Electronickeling solution and preparation method and application thereof

Abstract

The invention relates to the technical field of electroplating, and discloses an electroplating nickel solution as well as a preparation method and application thereof. The nickel electroplating solution comprises the following components by concentration: 150 to 300 g / L of nickel salt, 30 to 80 g / L of a complexing agent, 30 to 80 g / L of boric acid, 30 to 100 mg / L of a brightener, 20 to 100 mg / L of a leveling agent and 50 to 150 mg / L of an anti-pinhole agent. A solvent of the nickel electroplating solution is water; and the brightening agent comprises 2-hydroxypyrimidine hydrochloride. The nickel electroplating solution provided by the invention has relatively good stability, the 2-hydroxypyrimidine hydrochloride is used as a brightening agent, a plating layer with better brightness can be formed, a base material protection effect can be provided, the nickel electroplating solution is reasonable in component and working parameters, a plating layer with good uniformity and brightness and without folding and plating cracks can be formed, and the electroplating quality is improved. The problems of plating pinholes and plating darkening do not exist, and the method can be applied to nickel electroplating surface treatment of the ceramic substrate.

Description

Technical Field

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

[0002] Ceramic substrates have excellent thermal conductivity, insulation, low dielectric constant and dielectric loss. They are ideal heat dissipation packaging materials for the new generation of large-scale integrated circuits, semiconductor module circuits and high-power devices. They can be used in high-power power semiconductor modules, semiconductor refrigerators, electronic heaters, power control circuits, automotive electronics, solar panel components, lasers and other fields.

[0003] In order to improve the electrical conductivity, thermal conductivity, protection and other properties of ceramic substrates, they are usually subjected to electroplating surface treatment so that the metal ions in the electroplating solution are deposited on the surface to form a metal layer. Compared with other electroplating processes, electroplating nickel-gold surface treatment can better provide a low-resistance conductive path, thereby improving the conductivity of the substrate circuit, and both nickel and gold have good corrosion resistance, which can prevent the substrate from being corroded by chemicals and oxidation, thereby extending the service life of the product and is widely used. However, the existing electroplating nickel-gold surface treatment has defects such as poor coating uniformity, large electroplating loss, and dark coating due to plating pinholes, and cannot solve the electroplating problem of ceramic substrates. Summary of the invention

[0004] The present invention aims to solve at least one of the above-mentioned technical problems existing in the prior art. To this end, one of the purposes of the present invention is to provide a nickel electroplating solution; the second purpose of the present invention is to provide a method for preparing the nickel electroplating solution; the third purpose of the present invention is to provide an application of the nickel electroplating solution.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] The first aspect of the present invention provides a nickel electroplating solution, which comprises the following components in terms of concentration: 150-300 g / L of nickel salt, 30-80 g / L of complexing agent, 30-80 g / L of boric acid, 30-100 mg / L of brightener, 20-100 mg / L of leveling agent, and 50-150 mg / L of anti-pinhole agent; the solvent of the nickel electroplating solution is water; and the brightener comprises 2-hydroxypyrimidine hydrochloride.

[0007] Preferably, in terms of concentration, the nickel electroplating solution includes the following components: 120-240 g / L of nickel salt, 40-60 g / L of complexing agent, 40-60 g / L of boric acid, 40-80 mg / L of brightener, 30-90 mg / L of leveling agent, and 60-120 mg / L of anti-pinhole agent; the solvent of the nickel electroplating solution is water; and the brightener includes 2-hydroxypyrimidine hydrochloride.

[0008] Preferably, the nickel salt is selected from at least one of nickel chloride and nickel sulfate; further preferably, the nickel salt is nickel chloride.

[0009] Preferably, the complexing agent is selected from at least one of malic acid, citric acid, tartaric acid, ethylenediaminetetraacetic acid, and glycolic acid; more preferably, the complexing agent is malic acid.

[0010] Preferably, the leveler is selected from N-(4-fluoro-2-methoxy-5-nitrophenyl)-4-(1-methyl-1H-indol-3-yl)pyrimidin-2-amine hydrochloride, N-Boc-indoline-7-carboxylic acid or a combination thereof.

[0011] More preferably, the leveler is a mixture of N-(4-fluoro-2-methoxy-5-nitrophenyl)-4-(1-methyl-1H-indol-3-yl)pyrimidine-2-amine hydrochloride and N-Boc-indoline-7-carboxylic acid in a mass ratio of (1-2):1.

