A method for preparing diamond metal matrix composite based on high-speed laser cladding process

Abstract

The application discloses a method for preparing diamond metal matrix composite material based on high-speed laser cladding process and belongs to the technical field of high-power device thermal management materials. The main steps of the method comprise the following steps: (1) pretreatment of diamond particles; (2) vacuum micro-evaporation film coating; and (3) high-speed laser cladding. The method disclosed by the application does not need to use high-temperature and high-pressure synthesis press equipment to press diamond and metal powder, the preparation method is simple, the process is stable and reliable, the material size is not limited by the size of the cavity of the high-temperature and high-pressure synthesis press, and large-size preparation is facilitated; after cutting, polishing and other treatments of the prepared large-size material, the large-size material can be processed into a large number of small-size materials according to needs, and subsequent large-scale production work can be facilitated.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high-power device thermal management materials, and particularly relates to a method for preparing a diamond metal matrix composite material based on a high-speed laser cladding process. BACKGROUND

[0002] With the rapid development of quantum computer technology and 5G communication technology, electronic devices are running faster and faster. While the running speed of electronic devices is rapidly increasing, the operating power of electronic components is also increasing, and the heat generated in a unit space is also increasing, which puts higher requirements on the heat dissipation performance of power device heat dissipation materials. The traditional heat dissipation materials prepared from metals such as copper and aluminum for power device heat dissipation cannot well meet the heat dissipation requirements of future high-power devices due to their own thermal conductivity. Therefore, people turn their attention to heat dissipation materials with better heat dissipation performance, and diamond is one of the ideal materials.

[0003] In actual thermal conductivity testing, high-grade type IIa artificial white diamonds can achieve a thermal conductivity of 2000 W / (m·K) or higher, which is much higher than the thermal conductivity of 429 W / (m·K) of metallic silver, the thermal conductivity of 386 W / (m·K) of metallic copper, and the thermal conductivity of 205 W / (m·K) of metallic aluminum, and has very attractive application prospects in the technical field of high-power device thermal management materials. However, due to the extremely high surface energy of diamond, it is difficult for it to be infiltrated by metal materials, and the bonding force between the diamond and the metal material is low, which is not conducive to the improvement of the overall thermal conductivity of the diamond metal matrix composite material. Therefore, diamond particles and carbonizable metal powder are usually coated with a vacuum micro-evaporation film to form a metal carbide on the outside of the diamond, so that the diamond and the metal coating are chemically bonded through the metal carbide to improve the bonding force between the diamond and the metal material, thereby improving the overall thermal conductivity of the diamond metal matrix composite material.

[0004] At present, the commonly used method is to mix the metal copper powder with the industrial diamond particles after vacuum micro-evaporation coating, and then put them in the cavity of the high temperature and high pressure synthesis press equipment, and then treat them by high temperature and high pressure to prepare the diamond metal copper-based material. This kind of material has many shortcomings. First, the thermal conductivity of the metal copper powder is lower than that of silver, and the thermal conductivity of the industrial diamond 1100 W / (m•K) is also much lower than that of the artificially cultivated white diamond IIa type 2000 W / (m•K) and above. The thermal conductivity of the prepared material is low. Secondly, the copper on the surface of the material is exposed to the air and is easy to produce green copper rust. After further post-processing process such as electroplating of metal nickel and gold plating, it can be combined with high-power devices. Copper rust is not conducive to the combination of the material and the high-power device, and the material stability is poor, and the practical value is low. Finally, due to the size limitation of the cavity of the high temperature and high pressure synthesis press equipment, the size of the product is limited by the size of the cavity of the high temperature and high pressure synthesis press equipment, which is not conducive to the subsequent large-scale production work. SUMMARY

[0005] In order to solve the problems existing in the diamond metal copper-based material prepared by the existing high temperature and high pressure method in actual application, the purpose of the present application is to provide a method for preparing diamond metal matrix composite material based on high-speed laser cladding process.

[0006] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is:

[0007] A method for preparing diamond metal matrix composite material based on high-speed laser cladding process, which comprises the following steps:

[0008] (1) Pretreatment of diamond particles

[0009] A proper amount of colorless and translucent diamond particles after surface treatment is placed in a crusher for crushing. After crushing, the diamond particles are screened and placed in an ultrasonic cleaning equipment for oscillation cleaning with anhydrous ethanol. Then, the diamond particles are taken out, washed clean with pure water, and then placed in a drying box for drying for standby use.

