Preparation method of diamond micro-powder chemical nickel plating solution for fretsaw

Abstract

The invention discloses a preparation method of a diamond micro-powder chemical nickel plating solution for a fretsaw, and relates to the technical field of chemistry and materials. The diamond micro-powder chemical nickel plating solution for the fret saw is prepared from the following components in parts by weight: 10 to 40 g / L of nickel sulfate hexahydrate, 20 to 40 g / L of sodium hypophosphite, 10 to 20 g / L of sodium citrate, 20 to 40 g / L of ammonium chloride, 0.001 to 0.0012 g / L of thiourea, 1 g / L of sodium dodecyl benzene sulfonate and 0.06 to 0.12 g / L of saccharin sodium salt. The formula of the nickel plating solution is optimized through a Taguchi design method, so that a plating layer is compact and uniform, skip plating and agglomeration are reduced, the efficiency is improved, and the cost is reduced; the water washing time is shortened by adopting a micro-powder filtering device; the sensitization activating solution promotes nickel deposition; a plating layer with the phosphorus content of 1%-6% can be obtained, and the problem that the plating solution is poor in stability is solved.

Description

Technical Field

[0001] This invention relates to the fields of chemistry and materials technology, specifically to a method for preparing a chemical nickel plating solution using diamond micron powder for wire saws. Background Technology

[0002] With the rapid development of new technologies, traditional grinding processes have gradually revealed their limitations. Hard and brittle materials have extremely high requirements for grinding precision and surface quality, and traditional abrasives such as quartz sand, brown fused alumina, and white fused alumina can no longer meet the growing demands. Therefore, finding more suitable abrasive materials has become a focus of attention in the industry.

[0003] Diamond, with its unparalleled physical properties, is hailed as a key to solving many technical challenges. It is not only extremely hard and wear-resistant, but also possesses excellent thermal and electrical conductivity. These properties make diamond an indispensable raw material in numerous technological innovation projects, especially in fields demanding extreme durability and performance, such as precision instrument manufacturing, machining, and advanced energy technologies. Diamond's extremely high hardness and corrosion resistance allow it to maintain its sharpness under extreme conditions, and it exhibits good thermal conductivity during grinding. Compared to other abrasives, diamond offers superior machining capabilities, achieves higher sharpness, excels in maintaining precision, and ensures the reliability of the machining process. These properties make diamond particularly important when machining hard and brittle materials, making it one of the most effective abrasives.

[0004] Currently, commonly used diamond surface coating methods include: electroless plating, electroplating, CVD (CVD) processes, PVD processes, vapor deposition, and salt bath plating. Electroless plating is one of the diamond surface coating technologies. Electroless nickel plating of diamond micropowder is performed without an external power source. It uses hypophosphite in the plating bath as a reducing agent to reduce metallic nickel ions to metallic nickel, which is then deposited on the diamond surface to form a dense and uniform metallic coating. Electroless plating is widely used due to its simple operation and low cost.

[0005] Currently, there are still some problems with electroless nickel plating of diamond micron powder, such as poor stability of the electroless plating solution, uneven and dense coating, and easy detachment of the coating. In mass production, problems such as missed plating, agglomeration, and low plating coverage also occur. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a method for preparing a chemical nickel plating solution using diamond micron powder for wire saws, which solves the problems of poor stability of the chemical plating solution, uneven and dense coating, and easy detachment of the coating.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A chemical nickel plating solution using diamond micron powder for wire saws, wherein the nickel plating solution, by mass concentration, comprises the following components in parts by weight: nickel sulfate hexahydrate 10~40 g / L, sodium hypophosphite 20~40 g / L, sodium citrate 10~20 g / L, ammonium chloride 20~40 g / L, thiourea 0.001~0.0012 g / L, sodium dodecylbenzenesulfonate 1 g / L, and sodium saccharin 0.06~0.12 g / L.

