A forward and reverse pulse electrolytic nickel-phosphorus alloy solution, a preparation method, an electroplating method and a nickel-phosphorus alloy coating

Abstract

The present application belongs to the technical field of electroplating nickel-phosphorus alloy, and particularly relates to a positive and reverse pulse electrolytic nickel-phosphorus alloy solution, a preparation method, an electroplating method and a nickel-phosphorus alloy coating. The nickel-phosphorus alloy solution comprises 20-500 g / L of nickel salt, 30-300 g / L of phosphorous acid compound, 5-30 g / L of boric acid, 0.5-50 g / L of organic acid and 0.2-35 g / L of pyridinium compound. The present application adopts a positive and reverse pulse cyclic electroplating method, can obtain a nickel-phosphorus alloy electroplating product with uniform coating distribution, saves the amount of nickel-phosphorus alloy used for each plating piece, reduces the production cost, improves the product quality, and can meet the trend of high-end development of electroplating manufacturing nickel-phosphorus alloy coating in the field of electronic product manufacturing.

Description

Technical Field

[0001] This invention belongs to the field of nickel-phosphorus alloy electroplating technology, and particularly relates to a forward and reverse pulse electrolytic nickel-phosphorus alloy solution, its preparation method, its electroplating method, and its nickel-phosphorus alloy coating. Background Technology

[0002] Nickel-phosphorus alloy coatings possess characteristics such as dense surface, high hardness, corrosion resistance, and excellent magnetic properties, making them widely used in electronic products such as new energy vehicles, aerospace, and communications. Common chemical plating methods for preparing nickel-phosphorus alloy coatings suffer from high production costs due to long processing times, low throughput, low yield, and frequent tank restarts. Therefore, in recent years, the development trend of high-end electrolytic manufacturing of nickel-phosphorus alloy coatings has become unstoppable in the electronics manufacturing sector.

[0003] The nickel-phosphorus alloy electroplating solution provided by patent CN114232040A has the characteristics of low internal stress in the plating layer and fast electroplating deposition speed. At the same time, the nickel-phosphorus alloy electroplating solution can be used on a variety of substrates, the electroplating process is simple, and it has a significant cost advantage compared with the commonly used nickel-tungsten electroplating solutions.

[0004] The electroplating solution provided by patent CN112853415B uses a nickel-phosphorus alloy process to replace the semi-bright nickel process and combines it with the bright nickel electroplating process. This can ensure the corrosion resistance of the electroplating protection system while significantly reducing the overall amount of nickel used, thereby achieving the effects of reducing the amount of nickel used, saving resources and reducing production costs.

[0005] However, in the existing electrolytic nickel-phosphorus technologies mentioned above, when using high-frequency DC power supplies and pulsed power supplies, depending on the shape of the electrolytic product, the current distribution is higher in the edge areas, resulting in an excessively thick edge nickel-phosphorus alloy coating; while the flat central area of ​​the product has a larger surface area and lower current distribution, causing the central nickel-phosphorus alloy coating to be too thin. Consequently, while the nickel-phosphorus alloy coating in the central area meets the product's technical standards, the coating in the edge areas far exceeds the standard value, causing unnecessary waste. This not only increases production costs but also causes friction damage during subsequent product assembly, affecting the quality of high-end electronic products.

[0006] In view of this, the present invention is proposed. Summary of the Invention

[0007] To address the problem of uneven coating in existing nickel-phosphorus alloy electroplating technologies, which leads to issues in production and processing, this invention provides a forward and reverse pulse electrolytic nickel-phosphorus alloy solution, its preparation method, electroplating method, and the resulting nickel-phosphorus alloy coating. By adding organic acids and pyridinium compounds to the forward and reverse pulse electrolytic nickel-phosphorus alloy solution, this invention exhibits stable characteristics against both forward and reverse pulse signal impacts, demonstrating good stability even under high-speed switching conditions of the forward and reverse pulse power signals. Furthermore, this invention employs a forward and reverse pulse cyclic electroplating method, resulting in nickel-phosphorus alloy electroplated products with uniform coating distribution, reducing the amount of nickel-phosphorus alloy used per plated part, and improving product quality.

[0008] This invention is achieved through the following technical solution:

[0009] This invention provides a forward and reverse pulse electrolysis solution for nickel-phosphorus alloys, comprising the following components:

[0010] Nickel salts 20-500 g / L, phosphorous compounds 30-300 g / L, boric acid 5-30 g / L, organic acids 0.5-50 g / L, and pyridinium compounds 0.2-35 g / L.

[0011] Preferably, the nickel salt is one or more selected from nickel sulfate, nickel aminosulfonate, nickel chloride, and nickel carbonate;

[0012] The phosphorous compounds are one or more selected from phosphorous acid, sodium phosphite, potassium phosphite, potassium dihydrogen phosphite, and sodium dihydrogen phosphite.