[0010] (2) Vacuum micro-evaporation coating

[0011] The diamond particles obtained in step (1) are mixed with hafnium powder and potassium chloride in a mixer according to the mass ratio of (150-200):(10-20):(1-2), and then placed in a vacuum micro-evaporation coating equipment for coating the surface of the diamond particles.

[0012] (3) High-speed laser cladding

[0013] The silver powder, hafnium powder, rhodium powder and cerium powder are mixed in a rolling ball mill mixer according to a mass ratio of (50-100):(0.05-0.1):(0.001-0.002):(0.01-0.02), the mixed metal powder is placed in a metal powder storage bin of a high-speed laser cladding device, the coated diamond particles in step (2) are evenly covered on the silver metal carrier, and metal cladding is performed under the nozzle of the high-speed laser cladding device, after the diamond particles on the silver metal carrier are cladded, the coated diamond particles are again evenly covered on the diamond-metal composite cladding layer prepared by cladding, and metal cladding is performed under the nozzle of the high-speed laser cladding device, and the process is repeated until the thickness of the finished product is slightly larger than the required thickness, and the cladding is stopped.

[0014] Preferably, the colorless translucent diamond particles in step (1) are type IIa artificial white diamonds, and the thermal conductivity is higher than 2000 W / (m·K); the particle size of the selected diamond particles is any one of 270 / 325, 325 / 400 and 400 / 500.

[0015] Preferably, the amount of the diamond particles in step (2) is 1500.00-2000.00 g, the amount of the hafnium powder is 100.00-200.00 g, and the amount of the potassium chloride is 10.00-20.00 g.

[0016] Preferably, the purity of the hafnium powder in step (2) is 99.90%, and the particle size is 400-500 mesh.

[0017] Preferably, the process parameters for coating in step (2) are: a vacuum degree of 10 -6 ~10 -3 Pa, a temperature of 800-1100℃, and a time of 30-120 min.

[0018] Preferably, the amount of the silver powder in step (3) is 50.00-100.00 g, the amount of the hafnium powder is 0.05-0.10 g, the amount of the rhodium powder is 0.001-0.002 g, and the amount of the cerium powder is 0.01-0.02 g.

[0019] Preferably, the purity of the silver powder in step (3) is 99.99%, and the particle size is any one of 800 mesh, 900 mesh and 1000 mesh; the purity of the hafnium powder is 99.90%, and the particle size is any one of 400 mesh and 500 mesh; the purity of the rhodium powder is 99.99%, and the particle size is any one of 200 mesh and 325 mesh; and the purity of the cerium powder is 99.90%, and the particle size is any one of 200 mesh and 300 mesh.

[0020] Preferably, the cladding process parameters in step (3) are: laser power is 2000-3000 W, powder feeding speed is 20-30 rad / min, and scanning speed is 5-10 m / min.

[0021] Preferably, the size of the metal carrier silver sheet in step (3) is 100 mm*100 mm, and the thickness is 0.5 mm, and a metal copper pad for heat dissipation is placed below the metal carrier silver sheet, and the hole of the metal copper pad can be cooled by the ultra-pure water with controllable flow rate.

[0022] Preferably, the required thickness in step (3) is 5 mm, and the finished product thickness is greater than the required thickness by 1-2 mm.

[0023] The beneficial effects of the present application are:

