Nickel-plated diamond and preparation method thereof

Abstract

The invention relates to the technical field of nickel plating of diamonds, and provides a nickel-plated diamond and a preparation method thereof. The preparation method of the nickel-plated diamond comprises the following steps that diamond is sequentially subjected to purification treatment and roughening treatment, the roughened diamond is sequentially subjected to sensitization treatment and activation treatment, the activated diamond is placed in a nickel plating solution to be subjected to nickel plating, and the nickel-plated diamond is obtained. The nickel plating solution comprises the following components in parts by mass: 20-40 parts of nickel sulfate, 10-30 parts of sodium hypophosphite, 5-20 parts of a complexing agent, 10-15 parts of a buffering agent, 0.02-0.2 part of a stabilizer and 2-10 parts of a wetting agent, wherein the wetting agent comprises cyclopentyl methanol and / or polyethylene glycol. By means of the technical scheme, the problem that in the prior art, the nickel-plated diamond is high in plating leakage rate is solved.

Description

Technical Field

[0001] The invention relates to the technical field of diamond nickel plating, and in particular to a nickel-plated diamond and a preparation method thereof. Background Art

[0002] Diamond is one of the hardest substances in nature. It has the advantages of high hardness, wear resistance, high temperature resistance, and corrosion resistance. It is widely used as a cutting and grinding material. However, due to the high interface energy and poor adhesion between diamond particles and other materials such as metals, alloys, and ceramics, diamond particles are easy to fall off when cutting and grinding diamond tools are used, which greatly reduces the service life of diamond tools. Plating a nickel layer on the surface of diamond can reduce the shedding of diamond. However, nickel-plated diamond currently has problems such as missed plating and uneven plating. Therefore, a nickel-plated diamond with a low missed plating rate is urgently needed. Summary of the invention

[0003] The invention provides a nickel-plated diamond and a preparation method thereof, which solves the problem of high leakage rate of nickel-plated diamond in the related art.

[0004] The technical solution of the present invention is as follows: The invention provides a method for preparing nickel-plated diamond, which comprises the following steps: sequentially performing purification treatment and roughening treatment on diamond, sequentially performing sensitization treatment and activation treatment on the roughened diamond, placing the activated diamond in a nickel plating solution for nickel plating to obtain the nickel-plated diamond, wherein the nickel plating solution comprises the following components by weight: 20-40 parts of nickel sulfate, 10-30 parts of sodium hypophosphite, 5-20 parts of a complexing agent, 10-15 parts of a buffer, 0.02-0.2 parts of a stabilizer, and 2-10 parts of a wetting agent, wherein the wetting agent comprises cyclopentylmethanol and / or polyethylene glycol.

[0005] As a further technical solution, the wetting agent includes cyclopentyl carbinol and polyethylene glycol in a mass ratio of 1:9 to 9:1.

[0006] As a further technical solution, the mass ratio of the cyclopentylmethanol to the polyethylene glycol is 1:3 to 3:1.

[0007] The present invention further reduces the leakage rate of nickel-plated diamond by limiting the mass ratio of cyclopentyl carbinol to polyethylene glycol to 1:3-3:1.

[0008] As a further technical solution, the diamond includes diamond with a particle size of 0.5 μm and diamond with a particle size of 3 μm in a mass ratio of 1:9 to 9:1.

[0009] The present invention improves the uniformity of the nickel-plated diamond coating by compounding the diamond with a particle size of 0.5 μm and the diamond with a particle size of 3 μm.

[0010] As a further technical solution, the mass ratio of the diamond with a particle size of 0.5 μm to the diamond with a particle size of 3 μm is 1:4 to 4:1.

[0011] The present invention reduces the inter-crystallization of nickel-plated diamond by limiting the mass ratio of diamond with a particle size of 0.5 μm to diamond with a particle size of 3 μm to 1:4-4:1.

[0012] As a further technical solution, the purification treatment comprises the following steps: placing the diamond in a sodium hydroxide solution for boiling and washing with water; The roughening treatment comprises the following steps: boiling the purified diamond in a nitric acid solution and washing with water.

[0013] As a further technical solution, the sensitization treatment comprises the following steps: mixing the roughened diamond with a sensitizing solution, performing a sensitization treatment, and washing to neutrality, wherein the sensitizing solution is a hydrochloric acid aqueous solution of tin dichloride; The activation treatment comprises the following steps: mixing the sensitized diamond with an activation solution, performing an activation treatment, and washing to neutrality, wherein the activation solution is a hydrochloric acid solution of palladium dichloride.