[0013] The organic acids are one or more of the following: carboxylic acids, sulfonic acids, lactic acid, and citric acid;

[0014] The nickel-phosphorus electrolyte in the prior art has the following problems when using the forward and reverse pulse method to electroplate nickel-phosphorus coatings: (1) Although nickel-phosphorus alloy products can be obtained by electrolysis, the nickel-phosphorus alloy solution will become turbid and unstable, and cannot be used in continuous electrolytic production; (2) During the electrolysis process, the nickel-phosphorus alloy solution generates suspended particles, which co-precipitate with nickel and phosphorus, resulting in impurities in the obtained nickel-phosphorus alloy coating; (3) No nickel-phosphorus alloy coating can be obtained after electrolysis.

[0015] To address the aforementioned problems, as a preferred embodiment, the pyridinium compound of the present invention employs 1-(carboxymethyl)pyridinium, 1-(2-oxo-2-phenylethyl)pyridinium, 1-butyl-4-methylpyridinium, 1-methyl-2-carboxypyridinium, 1-methyl-2-methoxycarbonylpyridinium, 1-methyl-2-phenylpyridinium, 1-methyl-2-cyanopyridinium, 1-ethyl-2-aminopyridinium, 1-ethyl-2-carboxypyridinium, 1-ethyl-2-methoxycarbonylpyridinium, 1-propyl-2-aminopyridinium, 1-propyl-2-carboxypyridinium, and 1-propyl-2-methoxycarbonyl... One or more of pyridinium, 1-propyl-2-phenylpyridinium, 1-propyl-2-cyanopyridinium, 1-butyl-2-methylpyridinium, 1-butyl-2-ethylpyridinium, 1-butyl-2-butylpyridinium, 1-butyl-2-sulfopyridinium, 1-butyl-2-methoxysulfonylpyridinium, 1-butyl-2-aminopyridinium, 1-butyl-4-phenylpyridinium, 1-butyl-4-cyanopyridinium, 1-methyl-2-chloropyridinium, 1-methyl-2-fluoropyridinium, 2,3-dimethylbenzothiazolylium, and 5,10,15,20-tetra(N-methyl-4-pyridinium)porphyrin.

[0016] Because of the low electron cloud density on the pyridine ring in the above-mentioned pyridinium compounds, they are not easily oxidized and have electromagnetic field resistance. Especially under acidic conditions, the nitrogen atom of pyridinium carries a positive charge, which strengthens the electron-withdrawing inductive effect, making the electron cloud density on the pyridine ring even lower, further increasing the stability against oxidants and electromagnetic fields.

[0017] As another preferred embodiment, the carboxylic acid described in this invention is one or more of the following: 4-hydroxybenzoic acid, 2-hydroxybenzoic acid, 2-amino-4-hydroxybenzoic acid, 3-amino-4-hydroxybenzoic acid, 2-amino-5-hydroxybenzoic acid, 3-amino-5-hydroxybenzoic acid, 4-amino-2-hydroxybenzoic acid, 2-amino-1,3,5-benzenetricarboxylic acid, 5-aminoisophthalic acid, 3-hydroxybenzoic acid, 3,4-dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, 2,3-dihydroxybenzoic acid, and 3,4,5-trihydroxybenzoic acid.

[0018] Because the aforementioned carboxylic acids are acidic and possess the dual properties of a hydrophobic hydrocarbon group and a hydrophilic carboxyl group, they are miscible with pure water in the forward and reverse pulse electrolysis nickel-phosphorus alloy solution of this invention. Furthermore, the carboxyl groups of organic carboxylic acids exhibit strong hydrogen bonding between molecules. Under acidic conditions, the oxygen atoms of the carboxylic acid groups carry a negative charge, enhancing the electron-donating inductive effect of the organic carboxylic acids and increasing their electron cloud density. This electron cloud density attracts the positively charged nickel metal ions and the positively charged nitrogen of the pyridinium in the forward and reverse pulse electrolysis nickel-phosphorus alloy solution, thus strengthening the stability of the solution.

[0019] The sulfonic acid is one or more of the following: benzenesulfonic acid, p-methylbenzenesulfonic acid, 2-methylbenzenesulfonic acid, 3-methylbenzenesulfonic acid, 3-aminobenzenesulfonic acid, 3-amino-4-hydroxybenzenesulfonic acid, 4-amino-1,3-dibenzenesulfonic acid, 4-(dimethylamino)benzenesulfonic acid, 3,4-diaminobenzenesulfonic acid, 2-aminobenzenesulfonic acid, 4-methoxybenzenesulfonic acid, 3-amino-4-methoxybenzenesulfonic acid, 4-fluorobenzenesulfonic acid, 4-chloro-3-nitrobenzenesulfonic acid, sodium 3-nitrobenzenesulfonate, sodium 2-amino-5-nitrobenzenesulfonate, 2-iodobenzenesulfonic acid, 4-hydroxybenzenesulfonic acid, 4-iodobenzenesulfonic acid, 3-bromobenzenesulfonic acid, and 4-mercaptobenzenesulfonic acid.