[0024] 1. The metal material for preparing the diamond metal matrix composite material in the present application is mainly metal silver, and the thermal conductivity is greater than that of metal copper; the diamond is type IIa artificial white diamond, and the thermal conductivity is also greater than that of industrial diamond. According to the content of impurity nitrogen atoms and the lattice defect in the diamond crystal, the diamond is usually divided into four grades of Ia, Ib, IIa and IIb, and the commonly used industrial diamond is type Ib, and the content of impurity nitrogen atoms and the lattice defect in the crystal lattice are much higher than those of type IIa artificial white diamond. When heat transfer is carried out, the impurity nitrogen atoms and the lattice defect in the crystal lattice will cause the thermal resistance of the diamond crystal to increase, and the macroscopic performance is the decrease of the thermal conductivity. The content of impurity nitrogen atoms in type IIa artificial white diamond is below 1 ppm, which is much lower than that of type Ib industrial diamond which is above 90 ppm. Therefore, in terms of thermal conductivity, type IIa artificial white diamond has more advantages than type Ib industrial diamond. In addition, compared with the high-temperature and high-pressure method for preparing diamond metal copper matrix composite material, the high-speed laser cladding process in the present application does not need to press the material at high temperature and high pressure, and can avoid the generation of cracks and pores in the diamond crystal under high temperature and high pressure. Since the cracks and pores in the diamond crystal under high temperature and high pressure will bring great thermal resistance to heat transfer, avoiding the generation of cracks and pores in the diamond crystal during the preparation process is crucial to maintaining the high thermal conductivity of the diamond crystal, and can maximize the avoidance of the decrease of the thermal conductivity of the diamond crystal when used in composite material preparation. Therefore, compared with the diamond metal copper matrix composite material prepared by the high-temperature and high-pressure method, the diamond metal matrix composite material prepared by using metal silver, type IIa artificial white diamond and high-speed laser cladding process in the present application has better thermal conductivity and higher thermal conductivity, and the highest thermal conductivity can reach 906 W / (m•K).

[0025] 2. The metal material for preparing the diamond metal matrix composite material in the application can exist stably for a long time without rusting when exposed to air, and after preparation, no further post-processing process such as electroplating of metal nickel or gold plating is needed, and the material can be directly bonded with a high-power device, so that the material is stable and reliable and has higher practical value.

[0026] 3. The method for preparing the diamond metal matrix composite material based on the high-speed laser cladding process in the application does not need to use a high-temperature and high-pressure synthesis press device to press the diamond and metal powder, the preparation method is simple, the process is stable and reliable, the material size is not limited by the size of the cavity of the high-temperature and high-pressure synthesis press, and large-size preparation is facilitated; in addition, after the prepared large-size material is cut and polished, a large number of small-size materials can be processed according to needs, so that subsequent large-scale production work can be carried out. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 it is a micrograph of the diamond particles after vacuum micro-evaporation plating in example 2;

[0028] Figure 2 it is an X-ray diffraction diagram of the diamond particles after vacuum micro-evaporation plating in example 2;

[0029] Figure 3 it is a cross-sectional micrograph of the diamond metal matrix composite material before cutting and polishing in example 2;

[0030] Figure 4 it is a plan view of the diamond metal matrix composite material after preliminary cutting and polishing in example 2. DETAILED DESCRIPTION

[0031] The application will be further described in combination with specific embodiments.

[0032] Example 1

[0033] A method for preparing a diamond metal matrix composite material based on a high-speed laser cladding process, comprising the following steps:

[0034] (1) Pretreatment of diamond particles

[0035] An appropriate amount of colorless and translucent diamond particles after surface treatment is placed in a crusher for crushing, and the crushed diamond particles are screened, placed in an ultrasonic cleaning device for oscillation cleaning with anhydrous ethanol, then taken out, cleaned with pure water, and placed in a drying box for drying for standby use; the colorless and translucent diamond particles are type IIa artificial white diamonds, and the thermal conductivity is higher than 2000 W / (m•K); the particle size of the screened diamond particles is 270 / 325;

[0036] (2) Vacuum micro-evaporation coating

[0037] The diamond particles obtained in step (1) are mixed with hafnium powder and potassium chloride in a mixer according to a determined amount, wherein the amount of diamond is 2000.00 g, the amount of hafnium powder is 100.00 g, and the amount of potassium chloride is 10.00 g for each mixing process. After mixing, the mixture is placed in a vacuum micro-evaporation coating device to coat the surface of the diamond particles. The process parameters during coating are: vacuum degree 10 -3 Pa, temperature 800℃, time 30min. After coating, the definition and method of "3.3 Coating weight percentage (the percentage of the mass of the titanium-coated diamond coating layer to the mass of the diamond before coating) " in the Chinese machinery industry standard "JB / T 12206-2015 Superhard Abrasive Titanium-coated Diamond" are referred to, and the concept of "coating weight percentage" is used to describe the overall coating of all diamond particles after vacuum micro-evaporation coating in a macroscopic way. In this embodiment, the coating weight percentage of the diamond particles after vacuum micro-evaporation coating is 0.11%. The purity of the hafnium powder used for vacuum micro-evaporation coating is 99.90%, and the particle size is 400 mesh.

