A method of making a high wear resistant diamond coating

Abstract

This invention relates to a method for preparing a high-wear-resistant diamond coating, belonging to the technical field of wear-resistant coating materials and preparation processes. The method includes the following steps: first, mixing diamond particles with alcohol via ultrasonic treatment to ensure good distribution of the diamond particles; then, applying the dispersed diamond-containing suspension to the surface of a polished aluminum substrate by brushing; finally, using a heat treatment method to allow the diamond particles to chemically react with the aluminum alloy surface, resulting in a well-bonded, high-wear-resistant diamond coating on the aluminum alloy surface. This preparation method effectively improves the hardness and wear resistance of aluminum alloy surfaces and significantly reduces the deposition cost of the coating.

Description

Technical Field

[0001] This invention belongs to the field of wear-resistant coating materials and preparation processes, and in particular relates to a method for preparing a high wear-resistant diamond coating on the surface of aluminum alloy. Background Technology

[0002] In high-end manufacturing fields such as aerospace, automotive manufacturing, electronic equipment, and precision instruments, aluminum alloys have become the preferred material for key structural components due to their lightweight, high specific strength, good thermal conductivity, and machinability. In aerospace, aluminum alloys are widely used in components such as fuselage frames and wing structures to achieve lightweight aircraft design. In automotive manufacturing, aluminum alloys are used in components such as engine blocks, pistons, and wheel hubs, not only reducing overall vehicle weight but also improving fuel efficiency. In electronic equipment, aluminum alloys are used in components such as radiators and housings to meet high heat dissipation requirements and structural strength requirements.

[0003] However, the inherent properties of aluminum alloys result in poor surface wear resistance, making them highly susceptible to surface damage under friction and wear conditions. This severely impacts the service life of components and the operational reliability of equipment. Specifically, in aerospace engine components, friction and wear between aluminum alloy piston rings and cylinder liners lead to decreased engine efficiency and increased failure risk; in automotive engines, wear between aluminum alloy pistons and cylinder blocks results in increased oil consumption and reduced power; and in electronic equipment, wear on precision aluminum alloy components leads to decreased accuracy and equipment malfunction. Industry statistics indicate that component failures due to aluminum alloy surface wear account for over 30% of mechanical component failures, causing billions of dollars in economic losses annually.

[0004] To address the insufficient wear resistance of aluminum alloys, researchers have explored various surface modification techniques, primarily including traditional hard coatings (such as TiN and TiC) and diamond coatings. While traditional hard coatings can improve surface hardness, their upper limit (typically <3000 HV) is orders of magnitude lower than that of diamond (approximately 10000 HV), resulting in significantly insufficient resistance to abrasive wear under extreme conditions. More importantly, there is a significant mismatch in the coefficients of thermal expansion between traditional hard coatings and the aluminum alloy substrate (TiN: 5.4 × 10⁻⁶ / ℃, aluminum alloy: 23 × 10⁻⁶ / ℃), generating high residual stress (up to 300 MPa or more) at the interface. This leads to low coating bonding strength, making the coating highly susceptible to peeling and severely limiting its service life.

[0005] Diamond, as the hardest known material, possesses extremely high hardness (10000 HV), an ultra-low coefficient of friction (0.05-0.1), excellent wear resistance, and outstanding chemical stability. Applying diamond as a coating to aluminum alloy surfaces can significantly enhance the wear resistance of the surface while retaining the inherent advantages of aluminum alloys, such as their lightweight and thermal conductivity. However, bonding diamond to aluminum alloys has always been a technical challenge. Anodizing enhances bonding by forming an alumina transition layer, but the alumina layer is inherently brittle and prone to micro-cracking and peeling under impact or localized high stress. Furthermore, the process is complex, making it difficult to control the coating thickness and uniformity. Electroplating / chemical plating utilizes the co-deposition of the coating with diamond particles, but the dense oxide film on the aluminum substrate surface hinders the formation of a strong bond between the coating and the substrate, resulting in a bonding strength generally below 50 MPa. Moreover, electroplating processes pose serious environmental pollution problems. Thermal spraying uses a high-temperature flame to spray diamond particles onto the substrate surface. However, during thermal spraying, diamond is prone to graphitization (>1000℃), which leads to a decrease in coating hardness. Furthermore, the coating and the substrate are mainly mechanically bonded, resulting in low bonding strength (<100MPa) and insufficient reliability under long-term alternating load conditions.