[0020] Because benzenesulfonic acids are non-oxidizing strong organic acids, they have excellent antiseptic, antibacterial, and bactericidal properties. At the same time, under acidic conditions, the oxygen atom of the phenylsulfonic acid group carries a negative charge, which enhances the electron-induced effect and increases the electron cloud density of the phenylsulfonic acid group. This corresponds to the positive charge of nitrogen in the pyridinium group, further increasing its stability against oxidants and electromagnetic fields.

[0021] The present invention also provides a method for preparing the aforementioned forward and reverse pulse electrolytic nickel-phosphorus alloy solution, comprising the following steps:

[0022] S1. Under heating and stirring conditions, add boric acid to a portion of pure water in small amounts several times.

[0023] S2. After the boric acid has completely dissolved, add the nickel salt in small amounts several times.

[0024] S3. After the nickel salt has completely dissolved, add the phosphite compound and stir well.

[0025] S4. Add organic acids and pyridinium compounds in sequence, stir evenly, add the remaining pure water to obtain the forward and reverse pulse electrolytic nickel-phosphorus alloy solution.

[0026] In order to facilitate the complete dissolution of all components in the nickel-phosphorus alloy solution, the present invention uses a heating temperature of 40-60℃.

[0027] The present invention also provides a method for electroplating nickel-phosphorus alloys using forward and reverse pulse electroplating, comprising the following steps:

[0028] (1) Place the nickel-phosphorus alloy electrolyte into the electrolytic cell and heat it to 40-60℃;

[0029] (2) Connect the nickel plate to the positive terminal of the pulse reverse power supply through the positive conductive connecting rod, and connect the plated part to the negative terminal of the pulse reverse power supply through the negative conductive connecting rod;

[0030] (3) Electroplating using forward and reverse pulses: at a current density of 0.5-8.0 A / dm 2 Within the range, a forward pulse current I1 is applied for a forward pulse time t1, and then a reverse pulse current I2 is applied for a reverse pulse time t2, completing one cycle of forward and reverse pulse electroplating;

[0031] (4) Repeat the forward and reverse pulse cycle of step (3) until the set electroplating time ends.

[0032] It should be noted that when performing the forward and reverse pulse cycle electroplating of nickel-phosphorus alloy coating according to the present invention, in one cycle, when the forward pulse is applied first, the current distribution in the edge area of ​​the workpiece is greater, resulting in a thicker edge coating. When the reverse pulse is applied, the workpiece will undergo anodic dissolution. Similarly, due to the greater current distribution in the edge area, the edge coating dissolves faster than the central area, ultimately resulting in a uniform thickness of the entire coating product. Furthermore, during the reverse pulse, the anodic dissolution greatly reduces the inclusion of impurities in the coating, improving the purity and density of the coating.

[0033] As can be seen from the above, the setting of pulse current and pulse time in each forward and reverse pulse cycle affects the overall coating quality. As a preferred scheme, the ratio of t1 to t2 is in the range of (10-100):1; the ratio of I1 to I2 is in the range of 1:(2-5). By setting the magnitude and pulse time of the forward and reverse pulse currents, the deposition rate and dissolution rate of the nickel-phosphorus coating at the edge and middle regions can be effectively controlled, resulting in uniform thickness of the final electroplated nickel-phosphorus alloy coating at both the edge and middle regions.

[0034] Preferably, the electroplating time is 1-60 min, and the thickness of the nickel-phosphorus alloy coating obtained by electroplating is 0.5-100 μm.

[0035] The present invention also provides a nickel-phosphorus alloy coating obtained by electroplating according to the method, wherein the composition of the nickel-phosphorus alloy coating is Ni. 100-m P m m is the percentage of phosphorus atoms, and 10% ≤ m ≤ 16%.

[0036] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0037] (1) The present invention adds pyridinium compounds and organic acids to the forward and reverse pulse electrolytic nickel-phosphorus alloy solution, which has stable characteristics to withstand the impact of forward and reverse pulse signals. Under the condition of high-speed conversion of forward and reverse pulse power signals, it has good stability, avoids the problem of turbidity of nickel-phosphorus alloy solution and the formation of suspended particles in nickel-phosphorus alloy solution, which co-precipitate with nickel-phosphorus alloy and cause impurities in the obtained nickel-phosphorus alloy coating, thereby ensuring that the subsequent electroplating products have good quality.

[0038] (2) In the process of forward and reverse pulse electroplating of nickel-phosphorus alloy coating, a nickel-phosphorus alloy coating with uniform thickness is obtained by cyclically applying forward pulse and reverse pulse. Compared with the existing electroplating technology, when electroplating nickel-phosphorus alloy coating with a thickness of 5.0-50μm, the electroplating method of the present invention can save 48-228 grams of nickel-phosphorus alloy per part; and the thicker the nickel-phosphorus alloy coating, the more nickel-phosphorus alloy is saved by the electroplating method of the present invention. Attached Figure Description

[0039] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0040] Figure 1 This is a schematic diagram of the forward and reverse pulse electroplating nickel-phosphorus alloy apparatus of the present invention, wherein (a) is a schematic diagram of applying a forward pulse current and (b) is a schematic diagram of applying a reverse pulse current;

[0041] Figure 2 This is a schematic diagram of the pulse reverse power supply electrolysis of the present invention;

[0042] Figure 3 The diagram shows the thickness distribution of a standard nickel-phosphorus alloy plated part with a thickness of 5 μm and the nickel-phosphorus alloy plated parts of Example 1 and Comparative Example 4, where:

[0043] (a) is a schematic diagram of the thickness distribution of a standard nickel-phosphorus alloy plated part with a coating thickness of 5 μm.