[0038] (3) High-speed laser cladding

[0039] The silver powder, hafnium powder, rhodium powder, and cerium powder are mixed in a rolling ball mill mixer according to the determined amount, wherein the amount of silver powder is 50.00 g, the purity of silver powder is 99.99%, and the particle size is 800 mesh; the amount of hafnium powder is 0.10 g, the purity of hafnium powder is 99.90%, and the particle size is 400 mesh; the amount of rhodium powder is 0.002 g, the purity of rhodium powder is 99.99%, and the particle size is 200 mesh; the amount of cerium powder is 0.02 g, the purity of cerium powder is 99.90%, and the particle size is 200 mesh. The mixed metal powder is placed in the metal powder storage bin of the high-speed laser cladding equipment. The diamond particles coated in step (2) are uniformly covered on the metal carrier silver sheet, and metal cladding is carried out under the nozzle of the high-speed laser cladding equipment. After the diamond particles on the metal carrier silver sheet are cladded, the coated diamond particles are again uniformly covered on the diamond-metal composite cladding layer prepared by cladding, and metal cladding is carried out under the nozzle of the high-speed laser cladding equipment. Repeat this process until a metal composite cladding layer with a thickness of about 7 mm is obtained, and then stop cladding. The thickness is greater than the required thickness of 5 mm because the subsequent milling, grinding, and polishing processes will thin the product, i.e., the thickness of the finished product is less than the thickness of the product blank. After the subsequent milling, grinding, and polishing processes, the finished product is obtained. The thickness of the finished product is measured using a micrometer, and the result is 5.012 mm. The cladding process parameters are: laser power is 3000 W, powder feeding speed is 30 rad / min, and scanning speed is 10 m / min. The size of the metal carrier silver sheet is 100 mm x 100 mm, and the thickness is 0.5 mm. A metal copper pad is placed under the metal carrier silver sheet for heat dissipation. The hole in the metal copper pad can be cooled by ultra-pure water with a controllable flow rate.

[0040] The diamond-metal composite material prepared above can be processed into a large number of small-sized materials after being cut and polished according to needs.

[0041] In this embodiment, the thermal conductivity of the diamond-metal composite material prepared in this embodiment is tested by a LFA467 laser thermal conductivity instrument produced by Nanjing Nanoci Company, Germany, according to the laser flash method (Laser Flash Method). The measured thermal conductivity is 827 W / (m•K).

[0042] Example 2

[0043] A method for preparing a diamond-metal composite material based on a high-speed laser cladding process, the main steps of which are the same as steps (1)-(3) in Example 1, except that:

[0044] In this embodiment, the particle size of the diamond particles selected in step (1) is 325 / 400.

[0045] In this embodiment, the purity of the hafnium powder used in vacuum micro-evaporation coating in step (2) is 99.90%, and the particle size is 500 mesh; the amount of diamond is 1800.00 g, the amount of hafnium powder is 200.00 g, and the amount of potassium chloride is 20.00 g.

[0046] In this embodiment, the process parameters during coating in step (2) are: vacuum degree is 10 -5 Pa, temperature is 900℃, and time is 90 min; the coating weight gain rate of the diamond particles after vacuum micro-evaporation coating is 0.26%; the diamond particles after vacuum micro-evaporation coating are shown in Figure 1 , it can be seen that Figure 1 After vacuum micro-evaporation coating, the carbon atoms on the surface of the diamond particles will react with the metal powder, forming a layer of metal carbide on the outside of the diamond particles; the X-ray diffraction pattern of the diamond particles after vacuum micro-evaporation coating is shown in Figure 2 , and the HfC in the attached Figure 2 The elemental carbon atoms in the diamond can be chemically bonded to the metal coating through the metal carbide, which can reduce the surface energy of the diamond particles, improve the wettability of the diamond particles, and improve the bonding force between the diamond particles and the metal material, thereby achieving the purpose of improving the thermal conductivity of the diamond metal matrix composite.

[0047] In this embodiment, the purity of the silver powder in step (3) is 99.99%, and the particle size is 900 mesh; the purity of the hafnium powder is 99.90%, and the particle size is 500 mesh; the purity of the rhodium powder is 99.99%, and the particle size is 325 mesh; the purity of the cerium powder is 99.90%, and the particle size is 300 mesh; the amount of silver powder is 100.00 g, the amount of hafnium powder is 0.05 g, the amount of rhodium powder is 0.001 g, and the amount of cerium powder is 0.01 g.

