A method for preparing titanium carbide-coated diamond particles

Abstract

This invention provides a method for preparing titanium carbide-coated diamond particles, belonging to the field of diamond-reinforced metal matrix composites. The method includes the following steps: depositing a titanium film on the surface of diamond particles using a high-purity titanium target via vibration-assisted magnetron sputtering; placing the titanium-coated diamond particles in a small crucible, and laying zirconium particles flat at the bottom of a large crucible; placing the small crucible inside the large crucible; and placing the resulting nested crucibles into a vacuum heat treatment furnace; evacuating the heat treatment furnace, introducing an argon-hydrogen mixture, and heating for heat treatment, with the argon-hydrogen mixture flowing continuously throughout the entire heat treatment process. This invention employs a synergistic strategy of "zirconium particle oxygen absorption - argon-hydrogen gas reduction," combined with a high-temperature in-situ carbide method to prepare titanium carbide-coated diamond particles. The oxygen content of the prepared titanium carbide film is as low as 8 at.%, which is 82% lower than that of uncoated zirconium particles. It can be directly integrated into existing composite material production lines and is suitable for batch processing of diamond particles.

Description

Technical Field

[0001] This invention belongs to the technical field of diamond-reinforced metal matrix composite materials, specifically relating to a method for preparing titanium carbide-coated diamond particles. Background Technology

[0002] The development of high-power electronic devices has created an urgent need for high-performance thermal management materials. A diamond / aluminum composite material prepared using a liquid-phase method achieves a thermal conductivity of 1021 W / mK and has an adjustable coefficient of thermal expansion, making it a promising candidate for high-power devices in the aerospace field.

[0003] The interfacial state of diamond / aluminum composites plays a crucial role in stress distribution, load conduction, heat transport, and mechanical properties. During the preparation of diamond / aluminum composites, under high-temperature conditions, the contact between aluminum and diamond particles readily leads to the formation of an easily hydrolyzable Al4C3 phase at the interface, increasing the risk of interfacial cracking when the composite is used in humid environments. Therefore, optimizing the interfacial structure of diamond / aluminum composites is key to improving the overall performance of the composite. A common approach is diamond surface metallization, which involves depositing a continuous and dense metal film onto the surface of diamond particles before preparing the composite with an aluminum matrix. This method avoids direct contact between aluminum and diamond, effectively reducing the formation of the Al4C3 phase.

[0004] Common metal modification elements for diamond surfaces include titanium, zirconium, chromium, and tungsten, among which titanium-plated diamond / aluminum composites achieve a thermal conductivity of 646 W / mK. However, during the preparation of diamond / aluminum composites, the reaction between titanium and aluminum forms a harmful intermetallic compound, Al3Ti, which is detrimental to the overall performance of the titanium-plated diamond / aluminum composite. Titanium carbide possesses good chemical stability, and coating diamond particles with titanium carbide can effectively reduce the formation of the Al3Ti phase at the interface. However, when using techniques such as plasma spraying and chemical vapor deposition to directly deposit a titanium carbide coating on the surface of diamond particles at high temperatures, it is difficult to avoid the formation of titanium oxide. Since the bond between titanium oxide and diamond particles is physical, the bonding force is relatively weak.

[0005] Titanium carbide coatings can be prepared by high-temperature in-situ carbonization of titanium-coated diamond particles, which can improve the adhesion between the titanium carbide coating and the diamond particles. However, the titanium film is easily oxidized during the high-temperature in-situ carbonization process. Therefore, existing technologies cannot produce high-quality titanium carbide-coated diamond particles. Summary of the Invention

[0006] To avoid the generation of harmful Al3Ti phase during the preparation of diamond / aluminum composite materials and to overcome the technical defects of titanium oxide generated by direct plating of titanium carbide, this invention proposes a method for preparing titanium carbide-coated diamond particles.

[0007] This invention provides a method for preparing titanium carbide-coated diamond particles, comprising the following steps:

[0008] 1) At room temperature, a high-purity titanium target is used to deposit a titanium film on the surface of diamond particles using vibration-assisted magnetron sputtering technology.

[0009] 2) Prepare two crucibles with different volumes. Place the titanium-plated diamond particles obtained in step 1) into the small crucible and spread metallic zirconium particles on the bottom of the large crucible.

[0010] 3) Place the small crucible inside the large crucible to obtain nested crucibles, and then place the nested crucibles into a vacuum heat treatment furnace;

[0011] 4) After evacuating the heat treatment furnace, introduce an argon-hydrogen mixture.

[0012] 5) Raise the furnace temperature to the required temperature, hold it at that temperature for a period of time, and then cool the furnace temperature to room temperature. Argon-hydrogen mixed gas should be circulated throughout the entire heat treatment process.