[0014] As a further technical solution, the complexing agent includes one or more of citric acid, malic acid, potassium sodium tartrate, ammonium chloride, and triethanolamine, the buffer includes one or more of citrate, sodium acetate, and boric acid, and the stabilizer includes one or two of thiourea and molybdenum trioxide.

[0015] As a further technical solution, the mass ratio of the diamond to the nickel plating solution is 1:40~80.

[0016] The present invention also provides a nickel-plated diamond prepared by the method for preparing the nickel-plated diamond.

[0017] The working principle and beneficial effects of the present invention are: In the present invention, cyclopentyl carbinol and / or polyethylene glycol are selected as wetting agents of nickel-plated diamond nickel plating solution, and nickel-plated diamond with low leakage rate is prepared by using cyclopentyl carbinol and / or polyethylene glycol together with components such as nickel sulfate, sodium hypophosphite, complexing agent, buffer, stabilizer, etc. and adjusting and optimizing the dosage of each component. Through the composite use of cyclopentyl carbinol and polyethylene glycol, the two synergistically reduce the leakage rate of nickel-plated diamond, solving the problem of high leakage rate of nickel-plated diamond in the prior art. DETAILED DESCRIPTION

[0018] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] In the following examples and comparative examples, the parameters of each raw material are as follows: Diamond particle size: 0.5μm, 3μm; The polyethylene glycol was PEG-2000.

[0020] Example 1 A nickel-plated diamond, and a preparation method thereof, comprising the following steps: S1. Purify the diamond: place 10 parts of diamond with a particle size of 3 μm in a 100 g / L sodium hydroxide solution and boil for 35 min, then wash with water until the pH value is 7; S2. Roughening the diamond: Boil the purified diamond in a 50% by volume nitric acid solution for 20 minutes, and wash with water until the pH value is 7; S3, sensitizing the diamond: prepare 500mL of 25mL / L hydrochloric acid solution, weigh 7.5g of tin dichloride and add it, stir to dissolve it, prepare a sensitizing solution, add the roughened diamond into the sensitizing solution, stir for 15min, and wash with water until the pH value is 7; S4, activating the diamond: prepare 500mL of 10mL / L hydrochloric acid solution, weigh 0.2g of palladium dichloride and add it, stir to dissolve it, prepare an activation solution, mix the sensitized diamond with the activation solution, stir for 15min, and wash with water until the pH value is 7; S5, dissolve 200g of nickel sulfate, 100g of sodium hypophosphite, 50g of citric acid, 100g of sodium citrate, 0.2g of thiourea, and 20g of cyclopentylmethanol in 10L of water, add 10% by mass ammonia solution to adjust the pH to 4.5, and prepare a nickel plating solution; S6. Add 10 g of activated diamond into 400 g of nickel plating solution for nickel plating. Stir for 60 seconds every 10 minutes at 90°C. After stirring for 5 times, filter, wash with water, and dry to obtain nickel-plated diamond.

[0021] Example 2 A nickel-plated diamond, and a preparation method thereof, comprising the following steps: S1. Purify the diamond: place 10 parts of diamond with a particle size of 3 μm in a 100 g / L sodium hydroxide solution and boil for 35 min, then wash with water until the pH value is 7; S2. Roughening the diamond: Boil the purified diamond in a 50% by volume nitric acid solution for 20 minutes, and wash with water until the pH value is 7; S3, sensitizing the diamond: prepare 500mL of 25mL / L hydrochloric acid solution, weigh 7.5g of tin dichloride and add it, stir to dissolve it, prepare a sensitizing solution, add the roughened diamond into the sensitizing solution, stir for 15min, and wash with water until the pH value is 7; S4, activating the diamond: prepare 500mL of 10mL / L hydrochloric acid solution, weigh 0.2g of palladium dichloride and add it, stir to dissolve it, prepare an activation solution, mix the sensitized diamond with the activation solution, stir for 15min, and wash with water until the pH value is 7; S5, dissolve 400g of nickel sulfate, 300g of sodium hypophosphite, 200g of malic acid, 150g of sodium acetate, 2g of thiourea, and 100g of cyclopentylmethanol in 10L of water, add 10% by mass ammonia solution to adjust the pH to 4.5, and prepare a nickel plating solution; S6. Add 10 g of activated diamond into 800 g of nickel plating solution for nickel plating. Stir for 60 seconds every 10 minutes at 90°C. After stirring for 5 times, filter, wash with water, and dry to obtain nickel-plated diamond.

[0022] Example 3 The only difference from Example 1 is that cyclopentylmethanol is replaced by polyethylene glycol of the same mass.

