Processing technology of diamond chemical plating layer

Abstract

The invention discloses a processing technology of a diamond chemical plating layer, and relates to the technical field of diamond raw material treatment. Comprising the steps of oil removal, hydrophilization, sensitization, activation, chemical nickel plating, post-treatment and performance testing. The plating solution suitable for chemical plating is prepared. The plating solution can form a uniform and compact metal coating on the surface of a base material, and has good adhesive force and corrosion resistance. And by optimizing process parameters, the surface performance of the diamond micro-powder can be remarkably improved, and the using effect of the diamond micro-powder in various applications is enhanced. The diamond micro-powder can be applied to the fields of cutting, grinding, polishing and the like, and the chemically-plated diamond micro-powder can remarkably prolong the service life of a tool and improve the working efficiency of the tool.

Description

Technical Field

[0001] The present invention relates to the technical field of diamond raw material processing, in particular to a processing technology for diamond chemical plating layer. Background Art

[0002] Diamond micropowder is an emerging strategic material with extremely high hardness, excellent thermal conductivity, outstanding biocompatibility and strong corrosion resistance. It has been widely used in various fields such as photovoltaics, precision manufacturing, aerospace, electronics, automobiles, military industry, machine tools, building materials, etc.

[0003] In addition to the introduction of impurities into diamond powder during the production process, defects such as cracks and pores can also develop, directly impacting diamond quality. Diamond also possesses exceptional chemical stability, resulting in high interfacial energy with metal and resin binders. This leads to weak interfacial bonding between the diamond and the binder in diamond tools, resulting in poor adhesion. Therefore, a metal coating is often applied to the diamond surface to enhance its substrate bonding.

[0004] Diamonds are generally non-conductive and require a metal coating through other plating processes before electroplating. Chemical plating is often used to apply a metal layer. The phosphorus content in the chemically plated coating significantly affects its quality. High-phosphorus coatings offer better corrosion resistance in acidic environments.

[0005] The most direct way to improve the quality of diamond micropowder is to maximize the level of surface plating technology, ensuring that the coated diamond micropowder has the best quality and coating performance, making it most suitable for industrial production needs. With the development of diamond micropowder surface plating, the quality of diamond micropowder has greatly improved. However, with the demand for fine-grained diamond micropowder in industrial production, single chemical plating and electroplating processes cannot meet the needs of high-quality diamond micropowder. At the same time, the optimization of various parameters of chemical plating and electroplating requires a large amount of experimental data support, which wastes a lot of manpower, material and financial resources. To address this dilemma, the present invention designs a processing technology for diamond chemical plating. Summary of the Invention

[0006] To address the shortcomings of the existing technology, the present invention aims to provide a simple process for chemically plating diamonds, effectively coating the diamond surface with a layer of metal, improving its mechanical properties and high-temperature resistance, and making it suitable for manufacturing various high-performance diamond tools. The resulting diamond powder can significantly increase the tool's service life and operating efficiency.

[0007] In order to achieve the above object, the present invention is implemented through the following technical solution: a processing technology for chemical diamond plating, comprising the following steps:

[0008] 1. Degreasing: Prepare 50-200ml of sodium hydroxide solution, add diamond powder into it, and stir with an electric stirrer at a speed of 300r / min to suspend the diamond particles in the solution. Stir for 25-30 minutes and then stop. Rinse with deionized water for 4-5 times.

[0009] 2. Hydrophilization: Use 10-200ml of dilute nitric acid solution as the hydrophilization solution. Place the degreased diamond into the dilute nitric acid solution and stir the solution with an electric stirrer to suspend the diamond in the dilute nitric acid. After 25-30 minutes, rinse with deionized water until it becomes neutral.

[0010] 3. Sensitization: Use stannous chloride solution to sensitize the diamond powder. Soak the diamond powder in the sensitization solution for 30 minutes, and then rinse with deionized water until it becomes neutral.

[0011] 4. Activation: Use palladium chloride solution to activate. Soak the sensitized diamond powder in palladium chloride solution for 30 minutes, then rinse with deionized water until neutral;

[0012] 5. Chemical plating: First, prepare the chemical plating solution, add 40-80g / L citric acid, 40-80g / L sodium hypophosphite, 0.001-1g / L thiourea, 2-10ml / L lactic acid, 3000-8000ml nickel sulfamate, and finally adjust the pH value of the chemical plating solution to 6-9 with an appropriate amount of ammonia water; after the chemical plating solution is prepared, add diamond powder, use ultrasonic water bath heating, and stir continuously for 2-4 hours. During the stirring process, increase the liquid to maintain the concentration of the chemical plating solution, then rinse with deionized water until neutral, and then place in an electric constant temperature air drying oven at 30-200℃ for 1-3 hours;

[0013] 6. Post-processing: The dried diamond powder is filtered through a sieve to remove impurities, and the dried diamond powder is characterized and tested.