[0006] T6 heat treatment is a typical heat treatment process for aluminum alloys, which can significantly improve the hardness and strength of aluminum alloys (hardness can reach 150-200HB), but it is mainly used for matrix strengthening rather than coating preparation.

[0007] Therefore, there is an urgent need for a coating preparation method that can effectively solve the problem of bonding diamond to aluminum alloy while maintaining the high hardness and wear resistance of diamond. Summary of the Invention

[0008] To address the aforementioned technical problems and overcome the shortcomings of traditional deposition processes and the inherent weaknesses of coating materials under different working conditions, such as insufficient adhesion, brittleness, and poor high-temperature stability, this invention provides a method for preparing a high-wear-resistant diamond coating on aluminum alloy surfaces based on heat treatment. By combining pretreatment of diamond particles, brush deposition, and heat treatment, a chemical bond between diamond and the aluminum alloy substrate is achieved, significantly improving the coating's bonding strength and wear resistance while substantially reducing preparation costs. This provides technical support for the application of aluminum alloys under high-wear conditions. This technology not only solves the key problem of insufficient wear resistance on aluminum alloy surfaces but also overcomes the limitations of traditional coating preparation processes, demonstrating significant technological advancement and economic value.

[0009] The objective of this invention is achieved through the following technical solution:

[0010] This invention discloses a method for preparing a high-wear-resistant diamond coating, comprising the following steps:

[0011] (1) Place diamond particles in a solvent and prepare a high-concentration diamond suspension by ultrasound;

[0012] (2) Physical deposition is achieved by brushing a suspension containing high concentrations of diamond onto the surface of an aluminum alloy;

[0013] (3) The aluminum alloy with diamond particles deposited on its surface is subjected to heat treatment to achieve chemical deposition;

[0014] (4) Remove excess diamond particles from the surface of the aluminum alloy to achieve the preparation of diamond coating.

[0015] Furthermore, the diamond particles in step (1) are micro-nano-scale artificial diamond particles with a size of 10um-0.05um and are irregularly shaped particles.

[0016] Furthermore, in step (1), before placing the diamond particles in the solvent, the diamond particles are first ultrasonically cleaned. The cleaning solution is acetone solution to remove stains on the diamond surface. The ultrasonic frequency is 20–40 kHz, and the cleaning time is 1 min–15 min.

[0017] Further, in step (1), the diamond particles are placed in a solvent and subjected to ultrasonic cleaning. The solvent used is anhydrous ethanol solution. Anhydrous ethanol is used to ultrasonically clean the acetone residue on the diamond surface. The ultrasonic frequency is 20–40 kHz and the cleaning time is 30s–180s.

[0018] Furthermore, in step (1), a high-concentration diamond suspension is prepared by ultrasonication. The mass ratio of diamond particles to solvent in the suspension is 1:1-30:1, the ultrasonic frequency is 30-60 kHz, and the ultrasonic time is 3 min-50 min.

[0019] Furthermore, in step (2), the aluminum alloy surface is pretreated before brushing. The pretreatment is divided into two steps: grinding and cleaning. The grinding step is to use 100#-2000# sandpaper to grind from coarse to fine. The cleaning step is to use ultrasound to clean the surface. The cleaning solution is anhydrous ethanol, the ultrasonic frequency is 20-40 kHz, and the cleaning time is 3min-30min.

[0020] Furthermore, in step (2), the brushing method is physical brushing, the coating thickness of the diamond suspension is 1um-20um, and after brushing, it is placed in a drying oven to remove anhydrous ethanol. The removal temperature is 60℃-120℃ and the time is 30min-150min.

[0021] Furthermore, in step (3), the heat treatment temperature is 450℃-570℃, the heat treatment time is 0.5h-10h, the heating rate is 2℃ / min-10℃ / min, the cooling method after heat treatment is furnace cooling, and the cooling rate is 0.5℃ / min-5℃ / min.

[0022] Furthermore, in step (3), the atmosphere of the entire heat treatment process is an argon atmosphere, and the gas flow rate is 3ml / min-15mL / min.

[0023] Furthermore, in step (4), excess diamond particles on the surface of the aluminum alloy are removed by two steps: oscillation and blowing. The oscillation is mechanical oscillation, and the blowing gas is compressed air with a wind speed of 10m / s-35m / s.