[0044] (b) is a schematic diagram of the thickness distribution of the nickel-phosphorus alloy plating obtained in Comparative Example 4.

[0045] (c) is a schematic diagram comparing the thickness distribution of the nickel-phosphorus alloy plated part obtained in Comparative Example 4 with that of the standard plated part.

[0046] (d) is a schematic diagram of the thickness distribution of the nickel-phosphorus alloy plating obtained in Example 1.

[0047] (e) is a schematic diagram comparing the thickness distribution of the nickel-phosphorus alloy plated part obtained in Example 1 with that of the standard plated part;

[0048] Figure 4(a) A schematic diagram comparing the thickness distribution of the nickel-phosphorus alloy plating obtained in Comparative Example 5 with that of a 20 μm standard plating part, and (b) A schematic diagram comparing the thickness distribution of the nickel-phosphorus alloy plating obtained in Comparative Example 5 with that of the nickel-phosphorus alloy plating prepared in Example 3.

[0049] Figure 5 (a) A schematic diagram comparing the thickness distribution of the nickel-phosphorus alloy plating obtained in Comparative Example 6 with that of a 50 μm standard plating part, and (b) A schematic diagram comparing the thickness distribution of the nickel-phosphorus alloy plating obtained in Comparative Example 6 with that of the nickel-phosphorus alloy plating prepared in Example 5.

[0050] Wherein, 10-nickel-phosphorus alloy electrolyte, 20-nickel plate, 21-positive electrode conductive connecting rod, 30-plated part, 31-negative electrode conductive connecting rod, 35-standard nickel-phosphorus alloy plating 35, 36-nickel-phosphorus plating prepared in the comparative example, 37-excess plating, 38-nickel-phosphorus alloy plating prepared in the embodiment of the present invention, 39-excess electroplating portion, 50-electrolytic cell, 100-pulse reverse power supply. Detailed Implementation

[0051] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0052] Example 1

[0053] This embodiment provides a forward and reverse pulse electrolytic nickel-phosphorus alloy solution, comprising: nickel aminosulfonate 110 g / L, phosphorous acid 165 g / L, boric acid 10 g / L, 4-methylbenzenesulfonic acid 1 g / L and 1-methyl-2-carboxypyridinium 0.5 g / L.

[0054] The preparation method of the above-mentioned nickel-phosphorus alloy electrolyte includes the following steps:

[0055] S0. Add 13 liters of pure water to the cleaned 25-liter electrolytic cell 50, turn on the internal circulation pump, and turn on the heating system to raise the temperature while the pure water is circulating and stirring.

[0056] S1. When the temperature of the pure water in the electrolytic cell reaches 40°C, add 200 grams of analytical grade boric acid crystals to the electrolytic cell 50 in small amounts several times.

[0057] S2. After all the boric acid crystals in the electrolytic cell 50 have dissolved, add 2200 grams of analytical grade nickel aminosulfonate solid in multiple portions to the electrolytic cell 50.

[0058] S3. After all the nickel aminosulfonate solid in electrolytic cell 50 has dissolved, add 2000 ml (3300 g) of analytical grade phosphorous acid to electrolytic cell 50 in multiple portions.

[0059] S4. After the phosphorous acid in the electrolytic cell 50 is stirred evenly, add 20 grams of analytical grade 4-methylbenzenesulfonic acid to the electrolytic cell 50 in two portions.

[0060] S5. After the 4-methylbenzenesulfonic acid in the electrolytic cell 50 is completely stirred evenly, 10 grams of analytical grade 1-methyl-2-carboxypyridinium is added to the electrolytic cell 50 in two portions.

[0061] S6. After the 1-methyl-2-carboxypyridinium in the electrolytic cell 50 is stirred evenly, pure water is added to make the solution volume in the electrolytic cell 50 reach 20 liters, and nickel-phosphorus alloy electrolyte 10 is obtained for later use.

[0062] like Figure 1 As shown, using the method of forward and reverse pulse electroplating of nickel-phosphorus alloy, when the forward pulse is running, the nickel plate 20 is coated with a positive electrode, and the plated part 30 is coated with a negative electrode. Figure 1 As shown in (a), when the reverse pulse is running, the nickel plate 20 is applied with a negative electrode, and the plated part 30 is applied with a positive electrode. Figure 1 As shown in (b), an electroplating nickel-phosphorus alloy coating is performed, requiring a coating thickness of 5 μm. The specific steps include the following:

[0063] (1) The nickel-phosphorus alloy electrolyte 10 prepared in the above electrolytic cell 50 is directly used and heated to 55°C;

[0064] (2) A copper plate with a size of 100×100mm and a thickness of 2mm is used as the plated part 30. One side of the plated part 30 is covered by a special protective film and then only the other side is exposed and set opposite to the nickel plate 20.