[0012] More preferably, the leveler is a mixture of N-(4-fluoro-2-methoxy-5-nitrophenyl)-4-(1-methyl-1H-indol-3-yl)pyrimidine-2-amine hydrochloride and N-Boc-indoline-7-carboxylic acid in a mass ratio of (1-1.5):1.

[0013] Preferably, the anti-pinhole agent is selected from pterin-6-carboxylic acid, 6-hydroxypyridazine-3-carboxamide or a combination thereof.

[0014] Further preferably, the anti-pinhole agent is a mixture of pterin-6-carboxylic acid and 6-hydroxypyridazine-3-carboxamide in a mass ratio of (1-2):1.

[0015] More preferably, the anti-pinhole agent is a mixture of pterin-6-carboxylic acid and 6-hydroxypyridazine-3-carboxamide in a mass ratio of (1-1.5):1.

[0016] Preferably, the pH of the electroplating solution is 3.5-5.0; further preferably, the pH of the nickel electroplating solution is 3.7-4.7.

[0017] Preferably, the pH of the electroplating solution is adjusted by a sodium hydroxide solution with a mass concentration of 4-6% and / or a hydrochloric acid solution with a volume concentration of 4-6%.

[0018] Preferably, the working parameters of the nickel electroplating solution include at least one of the following:

[0019] 1) Working temperature is 20-40℃;

[0020] 2) Current density is 0.1-5A / dm 2 ;

[0021] 3) Working time is 10-40min.

[0022] Further preferably, the working parameters of the nickel electroplating solution include at least one of the following:

[0023] 1) Working temperature is 25-35℃;

[0024] 2) Current density is 0.1-4.5A / dm 2 ;

[0025] 3) Working time is 20-40min.

[0026] The second aspect of the present invention provides a method for preparing the nickel electroplating solution according to the first aspect of the present invention, comprising the following steps:

[0027] The components including nickel salt, complexing agent, boric acid, brightener, leveling agent and anti-pinhole agent are mixed with solvent according to concentration ratio to obtain the nickel electroplating solution.

[0028] The third aspect of the present invention provides the use of the nickel electroplating solution described in the first aspect of the present invention in the surface treatment of a ceramic substrate.

[0029] Preferably, the surface treatment is nickel electroplating surface treatment.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1) The nickel electroplating solution provided by the present invention has good stability, and 2-hydroxypyrimidine hydrochloride is used as a brightener, which can not only form a plating layer with better brightness, but also provide a substrate protection effect;

[0032] 2) The nickel electroplating solution provided by the present invention has reasonable composition and working parameters, can form a coating with good uniformity and brightness, no folding cracks, no coating pinholes and dark coating problems, can provide uniform and consistent coating protection and decorative performance, improve product aesthetics, and ensure product stability and reliability under various environmental conditions;

[0033] 3) The nickel electroplating solution provided by the present invention can be applied to the nickel electroplating surface treatment of ceramic substrates, which is conducive to further expanding the application of ceramic substrates. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below by specific examples. Unless otherwise specified, the raw materials, reagents or devices used in the examples and comparative examples can be obtained from conventional commercial sources or can be obtained by prior art methods. Unless otherwise specified, the experiments or test methods are conventional methods in the art.

[0035] Example 1

[0036] This embodiment provides a nickel electroplating solution, the components and contents of which are shown in Table 1:

[0037] Table 1 Example 1 Nickel electroplating solution components and contents

[0038]

[0039] The nickel electroplating solution is prepared by the following steps:

[0040] Nickel salt, complexing agent, boric acid, brightener, leveling agent, anti-pinhole agent are mixed with deionized water according to concentration ratio, and pH value is adjusted to 4.0 using sodium hydroxide solution with mass concentration of 5% and / or hydrochloric acid solution with volume concentration of 5% to obtain nickel electroplating solution.

[0041] Example 2

[0042] This embodiment provides a nickel electroplating solution, the components and contents of which are shown in Table 2:

[0043] Table 2 Example 2 Nickel electroplating solution components and contents

[0044]

[0045] The nickel electroplating solution is prepared by the following steps:

[0046] Nickel salt, complexing agent, boric acid, brightener, leveling agent, anti-pinhole agent are mixed with deionized water according to concentration ratio, and pH value is adjusted to 4.0 using sodium hydroxide solution with mass concentration of 5% and / or hydrochloric acid solution with volume concentration of 5% to obtain nickel electroplating solution.