[0013] Preferably, in step 1), the purity of the high-purity titanium target is 99.9~99.999%, and the particle size of the diamond particles is 50~700 μm.

[0014] Preferably, in step 1), the magnetron sputtering power is 50~400 W and the argon flow rate is 20~40 sccm.

[0015] Preferably, in step 1), the vibration frequency is 10-60 times per minute, more preferably 20-40 times per minute. The purpose of the vibration is to ensure that each facet of the diamond particle is coated with a titanium film. The above frequency range can ensure uniform coating while avoiding excessive collisions between particles that could damage the film.

[0016] Preferably, in step 1), the thickness of the titanium film is 10~500 nm.

[0017] Preferably, in step 2), the crucible is made of either quartz or alumina. These materials do not react with the sample inside the crucible at high temperatures.

[0018] Preferably, in step 2), the volume of the small crucible is 5~7000 cm³. 3 The volume of the large crucible is 10~8000 cm³. 3 Furthermore, the large crucible can completely accommodate the small crucible. The small crucible in this invention serves as a physical barrier, preventing the reaction between metallic zirconium and the titanium film on the surface of the diamond particles, while also avoiding contamination of the titanium film and the subsequently formed titanium carbide film by zirconium oxide powder. More preferably, the volume of the small crucible is ≤ 4 / 5 of the volume of the large crucible, ensuring sufficient flow of the argon-hydrogen mixture within the nested gap.

[0019] Preferably, in step 2), the purity of the zirconium particles is 99-99.99%, and the dosage is 10-1000 g. Since zirconium reacts with residual oxygen in the heat treatment chamber, it removes the residual oxygen. The residual oxygen content is related to the size of the chamber; therefore, the dosage of zirconium is determined based on the dimensions of the heat treatment chamber and the volume of the large crucible. Adding too much zirconium will result in waste, while adding too little will lead to a poorer deoxygenation effect.

[0020] Preferably, in step 4), the heat treatment furnace is evacuated until the vacuum level is below 10. -3 Stop after Pa; introducing an argon-hydrogen mixed gas can reduce trace amounts of titanium oxide in the titanium carbide film and / or zirconium oxide in the large crucible. The argon / hydrogen volume ratio in the argon-hydrogen mixed gas is 4:1 to 99:1, the flow rate of the mixed gas is 1 to 30 L / min, and the flow time is 1 to 30 min.

[0021] Preferably, in step 5), the heat treatment heating rate is 1~30 ℃ / min, the heat treatment temperature is 600~1200 ℃, the holding time is 5~600 min, and the cooling rate after the heat treatment is 1~30 ℃ / min. During the heat treatment process, carbon atoms on the diamond surface gain sufficient energy to diffuse at high temperature, and the carbon atoms diffuse into the titanium film, where they react with titanium at high temperature to form titanium carbide.

[0022] The present invention also provides titanium carbide-coated diamond particles prepared by the method, wherein the surface of the diamond particles is coated with a titanium carbide film, and the oxygen content in the titanium carbide film is at least 8 at.%.

[0023] The present invention also provides an apparatus for implementing the above method, comprising crucibles of different sizes, metallic zirconium particles, and titanium-plated diamond particles. The metallic zirconium particles are laid flat at the bottom of the large crucible; the titanium-plated diamond particles are placed inside the small crucible; the large crucible can completely contain the small crucible; and by placing the small crucible inside the large crucible, argon-hydrogen gas can circulate between the embedded crucibles.

[0024] The present invention has the following beneficial effects:

[0025] This invention employs a synergistic strategy of "zirconium particle oxygen absorption - argon-hydrogen gas reduction," combined with a high-temperature in-situ carbonization method to prepare titanium carbide-coated diamond particles. The resulting titanium carbide film exhibits an oxygen content as low as 8 at.%, a reduction of 82% compared to films without zirconium particles. By controlling the amount of zirconium particles used, the amount of titanium oxide in the titanium carbide layer can be reduced, solving the oxidation problem during the in-situ carbonization process of titanium-coated diamond particles. The titanium carbide layer prepared through the high-temperature in-situ carbonization reaction exhibits a stronger chemical bond between the titanium carbide layer and the diamond particles. This invention can be directly integrated into existing composite material production lines, is suitable for batch processing of diamond particles, requires no major equipment modifications, and produces no secondary pollution. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0027] Figure 1 This is a schematic diagram of the device structure for achieving titanium carbide-coated diamond particles according to the present invention;

[0028] Figure 2 The surface morphology of titanium carbide-coated diamond particles prepared as a comparative example is shown.

[0029] Figure 3 The surface morphology of the titanium carbide-coated diamond particles prepared in Example 1 is shown in Figure 1.

[0030] Figure 4 The surface morphology of the titanium carbide-coated diamond particles prepared in Example 2 is shown in the image.