[0009] A method for preparing a chemical nickel plating solution using diamond micron powder for wire saws, the specific preparation steps are as follows:

[0010] A1. According to the amount of nickel plating solution to be prepared (100mL), weigh out sodium citrate, nickel sulfate hexahydrate, sodium hypophosphite, ammonium chloride, thiourea, sodium saccharin, and sodium dodecylbenzene sulfonate, dissolve them separately in a small amount of deionized water, and continue heating and stirring until completely dissolved.

[0011] A2. In a sodium citrate solution, add dissolved nickel sulfate hexahydrate, sodium hypophosphite, ammonium chloride, thiourea, sodium dodecylbenzenesulfonate, and sodium saccharin in sequence. Heat and stir continuously, add deionized water to 100 mL, stir thoroughly, then add ammonia to adjust the plating solution to the working pH value, and heat the plating solution to the working temperature to obtain a diamond micro powder electroless nickel plating solution for wire saws.

[0012] Furthermore, the working pH value is 8.0~9.5, and the working temperature is 40~70℃.

[0013] A method for electroless nickel plating with diamond micron powder for wire saws, the specific operation of which is as follows:

[0014] After the plating solution reaches the working temperature and stabilizes, the pretreated diamond micro powder is slowly added to the plating solution and mechanically stirred immediately. After stirring, if no bubbles are generated in the plating solution, the reaction ends and the electroless nickel plating is completed. The electroless nickel-plated diamond micro powder is taken out, immediately washed with deionized water to remove residual plating solution, and then dried for later use.

[0015] Furthermore, the diamond micro powder has a concentration of 15~20 g / L; the stirring speed is 250 r / min; and the stirring time is 15~30 min.

[0016] Furthermore, the diamond micron powder includes the following pretreatment steps:

[0017] B1. Degreasing treatment: Boil the diamond micro powder in a 10% degreasing powder solution for half an hour while stirring. After degreasing, rinse with ultrapure water until the pH value is neutral.

[0018] B2. Pickling treatment: After degreasing, the diamond micro powder is boiled in a 20% dilute nitric acid solution for half an hour with stirring. After the pickling treatment, it is rinsed with ultrapure water until the pH value is neutral.

[0019] B3. Alkali washing treatment: Boil the diamond micro powder in a 10% sodium hydroxide solution for half an hour while stirring. After the alkali washing treatment is completed, rinse with ultrapure water until the pH value is neutral.

[0020] B4. Sensitization treatment: Place the diamond micro powder into the prepared sensitization solution and soak it at 40℃ for 32 minutes. After the treatment, rinse with ultrapure water until the pH value is neutral.

[0021] B5. Activation treatment: The diamond micro powder is placed in the prepared activation solution and soaked at 40°C for 32 minutes. After the treatment, it is rinsed with ultrapure water until the pH value is neutral.

[0022] B6. Reduction treatment: Take sodium hypophosphite and add water to form a reducing solution. Add diamond micro powder to the reducing solution and soak for 2 hours. After the treatment, rinse with ultrapure water until the pH value is neutral.

[0023] Furthermore, the stirring speed is 150 r / min; the sensitization solution is an aqueous solution containing 1 g stannous chloride and 5 mL hydrochloric acid per 100 mL; the activation solution is an aqueous solution containing 0.1 g palladium chloride and 5 mL hydrochloric acid per 100 mL; and the reducing solution is an aqueous solution containing 3 g sodium hypophosphite per 100 mL.

[0024] Furthermore, in the pretreatment step, the sample is washed with water using a vacuum filtration device after each treatment.

[0025] This invention provides a method for preparing a chemical nickel plating solution using diamond micron powder for wire saws, which has the following beneficial effects:

[0026] 1. This invention employs the Taguchi design method to adjust different proportions of reagents in the electroless nickel plating solution, conducts experimental optimization, and determines the optimal reagent formula. This results in a denser and more uniform plating layer, reduces incomplete plating, effectively prevents micro-powder agglomeration, improves production efficiency, and significantly reduces production costs.

[0027] 2. The present invention uses a micro powder filtration device to wash the diamond micro powder before and after pretreatment with water. This method can greatly shorten the washing time of diamond micro powder, improve the efficiency before and after pretreatment, and at the same time, it does not affect the test results.

