Process for electroplating nickel on super-hard abrasive with few continuous crystals

Abstract

The invention discloses a process for electroplating nickel on a superhard abrasive with few continuous crystals, and relates to the technical field of superhard abrasive electroplating, the electroplating process comprises 150g / L of nickel sulfate, 40g / L of boric acid, 100g / L of nickel chloride, 10g / L of sodium citrate and a plurality of dispersed particles; the process comprises the following steps: S1, preparing a plating solution, namely adding nickel sulfate, boric acid, nickel chloride and sodium citrate into a proper amount of deionized water according to a preset proportion; s2, adjusting a plating solution, and monitoring the pH value of the plating solution; s3, an electroplating process is conducted, specifically, the prepared superhard abrasive is put into a plating tank, and electroplating is conducted by setting proper current density and time; s4, electroplating and cleaning are completed, and after electroplating is completed, the surface of a plating layer is washed with clear water; and S5, post-treatment is conducted, specifically, the cleaned electroplated product is subjected to drying and heat treatment, and the dispersed particles are cleaned. According to the superhard abrasive nickel electroplating small-crystal-connection technology, the internal crystal connection rate can be remarkably reduced by adjusting electroplating parameters such as the current density, the temperature and the pH value.

Description

Technical Field

[0001] The invention relates to the technical field of superhard abrasive electroplating, in particular to a superhard abrasive electroplating nickel few-linked crystal process. Background Art

[0002] Electroplated nickel is more stable than chemical nickel solution, has a longer service life, and is easier to control the thickness of the coating. Electroplated nickel (rather than nickel-phosphorus alloy) has a slightly lower hardness and is less brittle than chemical nickel. Electroplated nickel superhard abrasives can be used to make resin grinding wheels and wet grinding of cemented carbide. In addition, electroplated nickel abrasives are also used in the manufacture of diamond saw blades and drill bits. At the same time, electroplated nickel and its alloys (such as nickel-cobalt alloys) are also used as a metal binder to manufacture a large class of diamond products - electroplated diamond products. Electroplated nickel is one of the most widely used plating types in the world.

[0003] At present, the products plated by super-hard abrasive nickel electroplating process formula have more continuous crystals, which is a major difficulty of nickel electroplating. As a result, many unqualified products are produced. The pursuit of low continuous crystal rate is a difficult problem that abrasive electroplating workers have always wanted to solve. Summary of the invention

[0004] The main purpose of the present invention is to provide a process for electroplating nickel with super-hard abrasives with less continuous crystals, and through the steps S1-S5, the present invention solves the problem that the products plated with the current super-hard abrasive electroplating nickel process formula have more continuous crystals, which is a major difficulty in electroplating nickel, and the problem that more unqualified products are produced in this way.

[0005] To achieve the above object, the present invention provides the following technical solutions: Super-hard abrasive electroplating nickel with few continuous crystals, the electroplating process formula includes: 150g / L nickel sulfate, 40g / L boric acid, 100g / L nickel chloride, 10g / L sodium citrate, and a number of dispersed particles; The super-hard abrasive nickel electroplating process with few continuous crystals comprises the following steps: S1. Preparation of plating solution: adding nickel sulfate, boric acid, nickel chloride and sodium citrate into an appropriate amount of deionized water according to a predetermined ratio, stirring them evenly, and forming a plating solution after dissolution. According to the performance and requirements of the dispersed particles, a specific amount of dispersed particles is added to ensure uniform dispersion; S2, plating solution adjustment, monitoring the pH value of the plating solution and adjusting it by adding appropriate amount of acid or alkali; S3, electroplating process, put the prepared superhard abrasive into the plating tank, ensure that it is in good contact with the power supply, turn on the power supply, set the appropriate current density and time for electroplating; S4, finishing electroplating and cleaning. After the electroplating is completed, turn off the power, take out the plated product, and rinse the plated surface with clean water; S5, post-processing, drying and heat treating the cleaned electroplated products, and cleaning the dispersed particles.