[0024] The beneficial effects of this invention are as follows:

[0025] 1. This invention first involves ultrasonically mixing diamond particles with alcohol to ensure good distribution of the diamond particles. The dispersed diamond-containing suspension is then brushed onto a polished aluminum substrate surface. A heat treatment process is then used to chemically react the diamond particles with the aluminum alloy surface, resulting in a well-bonded, highly wear-resistant diamond coating. The diamond coating obtained using this invention exhibits extreme hardness (up to 60 GPa) and an ultra-low coefficient of friction, giving the aluminum alloy surface exceptional wear resistance. It also possesses excellent chemical stability and high thermal conductivity, significantly improving component performance and lifespan under harsh conditions such as strong corrosion and high heat dissipation.

[0026] 2. The present invention employs a pretreatment method, which first pretreats the diamond micro powder. The diamond micro powder that has undergone ultrasonic treatment has a significantly improved uniform distribution, prevents agglomeration, reduces defects, and improves the mechanical properties of the diamond coating.

[0027] 3. This invention employs a brush coating combined with heat treatment method. First, pre-treated diamond micro powder is brushed onto the surface of the aluminum alloy, and then heat treatment is used to strengthen the bond between the diamond and the aluminum alloy. Compared with traditional coating deposition processes, this method is simple, low-cost, easy to operate, suitable for workpieces with complex shapes, can achieve local deposition, and is flexible in process, making it easy to adjust the coating composition and thickness.

[0028] 4. The preparation method of the present invention is also applicable to the preparation of wear-resistant coatings for diamond-reinforced alloys such as magnesium and magnesium alloys. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the surface of an aluminum alloy substrate that has not been treated after grinding under a light microscope.

[0030] Figure 2 This is a schematic diagram of the surface of an aluminum alloy substrate after grinding under an optical microscope and then brushing on a diamond coating.

[0031] Figure 3 This is a schematic diagram of the surface of an aluminum alloy substrate that has been ground under an optical microscope, coated with a diamond coating, and then heat-treated.

[0032] Figure 4 The above chart shows a comparison of the hardness of aluminum alloys under the three different experimental conditions.

[0033] Figure 5 The graph shows a comparison of the friction and wear curves of aluminum alloy under the three different experimental conditions mentioned above.

[0034] Figure 6 The above chart shows a comparison of the hardness of magnesium alloys under three different experimental conditions.

[0035] Figure 7 The graph shows a comparison of the friction and wear curves of magnesium alloys under the three different experimental conditions mentioned above. Detailed Implementation

[0036] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0037] Example 1:

[0038] This invention discloses a method for preparing a high wear-resistant diamond coating on an aluminum alloy surface based on heat treatment, comprising the following steps:

[0039] (1) The diamond particles used are micro-nano-sized artificial diamond particles with a size of 0.05 μm and irregular particle shape. The solvent used is anhydrous ethanol solution. Before the diamond particles are placed in the solvent, the diamond particles are first ultrasonically cleaned with acetone solution to remove stains on the diamond surface. The ultrasonic frequency is 20 kHz and the cleaning time is 15 min. Then, the residual acetone on the diamond surface is ultrasonically cleaned with anhydrous ethanol at a frequency of 20 kHz and a cleaning time of 180 s. The mass ratio of diamond particles to anhydrous ethanol in the suspension is 1:1, the ultrasonic frequency is 30 kHz, and the ultrasonic time is 50 min.

[0040] (2) Apply a high-concentration diamond suspension to the surface of the aluminum alloy by brushing. Before brushing, the surface of the aluminum alloy is pretreated by two steps: grinding and cleaning. The first step is to use 100#-2000# sandpaper to grind from coarse to fine. The second step is to use ultrasonic cleaning. The cleaning solution is anhydrous ethanol, the ultrasonic frequency is 20kHz, and the cleaning time is 30min. The brushing method is physical brushing. The thickness of the diamond coating is 1um. After brushing, the surface is placed in a drying oven to remove the anhydrous ethanol. The removal temperature is 60℃ and the time is 150min.

[0041] (3) The aluminum alloy with diamond particles deposited on the surface is heat-treated at a temperature of 450℃ for 0.5h, with a heating rate of 10℃ / min. The cooling method after heat treatment is furnace cooling. The atmosphere during the entire heat treatment process is argon, with a gas flow rate of 3ml / min and a furnace cooling rate of 5℃ / min.