[0028] 3. The method of the present invention can make a coating of diamond micro powder with a phosphorus content of 1%-6%.

[0029] 4. In the sensitization and activation process of this invention, stannous chloride and palladium chloride are dissolved in concentrated hydrochloric acid to form sensitization solution and activation solution, which can effectively allow ions to be adsorbed on the surface of diamond particles, which is beneficial to the subsequent deposition of nickel and makes the coating dense and uniform. Attached Figure Description

[0030] Figure 1 The main effect plot of signal-to-noise ratio for each factor;

[0031] Figure 2 The effect of stirring speed on the results of electroless nickel plating;

[0032] Figure 3 The surface morphology is shown at a stirring speed of 250 r / min.

[0033] Figure 4 The effect of plating bath temperature on the results of electroless nickel plating;

[0034] Figure 5 The surface morphology is shown at a plating bath temperature of 60℃.

[0035] Figure 6 The effect of the pH value of the plating solution on the results of electroless nickel plating;

[0036] Figure 7 The surface morphology is shown when the pH value of the plating solution is 9. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0038] Example 1: Pretreatment of diamond micron powder, the specific steps are as follows:

[0039] B1. Degreasing treatment: Boil the diamond micro powder in a 10% degreasing powder solution for half an hour, stirring at 150 r / min. After degreasing, wash with ultrapure water until the pH value is neutral.

[0040] B2. Pickling treatment: Boil the degreased diamond micro powder in a 20% dilute nitric acid solution for half an hour and stir at 150 r / min. After the pickling treatment, wash with ultrapure water until the pH value is neutral.

[0041] B3. Alkali washing treatment: Boil the diamond micro powder in a 10% sodium hydroxide solution for half an hour, stirring at 150 r / min. After the alkali washing treatment, wash with ultrapure water until the pH value is neutral.

[0042] B4. Sensitization treatment: Place the diamond micro powder into a sensitization solution containing 1g stannous chloride and 5mL hydrochloric acid per 100mL, soak at 40℃ for 32min, and rinse with ultrapure water until the pH value is neutral after treatment.

[0043] B5. Activation treatment: The diamond micro powder is placed in an activation solution containing 0.1g palladium chloride and 5mL hydrochloric acid per 100mL and soaked at 40℃ for 32min. After the treatment, it is rinsed with ultrapure water until the pH value is neutral.

[0044] B6. Reduction treatment: Take sodium hypophosphite and add water to form a reducing solution containing 3g of sodium hypophosphite per 100mL. Add diamond micro powder to the reducing solution and soak for 2 hours. After the treatment, rinse with ultrapure water until the pH value is neutral.

[0045] Example 2: Electroless nickel plating with diamond micron powder for wire saws, the specific operation is as follows:

[0046] A1. Weigh 1g of nickel sulfate hexahydrate, 2g of sodium hypophosphite, 1g of sodium citrate, 2g of ammonium chloride, 0.0001g of thiourea, 0.006g of sodium saccharin, and 0.1g of sodium dodecylbenzenesulfonate, and dissolve them in a small amount of deionized water. Continue heating and stirring until dissolved.

[0047] A2. Add dissolved nickel sulfate hexahydrate, sodium hypophosphite, ammonium chloride, thiourea, sodium dodecylbenzenesulfonate, and sodium saccharin to the sodium citrate solution in sequence, heat and stir continuously, add deionized water to 100 mL, stir thoroughly, then add ammonia water to adjust the plating solution to the working pH value of 8, heat the plating solution to the working temperature of 40℃, and obtain the diamond micro powder chemical nickel plating solution for wire saws.

[0048] A3. After the plating solution reaches the working temperature and stabilizes, slowly add 1.5g of pretreated diamond micro powder to the plating solution and immediately perform mechanical stirring at a speed of 250r / min for 15min. After stirring, if no bubbles are generated in the plating solution, the reaction is complete and the electroless nickel plating is finished. Take out the diamond micro powder after electroless nickel plating, immediately wash it with deionized water to remove residual plating solution, and then dry it for later use.

