A diamond particle surface-coated with an aluminum nitride / aluminum carbide coating and a method for producing the same

Abstract

The present application belongs to the technical field of ceramic coating, and provides a kind of diamond particles with surface plated aluminum nitride / aluminum carbide coating and a preparation method thereof.The method of the present application comprises the following steps: mixing diamond particles, aluminum powder and melamine powder to obtain mixed powder; the mixed powder is placed in a closed device to obtain closed mixed powder; the closed mixed powder is heat treated under a protective atmosphere to obtain diamond particles with surface plated aluminum nitride / aluminum carbide coating.The raw material cost of the coating of the present application is relatively low, and aluminum powder and melamine powder are used as the raw material of the coating, which is low in cost and easy to obtain; a simple sealing method is used in combination with a high-temperature heat treatment process, which is simple in process and operation and easy to realize large-scale production; by optimizing the raw material ratio and heat treatment process parameters, the present application can realize the controllable adjustment of the coating and meet the performance requirements of diamond in different application fields.

Description

Technical Field

[0001] This invention relates to the field of ceramic coating technology, and in particular to a diamond particle with an aluminum nitride / aluminum carbide coating on its surface and its preparation method. Background Technology

[0002] Diamond, one of the hardest materials in nature, is widely used in cutting, grinding, and drilling due to its excellent mechanical properties and thermal stability. However, diamond exhibits significant poor wettability with other materials, resulting in weak bonding strength with binders. This characteristic manifests itself in the easy shedding of diamond particles during tool use, leading to a significant reduction in the lifespan of diamond tools. Therefore, surface modification treatment of diamond is often necessary, and surface coating of diamond particles is a common technique.

[0003] In recent years, significant progress has been made in diamond particle coating technology. Traditional coating methods include electroplating, electroless plating, vapor deposition, and micro-evaporation plating. These coating technologies mainly achieve metal coatings and are relatively mature. Metal coating on diamond surfaces is primarily used in metal-bonded and resin-bonded diamond products. Ceramic-bonded diamond products, especially abrasive tools, require ceramic coatings on the diamond particle surface. Currently, the main method for ceramic coating is the sol-gel process. The disadvantages of this technology include high raw material costs, complex processes, and relatively weak coating adhesion.

[0004] Therefore, developing a method for coating ceramic materials onto diamond surfaces that is both economical and efficient has significant research and application value. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art by providing diamond particles with an aluminum nitride / aluminum carbide coating on the surface and a method for preparing the same.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides a method for preparing diamond particles with a surface coated with aluminum nitride / aluminum carbide, comprising the following steps:

[0008] 1) Mix diamond particles, aluminum powder and melamine powder to obtain a mixed powder;

[0009] 2) The mixed powder is placed in a sealed device to obtain a sealed mixed powder;

[0010] 3) The sealed mixed powder is heat-treated under a protective atmosphere to obtain diamond particles with an aluminum nitride / aluminum carbide coating on the surface.

[0011] Preferably, the diamond particles in step 1) have a particle size of 50–300 μm, the aluminum powder has a particle size of 50–100 μm, and the purity of the aluminum powder is ≥99 wt%.

[0012] Preferably, the mass ratio of aluminum powder to melamine powder in step 1) is 1:2 to 4, and the mass fraction of diamond particles in the mixed powder is 20 to 60%.

[0013] Preferably, the mixing speed in step 1) is 200-300 r / min, the mixing time is 22-26 h, and during the mixing process, the total mass ratio of diamond particles, aluminum powder and melamine powder to the mass ratio of grinding balls is 1:10-20.

[0014] As a preferred embodiment, the specific process of placing the mixed powder in the sealed device in step 2) is as follows: the mixed powder is placed in the bearing steel sleeve, the two ends of the bearing steel sleeve are sealed with stainless steel gaskets, and then the stainless steel gaskets are clamped with a tiger clamp.