[0023] Example 4 A nickel-plated diamond, and a preparation method thereof, comprising the following steps: S1. Purify the diamond: place 10 parts of diamond with a particle size of 3 μm in a 100 g / L sodium hydroxide solution and boil for 35 min, then wash with water until the pH value is 7; S2. Roughening the diamond: Boil the purified diamond in a 50% by volume nitric acid solution for 20 minutes, and wash with water until the pH value is 7; S3, sensitizing the diamond: prepare 500mL of 25mL / L hydrochloric acid solution, weigh 7.5g of tin dichloride and add it, stir to dissolve it, prepare a sensitizing solution, add the roughened diamond into the sensitizing solution, stir for 15min, and wash with water until the pH value is 7; S4, activating the diamond: prepare 500mL of 10mL / L hydrochloric acid solution, weigh 0.2g of palladium dichloride and add it, stir to dissolve it, prepare an activation solution, mix the sensitized diamond with the activation solution, stir for 15min, and wash with water until the pH value is 7; S5, dissolve 200g of nickel sulfate, 100g of sodium hypophosphite, 50g of citric acid, 100g of sodium citrate, 0.2g of thiourea, 2g of cyclopentylmethanol, and 18g of polyethylene glycol in 10L of water, add 10% by mass ammonia solution to adjust the pH to 4.5, and prepare a nickel plating solution; S6. Add 10 g of activated diamond into 400 g of nickel plating solution for nickel plating. Stir for 60 seconds every 10 minutes at 90°C. After stirring for 5 times, filter, wash with water, and dry to obtain nickel-plated diamond.

[0024] Example 5 The only difference from Example 4 is: 18 g of cyclopentylmethanol and 2 g of polyethylene glycol.

[0025] Example 6 The only difference from Example 4 is: 5 g of cyclopentylmethanol and 15 g of polyethylene glycol.

[0026] Example 7 The only difference from Example 4 is: 15 g of cyclopentylmethanol and 5 g of polyethylene glycol.

[0027] Example 8 A nickel-plated diamond, and a preparation method thereof, comprising the following steps: S1. Purify the diamonds: place 1 part of diamonds with a particle size of 0.5 μm and 9 parts of diamonds with a particle size of 3 μm in a 100 g / L sodium hydroxide solution and boil for 35 min, then wash with water until the pH value is 7; S2. Roughening the diamond: Boil the purified diamond in a 50% by volume nitric acid solution for 20 minutes, and wash with water until the pH value is 7; S3, sensitizing the diamond: prepare 500mL of 25mL / L hydrochloric acid solution, weigh 7.5g of tin dichloride and add it, stir to dissolve it, prepare a sensitizing solution, add the roughened diamond into the sensitizing solution, stir for 15min, and wash with water until the pH value is 7; S4, activating the diamond: prepare 500mL of 10mL / L hydrochloric acid solution, weigh 0.2g of palladium dichloride and add it, stir to dissolve it, prepare an activation solution, mix the sensitized diamond with the activation solution, stir for 15min, and wash with water until the pH value is 7; S5, dissolve 200g of nickel sulfate, 100g of sodium hypophosphite, 50g of citric acid, 100g of sodium citrate, 0.2g of thiourea, 5g of cyclopentylmethanol, and 15g of polyethylene glycol in 10L of water, add 10% by mass ammonia solution to adjust the pH to 4.5, and prepare a nickel plating solution; S6. Add 10 g of activated diamond into 400 g of nickel plating solution for nickel plating. Stir for 60 seconds every 10 minutes at 90°C. After stirring for 5 times, filter, wash with water, and dry to obtain nickel-plated diamond.

[0028] Example 9 The only difference from Example 8 is that there are 9 parts of diamond with a particle size of 0.5 μm and 1 part of diamond with a particle size of 3 μm.

[0029] Example 10 The only difference from Example 8 is that there are 2 parts of diamonds with a particle size of 0.5 μm and 8 parts of diamonds with a particle size of 3 μm.

[0030] Embodiment 11 The only difference from Example 8 is that there are 8 parts of diamonds with a particle size of 0.5 μm and 2 parts of diamonds with a particle size of 3 μm.

[0031] Test example The SEM detection was performed on the leakage plating of the nickel-plated diamond prepared in Examples 1 to 11. The detection results are shown in Table 1.

[0032] Table 1 Test results of leakage rate of nickel-plated diamond prepared in Examples 1 to 11

[0033] Compared with Example 1 and Example 3, the wetting agent for the nickel-plated diamond prepared in Examples 4 to 7 is a compound of cyclopentylmethanol and polyethylene glycol. As a result, the leakage plating rate of Examples 4 to 7 is lower than that of Example 1 and Example 3, indicating that the compound use of cyclopentylmethanol and polyethylene glycol synergistically reduces the leakage plating rate of nickel-plated diamond.