[0047] Example 3

[0048] This embodiment provides a nickel electroplating solution, the components and contents of which are shown in Table 3:

[0049] Table 3 Example 3 Nickel electroplating solution components and contents

[0050]

[0051] The nickel electroplating solution is prepared by the following steps:

[0052] Nickel salt, complexing agent, boric acid, brightener, leveling agent, anti-pinhole agent are mixed with deionized water according to concentration ratio, and pH value is adjusted to 4.0 using sodium hydroxide solution with mass concentration of 5% and / or hydrochloric acid solution with volume concentration of 5% to obtain nickel electroplating solution.

[0053] Comparative Example 1

[0054] This comparative example provides a nickel electroplating solution, the components and contents of which are shown in Table 4:

[0055] Table 4 Comparative Example 1 Nickel Electroplating Solution Components and Contents

[0056]

[0057] The nickel electroplating solution is prepared by the following steps:

[0058] Nickel salt, complexing agent, boric acid, leveling agent, anti-pinhole agent are mixed with deionized water according to concentration ratio, and pH is adjusted to 4.0 using 5% mass concentration sodium hydroxide solution and / or 5% volume concentration hydrochloric acid solution to obtain nickel electroplating solution.

[0059] Comparative Example 2

[0060] This comparative example provides a nickel electroplating solution, the components and contents of which are shown in Table 5:

[0061] Table 5 Comparative Example 2 Nickel Electroplating Solution Components and Contents

[0062]

[0063]

[0064] The nickel electroplating solution is prepared by the following steps:

[0065] Nickel salt, complexing agent, boric acid, brightener, anti-pinhole agent are mixed with deionized water according to concentration ratio, and pH value is adjusted to 4.0 using sodium hydroxide solution with mass concentration of 5% and / or hydrochloric acid solution with volume concentration of 5% to obtain nickel electroplating solution.

[0066] Comparative Example 3

[0067] This comparative example provides a nickel electroplating solution, the components and contents of which are shown in Table 6:

[0068] Table 6 Comparative Example 3 Nickel Electroplating Solution Components and Contents

[0069]

[0070] The nickel electroplating solution is prepared by the following steps:

[0071] Nickel salt, complexing agent, boric acid, brightener and leveling agent are mixed with deionized water according to concentration ratio, and pH value is adjusted to 4.0 using sodium hydroxide solution with mass concentration of 5% and / or hydrochloric acid solution with volume concentration of 5% to obtain nickel electroplating solution.

[0072] Comparative Example 4

[0073] This comparative example provides a nickel electroplating solution, the components and contents of which are shown in Table 7:

[0074] Table 7 Comparative Example 4 Nickel Electroplating Solution Components and Contents

[0075]

[0076]

[0077] The nickel electroplating solution is prepared by the following steps:

[0078] Nickel salt, boric acid, brightener, leveler, and anti-pinhole agent are mixed with deionized water according to a concentration ratio, and a sodium hydroxide solution with a mass concentration of 5% and / or a hydrochloric acid solution with a volume concentration of 5% is used to adjust the pH to 4.0 to obtain a nickel electroplating solution.

[0079] Performance Testing

[0080] The nickel electroplating solutions in Examples 1-3 and Comparative Examples 1-4 were used to perform nickel electroplating on the ceramic substrates. Each nickel electroplating solution was used to treat 5 substrates. The working temperature of the nickel electroplating solution was 30° C. and the current density was 2.0 A / dm 2 , time is 30min, to form a coating.

[0081] 1. Coating uniformity and brightness: Take the coating thickness of 5 substrates treated with each electroplating nickel solution, calculate the extreme value and average value to evaluate the coating uniformity, observe the surface brightness of the coating and whether there is nickel. The uniformity and brightness evaluation standards are shown in Table 8.

[0082] Table 8 Evaluation criteria for coating uniformity and brightness

[0083]

[0084] 2. Use SEM to observe whether the coating has fold-plating cracks. The grade is divided according to the magnification required to observe the fold-plating cracks. The evaluation criteria for the fold-plating crack phenomenon are shown in Table 9.

[0085] Table 9 Evaluation criteria for fold-plating crack phenomenon on coating surface

[0086] Evaluation indicators grade Dense and smooth without folding cracks excellent Occasionally, fine cracks are seen, which can be seen when SEM is magnified 3000 times good The crack is large and can be seen at 1000 times SEM magnification. Poor There are many cracks, which can be seen when SEM is magnified 500 times Difference There are many cracks, which can be seen at SEM magnification of 200 times or less Very bad

[0087] 3. Nickel cylinder stability test: The experimental amount of each nickel electroplating solution is 5 tank solutions, which are used normally for a period of one month. The state of the nickel electroplating solution in the nickel cylinder (including turbidity, tank solution color, and whether precipitation occurs) is observed to evaluate its stability. The evaluation criteria are shown in Table 10.