[0048] In this embodiment, the process parameters for laser cladding in step (3) are: laser power is 2800 W, powder feeding speed is 20 rad / min, and scanning speed is 5 m / min; a diamond metal matrix composite with a metal composite cladding layer of about 7 mm thick is obtained, as shown in the attached Figure 3 , which is a cross-sectional picture of the diamond metal matrix composite described in this embodiment before being cut, polished and other treatments, and from the cross-section, a layer-by-layer texture structure generated by the high-speed laser cladding process can be clearly observed; after subsequent milling, grinding and polishing processes, a product with a thickness of 5.019 mm is obtained, as shown in the attached Figure 4 , which is a picture of the diamond metal matrix composite described in this embodiment after preliminary cutting, polishing and other treatments.

[0049] In this embodiment, the diamond metal matrix composite prepared in this embodiment was tested for thermal conductivity using a LFA467 laser thermal conductivity instrument produced by Netzsch, Germany, according to the laser flash method (Laser Flash Method), and the measured thermal conductivity was 906 W / (m•K); it should be further pointed out that the thermal conductivity result measured in this embodiment is the highest value of the thermal conductivity measured in the results of numerous design experiments such as orthogonal design experiments and single-factor variable control experiments.

[0050] In this embodiment, the other conditions are the same as in Example 1.

[0051] Example 3

[0052] A method for preparing a diamond metal matrix composite based on a high-speed laser cladding process, the main steps of the method are the same as steps (1)-(3) in Example 1, the difference is that:

[0053] In this embodiment, the particle size of the diamond particles selected in step (1) is 400 / 500.

[0054] In this embodiment, the purity of the hafnium metal powder used for vacuum micro-evaporation coating in step (2) is 99.90%, and the particle size is 500 mesh; the amount of diamond is 1500.00g, the amount of hafnium powder is 200.00g, and the amount of potassium chloride is 20.00g.

[0055] In this embodiment, the process parameters during coating in step (2) are: vacuum degree is 10 -6 Pa, temperature is 1100℃, time is 120min; the coating weight gain rate of the diamond particles after vacuum micro-evaporation coating is 0.49%.

[0056] In this embodiment, the purity of the silver powder in step (3) is 99.99%, and the particle size is 1000 mesh; the purity of the hafnium powder is 99.90%, and the particle size is 500 mesh; the purity of the rhodium powder is 99.99%, and the particle size is 325 mesh; the purity of the cerium powder is 99.90%, and the particle size is 300 mesh; the amount of silver powder is 100.00g, the amount of hafnium powder is 0.10g, the amount of rhodium powder is 0.002g, and the amount of cerium powder is 0.02g.

[0057] In this embodiment, the cladding process parameters in step (3) are: laser power is 2000W, powder feeding speed is 20rad / min, and scanning speed is 5m / min; a diamond metal matrix composite with a metal composite cladding layer about 7mm thick is obtained, and after subsequent milling, grinding and polishing processes, a product finished product with a thickness of 5.021mm is obtained.

[0058] In the embodiment, the diamond metal matrix composite prepared in the embodiment is tested for thermal conductivity by using a LFA467 laser thermal conductivity instrument produced by Netzsch Company, Germany, according to the laser flash method (Laser Flash Method), and the measured thermal conductivity is 881 W / (m•K).

[0059] In the embodiment, other conditions are the same as in Example 1.

[0060] To better understand the content described in the present application, the main process parameters and measurement data in Examples 1-3 above are analyzed, and the results are shown in Table 1:

[0061] Table 1

[0062]

[0063] As shown in Table 1, the thermal conductivity of the diamond metal matrix composite in Example 1 is the lowest, which is 827 W / (m•K), and the thermal conductivity of the diamond metal matrix composite in Example 2 is the highest, which is 906 W / (m•K). In Example 1, the vacuum micro-evaporation coating time of the diamond particles is the shortest, the temperature is the lowest, and the vacuum degree is the highest. The reaction between the hafnium metal powder and the carbon atoms on the surface of the diamond is insufficient, the coating weight gain rate is low, the extremely high surface energy of the diamond surface is reduced to a certain extent, but the wettability between the diamond particles and the metal material is poor, and the bonding force between the diamond particles and the metal material is poor, resulting in the lowest thermal conductivity of the prepared diamond metal matrix composite. In Example 3, the vacuum micro-evaporation coating time is the longest, the temperature is the highest, and the vacuum degree is the lowest. The reaction between the hafnium metal powder and the carbon atoms on the surface of the diamond is sufficient, and the coating weight gain rate is the highest. However, due to the too high coating weight gain rate, the film thickness of each diamond particle is too large on a micro level. Since the thermal conductivity of the film layer is far lower than that of diamond and silver, the too large film thickness will increase the thermal resistance of the whole material, and thus reduce the thermal conductivity of the prepared diamond metal matrix composite, which is lower than that in Example 2. Therefore, controlling the process parameters during vacuum micro-evaporation coating to obtain a suitable coating weight gain rate is crucial for obtaining an ideal thermal conductivity of the diamond metal matrix composite.

