer the best results, resulting in a colorant that produces minimal foaming, is easily cleaned without residue, and creates a more uniform yellow appearance. The coating also withstands high temperatures without discoloration, and exhibits improved corrosion resistance.

[0023] Another object of the present invention is to provide a method for preparing the above-mentioned environmentally friendly yellow colorant for chemical nickel plating, the preparation method being as follows:

[0024] Into half the required volume of deionized water, the main colorant, auxiliary colorant, pH buffer, surfactant, and color fixing agent are added in sequence, and after dissolving, water is added to the required volume and stirred evenly to obtain the yellow colorant for the chemical nickel plating layer.

[0025] Preferably, the pH value of the yellow colorant of the chemical nickel plating layer is 4-8.

[0026] Another object of the present invention is to provide a method for coloring the above-mentioned environmentally friendly chemical nickel plating layer with a yellow colorant, characterized in that the coloring process is as follows:

[0027] Heat the colorant to a certain temperature and keep it constant, and treat the chemical nickel-plated workpiece by immersion, spraying, brushing or roller coating. The process ensures full and uniform contact between the workpiece and the colorant. After a certain period of time, rinse with water and dry to obtain a colored chemical nickel-phosphorus coating.

[0028] Preferably, the certain temperature is 40-70°C;

[0029] The certain time is 10 to 40 minutes;

[0030] The drying is one of natural air drying, blow drying, oven drying and spin drying.

[0031] The electroless nickel plating colorant of the present invention fills a market gap in yellow electroless nickel plating products. The colorant is clean and environmentally friendly, free of heavy metal pollution, has a long lifespan, offers stable effects, and has a wide range of applications. It can be used to color a variety of low-phosphorus, medium-phosphorus, and high-phosphorus coatings. The colorant can produce corrosion-resistant, fingerprint-resistant, uniform, bright, and long-lasting golden electroless nickel coatings, meeting the decorative requirements of various hardware and bathroom products, as well as automotive, mobile phone, and computer components.

[0032] As mentioned above, the main colorant and the auxiliary colorant in the colorant of the present invention are the main substances that react with the chemical nickel plating layer to form a golden oxide film, and are the key to ensuring that the colored film layer is uniform and dense. The pH buffer has the function of maintaining the coloring effect of the colorant and extending the service life of the colorant. It can not only stabilize the pH of the colorant, ensure that the active ingredients are in the best oxidation state, prevent the pH from being too low, resulting in excessive yellowing and blackening and corrosion of the coating, or the coloring from being too high, which causes deterioration or failure, but also can complex the nickel ions generated by the reaction to avoid the metal ions affecting the coloring effect. The addition of surfactants is to promote uniform contact between the colorant and the coating, making the appearance of the colored coating more uniform and dense; the addition of a color fixing agent can quickly dehydrate the colored workpiece, keep the surface dry, avoid the adsorption of pollutants that cause changes in the appearance, and maintain the color for a long time. The golden oxide film layer prepared by the colorant is uniform and dense, and will not affect the corrosion resistance of the chemical nickel plating layer itself.

[0033] Overall, the aforementioned electroless nickel colorant fills a market gap in yellow electroless nickel plating. This technology contains no heavy metals, offers a simple and controllable process, and is suitable for electroless nickel plating with various phosphorus contents. The resulting coatings offer a uniform and stable color, adjustable to a variety of shades, from elegant light yellow to luxurious golden yellow. They are particularly well-suited for the manufacture of high-value-added products with demanding decorative and functional qualities. In industrial applications, they can be widely used for decorative treatments of automotive interiors, electronic product housings, and instrument panels. In the engineering equipment sector, they are particularly suitable for surface coloring functional products such as medical devices and precision machinery parts. In the high-end decorative sector, they are ideal for surface treatments of luxury accessories, jewelry, and high-end bathroom hardware, significantly enhancing product durability and market competitiveness while maintaining aesthetic appeal.

[0034] It can be seen from the above technical solutions that compared with the prior art, the present invention has the following beneficial effects:

[0035] (1) Green and environmentally friendly: does not contain heavy metals such as Cr, Pb, Cd, and complies with RoHS and REACH environmental standards;

[0036] (2) Strong applicability: It is suitable for chemical nickel plating layers with different phosphorus contents, and has a good coloring effect on low-phosphorus, medium-phosphorus, and high-phosphorus chemical nickel plating layers;

[0037] (3) Excellent performance: The obtained coating has uniform and stable color and good wear resistance and corrosion resistance;

[0038] (4) Rich colors: By adjusting parameters, a variety of tones from elegant light yellow to luxurious golden can be achieved.