[0088] Table 10 Nickel cylinder stability evaluation standard

[0089] Evaluation indicators grade The solution is clear and transparent within one month without turbidity excellent The solution is clear within one month, and the tank liquid is slightly milky white good The solution will settle slightly within one month. Poor The solution precipitation tank is obvious within one month Difference Within one month, the solution is turbid in the precipitate tank, and there is a lot of lumpy nickel Very bad

[0090] 4. Nickel corrosion test: Perform nickel-gold electroplating normally. After stripping, use SEM to observe the corrosion phenomenon on the surface of the nickel layer at a magnification of 3000 times to evaluate the nickel corrosion performance of the nickel electroplating solution. The evaluation standards are shown in Table 11.

[0091] Table 11 Nickel corrosion test evaluation standards

[0092] Evaluation indicators grade Nickel layer has no corrosion spots excellent Occasional corrosion spots on the nickel layer good There are some corrosion spots on the nickel layer Poor Nickel layer has many corrosion points Difference Nickel layer has dense corrosion points Very bad

[0093] The performance test results are shown in Table 12:

[0094] Table 12 Performance test results of nickel plating solution in Examples 1-3 and Comparative Examples 1-4

[0095]

[0096] Table 12 is the performance test results of the nickel electroplating solution in Examples 1-3 and Comparative Examples 1-4. It can be seen from Table 12 that the nickel electroplating solution prepared in Examples 1-3 can be used for nickel electroplating surface treatment of ceramic substrates, and the formed coating has good uniformity and brightness, and there is no folding crack. It shows that the composition and working parameters of the nickel electroplating solution provided by the present invention are reasonable, which is conducive to forming a uniform coating, ensuring that the protection and decorative properties of the coating are uniform and consistent; it is conducive to forming a bright coating, improving the aesthetics of the product; it is also conducive to forming a defect-free surface, and improving the stability and reliability of the product under various environmental conditions. In addition, the nickel cylinder of the nickel electroplating solution in Examples 1-3 has good stability, and the solution is clear and transparent within one month without turbidity; the nickel corrosion performance of the nickel electroplating solution is good, and there is no corrosion point in the nickel layer after the gold is withdrawn, indicating that the nickel layer formed by the nickel electroplating solution provided by the present invention is of high quality and excellent corrosion resistance, and can contact and coexist with other metal layers in practical applications.

[0097] The difference between Comparative Example 1 and Example 1 is that the brightener 2-hydroxypyrimidine hydrochloride is not added, and it can be seen that the uniformity and brightness of the coating are poor, fine cracks are occasionally seen on the surface, and the nickel layer is corroded. Some corrosion spots appear on the surface of the nickel layer, and the overall performance of the electroplating nickel solution is reduced.

[0098] The difference between Comparative Example 2 and Example 1 is that the composite leveling agent N-(4-fluoro-2-methoxy-5-nitrophenyl)-4-(1-methyl-1H-indol-3-yl)pyrimidine-2-amine hydrochloride and N-Boc-indoline-7-carboxylic acid are not added. It can be seen that the uniformity and brightness of the coating are reduced, fine cracks appear on the surface, and the nickel layer is corroded, and the overall performance of the nickel electroplating solution is reduced.

[0099] The difference between Comparative Example 3 and Example 1 is that the composite anti-pinhole agent pterin-6-carboxylic acid and 6-hydroxypyridazine-3-carboxamide are not added. It can be seen that the uniformity and brightness of the coating are not as good as those of Example 1, folding cracks appear, and some corrosion spots appear on the surface of the nickel layer after gold stripping, and the overall performance of the nickel electroplating solution is reduced.

[0100] The difference between Comparative Example 4 and Example 1 is that the complexing agent malic acid is not added, so that the nickel ions are precipitated in the solution. It can be seen that the uniformity and brightness of the coating are reduced, fine cracks appear on the surface, and the stability of the nickel electroplating solution is reduced. Within one month, the solution in the nickel cylinder is clear, but the tank liquid is slightly milky white, and corrosion spots are occasionally seen on the nickel layer after gold stripping.