[0015] The thickness of the bearing steel sleeve is 3-4 mm, and the length of the bearing steel sleeve is less than 2 / 3 of the opening of the tiger clamp; the outer diameter of the bearing steel sleeve is similar to the edge length of the tiger clamp; the thickness of the stainless steel gasket is 2-4 mm.

[0016] Preferably, the protective atmosphere in step 3) is an argon atmosphere or a nitrogen atmosphere, the purity of the protective atmosphere is 99-99.9%, and the flow rate of the protective atmosphere is 50-100 ppm.

[0017] Preferably, the heat treatment in step 3) includes a first heat treatment and a second heat treatment. The temperature of the first heat treatment is 550-600℃ and the time of the first heat treatment is 1-2 hours. The temperature of the second heat treatment is 900-1000℃ and the time of the second heat treatment is 1-2 hours.

[0018] Preferably, the heating rate of the heat treatment in step 3) is 10-20°C / min.

[0019] The present invention also provides diamond particles with an aluminum nitride / aluminum carbide coating on the surface prepared by the above preparation method.

[0020] The beneficial effects of this invention include the following:

[0021] 1) The raw materials used for the coating of the present invention are relatively inexpensive. Aluminum powder and melamine powder are used as the raw materials for the coating, which are low in cost and easy to obtain.

[0022] 2) This invention employs a simple sealing method combined with a high-temperature heat treatment process, which is simple to operate and easy to achieve large-scale production.

[0023] 3) By optimizing the raw material ratio and heat treatment process parameters, this invention can achieve controllable adjustment of the coating to meet the performance requirements of diamond in different application fields. Attached Figure Description

[0024] Figure 1 The diagram shows the tiger clamp, bearing steel sleeve, and stainless steel gasket of the present invention, wherein a is the tiger clamp, b is the bearing steel sleeve, and c is the stainless steel gasket.

[0025] Figure 2 The image shows the XRD pattern of diamond particles coated with aluminum nitride / aluminum carbide in Example 1.

[0026] Figure 3 SEM image of diamond particles coated with aluminum nitride / aluminum carbide in Example 1;

[0027] Figure 4 This is a SEM image of diamond particles coated with aluminum nitride / aluminum carbide in Example 2. Detailed Implementation

[0028] This invention provides a method for preparing diamond particles with a surface coated with aluminum nitride / aluminum carbide, comprising the following steps:

[0029] 1) Mix diamond particles, aluminum powder and melamine powder to obtain a mixed powder;

[0030] 2) The mixed powder is placed in a sealed device to obtain a sealed mixed powder;

[0031] 3) The sealed mixed powder is heat-treated under a protective atmosphere to obtain diamond particles with an aluminum nitride / aluminum carbide coating on the surface.

[0032] In this invention, the particle size of the diamond particles in step 1) is preferably 50-300 μm, more preferably 100-250 μm, and even more preferably 150-200 μm; the particle size of the aluminum powder is preferably 50-100 μm, more preferably 60-90 μm, and even more preferably 70-80 μm; and the purity of the aluminum powder is preferably ≥99 wt%, and even more preferably ≥99.2 wt%.

[0033] In this invention, the mass ratio of aluminum powder to melamine powder in step 1) is preferably 1:2 to 4, more preferably 1:2.5 to 3.5, and even more preferably 1:3. The mass fraction of diamond particles in the mixed powder is preferably 20 to 60%, more preferably 30 to 50%, and even more preferably 40%.

[0034] In this invention, the melamine is of analytical grade.

[0035] In this invention, the mixing speed in step 1) is preferably 200-300 r / min, more preferably 220-280 r / min, and even more preferably 250-260 r / min; the mixing time is preferably 22-26 h, more preferably 23-25 ​​h, and even more preferably 24 h; during the mixing process, the mass ratio of the total mass of diamond particles, aluminum powder, and melamine powder to the mass of the grinding ball is preferably 1:10-20, more preferably 1:12-18, and even more preferably 1:15-16; the grinding ball is preferably made of agate or stainless steel, and the diameter of the grinding ball is preferably 6 mm or 10 mm.