[0049] Example 3: Electroless nickel plating with diamond micron powder for wire saws, the specific operation is as follows:

[0050] A1. Weigh 4g of nickel sulfate hexahydrate, 4g of sodium hypophosphite, 2g of sodium citrate, 4g of ammonium chloride, 0.00012g of thiourea, 0.012g of sodium saccharin, and 0.1g of sodium dodecylbenzenesulfonate, and dissolve them in a small amount of deionized water. Continue heating and stirring until dissolved.

[0051] A2. Add the dissolved nickel sulfate hexahydrate, sodium hypophosphite, ammonium chloride, thiourea, sodium dodecylbenzenesulfonate, and sodium saccharin to the sodium citrate solution in sequence, and continue heating and stirring; add deionized water to 100 mL, stir thoroughly, then add ammonia to adjust the plating solution to the working pH value of 9.5, and heat the plating solution to the working temperature of 70℃.

[0052] A3. After the plating solution reaches the working temperature and stabilizes, slowly add 2.0g of pretreated diamond micro powder to the plating solution and immediately perform mechanical stirring at a speed of 250r / min for 30min. After stirring, if no bubbles are generated in the plating solution, the reaction is complete and the electroless nickel plating is finished. Take out the diamond micro powder after electroless nickel plating, immediately wash it with deionized water to remove residual plating solution, and then dry it for later use.

[0053] Example 4: Electroless nickel plating with diamond micron powder for wire saws, the specific operation is as follows:

[0054] A1. Weigh 2g of nickel sulfate hexahydrate, 3g of sodium hypophosphite, 1g of sodium citrate, 3g of ammonium chloride, 0.0001g of thiourea, 0.006g of sodium saccharin, and 0.1g of sodium dodecylbenzenesulfonate, and dissolve them separately in a small amount of deionized water. Continue heating and stirring until dissolved.

[0055] A2. Add the dissolved nickel sulfate hexahydrate, sodium hypophosphite, ammonium chloride, thiourea, sodium dodecylbenzenesulfonate, and sodium saccharin to the sodium citrate solution in sequence, heat and stir continuously, add deionized water to 100 mL, stir thoroughly, then add ammonia water to adjust the plating solution to the working pH value of 9, and heat the plating solution to the working temperature of 60℃.

[0056] A3. After the plating solution reaches the working temperature and stabilizes, slowly add 1.5g of pretreated diamond micro powder to the plating solution and immediately perform mechanical stirring at a speed of 250r / min for 25min. After stirring, if no bubbles are generated in the plating solution, the reaction is complete and the electroless nickel plating is finished. Take out the diamond micro powder after electroless nickel plating, immediately wash it with deionized water to remove residual plating solution, and then dry it for later use.

[0057] Performance test results analysis

[0058] Comparative experimental data:

[0059] 1. The effect of parameter content on the results of electroless nickel plating

[0060] In the electroless nickel plating process using diamond micron powder, the parameters of the plating solution have a significant impact on the plating rate and surface morphology. Selecting appropriate parameter concentrations can improve the deposition rate of free nickel ions, increase the stability of the plating solution, and enhance the surface quality of the coating. Due to the large number of experiments, the traditional orthogonal method cannot meet the requirements of this experiment; therefore, the Taguchi design method was chosen to reduce the interference of noise factors on the output and achieve robust design. The Taguchi design method was used to investigate the effects of sodium citrate, ammonium chloride, temperature, and pH on the weight gain of electroless nickel plating, and the results are shown in Table 1.

[0061]

[0062] From the signal-to-noise ratio characteristic response analysis of the coating rate in Table 2, it can be concluded that the influence of different experimental parameter contents on the coating rate is ranked as follows: pH value > sodium citrate > temperature > ammonium chloride. Figure 1 As shown, the main effect diagram of the signal-to-noise ratio for each factor in the experiment was obtained. When the concentrations of nickel sulfate hexahydrate (20 g / L), sodium citrate (10 g / L), ammonium chloride (30 g / L), sodium hypophosphite (30 g / L), thiourea (0.001 g / L), sodium dodecylbenzenesulfonate (1 g / L), and sodium saccharin (0.06 g / L) were 60 °C, and the pH of the plating solution was 9, the electroless nickel plating achieved the expected results.