[0064] In addition, in the high-speed laser cladding process, the laser power, powder feeding speed and scanning speed in Example 1 are the highest, which is not conducive to the full combination of the diamond particles and the metal material after coating, and also causes too high temperature in the process, due to the difference in the thermal expansion coefficients of the diamond and the metal material, the too high temperature causes the increase in the tiny pores and the decrease in the density of the diamond metal matrix composite after cooling, and further causes the decrease in the thermal conductivity, and the proportion of the metal silver powder in the metal material in Example 1 is the lowest, which also causes the decrease in the thermal conductivity; and the laser power in Example 3 is the lowest, and the too low laser power causes the insufficient melting of the metal powder, which affects the bonding force between the diamond particles and the metal material, and further has an adverse effect on the thermal conductivity; therefore, the control of the process parameters in the high-speed laser cladding process is also crucial for the subsequent obtaining of the ideal thermal conductivity of the diamond metal matrix composite.

Claims

1. A method for preparing diamond metal matrix composite based on high speed laser cladding process, characterized in that, The method comprises the following steps: (1) Pretreatment of diamond particles An appropriate amount of colorless and translucent diamond particles with clean surface is placed in a crusher for crushing. After crushing, the diamond particles are screened and placed in an ultrasonic cleaning device for cleaning with anhydrous ethanol. Then, the diamond particles are taken out, cleaned with pure water, and dried in a drying box for standby use. (2) Vacuum micro-evaporation coating The diamond particles obtained in step (1), hafnium powder and potassium chloride are mixed in a mixer according to a mass ratio of (150-200):(10-20):(1-2), and then placed in a vacuum micro-evaporation coating device for coating the surface of the diamond particles. (3) High-speed laser cladding Metallic silver powder, hafnium powder, rhodium powder and cerium powder are mixed in a rolling ball mill mixer according to a mass ratio of (50-100):(0.05-0.1):(0.001-0.002):(0.01-0.02). The mixed metal powder is placed in a metal powder storage bin of a high-speed laser cladding device. The coated diamond particles in step (2) are evenly covered on a metal carrier silver sheet, and metal cladding is performed under the nozzle of the high-speed laser cladding device. After the diamond particles on the metal carrier silver sheet are cladded, the coated diamond particles are again evenly covered on the diamond-metal composite cladding layer prepared by cladding, and metal cladding is performed under the nozzle of the high-speed laser cladding device. This process is repeated until the thickness of the product is 1-2 mm greater than the required thickness, i.e., the cladding is stopped.

2. The method of claim 1, wherein: The colorless and translucent diamond particles in step (1) are type IIa artificial white diamonds, and the thermal conductivity is higher than 2000 W / (m•K). The particle size of the screened diamond particles is any one of 270 / 325, 325 / 400 and 400 / 500.

3. The method of claim 1, wherein: The purity of the hafnium powder in step (2) is 99.90%, and the particle size is 400-500 mesh.

4. The method of claim 1, wherein: The process parameters for coating in step (2) are: vacuum degree of 10 -6 ~10 -3 Pa, temperature 800~1100℃, time 30~120min.

5. The method of claim 1, wherein: The purity of the silver powder in step (3) is 99.99%, and the particle size is 800-1000 mesh. The purity of the hafnium powder is 99.90%, and the particle size is 400-500 mesh. The purity of the rhodium powder is 99.99%, and the particle size is 200-325 mesh. The purity of the cerium powder is 99.90%, and the particle size is 200-300 mesh.

6. The method of claim 1, wherein: The cladding process parameters in step (3) are as follows: laser power is 2000-3000 W, powder feeding speed is 20-30 rad / min, and scanning speed is 5-10 m / min.

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