[0042] (4) Remove excess diamond particles from the surface of aluminum alloy. Use two steps, vibration and air blowing, to remove excess diamond particles from the surface of aluminum alloy. Vibrate first and then blow air. Vibration is mechanical vibration, and the air blowing gas is compressed air with a wind speed of 10m / s.

[0043] The diamond coating deposited on the aluminum alloy surface using the above process method is uniform, such as Figure 1-3 As shown, after heat treatment, the interfacial bonding between diamond and the aluminum substrate changes from physical adhesion to chemical bonding, thus improving the bonding ability. After physical deposition of the diamond coating, the surface hardness of the aluminum alloy increases by 2.97%, and the wear resistance is also effectively improved. Under the condition of using YG6 tungsten carbide balls as the grinding material and a pressure of 20N, after 20 minutes of grinding, the wear volume decreases by 30%, and the friction coefficient decreases by 22.76%. After heat treatment, under the same test conditions, the surface hardness of the aluminum alloy increases by 9.93%, the wear volume decreases by 72%, and the friction coefficient decreases by 51.76%. Figure 4 and 5 As shown.

[0044] Example 2: A method for preparing a high wear-resistant diamond coating on an aluminum alloy surface based on heat treatment, comprising the following steps:

[0045] (1) The diamond particles used are 10 μm in size and are irregularly shaped. The solvent used is anhydrous ethanol solution. Before placing the diamond particles in the solvent, the diamond particles are first ultrasonically cleaned with acetone solution. The ultrasonic frequency is 40 kHz and the cleaning time is 1 min. Then, the residual acetone on the diamond surface is ultrasonically cleaned with anhydrous ethanol at a frequency of 40 kHz for 30 s. The mass ratio of diamond particles to anhydrous ethanol in the suspension is 30:1. The ultrasonic frequency is 60 kHz and the ultrasonic time is 3 min.

[0046] (2) Apply a high-concentration diamond suspension to the aluminum alloy surface. Before brushing, the aluminum alloy surface is treated. The pretreatment consists of two steps: grinding and cleaning. The first step is to use 100#-2000# sandpaper to grind from coarse to fine. The second step is to use ultrasonic cleaning. The cleaning solution is anhydrous ethanol, the ultrasonic frequency is 40kHz, and the cleaning time is 3min. The brushing method is physical brushing. The diamond coating thickness is 20um. After brushing, the surface is placed in a drying oven to remove anhydrous ethanol. The removal temperature is 120℃ and the time is 30min.

[0047] (3) The aluminum alloy with diamond particles deposited on the surface was heat-treated at a temperature of 570℃ for 10 hours, with a heating rate of 2℃ / min. The cooling method after heat treatment was furnace cooling. The atmosphere during the entire heat treatment process was argon, with a gas flow rate of 15ml / min and a furnace cooling rate of 0.5℃ / min.

[0048] (4) Remove excess diamond particles from the surface of aluminum alloy. Use two steps, vibration and air blowing, to remove excess diamond particles from the surface of aluminum alloy. Vibrate first and then blow air. Vibration is mechanical vibration, and the air blowing gas is compressed air with a wind speed of 35 m / s.

[0049] The diamond coating deposited on the aluminum alloy surface using the above process method is uniform, such as Figure 1-3 As shown, after heat treatment, the interfacial bonding between diamond and the aluminum substrate changes from physical adhesion to chemical bonding, thus improving the bonding ability. After physical deposition of the diamond coating, the surface hardness of the aluminum alloy increases by 3.57%, and the wear resistance is also effectively improved. Under the condition of using YG6 tungsten carbide balls as the grinding material and a pressure of 20N, after 20 minutes of grinding, the wear volume decreases by 32%, and the friction coefficient decreases by 23.46%. After heat treatment, under the same test conditions, the surface hardness of the aluminum alloy increases by 10.13%, the wear volume decreases by 75%, and the friction coefficient decreases by 51.96%. Figure 4 and 5 As shown.

[0050] Example 3: A method for preparing a high wear-resistant diamond coating on an aluminum alloy surface based on heat treatment, comprising the following steps:

[0051] (1) The diamond particles used are 5 μm in size and are irregularly shaped. The solvent used is anhydrous ethanol solution. Before the diamond particles are placed in the solvent, the diamond particles are first ultrasonically cleaned with acetone solution. The ultrasonic frequency is 30 kHz and the cleaning time is 10 min. Then, the residual acetone on the diamond surface is ultrasonically cleaned with anhydrous ethanol at a frequency of 30 kHz and a cleaning time of 100 s. The mass ratio of diamond particles to anhydrous ethanol in the suspension is 15:1, the ultrasonic frequency is 50 kHz, and the ultrasonic time is 25 min.