[0063] 2. The Influence of Process Conditions on the Results of Electroless Nickel Plating

[0064] 1) The effect of stirring speed on the results of electroless nickel plating

[0065] Depend on Figure 2 As shown, the coating rates are not significantly different at stirring speeds of 150 r / min and 400 r / min, and at stirring speeds of 200 r / min and 350 r / min. The best coating effect is achieved at a stirring speed of 250 r / min. An appropriate stirring speed can increase the coating rate, raise the pH value within the diffusion layer, ensure the diamond powder is uniformly suspended in the plating solution and can fully contact the solution, maximizing the diamond powder coating rate, stabilizing the nickel deposition rate, and resulting in a uniform and dense coating surface. At lower stirring speeds, the rate at which nickel ions and hypophosphite ions diffuse to the diamond powder surface is lower, leading to insufficient local concentrations in the plating solution, thus affecting the nickel deposition rate, reducing the coating rate, and potentially causing uneven coating surfaces, incomplete plating, and nickel nodules. At higher stirring speeds, the resulting turbulence may wash away or peel off the deposited coating, inhibiting orderly grain growth, preventing continuous plating, and causing incomplete plating and poor coating quality. Therefore, a stirring speed of 250 r / min was chosen. Figure 3 The figure shows the surface morphology at this velocity.

[0066] 2) Effect of plating bath temperature on the results of electroless nickel plating

[0067] Depend on Figure 4As shown, when the plating temperature is below 60℃, the reduction reaction rate decreases, inhibiting the nickel deposition reaction; the resulting coating surface is smooth and uniform, but incomplete plating occurs, resulting in a low plating rate. When the plating temperature is within the 60℃ range, the activation energy of the reaction reaches equilibrium with the oxidation rate of hypophosphite, and the plating solution concentration is stable; the high nucleation density of nickel grains allows for uniform coverage of the diamond micropowder surface, resulting in a uniform and dense coating surface. However, when the temperature exceeds 60℃, the plating rate begins to decrease. This is because the oxidation rate of hypophosphite increases, decomposing a large number of hydrogen ions, leading to a decrease in the local pH value of the plating solution, which easily triggers a self-decomposition reaction; at high temperatures, grain growth is rapid, causing nickel nodules or continuous crystal formation on the surface of the diamond micropowder coating, and even leading to partial coating peeling, thus reducing the plating rate. Therefore, the temperature is selected within the range of 60±2℃. Figure 5 The figure shows the surface morphology at this temperature.

[0068] 3) The effect of plating bath pH on the results of electroless nickel plating

[0069] Depend on Figure 6 As shown, when the pH value is low, the oxidation-reduction of hypophosphite ions to hydrogen phosphite ions in sodium hypophosphite is inhibited, resulting in an unstable concentration of free nickel ions in the plating solution. This leads to a low nickel deposition rate, producing a smooth but thin coating, and may also be accompanied by incomplete plating or nickel nodules. When the pH value in the plating solution is high, the oxidation-reduction reaction rate of sodium hypophosphite is fast, which will react with nickel ions to form insoluble nickel hydroxide precipitate, generating more by-reactions and decreasing the nickel ion concentration in the plating solution, thus reducing the plating coverage. When the pH value in the plating solution is moderate, the oxidation-reduction reaction rate of sodium hypophosphite and the nickel deposition rate reach a dynamic equilibrium, forming a stable mixed ligand complex. The coating surface is dense and uniform, without obvious incomplete plating or nickel nodules. Therefore, the pH value is selected within the range of 9 ± 0.02. Figure 7 The image shows the surface morphology at this pH value.

[0070] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, they should all fall within the protection scope of the present invention.