[0036] In this invention, the mixing in step 1) is preferably carried out in a three-dimensional oscillating ball mill.

[0037] In this invention, the preferred process for placing the mixed powder in the sealed device in step 2) is as follows: the mixed powder is placed in the bearing steel sleeve, the two ends of the bearing steel sleeve are sealed with stainless steel gaskets, and then the stainless steel gaskets are clamped with a tiger clamp.

[0038] The thickness of the bearing steel sleeve is preferably 3-4 mm, more preferably 3.2-3.8 mm, and even more preferably 3.5-3.6 mm. The length of the bearing steel sleeve is preferably less than 2 / 3 of the opening of the tiger clamp. The outer diameter of the bearing steel sleeve is preferably similar to the edge length of the tiger clamp. The thickness of the stainless steel gasket is preferably 2-4 mm, more preferably 2.5-3.5 mm, and even more preferably 3 mm.

[0039] In this invention, the protective atmosphere in step 3) is preferably an argon atmosphere or a nitrogen atmosphere, the purity of the protective atmosphere is preferably 99-99.9%, the flow rate of the protective atmosphere is preferably 50-100 ppm, more preferably 60-90 ppm, and even more preferably 70-80 ppm.

[0040] In this invention, the heat treatment in step 3) preferably includes a first heat treatment and a second heat treatment. The temperature of the first heat treatment is preferably 550-600℃, more preferably 560-590℃, and even more preferably 570-580℃. The time of the first heat treatment is preferably 1-2 hours, and even more preferably 1.5 hours. The temperature of the second heat treatment is preferably 900-1000℃, more preferably 920-980℃, and even more preferably 950-960℃. The time of the second heat treatment is preferably 1-2 hours, and even more preferably 1.5 hours.

[0041] In this invention, the heating rate of the heat treatment in step 3) is preferably 10-20℃ / min, more preferably 12-18℃ / min, and even more preferably 15-16℃ / min.

[0042] In this invention, after the heat treatment is completed, the diamond particles coated with aluminum nitride / aluminum carbide are naturally cooled to room temperature, the tiger clamp is removed, and the diamond particles are separated by sieving with a sieve.

[0043] The present invention also provides diamond particles with an aluminum nitride / aluminum carbide coating on the surface prepared by the above preparation method.

[0044] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0045] In this embodiment, the manufacturer and model of the three-dimensional oscillating mixer is Changsha Miqi QM-QX4L.

[0046] Example 1

[0047] 16g of diamond particles with a particle size of 120μm, 4g of aluminum powder with a particle size of 70μm (purity of 99wt%), and 12g of analytical grade melamine powder were loaded into a three-dimensional oscillating mixer and ball-milled at a speed of 300r / min for 24h. The total mass ratio of diamond particles, aluminum powder, and melamine powder to the mass of the grinding balls (agate balls with a diameter of 6mm) was 1:20, resulting in a uniform mixed powder.

[0048] The mixed powder was placed into a bearing steel sleeve with a thickness of 3 mm, an inner diameter of 2 cm, and a height of 5 cm. Stainless steel gaskets were used to seal both ends of the bearing steel sleeve. A clamping device (opening greater than 7.5 cm, edge length 2.5 cm) was then used to clamp the stainless steel gasket. The sleeve was placed in a high-temperature furnace for heat treatment, protected by 99% pure argon gas at a flow rate of 100 ppm. The heat treatment process was as follows: first, the temperature was increased to 550℃ at a heating rate of 20℃ / min and held for 1 hour; then, the temperature was increased to 900℃ at a heating rate of 20℃ / min and held for 1 hour. After heat treatment, the sleeve was allowed to cool naturally to room temperature. The clamping device was removed, and the diamond particles coated with aluminum nitride / aluminum carbide were sieved through a 130-mesh sieve.