[0034] Compared with Examples 4 to 5, the mass ratio of cyclopentylmethanol to polyethylene glycol in the nickel-plated diamond prepared in Examples 6 to 11 is 1:3 to 3:1. As a result, the leakage rate of Examples 6 to 11 is lower than that of Examples 4 to 5, indicating that the mass ratio of cyclopentylmethanol to polyethylene glycol in the nickel-plated diamond is 1:3 to 3:1, which further reduces the leakage rate of the nickel-plated diamond.

[0035] The nickel-plated diamonds prepared in Examples 6 to 11 were subjected to SEM testing to observe the uniformity of the coating. The test results are shown in Table 2.

[0036] Table 2 Test results of coating uniformity of nickel-plated diamond prepared in Examples 6 to 11

[0037] The nickel-plated diamond coating uniformity of Examples 8 to 11 is better than that of Examples 6 to 7, indicating that the composite use of diamond with a particle size of 0.5 μm and diamond with a particle size of 3 μm improves the nickel-plated diamond coating uniformity.

[0038] The nickel-plated diamonds prepared in Examples 8 to 11 were subjected to SEM testing to observe the crystallization of the coating. The test results are shown in Table 3.

[0039] Table 3 Test results of the inter-crystal status of the nickel-plated diamond prepared in Examples 8 to 11

[0040] The nickel-plated diamond coatings prepared in Examples 10-11 have no continuous crystals, while the nickel-plated diamond coatings prepared in Examples 8-9 have continuous crystals, indicating that by limiting the mass ratio of diamond with a particle size of 0.5 μm to diamond with a particle size of 3 μm to 1:4-4:1, the continuous crystals in the nickel-plated diamond coatings are reduced.

[0041] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing nickel-plated diamond, characterized in that: The following steps are involved: The diamond is purified and roughened in sequence, the roughened diamond is sensitized and activated in sequence, and the activated diamond is placed in a nickel plating solution for nickel plating to obtain nickel-plated diamond. The nickel plating solution comprises the following components in parts by weight: 20 to 40 parts of nickel sulfate, 10 to 30 parts of sodium hypophosphite, 5 to 20 parts of a complexing agent, 10 to 15 parts of a buffer, 0.02 to 0.2 parts of a stabilizer, and 2 to 10 parts of a wetting agent, wherein the wetting agent comprises cyclopentylmethanol and / or polyethylene glycol.

2. The method for preparing nickel-plated diamond according to claim 1, characterized in that: The wetting agent includes cyclopentyl carbinol and polyethylene glycol in a mass ratio of 1:9 to 9:

1.

3. The method for preparing nickel-plated diamond according to claim 2, characterized in that: The mass ratio of the cyclopentylmethanol to the polyethylene glycol is 1:3 to 3:

1.

4. The method for preparing nickel-plated diamond according to claim 1, characterized in that: The diamonds include diamonds with a particle size of 0.5 μm and diamonds with a particle size of 3 μm at a mass ratio of 1:9 to 9:

1.

5. The method for preparing nickel-plated diamond according to claim 4, characterized in that: The mass ratio of the diamond with a particle size of 0.5 μm to the diamond with a particle size of 3 μm is 1:4 to 4:

1.

6. The method for preparing nickel-plated diamond according to claim 1, characterized in that: The purification process comprises the following steps: placing the diamond in a sodium hydroxide solution for boiling and washing with water; The roughening treatment comprises the following steps: boiling the purified diamond in a nitric acid solution and washing with water.

7. The method for preparing nickel-plated diamond according to claim 1, characterized in that: The sensitization treatment comprises the following steps: mixing the roughened diamond with a sensitizing solution, performing a sensitization treatment, and washing to neutrality, wherein the sensitizing solution is a hydrochloric acid aqueous solution of tin dichloride; The activation treatment comprises the following steps: mixing the sensitized diamond with an activation solution, performing an activation treatment, and washing to neutrality, wherein the activation solution is a hydrochloric acid solution of palladium dichloride.

8. The method for preparing nickel-plated diamond according to claim 1, characterized in that: The complexing agent includes one or more of citric acid, malic acid, potassium sodium tartrate, ammonium chloride, and triethanolamine; the buffer includes one or more of citrate, sodium acetate, and boric acid; and the stabilizer includes one or two of thiourea and molybdenum trioxide.

9. The method for preparing nickel-plated diamond according to claim 1, characterized in that: The mass ratio of the diamond to the nickel plating solution is 1:40-80.

10. Nickel-plated diamond prepared according to the method for preparing nickel-plated diamond according to any one of claims 1 to 9.

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