[0039] This invention is particularly suitable for the manufacturing of high-value-added products that require both decorative and functional properties. In the industrial sector, it can be widely used for decorative treatments of automotive interiors, electronic product housings, and instrument panels. In the engineering equipment sector, it is particularly suitable for surface coloring of functional products such as medical devices and precision machinery parts. In the high-end decoration sector, it can be perfectly applied to the surface treatment of luxury accessories, jewelry, and high-end bathroom hardware, significantly improving their durability and market competitiveness while ensuring their aesthetics. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0041] Figure 1 This is a diagram showing the coloring effect of the chemical nickel plating layer obtained in Example 1 of the present invention.

[0042] Figure 2 This is a diagram showing the coloring effect of the chemical nickel plating layer obtained in Example 2 of the present invention.

[0043] Figure 3 This is a diagram showing the coloring effect of the chemical nickel plating layer obtained in Example 3 of the present invention.

[0044] Figure 4 This is a diagram showing the coloring effect of the chemical nickel plating layer obtained in Example 4 of the present invention.

[0045] Figure 5 This is a diagram showing the coloring effect of the chemical nickel plating layer obtained in Example 5 of the present invention.

[0046] Figure 6 This is a diagram showing the coloring effect of the chemical nickel plating layer obtained in Example 6 of the present invention.

[0047] Figure 7 This is a diagram showing the coloring effect of the chemical nickel plating layer obtained in Example 7 of the present invention. DETAILED DESCRIPTION

[0048] 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.

[0049] The embodiment of the present invention provides an environmentally friendly yellow colorant for chemical nickel plating and a controllable coloring method thereof, comprising the following components: 50-100 g / L of a main colorant, 10-20 g / L of an auxiliary colorant, 30-50 g / L of a pH buffer, 0.1-1 g / L of a surfactant, 1-5 g / L of a color fixing agent, and 800-900 g / L of deionized water.

[0050] Specifically, the main colorant is one or more of potassium chlorate, sodium chlorate, and magnesium chlorate;

[0051] The auxiliary colorant is one or more of hydrogen peroxide, sodium nitrate, and sodium persulfate;

[0052] The pH buffer is one or more of acetic acid, citric acid, ammonia water, and sodium carbonate;

[0053] The surfactant includes one or more of sodium lauryl sulfate, sodium fatty alcohol ether sulfate, alcohol ether phosphate, fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether-10, and polyethylene glycol-400;

[0054] The fixing agent includes one or more of oleic acid, triethanolamine oleate, and triethyl phosphate.

[0055] The colorant concentration composition and coloring process of Examples 1 to 7 are shown in Table 1, in g / L:

[0056] Table 1

[0057] The raw materials and proportions used in Examples 1 to 3 are different.

[0058]

[0059] Compared with the coloring process, Example 7 eliminates the color fixing agent.

[0060] Examples 1 to 7 used carbon steel substrates as test materials. The electroless nickel plating solution used consisted of 25 g / L nickel sulfate, 30 g / L sodium hypophosphite, 20 g / L lactic acid, 10 g / L sodium acetate, and 10 g / L malic acid. The pH of the plating solution was 4.6 ± 0.2, the plating temperature was 88 ± 1°C, and the plated layer thickness was 10 ± 1 μm. Example 8 used electroplating nickel to deposit a 10 ± 1 μm nickel layer.

[0061] The plated test pieces were colored according to the colorants and processes listed in Table 1.

[0062] The coloring effect is shown in Table 2.

[0063] Table 2

[0064] Example 1 2 3 4 5 6 7 Appearance golden yellow champagne Rose gold dark yellow light champagne Rose gold golden yellow

[0065] From Table 2 and Figure 1 、 Figure 2 、 Figure 3 As can be seen, the electroless nickel layer appears golden yellow when colored with sodium chlorate as the primary colorant, champagne yellow when colored with potassium chlorate as the primary colorant, and rose gold when colored with magnesium chlorate as the primary colorant. This indicates that different primary colorants can produce different yellow appearances.

[0066] Compared with Example 1, the main colorant of Example 4 is the same, but the colorant temperature is increased, the pH value is reduced, and the coloring time is longer. Figure 1 、 Figure 4 It can be seen that the colored film of Example 4 is still golden yellow, but the color is darker than that of the colored film of Example 1. This is because the increased temperature and decreased pH increase the oxidizing property of the colorant, accelerate the coloring reaction, and the longer reaction time results in a thicker film layer, thus presenting a more intense color.