[0006] Preferably, the dispersed particles have a size of 1 mm to 10 mm.

[0007] Preferably, the amount of the dispersed particles added is determined according to the amount of abrasive added for electroplating and the size of the abrasive particles, and the amount of the dispersed particles added is in the range of 100-1000g.

[0008] Preferably, the dispersed particles in step S1 need to be cleaned or pretreated before being added.

[0009] Preferably, the appropriate amount of deionized water in step S1 is determined according to the total volume of the plating solution, the concentration of each component and the stirring effect.

[0010] Preferably, the pH value of the plating solution monitored in step S2 is maintained in the range of 3-4.

[0011] Preferably, the step S2 further comprises monitoring the temperature of the plating solution, and using a constant temperature controller to maintain the temperature of the plating solution at 28°C.

[0012] Preferably, the current density in step S3 is between 2 and 10 A / dm 2 The electroplating time is 5-60 minutes.

[0013] Preferably, in step S3, a soluble anode nickel plate is selected during the electroplating process, and a titanium basket is used to load the nickel corners to control the shape and area of ​​the anode, wherein the titanium basket is filled with a polypropylene anode bag.

[0014] Compared with the prior art, the present invention has the following beneficial effects: In the present invention, by adjusting the electroplating parameters such as current density, temperature, pH value, etc., and adding dispersed particles, the inter-crystal rate can be significantly reduced, the overall quality of the coating can be significantly improved, and the quality of the electroplated superhard abrasive can be improved, the product performance can be improved, and the stability of the production process can be enhanced, thereby bringing higher economic benefits and market competitiveness. This optimized design provides effective technical support for the development of the modern electroplating industry and promotes the improvement of the quality of related products. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a process flow chart of the few-connected crystal process of the present invention. DETAILED DESCRIPTION

[0016] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0017] Example 1: Figure 1As shown, the super-hard abrasive electroplating nickel few-crystal process, the electroplating process formula includes: 150g / L nickel sulfate, 40g / L boric acid, 100g / L nickel chloride, 10g / L sodium citrate, and a number of dispersed particles; The process of super-hard abrasive nickel electroplating with few continuous grains includes the following steps: S1. Preparation of plating solution: adding nickel sulfate, boric acid, nickel chloride and sodium citrate into an appropriate amount of deionized water according to a predetermined ratio, stirring them evenly, and forming a plating solution after dissolution. According to the performance and requirements of the dispersed particles, a specific amount of dispersed particles is added to ensure uniform dispersion; S2, plating solution adjustment, monitoring the pH value of the plating solution and adjusting it by adding appropriate amount of acid or alkali; S3, electroplating process, put the prepared superhard abrasive into the plating tank, ensure that it is in good contact with the power supply, turn on the power supply, set the appropriate current density and time for electroplating; S4, finishing electroplating and cleaning. After the electroplating is completed, turn off the power, take out the plated product, and rinse the plated surface with clean water; S5, post-processing, drying and heat treating the cleaned electroplated products, and cleaning the dispersed particles.

[0018] Among them, the functions of each component of the plating solution are: Nickel sulfate: It is the main salt in the plating solution. The key of nickel salt is to provide nickel metal ions required for nickel plating and also plays the role of conductive salt.

[0019] Boric acid: As a buffer, it maintains the pH value of the plating solution within a certain range. Practice has shown that when the pH value of the nickel plating solution is too low, the cathode current efficiency will decrease; when the pH value is too high, the pH value of the liquid layer close to the cathode surface will rise rapidly due to the continuous precipitation of hydrogen, resulting in the generation of Ni(OH)2 colloid, and Ni(OH)2 is mixed in the coating, which increases the brittleness of the coating. At the same time, the adsorption of Ni(OH)2 colloid on the electrode surface will also cause hydrogen bubbles to remain on the electrode surface, increasing the porosity of the coating. Boric acid not only has a pH buffering effect, but it can also enhance cathode polarization, thereby improving the performance of the plating solution and reducing the "burning" phenomenon under high current density. The presence of boric acid is also beneficial to improving the mechanical properties of the coating.