[0049] Example 2

[0050] 18g of diamond particles with a particle size of 300μm, 14g of aluminum powder with a particle size of 50μm (purity of 99wt%), and 28g of analytical grade melamine powder were loaded into a three-dimensional oscillating mixer and ball-milled at a speed of 200r / min for 25h. The total mass ratio of diamond particles, aluminum powder, and melamine powder to the mass of the grinding balls (agate balls with a diameter of 10mm) was 1:10, resulting in a uniform mixed powder.

[0051] The mixed powder was placed into a bearing steel sleeve with a thickness of 4 mm, an inner diameter of 3 cm, and a height of 4 cm. Stainless steel gaskets were used to seal both ends of the bearing steel sleeve. A clamping device (opening greater than 6 cm, edge length 3.5 cm) was then used to hold the stainless steel gasket in place. The sleeve was placed in a high-temperature furnace for heat treatment, protected by 99.9% pure nitrogen gas at a flow rate of 50 ppm. The heat treatment process was as follows: first, the temperature was increased to 550℃ at a heating rate of 18℃ / min and held for 2 hours; then, the temperature was increased to 1000℃ at a heating rate of 20℃ / min and held for 1 hour. After heat treatment, the sleeve was allowed to cool naturally to room temperature. The clamping device was removed, and the diamond particles coated with aluminum nitride / aluminum carbide were sieved through a 50-mesh sieve.

[0052] Figure 2 The image shows the XRD pattern of diamond particles coated with aluminum nitride / aluminum carbide in Example 1. Figure 3 SEM image of diamond particles coated with aluminum nitride / aluminum carbide in Example 1; Figure 4 This is a SEM image of diamond particles coated with aluminum nitride / aluminum carbide in Example 2.

[0053] Depend on Figure 2 As can be seen, aluminum nitride and aluminum carbide exhibit clear and sharp diffraction peaks, indicating that the aluminum nitride / aluminum carbide coating has a high degree of crystallinity. Highly crystallinity coatings typically possess better chemical stability and mechanical properties, effectively protecting diamond particles. Figure 3 and Figure 4 As can be seen from the SEM images, the coating surface is uniform and dense, without obvious pores or defects, indicating that the preparation method of the present invention can effectively achieve uniform coating coverage. This uniform and dense coating can effectively prevent adverse reactions such as oxidation and graphitization of diamond particles during high-temperature sintering or use.

[0054] Example 3

[0055] 15g of diamond particles with a particle size of 50μm, 2g of aluminum powder with a particle size of 80μm (purity of 99wt%), and 8g of analytical grade melamine powder were loaded into a three-dimensional oscillating mixer and ball-milled at a speed of 300r / min for 24h. The total mass ratio of diamond particles, aluminum powder, and melamine powder to the mass of the grinding balls (stainless steel balls with a diameter of 6mm) was 1:20, resulting in a uniform mixed powder.

[0056] The mixed powder was placed into a bearing steel sleeve with a thickness of 3 mm, an inner diameter of 2.5 cm, and a height of 3 cm. Stainless steel gaskets were used to seal both ends of the bearing steel sleeve. A clamping device (opening greater than 4.5 cm, edge length 3 cm) was then used to hold the stainless steel gasket in place. The sleeve was placed in a high-temperature furnace for heat treatment, protected by 99.9% pure argon gas at a flow rate of 50 ppm. The heat treatment process was as follows: first, the temperature was increased to 600℃ at a heating rate of 20℃ / min and held for 1 hour; then, the temperature was increased to 950℃ at a heating rate of 20℃ / min and held for 1 hour. After heat treatment, the sleeve was allowed to cool naturally to room temperature. The clamping device was removed, and the diamond particles coated with aluminum nitride / aluminum carbide were sieved through a 325-mesh sieve.

[0057] Example 4

[0058] 14g of diamond particles with a particle size of 200μm, 6g of aluminum powder with a particle size of 100μm (purity of 99wt%), and 15g of analytical grade melamine powder were loaded into a three-dimensional oscillating mixer and ball-milled at a speed of 200r / min for 23h. The total mass ratio of diamond particles, aluminum powder, and melamine powder to the mass of the grinding balls (the grinding balls were stainless steel balls with a diameter of 10mm) was 1:15, resulting in a uniform mixed powder.