[0101] It can be seen that the nickel electroplating solution provided by the present invention uses 2-hydroxypyrimidine hydrochloride as a brightener. Compared with traditional acetylene or alkyl sulfate brighteners, the brightening property is better, the brightening property can resist high current density, and the burning phenomenon will not occur. In particular, for aluminum-containing substrates, the brightening property will not cause corrosion cavitation, and the brightening property has a certain protective effect. N-(4-fluoro-2-methoxy-5-nitrophenyl)-4-(1-methyl-1H-indol-3-yl)pyrimidine-2-amine hydrochloride and N-Boc-indoline-7-carboxylic acid are used as composite leveling agents, which can improve the compactness of the coating and promote continuous nucleation in the crystallization process of the coating. At the same time, when used in combination with the brightener, the brightener can Rapid crystal growth under high current density, while the composite leveler can inhibit the excessive size of crystal particles and promote the growth of new crystal nuclei at low positions, thereby improving the density of the coating; the use of pterin-6-carboxylic acid and 6-hydroxypyridazine-3-carboxamide as composite anti-pinhole agents can solve the pores caused by gas reduction precipitation. During the electrolysis process, with the increase of current density, the electrolysis of water and the consumption of brighteners, residual substances or produced gases will cause uneven coating, while the anti-pinhole agent can wet the nickel surface and improve the continuous growth performance of nickel crystals; malic acid is used as a complexing agent, which can form a stable complex with nickel ions to prevent nickel ions from precipitating in the solution. Through the synergistic effect of each component, combined with the reasonable setting of the process parameters of the electroplating nickel solution, the electroplating nickel solution has good stability and corrosion resistance, and can be used for the electroplating nickel surface treatment of ceramic substrates to form a coating with good uniformity and brightness, no folding cracks, no coating pinholes and dark coating.

Claims

1. A nickel electroplating solution, It is characterized in that The electroplating nickel solution comprises the following components in terms of concentration: 150-300 g / L nickel salt, 30-80 g / L complexing agent, 30-80 g / L boric acid, 30-100 mg / L brightener, 20-100 mg / L leveler, and 50-150 mg / L anti-pinhole agent; the solvent of the electroplating nickel solution is water; and the brightener comprises 2-hydroxypyrimidine hydrochloride.

2. The nickel electroplating solution according to claim 1, It is characterized in that The nickel salt is selected from at least one of nickel chloride and nickel sulfate; And / or, the complexing agent is selected from at least one of malic acid, citric acid, tartaric acid, ethylenediaminetetraacetic acid, and glycolic acid.

3. The nickel electroplating solution according to claim 1, It is characterized in that The leveler is selected from N-(4-fluoro-2-methoxy-5-nitrophenyl)-4-(1-methyl-1H-indol-3-yl)pyrimidin-2-amine hydrochloride, N-Boc-indoline-7-carboxylic acid or a combination thereof.

4. The nickel electroplating solution according to claim 3, It is characterized in that The leveler is a mixture of N-(4-fluoro-2-methoxy-5-nitrophenyl)-4-(1-methyl-1H-indol-3-yl)pyrimidine-2-amine hydrochloride and N-Boc-indoline-7-carboxylic acid in a mass ratio of (1-2):

1.

5. The nickel electroplating solution according to claim 1, It is characterized in that The anti-pinhole agent is selected from pterin-6-carboxylic acid, 6-hydroxypyridazine-3-carboxamide or a combination thereof.

6. The nickel electroplating solution according to claim 5, It is characterized in that The anti-pinhole agent is a mixture of pterin-6-carboxylic acid and 6-hydroxypyridazine-3-carboxamide in a mass ratio of (1-2):

1.

7. The nickel electroplating solution according to any one of claims 1 to 6, It is characterized in that The pH value of the nickel electroplating solution is 3.5-5.

0.

8. The nickel electroplating solution according to claim 7, It is characterized in that The working parameters of the nickel electroplating solution include at least one of the following: 1) Working temperature is 20-40℃; 2) Current density is 0.1-5A / dm 2 ; 3) Working time is 10-40min.

9. A method for preparing a nickel electroplating solution according to any one of claims 1 to 8, It is characterized in that The following steps are involved: The components including nickel salt, complexing agent, boric acid, brightener, leveling agent and anti-pinhole agent are mixed with solvent according to concentration ratio to obtain the nickel electroplating solution.

10. Use of the nickel electroplating solution according to any one of claims 1 to 8 in surface treatment of ceramic substrates.

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