[0067] Compared with Example 2, the main colorant of Example 5 is the same, but the colorant temperature is lowered, the pH value is increased, and the coloring time is shortened. Figure 2 、 Figure 5 It can be seen that the colored film of Example 5 is a light champagne color, which is lighter than the colored film of Example 2. This is because the oxidizing property of the colorant decreases as the temperature decreases and the pH increases, slowing the coloring reaction. Furthermore, the shorter coloring time results in a thinner film layer, resulting in a lighter color.

[0068] Compared with Example 3, the main colorant of Example 6 is the same, but the colorant temperature is lowered, the pH value is lowered, and the coloring time remains unchanged. Figure 3 、 Figure 6 It can be seen that the coloring film of Example 6 is a deep rose gold color, which is darker than the coloring film of Example 3.

[0069] Compared with Example 1, the main colorant of Example 7 is the same, the colorant temperature increases, the pH value increases, and the coloring time decreases. Figure 1 、 Figure 7 It can be seen that the colored film of Example 7 is golden yellow, which is basically the same as that of Example 1.

[0070] In summary, the golden colorant for electroless nickel plating prepared by the present invention can produce a corrosion-resistant, fingerprint-resistant, uniform, bright, and long-lasting yellow appearance on the surface of the electroless nickel plating layer. The process is simple and controllable, and is applicable to electroless nickel plating layers with various phosphorus contents. The resulting coating has a uniform and stable color and can be adjusted to a variety of tones such as golden yellow, champagne, and rose gold according to demand. It is applicable to electroless nickel plating layers with various phosphorus contents. The resulting coating has a uniform and stable color and combines both aesthetics and practicality. It is particularly suitable for the manufacturing of high-value-added products with high requirements for both decorativeness and functionality, and has extremely high application value.

[0071] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0072] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An environmentally friendly yellow colorant for chemical nickel plating, characterized in that: Includes the following ingredients: Main colorant 50-100g / L, auxiliary colorant 10-20g / L, pH buffer 30-50g / L, surfactant 0.1-1g / L, color fixing agent 1-5g / L, and the balance is deionized water.

2. The environmentally friendly yellow colorant for chemical nickel plating according to claim 1, characterized in that: The primary colorant is chlorate.

3. The environmentally friendly yellow colorant for chemical nickel plating according to claim 1, characterized in that: The auxiliary colorant is one or more of hydrogen peroxide, sodium nitrate, and sodium persulfate.

4. An environmentally friendly yellow colorant for chemical nickel plating according to claim 1, characterized in that: The pH buffer is one or more of acetic acid, citric acid, ammonia water, and sodium carbonate.

5. The environmentally friendly yellow colorant for chemical nickel plating according to claim 1, characterized in that: The surfactant includes anionic surfactant and nonionic surfactant; Wherein, the anionic surfactant includes one or more of sodium lauryl sulfonate, sodium fatty alcohol ether sulfate, and alcohol ether phosphate; The nonionic surfactant includes one or more of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether-10, and polyethylene glycol-400.

6. The environmentally friendly yellow colorant for chemical nickel plating according to claim 1, characterized in that: The color fixing agent includes one or more of oleic acid, triethanolamine oleate, and triethyl phosphate.

7. A method for preparing an environmentally friendly yellow colorant for chemical nickel plating according to any one of claims 1 to 6, characterized in that: The preparation method is as follows: Into half the required volume of deionized water, the main colorant, auxiliary colorant, pH buffer, surfactant, and color fixing agent are added in sequence, dissolved, and then water is added to the required volume, and stirred evenly to obtain the yellow colorant for the chemical nickel plating layer.

8. The method for preparing an environmentally friendly yellow colorant for chemical nickel plating according to claim 7, characterized in that: The pH value of the yellow colorant of the chemical nickel plating layer is 4-8.

9. A method for coloring an environmentally friendly chemical nickel plating layer with a yellow colorant according to any one of claims 1 to 6, characterized in that: The coloring process is as follows: Heat the colorant to a certain temperature and keep it constant, and treat the chemical nickel-plated workpiece by immersion, spraying, brushing or roller coating. The process ensures full and uniform contact between the workpiece and the colorant. After a certain period of time, rinse with water and dry to obtain a colored chemical nickel-phosphorus coating.

10. The method for coloring an environmentally friendly yellow colorant for chemical nickel plating according to claim 9, characterized in that: The certain temperature is 40-70°C; The certain time is 10 to 40 minutes; The drying is one of natural air drying, blow drying, oven drying and spin drying.

Images