[0031] Figure 5 The image shows the surface morphology of the titanium carbide-coated diamond particles prepared in Example 3. Detailed Implementation

[0032] To make the technical problems, technical solutions, and advantages of the present invention clearer, a detailed description will be provided below in conjunction with the accompanying drawings, comparative examples, and specific embodiments.

[0033] Figure 1 This is a schematic diagram of the device used in this invention to achieve titanium carbide-coated diamond particles, including zirconium metal particles, an argon-hydrogen mixture, and a crucible. The zirconium metal particles are laid flat at the bottom of a large crucible, while the titanium-coated diamond particles are placed inside a smaller crucible. The large crucible can completely contain the smaller crucible; placing the smaller crucible inside the large crucible allows for the circulation of argon-hydrogen gas between the embedded crucibles.

[0034] This invention also provides a method for preparing titanium carbide-coated diamond particles, comprising the following steps:

[0035] 1) At room temperature, a titanium film of a certain thickness is deposited on the surface of diamond particles using vibration-assisted magnetron sputtering technology and a high-purity titanium target;

[0036] 2) Place the titanium-plated diamond particles obtained in step 1) into a small crucible;

[0037] 3) Spread metallic zirconium particles evenly at the bottom of the large crucible;

[0038] 4) Place the small crucible from step 2) into the large crucible from step 3);

[0039] 5) Place the nested crucible from step 4) into the vacuum heat treatment furnace;

[0040] 6) Evacuate the heat treatment furnace until the vacuum level is below 10. -3 Stop after Pa;

[0041] 7) Introduce a mixture of argon and hydrogen gas with a certain volume ratio into the heat treatment furnace and allow it to circulate for a period of time;

[0042] 8) Raise the furnace temperature to the required temperature at a certain heating rate, hold it at the temperature for a period of time, and then cool the furnace temperature to room temperature at a certain cooling rate. Argon-hydrogen mixed gas is always flowing throughout the entire heat treatment process.

[0043] This invention reduces the amount of zirconium metal particles used, thereby reducing the residual oxygen content in the heat treatment furnace and effectively lowering the probability of oxygen contacting the titanium metal film, thus improving the quality of the prepared titanium carbide film.

[0044] To better understand the present invention, specific comparative examples and embodiments are described in detail below. It should be noted that the following embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0045] Comparative Example 1

[0046] Compared to Example 1, step three was omitted, i.e., metallic zirconium particles were not placed inside the large crucible; instead, titanium-plated diamond particles were directly placed inside an empty large crucible. Other steps and parameters were the same as in Example 1.

[0047] Figure 2 The surface morphology of the titanium carbide-coated diamond particles prepared for this comparative example is shown. Due to the absence of zirconium particles, residual oxygen remained in the reaction chamber, resulting in incomplete conversion of the titanium film on the diamond surface into titanium carbide. It can be seen that the titanium carbide on the diamond particle surface is discontinuous, and a large amount of titanium oxide is present.

[0048] Comparative Example 2

[0049] Compared to Example 1, no argon-hydrogen mixed gas was circulated during the entire heat treatment process in step seven; that is, heat treatment was performed directly after the vacuuming in step six. Other steps and parameters were the same as in Example 1. Since no argon-hydrogen mixed gas was introduced, the trace amounts of titanium oxide in the titanium carbide film could not be reduced. Therefore, the surface morphology of the titanium carbide-coated diamond particles prepared in this comparative example is consistent with that in Comparative Example 1, and will not be described again.

[0050] Example 1

[0051] Step 1: At room temperature, the sample stage is vibrated at a frequency of 30 times / min, using a titanium target with a purity of 99.995%. Under sputtering parameters of 100 W power and argon flow rate of 30 sccm, a titanium film with a uniform thickness of 100 nm is deposited on the surface of 100 μm diamond particles.

[0052] Step 2: Place the titanium-plated diamond particles from step 1) in a 15 cm slab. 3 Inside the alumina crucible;

[0053] Step 3, at 25 cm 3 10 g of 99.5% pure zirconium metal particles were laid flat on the bottom of the alumina crucible;

[0054] Step 4: Place the small crucible from step 2 into the large crucible from step 3.

[0055] Step 5: Place the nested crucible from step 4) into the vacuum heat treatment furnace;

[0056] Step Six: Evacuate the heat treatment furnace until the vacuum level reaches 2.4 × 10⁻⁶. -4 Stop after Pa;

[0057] Step 7: Introduce an argon-hydrogen mixed gas with a volume ratio of 4:1 and a flow rate of 10 L / min into the heat treatment furnace. After 10 min of flow, proceed with high-temperature heat treatment. The heating and cooling rates are both 5 °C / min, and the temperature is held at 1000 °C for 180 min. The mixed gas is kept flowing throughout the entire heat treatment process.