[0014] Preferably, the chemical plating temperature is 30-55°C.

[0015] Preferably, the sodium hypophosphite is preferably 40-80 g / L.

[0016] Preferably, the pH value of the plating solution is 3-9.

[0017] Preferably, the characterization test uses the deposition rate, coating density and corrosion resistance of the chemical plating layer to evaluate.

[0018] The present invention provides a plating solution suitable for chemical plating. This solution can form a uniform, dense metal coating on a substrate surface, exhibiting excellent adhesion and corrosion resistance. By optimizing process parameters, the surface properties of diamond micropowder can be significantly improved, enhancing its effectiveness in various applications. The chemically plated diamond micropowder can significantly increase the service life and efficiency of tools used in cutting, grinding, and polishing. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments;

[0020] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0021] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below in conjunction with specific implementation methods.

[0022] Reference Figure 1 , this specific embodiment adopts the following technical solution: a processing technology for chemical diamond plating, comprising the following steps:

[0023] 1. Degreasing: Prepare 50-200ml of sodium hydroxide solution, add diamond powder into it, and stir with an electric stirrer at a speed of 300r / min to suspend the diamond particles in the solution. Stir for 25-30 minutes and then stop. Rinse with deionized water for 4-5 times.

[0024] 2. Hydrophilization: Use 10-200ml of dilute nitric acid solution as the hydrophilization solution. Place the degreased diamond into the dilute nitric acid solution and stir the solution with an electric stirrer to suspend the diamond in the dilute nitric acid. After 25-30 minutes, rinse with deionized water until it becomes neutral.

[0025] 3. Sensitization: Use stannous chloride solution to sensitize the diamond powder. Soak the diamond powder in the sensitization solution for 30 minutes, and then rinse with deionized water until it becomes neutral.

[0026] 4. Activation: Use palladium chloride solution to activate. Soak the sensitized diamond powder in palladium chloride solution for 30 minutes, then rinse with deionized water until neutral;

[0027] 5. Chemical plating: First, prepare the chemical plating solution, add 40-80g / L citric acid, 40-80g / L sodium hypophosphite, 0.001-1g / L thiourea, 2-10ml / L lactic acid, 3000-8000ml nickel sulfamate, and finally adjust the pH value of the chemical plating solution to 6-9 with an appropriate amount of ammonia water; after the chemical plating solution is prepared, add diamond powder, use ultrasonic water bath heating, and stir continuously for 2-4 hours. During the stirring process, increase the liquid to maintain the concentration of the chemical plating solution, then rinse with deionized water until neutral, and then place in an electric constant temperature air drying oven at 30-200℃ for 1-3 hours;

[0028] 6. Post-processing: The dried diamond powder is filtered through a sieve to remove impurities, and the dried diamond powder is characterized and tested.

[0029] It is noteworthy that the chemical plating temperature is 30-55°C.

[0030] It is worth noting that the sodium hypophosphite is preferably 40-80 g / L.

[0031] It is worth noting that the pH value of the plating solution is preferably 3-9.

[0032] In addition, the characterization test uses the deposition rate, coating density and corrosion resistance of the electroless coating to evaluate.

[0033] Coating deposition rate: The mass of diamond powder before chemical plating, m0, and the mass after chemical plating, m1, are measured by an electronic balance. The plating time is t, and the coating deposition rate, w, is calculated using formula (1):

[0034]

[0035] Coating density: The mass of diamond coating per unit volume represents the coating density. Diamond micropowder particles are often irregular in shape under microscope observation. For the convenience of calculation, the shape of diamond particles is approximated as spherical in this invention. The equivalent volume particle size of diamond micropowder before and after coating is measured by laser particle size analyzer and the average particle size is r0 and r1. The diamond density is ρ0 (3.5g / cm 3 ), n in (2) represents the number of particles in 3g of diamond powder, and the coating density ρ1 is calculated using formula (3):

[0036]

[0037] Acid corrosion resistance of the coating: The plated diamond powder was soaked in 10wt% hydrochloric acid for 24 hours. The mass of the corroded coating was used to represent the corrosion resistance of the coating. The greater the weight loss, the worse the acid corrosion resistance of the coating. The average particle size of the diamond powder after corrosion is r2, and the corrosion weight loss is m2. The calculation is done using formula (4):

[0038]

[0039] Coating morphology: The coating morphology on the surface of diamond powder was observed using a scanning electron microscope.