[0020] Nickel chloride: Nickel anode is very easy to passivate during the power-on process. In order to ensure the normal dissolution of the anode, a certain amount of anode activator is added to the plating solution. After testing, it was found that Cl- chloride ion is the best nickel anode activator. In nickel plating solution containing nickel chloride, nickel chloride not only acts as the main salt and conductive salt, but also plays the role of anode activator. In nickel plating solution that does not contain nickel chloride or has a low content of nickel chloride, a certain amount of nickel chloride needs to be added according to the actual situation.

[0021] Sodium citrate: As a complexing agent for nickel ions during nickel electroplating, it helps to reduce the concentration of free nickel ions in the plating solution, thereby enhancing the dispersibility and covering ability of the coating. Sodium citrate also acts as a buffer to maintain a stable pH value of the solution during the electroplating process.

[0022] Among them, the dispersed particle size is 1mm-10mm, and the dispersed particle density must be greater than the abrasive density to ensure uniform dispersion in the superhard abrasive. The particles do not undergo chemical reactions and only play a dispersing role. The particles can be cleaned and recycled after use without causing any pollution.

[0023] The amount of dispersed particles added is determined according to the amount of abrasive added for electroplating and the size of the abrasive particles, and the amount of dispersed particles added is in the range of 100-1000g.

[0024] The dispersed particles in step S1 need to be cleaned or pre-treated before being added.

[0025] The appropriate amount of deionized water in step S1 is determined according to the total volume of the plating solution, the concentration of each component and the stirring effect.

[0026] Among them, the pH value of the plating solution monitored in step S2 is maintained within the range of 3-4, and the pH value of the nickel plating electrolyte has a great influence on the performance of the coating and the electrolyte. In a strong acidic electroplating solution with a pH less than or equal to PH, there is no metal nickel deposition, only hydrogen is precipitated. The pH value of the conventional nickel plating electrolyte is maintained between 3-4, and the nickel plating solution with a higher pH value contains a higher dispersing force and a higher cathode current efficiency. However, when the pH value is too high, because the cathode continuously precipitates hydrogen during the electroplating process, the pH value of the coating around the cathode surface increases rapidly. When it is greater than 6, nickel hydroxide colloid will be generated, causing hydrogen bubbles to be retained and pinholes to appear in the coating. Sodium hydroxide is mixed in the coating and will also increase the brittleness of the coating. In a nickel plating solution with a lower pH, the anode dissolves well, which can increase the nickel salt content in the electrolyte, and a higher current density can be used, thereby strengthening production. The pH value increases when nickel carbonate is added, and decreases when sulfuric acid is added. The pH value is checked and adjusted every four hours during the working process.

[0027] Wherein, step S2 also includes monitoring the temperature of the plating solution, and using a constant temperature controller to keep the plating solution temperature at 28°C.

[0028] The current density in step S3 is between 2 and 10 A / dm 2 The electroplating time is 5-60 minutes.

[0029] Among them, step S3 selects a soluble anode nickel plate during the electroplating process, and uses a titanium basket to load the nickel corner to control the shape and area of ​​the anode. The titanium basket is filled with a polypropylene anode bag. The anode bag woven with polypropylene material can prevent the anode mud from falling into the plating solution. The holes should be cleaned and checked regularly to see if they are unobstructed. Before using the new anode bag, it should be soaked in boiling water.

[0030] Example 2: In the experiment, taking the electroplating of CBN115 80 / 100 10000ct as an example, without adding dispersed particles, the electroplating product was CBN115Ni56 17045ct, the output rate was 75%, and the continuous crystal rate was 25%. 200g of dispersed particles with a particle size of 5mm were added, and the electroplating product was CBN115Ni56 21591ct, the output rate was 95%, the continuous crystal rate was 5%, and the continuous crystal rate was reduced by 20%.