[0065] (3) After the shielding treatment, the plated part 30 is subjected to ultrasonic degreasing treatment for 15 seconds and then rinsed with pure water; after rinsing, the plated part 30 is subjected to cathodic electrolysis treatment for 10 seconds and then rinsed with pure water; then it is subjected to acid activation treatment for 20 seconds and then treated with pure water.

[0066] (4) Connect the nickel plate 20 to the positive terminal of the pulse reverse power supply 100 through the positive electrode conductive connecting rod 21, and connect the plated part 30 to the negative terminal of the pulse reverse power supply 100 through the negative electrode conductive connecting rod 31;

[0067] (5) Electroplating is performed using forward and reverse pulses, such as... Figure 2 As shown, at current densities of 0.5-8.0 A / dm 2Within the range, a forward pulse current I1 of 5A is applied, the forward pulse time t1 is 20 milliseconds, with an interval of 1 millisecond, and then a reverse pulse current I2 of 15A is applied, the reverse pulse time t2 is 2 seconds, completing one cycle of forward and reverse pulse electroplating;

[0068] (6) Repeat the forward and reverse pulse cycle of step (3) for a total electroplating time of 5-10 minutes to obtain the nickel-phosphorus alloy coating. In this embodiment, the coating thickness is 5 μm and the phosphorus content is 15.3%.

[0069] Examples 2-7

[0070] The composition of the forward and reverse pulse electrolytic nickel-phosphorus alloy solutions provided in Examples 2-7 is detailed in Table 1.

[0071] The preparation methods of the nickel-phosphorus alloy electrolytes in Examples 2-7 are the same as those in Example 1.

[0072] The methods for electroplating nickel-phosphorus alloy coatings in Examples 2-7 are basically the same as those in Example 1, except that:

[0073] In Example 2, the total electroplating time was 10-15 minutes, the coating thickness was 10 μm, and the phosphorus content was 14.6%.

[0074] In Example 3, the total electroplating time was 20-30 minutes, the coating thickness was 20 μm, and the phosphorus content was 15.1%.

[0075] In Example 4, the total electroplating time was 30-40 minutes, the coating thickness was 30 μm, and the phosphorus content was 13.8%.

[0076] In Example 5, the total electroplating time was 50-60 minutes, the coating thickness was 50 μm, and the phosphorus content was 12.9%.

[0077] In Example 6, the total electroplating time was 5-10 minutes, the coating thickness was 5 μm, and the phosphorus content was 11.7%.

[0078] The total electroplating time in Example 7 was 30-40 minutes, the coating thickness was 30 μm, and the phosphorus content was 13.5%.

[0079] Table 1. Composition of the forward and reverse pulse electrolytic nickel-phosphorus alloy solutions in Examples 1-7 and Comparative Examples 1-6

[0080]

[0081] Note: The symbols in the table are explained as follows:

[0082] * 1 20 grams of 4-methylbenzenesulfonic acid, * 2 10g of 4-methylbenzenesulfonic acid + 10g of 2,4-dihydroxybenzoic acid,*3 The mixture consists of 10 grams of 4-(dimethylamino)benzenesulfonic acid and 10 grams of 3,4,5-trihydroxybenzoic acid. 4 It consists of 10 grams of 3,4,5-trihydroxybenzoic acid and 20 grams of lactic acid. 5 The mixture consists of 10 grams of 4-chloro-3-nitrobenzenesulfonic acid and 10 grams of citric acid. 6 10 grams of 4-amino-2-hydroxybenzoic acid,* 7 It consists of 50 grams of 5-aminoisophthalic acid and 50 grams of 3-hydroxybenzoic acid.

[0083] #1 10 grams of 1-methyl-2-carboxypyridinium #2 10 grams of 1-ethyl-2-aminopyridinium #3 10 grams of 1-propyl-2-methoxycarbonylpyridinium #4 10 grams of 1-butyl-4-phenylpyridinium #5 The mixture consists of 5 g of 1-(carboxymethyl)pyridinium + 5 g of 1-butyl-2-methoxysulfonylpyridinium. #6 5 grams of 1-methyl-2-chloropyridinium #7 The contents are 400 g of 1-propyl-2-cyanopyridinium + 300 g of 5,10,15,20-tetra(N-methyl-4-pyridinium)porphyrin.

[0084] ^1 It contains 400 grams of nickel sulfate. ^2 The mixture consists of 4000 grams of nickel sulfate and 4500 grams of nickel chloride. @1 600 grams of sodium phosphite @2 The mixture consists of 3000 grams of potassium dihydrogen phosphite and 2500 grams of sodium dihydrogen phosphite.

[0085] &1 The mixture consists of 1500 grams of nickel sulfate and 700 grams of nickel chloride. &2 2 grams of sodium dodecyl sulfonate &3 For 1 gram of fructose, &4 3 grams of 1,4-butynediol &5 2 grams of 2-pyridinecarboxylic acid &6 20 grams of sodium o-benzoylsulfonylimide &7 1 gram of 2H-1-benzopyran-2-one.