Claims

1. A chemical nickel plating solution using diamond micron powder for wire saws, characterized in that: The nickel plating solution, by mass concentration, comprises the following components in parts by weight: nickel sulfate hexahydrate 10~40 g / L, sodium hypophosphite 20~40 g / L, sodium citrate 10~20 g / L, ammonium chloride 20~40 g / L, thiourea 0.001~0.0012 g / L, sodium dodecylbenzenesulfonate 1 g / L, and sodium saccharin 0.06~0.12 g / L.

2. A method for preparing a chemical nickel plating solution using diamond micron powder for wire saws, characterized in that: The specific preparation steps are as follows: A1. According to the amount of nickel plating solution to be prepared (100mL), weigh out sodium citrate, nickel sulfate hexahydrate, sodium hypophosphite, ammonium chloride, thiourea, sodium saccharin, and sodium dodecylbenzene sulfonate, dissolve them separately in a small amount of deionized water, and continue heating and stirring until completely dissolved. A2. In a sodium citrate solution, add dissolved nickel sulfate hexahydrate, sodium hypophosphite, ammonium chloride, thiourea, sodium dodecylbenzenesulfonate, and sodium saccharin in sequence. Heat and stir continuously, add deionized water to 100 mL, stir thoroughly, then add ammonia to adjust the plating solution to the working pH value, and heat the plating solution to the working temperature to obtain a diamond micro powder electroless nickel plating solution for wire saws.

3. The method for preparing a chemical nickel plating solution of diamond micron powder for wire saws according to claim 2, characterized in that: The operating pH value is 8.0~9.5, and the operating temperature is 40~70℃.

4. A method for electroless nickel plating with diamond micron powder for wire saws, the specific operation of which is as follows: After the plating solution reaches the working temperature and stabilizes, the pretreated diamond micro powder is slowly added to the plating solution and mechanically stirred immediately. After stirring, if no bubbles are generated in the plating solution, the reaction ends and the electroless nickel plating is completed. The electroless nickel-plated diamond micro powder is taken out, immediately washed with deionized water to remove residual plating solution, and then dried for later use.

5. The method for electroless nickel plating with diamond micron powder for wire saws according to claim 4, characterized in that: The diamond micro powder has a concentration of 15~20 g / L; the stirring speed is 250 r / min, and the stirring time is 15~30 min.

6. The method for electroless nickel plating with diamond micron powder for wire saws according to claim 4, characterized in that: The diamond micro powder includes the following pretreatment steps: B1. Degreasing treatment: Boil the diamond micro powder in a 10% degreasing powder solution for half an hour while stirring. After degreasing, wash with ultrapure water until the pH value is neutral. B2. Pickling treatment: Boil the degreased diamond powder in a 20% dilute nitric acid solution for half an hour while stirring. After the pickling treatment, rinse with ultrapure water until the pH value is neutral. B3. Alkali washing treatment: Boil the diamond micro powder in a 10% sodium hydroxide solution for half an hour while stirring. After the alkali washing treatment is completed, rinse with ultrapure water until the pH value is neutral. B4. Sensitization treatment: Place the diamond micro powder into the prepared sensitization solution and soak it at 40°C for 32 minutes. After the treatment, rinse with ultrapure water until the pH value is neutral. B5. Activation treatment: The diamond micro powder is placed in the prepared activation solution and soaked at 40°C for 32 minutes. After the treatment, it is rinsed with ultrapure water until the pH value is neutral. B6. Reduction treatment: Take sodium hypophosphite and add water to form a reducing solution. Add diamond micro powder to the reducing solution and soak for 2 hours. After the treatment, rinse with ultrapure water until the pH value is neutral.

7. The method for electroless nickel plating with diamond micron powder for wire saws according to claim 6, characterized in that: The stirring speed is 150 r / min; The sensitizing solution is an aqueous solution containing 1g of stannous chloride and 5mL of hydrochloric acid per 100mL; The activation solution is an aqueous solution containing 0.1g palladium chloride and 5mL hydrochloric acid per 100mL; The reducing solution is an aqueous solution containing 3g of sodium hypophosphite per 100mL.

8. The method for electroless nickel plating with diamond micron powder for wire saws according to claim 6, characterized in that: In the pretreatment step, the sample is washed with water using a vacuum filter after each treatment.

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