[0031] Example 3: In the experiment, taking the electroplating of CBN115 140 / 170 10000ct as an example, without adding dispersed particles, the electroplating product was CBN115Ni56 16364ct, the output rate was 72%, and the continuous crystal rate was 28%. 400g of dispersed particles with a particle size of 5mm were added, and the electroplating product was CBN115Ni56 20455ct, the output rate was 90%, the continuous crystal rate was 10%, and the continuous crystal rate was reduced by 18%.

[0032] Example 4: In the experiment, taking the electroplating of CBN115 325 / 400 10000ct as an example, without adding dispersed particles, the electroplating product was CBN115Ni56 15909ct, the output rate was 70%, and the continuous crystal rate was 30%. 900g of dispersed particles with a particle size of 5mm were added, and the electroplating product was CBN115Ni56 20682ct, the output rate was 91%, the continuous crystal rate was 9%, and the continuous crystal rate was reduced by 21%.

[0033] The above examples show that the use of dispersed particles can significantly reduce the rate of continuous crystals in electroplated products and improve production efficiency.

Claims

1. Super abrasive nickel electroplating process with few continuous crystals, characterized in that: The electroplating process formula includes: 150g / L nickel sulfate, 40g / L boric acid, 100g / L nickel chloride, 10g / L sodium citrate, and a number of dispersed particles; The super-hard abrasive nickel electroplating process with few continuous crystals comprises the following steps: S1. Preparation of plating solution: adding nickel sulfate, boric acid, nickel chloride and sodium citrate into an appropriate amount of deionized water according to a predetermined ratio, stirring them evenly, and forming a plating solution after dissolution. According to the performance and requirements of the dispersed particles, a specific amount of dispersed particles is added to ensure uniform dispersion; S2, plating solution adjustment, monitoring the pH value of the plating solution and adjusting it by adding appropriate amount of acid or alkali; S3, electroplating process, put the prepared superhard abrasive into the plating tank, ensure that it is in good contact with the power supply, turn on the power supply, set the appropriate current density and time for electroplating; S4, finishing electroplating and cleaning. After the electroplating is completed, turn off the power, take out the plated product, and rinse the plated surface with clean water; S5, post-processing, drying and heat treating the cleaned electroplated products, and cleaning the dispersed particles.

2. The process for electroplating nickel with few continuous crystals on super-hard abrasives according to claim 1, characterized in that: The dispersed particles have a size of 1 mm to 10 mm.

3. The process for electroplating nickel with few continuous crystals on super-hard abrasives according to claim 2, characterized in that: The amount of dispersed particles added is determined according to the amount of abrasive added for electroplating and the size of the abrasive particles, and the amount of dispersed particles added is in the range of 100-1000g.

4. The process for electroplating nickel with few continuous crystals on super-hard abrasives according to claim 3, characterized in that: The dispersed particles in step S1 need to be cleaned or pre-treated before being added.

5. The process for electroplating nickel with few continuous crystals on super-hard abrasives according to claim 4, characterized in that: The appropriate amount of deionized water in step S1 is determined according to the total volume of the plating solution, the concentration of each component and the stirring effect.

6. The process for electroplating nickel with few continuous crystals on super-hard abrasives according to claim 5, characterized in that: In step S2, the pH value of the plating solution is monitored to be maintained within the range of 3-4.

7. The process for electroplating nickel with few continuous crystals on super-hard abrasives according to claim 6, characterized in that: The step S2 also includes monitoring the temperature of the plating solution and using a constant temperature controller to maintain the plating solution temperature at 28°C.

8. The process for electroplating nickel with few continuous crystals on super-hard abrasives according to claim 7, characterized in that: The current density in step S3 is 2-10A / dm 2 The electroplating time is 5-60 minutes.

9. The process for electroplating nickel with few continuous crystals on super-hard abrasives according to claim 8, characterized in that: The step S3 selects a soluble anode nickel plate during the electroplating process and uses a titanium basket to load the nickel corners to control the shape and area of ​​the anode, wherein the titanium basket is filled with a polypropylene anode bag.

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