[0058] Example 2

[0059] In step three, add 25 cm 3 The mass of the zirconium metal particles at the bottom of the alumina crucible was 20 g, and the other steps and parameters were the same as in Example 1.

[0060] Example 3

[0061] In step three, add 25 cm 3 The mass of the zirconium metal particles at the bottom of the alumina crucible was 30 g, and the other steps and parameters were the same as in Example 1.

[0062] Figures 3-5 The images show the surface morphology of the titanium carbide-coated diamond particles prepared in Examples 1-3, respectively. It can be seen that the titanium carbide uniformly and continuously coats the diamond particles. In Example 1, a smaller amount of zirconium particles were added, and a small amount of titanium oxide remained in the titanium carbide film. In Examples 2 and 3, as the content of zirconium particles increased, the titanium oxide in the film was completely removed.

[0063] Table 1 shows the surface elemental analysis of the titanium carbide-coated diamond particles prepared in the above examples and Comparative Example 1. It indicates that in Examples 1-3, with the increase of zirconium metal, the oxygen content in the diamond surface film gradually decreases while the carbon content gradually increases, indicating that more carbon atoms enter the titanium film and react with titanium to form titanium carbide. Furthermore, the surface morphology of the films in Examples 2 and 3 is almost identical, but the energy dispersive spectroscopy results show that Example 3 has a lower oxygen content, meaning that Example 3 is more effective.

[0064] Energy dispersive spectroscopy analysis also showed that the oxygen content in the prepared titanium carbide film could be as low as 8 at.%, which was 82% lower than that in the sample without zirconium particles, effectively solving the oxidation problem in the in-situ carbonization process of titanium-coated diamond particles.

[0065] Table 1

[0066]

[0067] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing titanium carbide-coated diamond particles, characterized in that, Includes the following steps: 1) At room temperature, a high-purity titanium target is used to deposit a titanium film on the surface of diamond particles using vibration-assisted magnetron sputtering technology. 2) Prepare two crucibles with different volumes. Place the titanium-plated diamond particles obtained in step 1) into the small crucible and spread metallic zirconium particles on the bottom of the large crucible. 3) Place the small crucible inside the large crucible, and then place the resulting nested crucibles into a vacuum heat treatment furnace; 4) After evacuating the heat treatment furnace, introduce an argon-hydrogen mixture. 5) Raise the furnace temperature to the required temperature, hold it at that temperature for a period of time, and then cool the furnace temperature to room temperature. Argon-hydrogen mixed gas should be circulated throughout the entire heat treatment process.

2. The method for preparing titanium carbide-coated diamond particles according to claim 1, characterized in that, In step 1), the purity of the high-purity titanium target is 99.9~99.999%, and the particle size of the diamond particles is 50~700 μm.

3. The method for preparing titanium carbide-coated diamond particles according to claim 1, characterized in that, In step 1), the magnetron sputtering power is 50~400 W, and the argon flow rate is 20~40 sccm; And / or, the vibration frequency is 10 to 60 times per minute, preferably 20 to 40 times per minute.

4. The method for preparing titanium carbide-coated diamond particles according to any one of claims 1 to 3, characterized in that, In step 1), the thickness of the titanium film is 10~500 nm.

5. The method for preparing titanium carbide-coated diamond particles according to claim 1, characterized in that, In step 2), the material of the crucible is selected from quartz and alumina.

6. The method for preparing titanium carbide-coated diamond particles according to claim 1, characterized in that, In step 2), the volume of the small crucible is 5~7000 cm³. 3 The volume of the large crucible is 10~8000 cm³. 3 Furthermore, the large crucible completely accommodates the small crucible; Preferably, the volume of the small crucible is ≤ 4 / 5 of the volume of the large crucible.

7. The method for preparing titanium carbide-coated diamond particles according to claim 1, characterized in that, In step 2), the purity of the zirconium metal particles is 99~99.99%, and the amount used is 10~1000 g.

8. The method for preparing titanium carbide-coated diamond particles according to claim 1, characterized in that, In step 4), the heat treatment furnace is evacuated until the vacuum level is below 10. -3 The flow rate of the argon-hydrogen mixture is 1-30 L / min, and the flow time is 1-30 min. The argon / hydrogen volume ratio in the argon-hydrogen mixture is 4:1 to 99:

1.

9. The method for preparing titanium carbide-coated diamond particles according to claim 1, characterized in that, In step 5), the heating rate is 1~30 ℃ / min, the heat treatment temperature is 600~1200 ℃, the holding time is 5~600 min, and the cooling rate after the heat treatment is 1~30 ℃ / min.

10. The titanium carbide-coated diamond particles prepared by the method according to any one of claims 1 to 9, characterized in that, The diamond particles are coated with a titanium carbide film, and the oxygen content in the titanium carbide film is at least 8 at.%.

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