[0086] Comparative Examples 1-6

[0087] The compositions of the forward and reverse pulse electrolytic nickel-phosphorus alloy solutions provided in Comparative Examples 1-6 are detailed in Table 1.

[0088] The preparation methods of the nickel-phosphorus alloy electrolytes in Comparative Examples 1-6 are the same as those in Example 1, except that the corresponding components are replaced according to Table 1, and the order of adding the components remains unchanged.

[0089] The method for electroplating a nickel-phosphorus alloy coating in Comparative Example 1 is the same as that in Example 1. The methods for electroplating nickel-phosphorus alloy coatings in Comparative Examples 2-3 are basically the same as those in Example 1, except that:

[0090] The total electroplating time for Comparative Example 2 was 20-30 minutes, and the coating thickness was 20 μm.

[0091] The total electroplating time for Comparative Example 3 was 50-60 minutes, and the coating thickness was 50 μm.

[0092] The methods for electroplating nickel-phosphorus alloy coatings in Comparative Examples 4, 5, and 6 are the same as those in Comparative Examples 1, 2, and 3, respectively. The only difference is that in Comparative Examples 4, 5, and 6, a high-frequency power supply is used instead of the pulse reverse power supply 100 in Comparative Examples 1, 2, and 3. All other implementation conditions are the same as those in Comparative Examples 1, 2, and 3.

[0093] The thickness distribution of the nickel-phosphorus alloy plating parts prepared in Examples 1-7 and Comparative Examples 1-6 was analyzed. Here, the thickness distribution of the nickel-phosphorus alloy plating parts obtained in Examples 1 and 4, Examples 3 and 5, and Examples 5 and 6 were compared.

[0094] like Figure 3 As shown, Figure 3 (a) is a schematic diagram of the thickness distribution of a standard nickel-phosphorus alloy plated part with a coating thickness of 5 μm. Figure 3 (b) is a schematic diagram of the thickness distribution of the nickel-phosphorus alloy plating obtained in Comparative Example 4. Figure 3 (c) is a schematic diagram comparing the thickness distribution of the nickel-phosphorus alloy plated part obtained in Comparative Example 4 with that of the standard plated part. Figure 3 (d) is a schematic diagram of the thickness distribution of the nickel-phosphorus alloy plating obtained in Example 1. Figure 3 Figure (e) is a schematic diagram comparing the thickness distribution of the nickel-phosphorus alloy plating obtained in Example 1 with that of the standard plating. It can be seen that, compared to the standard nickel-phosphorus alloy plating 35, the excess plating layer 37 in Comparative Example 4, resulting in the use of 63.7% more nickel-phosphorus alloy, leads to the overuse of the standard nickel-phosphorus alloy plating 35. It should be noted that the thicker the standard nickel-phosphorus alloy plating 35, the greater the difference in the thickness distribution of the actual prepared nickel-phosphorus alloy plating, which in turn leads to a greater amount of nickel-phosphorus alloy being used in the excess plating layer 37, resulting in more waste.

[0095] To illustrate the advantages of the present invention's method of forward and reverse pulse electroplating of nickel-phosphorus alloys, from... Figure 3 As can be seen from (d) to (e), the thickness distribution of the nickel-phosphorus alloy coating 38 prepared by the present invention is relatively uniform, and compared with the standard nickel-phosphorus alloy coating 35, the excess electroplating part 39 of the present invention only uses 18.2% more nickel-phosphorus alloy.

[0096] Furthermore, for a standard nickel-phosphorus alloy plating with a product specification of 5μm, the nickel-phosphorus alloy plating 38 prepared by the electroplating method of Example 1 of the present invention uses 63.7%-18.2% = 45.5% less nickel-phosphorus alloy per plating part compared with the nickel-phosphorus alloy plating 36 prepared by the high-frequency power supply (Comparative Example 4), which translates to a reduction of 48 grams of nickel-phosphorus alloy per plating part.

[0097] like Figure 4 As shown, Figure 4 (a) is a schematic diagram comparing the thickness distribution of the nickel-phosphorus alloy plated part obtained in Comparative Example 5 with that of the 20μm standard plated part. Figure 4 (b) is a schematic diagram comparing the thickness distribution of the nickel-phosphorus alloy plating obtained in Comparative Example 5 and the nickel-phosphorus alloy plating prepared in Example 3. It can be seen that, for a standard nickel-phosphorus alloy plating with a product specification of 20 μm, the nickel-phosphorus alloy plating 38 prepared by Example 3 of this invention has a thickness distribution that, compared with the nickel-phosphorus plating 36 prepared by the high-frequency power supply in Comparative Example 5, requires 102 grams less nickel-phosphorus alloy per plating piece.