[0040] This specific embodiment obtains the optimal process parameters of diamond powder under different coating qualities by changing the extreme difference analysis of the coating deposition rate, coating density, and coating corrosion resistance under different parameters. When the coating deposition rate is optimal, the diamond process parameters are 30-70 g / L of sodium hypophosphite, 3-9 pH value of the plating solution, and 30-75°C of the plating solution temperature; when the coating density is optimal, the diamond process parameters are 40-80 g / L of sodium hypophosphite, 4-10 pH value of the plating solution, and 40-80°C of the plating solution; when the coating corrosion resistance is optimal, the diamond process parameters are 40-90 g / L of sodium hypophosphite, 4-9 pH value of the plating solution, and 40-80°C of the plating solution temperature.

[0041] This specific embodiment is achieved by preparing 50-200ml of sodium hydroxide (NaOH) solution. Sodium hydroxide is a strong base that can effectively decompose and remove grease and other organic impurities. Diamond micropowder is added to the prepared sodium hydroxide solution. An electric stirrer is used to stir the solution at a speed of 300r / min so that the diamond particles are evenly suspended in the solution. The stirring speed is selected to ensure that the diamond particles can fully contact the solution, thereby more effectively removing impurities on the surface. The stirring lasts for 15-30 minutes. This length of time is to ensure the thoroughness of the degreasing process while avoiding damage to the diamond particles caused by excessive stirring. After the degreasing step is completed, the diamond micropowder needs to be rinsed with deionized water 4 to 5 times to remove the sodium hydroxide solution and other impurities remaining on the surface. The degreasing step is very important for ensuring the quality and effect of subsequent chemical plating. Through effective degreasing treatment, the surface of the diamond micropowder can be ensured to be clean, thereby improving the adhesion and uniformity of the chemical plating layer.

[0042] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A process for producing chemical diamond plating, characterized in that: The following steps are involved: (1) Degreasing: Prepare 50-200 ml of sodium hydroxide solution, add diamond powder into it, and stir with an electric stirrer at a speed of 300 r / min to suspend the diamond particles in the solution. Stir for 25-30 minutes and then stop. Rinse with deionized water for 4-5 times. (2) Hydrophilization: Use 10-200 ml of dilute nitric acid solution as the hydrophilization solution. Place the degreased diamond into the dilute nitric acid solution and stir the solution with an electric stirrer to suspend the diamond in the dilute nitric acid. After 25-30 minutes, rinse with deionized water until it becomes neutral. (3) Sensitization: Use stannous chloride solution to sensitize the diamond powder. Soak the diamond powder in the sensitization solution for 30 minutes and then rinse with deionized water until it becomes neutral. (4) Activation: Use palladium chloride solution to activate, soak the sensitized diamond powder in the palladium chloride solution for 30 minutes, and then rinse with deionized water until neutral; (5) Chemical plating: first prepare a chemical plating solution, add 40-80g / L citric acid, 40-80g / L sodium hypophosphite, 0.001-1g / L thiourea, 2-10ml / L lactic acid, 3000-8000ml nickel sulfamate, and finally adjust the pH value of the chemical plating solution to 6-9 with an appropriate amount of ammonia water; after preparing the chemical plating solution, add diamond powder, use ultrasonic water bath heating, and continue stirring for 2-4 hours. During the stirring process, increase the liquid replenishment to maintain the concentration of the chemical plating solution, then rinse with deionized water until neutral, and then put it into an electric constant temperature air drying oven at 30-200°C for 1-3 hours; (6) Post-processing: The dried diamond powder is filtered through a sieve to remove impurities, and the dried diamond powder is characterized and tested.

2. The process for producing a diamond chemical plating layer according to claim 1, characterized in that: The chemical plating temperature is 30-55°C.

3. The process for producing a diamond chemical plating layer according to claim 1, characterized in that: The sodium hypophosphite is preferably 40-80g / L.

4. The process for producing a diamond chemical plating layer according to claim 1, characterized in that: The pH value of the plating solution is preferably 3-9.

5. The process for producing chemical diamond plating according to claim 1, characterized in that: The characterization test is evaluated by the deposition rate, coating density and corrosion resistance of the chemical coating.

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