[0052] (2) Apply a high-concentration diamond suspension to the aluminum alloy surface by brushing. Before brushing, the aluminum alloy surface is treated. The pretreatment consists of two steps: grinding and cleaning. The first step is to use 100#-2000# sandpaper to grind from coarse to fine. The second step is to use ultrasonic cleaning. The cleaning solution is anhydrous ethanol, the ultrasonic frequency is 30kHz, and the cleaning time is 20min. The brushing method is physical brushing. The diamond coating thickness is 10um. After brushing, the surface is placed in a drying oven to remove anhydrous ethanol. The removal temperature is 90℃ and the time is 90min.

[0053] (3) The aluminum alloy with diamond particles deposited on the surface was heat-treated at a temperature of 530℃ for 5 hours, with a heating rate of 6℃ / min. The cooling method after heat treatment was furnace cooling. The atmosphere during the entire heat treatment process was argon, with a gas flow rate of 9ml / min and a furnace cooling rate of 3℃ / min.

[0054] (4) Remove excess diamond particles from the surface of aluminum alloy. Use two steps, vibration and air blowing, to remove excess diamond particles from the surface of aluminum alloy. Vibrate first and then blow air. Vibration is mechanical vibration, and the air blowing gas is compressed air with a wind speed of 25 m / s.

[0055] The diamond coating deposited on the aluminum alloy surface using the above process method is uniform, such as Figure 1-3 As shown, after heat treatment, the interfacial bonding between diamond and the aluminum substrate changes from physical adhesion to chemical bonding, thus improving the bonding ability. After physical deposition of the diamond coating, the surface hardness of the aluminum alloy increases by 3.39%, and the wear resistance is also effectively improved. Under the condition of using YG6 tungsten carbide balls as the grinding material and a pressure of 20N, after 20 minutes of grinding, the wear volume decreases by 36%, and the friction coefficient decreases by 23.53%. After heat treatment, under the same test conditions, the surface hardness of the aluminum alloy increases by 10.78%, the wear volume decreases by 80%, and the friction coefficient decreases by 52.94%. Figure 4 and 5 As shown.

[0056] Example 4: A method for preparing a high wear-resistant diamond coating on a magnesium alloy surface based on heat treatment, comprising the following steps:

[0057] (1) The diamond particles used are 5 μm in size and are irregularly shaped. The solvent used is anhydrous ethanol solution. Before the diamond particles are placed in the solvent, the diamond particles are first ultrasonically cleaned with acetone solution. The ultrasonic frequency is 30 kHz and the cleaning time is 10 min. Then, the residual acetone on the diamond surface is ultrasonically cleaned with anhydrous ethanol at a frequency of 30 kHz and a cleaning time of 100 s. The mass ratio of diamond particles to anhydrous ethanol in the suspension is 15:1, the ultrasonic frequency is 50 kHz, and the ultrasonic time is 25 min.

[0058] (2) A high-concentration diamond suspension was brushed onto the surface of the magnesium alloy. Before brushing, the surface of the magnesium alloy was treated. The pretreatment consisted of two steps: grinding and cleaning. The first step was to use 100#-2000# sandpaper to grind from coarse to fine. The second step was to use ultrasonic cleaning. The cleaning solution was anhydrous ethanol, the ultrasonic frequency was 30kHz, and the cleaning time was 20min. The brushing method was physical brushing. The thickness of the diamond coating was 10um. After brushing, the coating was placed in a drying oven to remove the anhydrous ethanol. The removal temperature was 90℃ and the time was 90min.

[0059] (3) The magnesium alloy with diamond particles deposited on its surface was heat-treated at a temperature of 530°C for 5 hours, with a heating rate of 6°C / min. The cooling method after heat treatment was furnace cooling. The atmosphere during the entire heat treatment process was argon, with a gas flow rate of 9 ml / min and a furnace cooling rate of 3°C / min.

[0060] (4) Remove excess diamond particles from the surface of magnesium alloy. Use two steps, vibration and air blowing, to remove excess diamond particles from the surface of magnesium alloy. Vibrate first and then blow air. Vibration is mechanical vibration, and the air blowing gas is compressed air with a wind speed of 25 m / s.