[0098] like Figure 5 As shown, Figure 5 (a) is a schematic diagram comparing the thickness distribution of the nickel-phosphorus alloy plated part obtained in Comparative Example 6 with that of a 50 μm standard plated part. Figure 5 (b) is a schematic diagram comparing the thickness distribution of the nickel-phosphorus alloy plating obtained in Comparative Example 6 and the nickel-phosphorus alloy plating prepared in Example 5. It can be seen that, for a standard nickel-phosphorus alloy plating with a product specification of 50 μm, the nickel-phosphorus alloy plating 38 prepared by Example 5 of the present invention has a thickness distribution that, compared with the nickel-phosphorus plating 36 prepared by the high-frequency power supply in Comparative Example 6, requires 228 grams less nickel-phosphorus alloy per plating piece.

[0099] In summary, the nickel-phosphorus alloy coating prepared by the forward and reverse pulse electroplating method of the present invention has good uniformity, which greatly reduces the amount of nickel-phosphorus alloy used, saves raw material resources, and significantly reduces production costs.

[0100] To further illustrate the properties of the nickel-phosphorus alloy coatings prepared according to the present invention, the appearance, phosphorus content, coating hardness, and corrosion resistance of the nickel-phosphorus alloy coatings prepared in Examples 1-7 and Comparative Examples 1-6 will be tested below. The phosphorus content in the electrolytic nickel-phosphorus alloy coatings was tested using a Fischer X-ray XDV-SDD instrument. The neutral salt spray test standard was based on the artificial atmosphere corrosion test standard GB-10125-2012. The surface hardness test standard was based on the Vickers hardness test method in GB / T9790. The surface roughness was tested using a Keyence VR-5000 3D profile measuring instrument. The test results are shown in Table 2.

[0101] Table 2. Test results of nickel-phosphorus alloy coatings obtained in Examples 1-7 and Comparative Examples 1-6

[0102]

[0103] Table 3 Comparison of data for nickel-phosphorus alloy coatings obtained in Examples 1-7 and Comparative Examples 1-6

[0104]

[0105] Remark: ☆1 The area difference between the coating in Example 1 and the coating in Comparative Example 4 is represented by the following value. ☆2 The area difference between the coating in Example 3 and the coating in Comparative Example 5 is shown. ☆3 The area difference is between the coating of Example 5 and the coating of Comparative Example 6.

[0106] As can be seen from Table 2, the appearance and roughness of the nickel-phosphorus alloy coatings obtained in Examples 1-7 are significantly better than those in Comparative Examples 4-6; and the nickel-phosphorus alloy electrolytic solutions of Comparative Examples 1-3 in the prior art, when electroplated using a pulsed reverse power supply (100), do not yield the expected nickel-phosphorus alloy coating products.

[0107] As can be seen from Table 3, when comparing nickel-phosphorus alloy coatings of the same standard thickness, the nickel-phosphorus alloy coatings obtained in Examples 1, 3 and 5 exhibit significantly superior performance in terms of uniformity of coating distribution and amount of nickel-phosphorus alloy raw materials used compared to Comparative Examples 4, 5 and 6, as well as a substantial advantage in saving nickel-phosphorus alloy raw materials.

[0108] It is easy to see from the results in Tables 2 and 3 that the forward and reverse pulse electrolytic nickel-phosphorus alloy solution, preparation method, electroplating method and nickel-phosphorus alloy coating provided by the present invention not only have various excellent properties of electronic materials, which can meet the trend of high-end development of electroplating nickel-phosphorus alloy coatings in the field of electronic product manufacturing, but also can significantly save nickel-phosphorus alloy raw materials and reduce production costs.

[0109] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined by the scope of the claims.

Claims

1. A forward and reverse pulse electrolysis solution for nickel-phosphorus alloys, characterized in that, It includes the following components: Nickel salts 20-500 g / L, phosphorous compounds 30-300 g / L, boric acid 5-30 g / L, organic acids 0.5-50 g / L, and pyridinium compounds 0.2-35 g / L; The organic acids are one or more of carboxylic acids, sulfonic acids, lactic acid, and citric acid. The pyridinium compounds are 1-(carboxymethyl)pyridinium, 1-(2-oxo-2-phenylethyl)pyridinium, 1-butyl-4-methylpyridinium, 1-methyl-2-carboxypyridinium, 1-methyl-2-methoxycarbonylpyridinium, 1-methyl-2-phenylpyridinium, 1-methyl-2-cyanopyridinium, 1-ethyl-2-aminopyridinium, 1-ethyl-2-carboxypyridinium, 1-ethyl-2-methoxycarbonylpyridinium, 1-propyl-2-aminopyridinium, 1-propyl-2-carboxypyridinium, 1-propyl-2-methoxycarbonylpyridinium, 1-propyl-2-aminopyridinium, 1-propyl-2-carboxypyridinium, 1-propyl-2-methoxycarbonylpyridinium, 1-propyl-2-aminopyridinium, 1-propyl-2-carboxypyridinium, 1-propyl-2-methoxycarbonylpyridinium, 1-propyl-2-phenyl ... One or more of the following: 1-phenylpyridinium, 1-propyl-2-cyanopyridinium, 1-butyl-2-methylpyridinium, 1-butyl-2-ethylpyridinium, 1-butyl-2-butylpyridinium, 1-butyl-2-sulfopyridinium, 1-butyl-2-methoxysulfonylpyridinium, 1-butyl-2-aminopyridinium, 1-butyl-4-phenylpyridinium, 1-butyl-4-cyanopyridinium, 1-methyl-2-chloropyridinium, 1-methyl-2-fluoropyridinium, 2,3-dimethylbenzothiazolylium, and 5,10,15,20-tetra(N-methyl-4-pyridinium)porphyrin.