[0059] The mixed powder was placed into a bearing steel sleeve with a thickness of 4 mm, an inner diameter of 4 cm, and a height of 2.5 cm. Stainless steel gaskets were used to seal both ends of the bearing steel sleeve. A clamping device (opening greater than 5 cm, edge length 5 cm) was then used to clamp the stainless steel gasket. The sleeve was placed in a high-temperature furnace for heat treatment, protected by 99% pure argon gas at a flow rate of 100 ppm. The heat treatment process was as follows: first, the temperature was increased to 600℃ at a heating rate of 20℃ / min and held for 1 hour; then, the temperature was increased to 1000℃ at a heating rate of 20℃ / min and held for 2 hours. After heat treatment, the sleeve was allowed to cool naturally to room temperature. The clamping device was removed, and the diamond particles coated with aluminum nitride / aluminum carbide were sieved through a 70-mesh sieve.

[0060] This invention utilizes a mixture of aluminum powder, melamine, and diamond powder to rapidly coat the surface of diamond particles with aluminum nitride / aluminum carbide particles through high-temperature heat treatment. The method of this invention is not only simple in equipment and convenient in process, but also has low raw material costs and has broad application prospects.

[0061] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing diamond particles with a surface coated with aluminum nitride / aluminum carbide, characterized in that, It includes the following steps: 1) Mix diamond particles, aluminum powder and melamine powder to obtain a mixed powder; 2) The mixed powder is placed in a sealed device to obtain a sealed mixed powder; 3) The sealed mixed powder is heat-treated under a protective atmosphere to obtain diamond particles with an aluminum nitride / aluminum carbide coating on the surface.

2. The preparation method according to claim 1, characterized in that, Step 1) The diamond particles have a particle size of 50-300 μm, the aluminum powder has a particle size of 50-100 μm, and the purity of the aluminum powder is ≥99 wt%.

3. The preparation method according to claim 1 or 2, characterized in that, In step 1), the mass ratio of aluminum powder to melamine powder is 1:2 to 4, and the mass fraction of diamond particles in the mixed powder is 20% to 60%.

4. The preparation method according to claim 3, characterized in that, In step 1), the mixing speed is 200-300 r / min, the mixing time is 22-26 h, and during the mixing process, the total mass ratio of diamond particles, aluminum powder and melamine powder to the mass of the grinding ball is 1:10-20.

5. The preparation method according to claim 3, characterized in that, Step 2) The specific process of placing the mixed powder in the sealed device is as follows: the mixed powder is placed in the bearing steel sleeve, the two ends of the bearing steel sleeve are sealed with stainless steel gaskets, and then the stainless steel gaskets are clamped with a tiger clamp. The thickness of the bearing steel sleeve is 3-4 mm, and the length of the bearing steel sleeve is less than 2 / 3 of the opening of the tiger clamp; the outer diameter of the bearing steel sleeve is similar to the edge length of the tiger clamp; the thickness of the stainless steel gasket is 2-4 mm.

6. The preparation method according to claim 5, characterized in that, Step 3) The protective atmosphere is an argon atmosphere or a nitrogen atmosphere, the purity of the protective atmosphere is 99-99.9%, and the flow rate of the protective atmosphere is 50-100 ppm.

7. The preparation method according to claim 1 or 6, characterized in that, Step 3) The heat treatment includes a first heat treatment and a second heat treatment. The temperature of the first heat treatment is 550-600℃ and the time is 1-2 hours. The temperature of the second heat treatment is 900-1000℃ and the time is 1-2 hours.

8. The preparation method according to claim 7, characterized in that, The heating rate of the heat treatment in step 3) is 10-20℃ / min.

9. Diamond particles with an aluminum nitride / aluminum carbide coating on their surface, prepared by the preparation method according to any one of claims 1 to 8.

Images