[0061] The diamond coating deposited on the magnesium alloy surface using the above-mentioned process is uniform. After heat treatment, the interfacial bonding between the diamond and the magnesium substrate changes from physical adhesion to chemical bonding, thus improving the bonding ability. After physical deposition of the diamond coating, the surface hardness of the magnesium alloy increases by 4.9%, and the wear resistance is also effectively improved. Under the condition of using YG6 tungsten carbide balls as the grinding material and a pressure of 20N, after 20 minutes of grinding, the wear volume decreases by 39%, and the coefficient of friction decreases by 25.35%. After heat treatment, under the same test conditions, the surface hardness of the magnesium alloy increases by 13.57%, the wear volume decreases by 83%, and the coefficient of friction decreases by 54.82%. Figure 6 and 7 As shown.

[0062] The parts not described in detail in this application are all existing conventional technologies and will not be elaborated here.

[0063] It is understood that the above specific description of the present invention is only for illustrating the present invention and is not limited to the technical solutions described in the embodiments of the present invention. Those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention to achieve the same technical effect; as long as the use needs are met, they are all within the protection scope of the present invention.

Claims

1. A method for preparing a high wear-resistant diamond coating, characterized in that: Includes the following steps: (1) Place diamond particles in a solvent and prepare a high-concentration diamond suspension by ultrasound; (2) Physical deposition is achieved by brushing a suspension containing high concentrations of diamond onto the surface of an aluminum alloy; (3) The aluminum alloy with diamond particles deposited on its surface is subjected to heat treatment to achieve chemical deposition; (4) Remove excess diamond particles from the surface of the aluminum alloy to achieve the preparation of diamond coating.

2. The method according to claim 1, characterized in that: The diamond particles in step (1) are micro-nano-scale artificial diamond particles with a size of 10um-0.05um and are irregularly shaped particles.

3. The method according to claim 1, characterized in that: In step (1), before placing the diamond particles in the solvent, the diamond particles are first ultrasonically cleaned. The cleaning solution is acetone solution to remove stains on the diamond surface. The ultrasonic frequency is 20–40 kHz and the cleaning time is 1 min–15 min.

4. The method according to claim 3, characterized in that: In step (1), the diamond particles are placed in a solvent and ultrasonically cleaned. The solvent used is anhydrous ethanol solution. Anhydrous ethanol is used to ultrasonically clean the acetone residue on the diamond surface. The ultrasonic frequency is 20–40 kHz and the cleaning time is 30s–180s.

5. The method according to claim 1, characterized in that: In step (1), a high-concentration diamond suspension is prepared by ultrasonication. The mass ratio of diamond particles to solvent in the suspension is 1:1-30:1, the ultrasonic frequency is 30-60 kHz, and the ultrasonic time is 3 min-50 min.

6. The method according to claim 1, characterized in that: In step (2), the aluminum alloy surface is pretreated before brushing. The pretreatment is divided into two steps: grinding and cleaning. The grinding step is to use 100#-2000# sandpaper to grind from coarse to fine. The cleaning step is to use ultrasound to clean the surface. The cleaning solution is anhydrous ethanol, the ultrasonic frequency is 20-40 kHz, and the cleaning time is 3min-30min.

7. The method according to claim 1, characterized in that: In step (2), the brushing method is physical brushing. The coating thickness of the diamond suspension is 1um-20um. After brushing, it is placed in a drying oven to remove anhydrous ethanol. The removal temperature is 60℃-120℃ and the time is 30min-150min.

8. The method according to claim 1, characterized in that: In step (3), the heat treatment temperature is 450℃-570℃, the heat treatment time is 0.5h-10h, the heating rate is 2℃ / min-10℃ / min, and the cooling method after heat treatment is furnace cooling with a cooling rate of 0.5℃ / min-5℃ / min.

9. The method according to claim 7, characterized in that: In step (3), the atmosphere of the entire heat treatment process is an argon atmosphere with a gas flow rate of 3 ml / min-15 mL / min.

10. The method according to claim 1, characterized in that: In step (4), excess diamond particles on the surface of the aluminum alloy are removed by two steps: vibration and blowing. The vibration is mechanical vibration, and the blowing gas is compressed air with a wind speed of 10m / s-35m / s.

Images