2. The forward and reverse pulse electrolysis of nickel-phosphorus alloy solution according to claim 1, characterized in that, The nickel salt is one or more of nickel sulfate, nickel aminosulfonate, nickel chloride, and nickel carbonate; The phosphorous compounds are one or more of phosphorous acid, sodium phosphite, potassium phosphite, potassium dihydrogen phosphite, and sodium dihydrogen phosphite.

3. The forward and reverse pulse electrolysis of nickel-phosphorus alloy solution according to claim 1, characterized in that, The carboxylic acids are one or more selected from 4-hydroxybenzoic acid, 2-hydroxybenzoic acid, 2-amino-4-hydroxybenzoic acid, 3-amino-4-hydroxybenzoic acid, 2-amino-5-hydroxybenzoic acid, 3-amino-5-hydroxybenzoic acid, 4-amino-2-hydroxybenzoic acid, 2-amino-1,3,5-benzenetricarboxylic acid, 5-aminoisophthalic acid, 3-hydroxybenzoic acid, 3,4-dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, 2,3-dihydroxybenzoic acid, and 3,4,5-trihydroxybenzoic acid. The sulfonic acids are one or more of the following: benzenesulfonic acid, p-methylbenzenesulfonic acid, 2-methylbenzenesulfonic acid, 3-methylbenzenesulfonic acid, 3-aminobenzenesulfonic acid, 3-amino-4-hydroxybenzenesulfonic acid, 4-amino-1,3-dibenzenesulfonic acid, 4-(dimethylamino)benzenesulfonic acid, 3,4-diaminobenzenesulfonic acid, 2-aminobenzenesulfonic acid, 4-methoxybenzenesulfonic acid, 3-amino-4-methoxybenzenesulfonic acid, 4-fluorobenzenesulfonic acid, 4-chloro-3-nitrobenzenesulfonic acid, sodium 3-nitrobenzenesulfonate, sodium 2-amino-5-nitrobenzenesulfonate, 2-iodobenzenesulfonic acid, 4-hydroxybenzenesulfonic acid, 4-iodobenzenesulfonic acid, 3-bromobenzenesulfonic acid, and 4-mercaptobenzenesulfonic acid.

4. A method for preparing a forward and reverse pulse electrolytic nickel-phosphorus alloy solution according to any one of claims 1-3, characterized in that, Includes the following steps: S1. Under heating and stirring conditions, add boric acid to a portion of pure water in small amounts several times. S2. After the boric acid has completely dissolved, add the nickel salt in small amounts several times. S3. After the nickel salt has completely dissolved, add the phosphite compound and stir well. S4. Add organic acids and pyridinium compounds in sequence, stir evenly, add the remaining pure water to obtain the forward and reverse pulse electrolytic nickel-phosphorus alloy solution.

5. The preparation method according to claim 4, characterized in that, The heating temperature is 40-60℃.

6. A method for electroplating nickel-phosphorus alloys using forward and reverse pulse electroplating, characterized in that, Includes the following steps: (1) The nickel-phosphorus alloy electrolyte (10) according to any one of claims 1-3 is placed in an electrolytic cell (50) and heated to 40-60°C; (2) Connect the nickel plate (20) to the positive terminal of the pulse reverse power supply (100) through the positive conductive connecting rod (21), and connect the plated part (30) to the negative terminal of the pulse reverse power supply (100) through the negative conductive connecting rod (31); (3) Electroplating using forward and reverse pulses: at a current density of 0.5-8.0 A / dm 2 Within the range, a forward pulse current I1 is applied for a forward pulse time t1, and then a reverse pulse current I2 is applied for a reverse pulse time t2, completing one cycle of forward and reverse pulse electroplating; (4) Repeat the forward and reverse pulse cycle of step (3) until the set electroplating time ends.

7. A method for electroplating nickel-phosphorus alloy using forward and reverse pulse electroplating according to claim 6, characterized in that, The ratio of t1 to t2 is in the range of (10-100):

1.

8. A method for electroplating nickel-phosphorus alloy using forward and reverse pulse electroplating according to claim 6, characterized in that, The ratio of I1 to I2 is in the range of 1:(2-5).

9. A method for electroplating nickel-phosphorus alloy using forward and reverse pulse electroplating according to claim 6, characterized in that, The electroplating time is 1-60 min, and the thickness of the nickel-phosphorus alloy coating obtained by electroplating is 0.5-100 μm.

10. A nickel-phosphorus alloy coating obtained by electroplating according to any one of claims 6-9, characterized in that, The nickel-phosphorus alloy coating is composed of Ni. 100-m P m m is the percentage of phosphorus atoms, and 10% ≤ m ≤ 16%.

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