CN116021011B - Preparation method of graphene-coated copper powder particle reinforced cold spray copper-based composite coating - Google Patents

Abstract

A preparation method of a graphene coated copper powder particle reinforced cold spray copper-based composite coating relates to a preparation method of a copper-based composite coating. The invention discloses a preparation method of a graphene-coated copper powder particle reinforced cold spray copper-based composite coating, which comprises the steps of growing graphene on the surface of copper powder particles in situ by PECVD technology to obtain graphene-coated copper powder particles, using an optimized low-energy ball milling process to obtain copper composite powder with uniformly distributed graphene-coated copper powder particles, avoiding tissue defects caused by graphene agglomeration, improving the bonding strength of the coating and a substrate and the tissue uniformity inside the coating based on the low-temperature process and the extremely fast deposition rate of the cold spray technology, and being beneficial to obtaining the graphene-coated copper powder particle reinforced copper-based composite coating with excellent thermal, electric, mechanical and wear resistance.

Description

Preparation of a graphene-coated copper powder particle reinforced cold-sprayed copper-based composite coating method

technical field

The invention relates to a preparation method of a copper-based composite coating.

Background technique

Conductive coatings are widely used in construction, transportation, manufacturing, mining, education, military, aerospace and other fields. Pure copper coatings have excellent electrical and thermal conductivity, but their hardness and wear resistance are poor. Pure copper coatings It is easy to be severely worn or even broken under some extreme service conditions, which will cause serious safety hazards and economic and personnel losses.

Graphene is a two-dimensional allotrope of carbon that results from the hybridization of 1-s and 2-p orbitals to form hexagonal carbon rings. In graphene, each carbon atom has one free electron after ^sp2 hybridization, and these electrons appear in π orbitals. The π orbitals help delocalize the electronic network and couple high carrier (electron) concentrations with large carrier mobility at room temperature. These unique properties of graphene enable the localized conduction of carriers down to the near-micrometer scale, making it an ideal additive to enhance the thermoelectric properties of metals. After the copper coating is reinforced by graphene, its mechanical properties, thermoelectric properties and wear resistance will be significantly improved, but because graphene has a large specific surface area and high surface energy, it is prone to agglomeration, which is not conducive to uniform dispersion on the copper matrix. middle. The traditional methods of coating graphene on the copper surface include mechanical ball milling and chemical growth methods, etc. The mechanical ball milling method has poor coating uniformity, takes a long time, and the bonding strength between graphene and copper particles is low. After ball milling, graphene is easy to Separated from copper particles, the chemical growth method needs to use a variety of chemical reagents, which is complicated to operate and easy to cause environmental pollution.

Conventional graphene-enhanced copper-based composite coating preparation methods include thermal spraying, laser cladding, and chemical vapor deposition. In these methods, the process temperature of thermal spraying and laser cladding is extremely high, which is very easy to cause serious thermal damage to the substrate to be processed. , the formed coating also has high thermal stress, and the coating has defects such as cracks and voids; the thickness of the coating prepared by chemical vapor deposition is limited, usually below tens of microns, and the coating deposition rate is relatively slow, and The process of depositing graphene and copper composite film at the same time is more complicated.

Contents of the invention

In order to solve the above-mentioned deficiencies in the prior art, the present invention discloses a preparation method of graphene-coated copper powder particles reinforced cold-sprayed copper-based composite coating. Graphene was grown, and graphene-coated copper powder particles were obtained. Using an optimized low-energy ball milling process, a copper composite powder with uniform distribution of graphene-coated copper powder particles was obtained, which avoided the structural defects caused by graphene agglomeration, and based on The low-temperature process and extremely fast deposition rate of cold spray technology can improve the bonding strength between the coating and the substrate and the uniformity of the structure inside the coating, which is conducive to obtaining graphene coatings with excellent thermal, electrical, mechanical properties and wear resistance. Copper-clad powder particle reinforced copper-based composite coating.

The preparation method of graphene-coated copper powder particles of the present invention reinforced cold spray copper-based composite coating is carried out according to the following steps:

Step 1. In a methane atmosphere, a graphene layer is grown in situ on the surface of the copper powder by plasma-enhanced chemical vapor deposition to obtain graphene-coated copper powder particles;

Step 2, using a ball mill to carry out low-energy ball milling of the graphene-coated copper powder particles and the copper powder, so that the graphene-coated copper powder particles are evenly distributed in the copper powder to obtain a mixed powder; the copper powder and the graphene-coated copper powder The mass ratio of particles is 1 to 3:1;

Step 3: Spray the mixed powder obtained in Step 2 on the substrate by cold spraying to obtain a graphene-coated copper powder particle-reinforced copper-based composite coating.

Principle of the present invention and beneficial effect:

1. The present invention adopts the combination of PECVD method and low-energy ball milling to obtain graphene-coated copper powder particles, which can effectively improve the bonding strength of graphene and copper powder, and make graphene evenly distributed in copper powder. It has a good binding effect with copper particles and is not easy to agglomerate, which is conducive to the preparation of graphene-coated copper powder particles reinforced copper-based composite coatings with excellent thermal, electrical, mechanical properties and wear resistance.

2. The present invention adopts plasma-enhanced chemical vapor deposition (PECVD) technology to grow graphene in situ on the surface of copper powder particles. Since the surface in contact with gas can realize film deposition, it also has a good effect on complex geometric surfaces. film deposition effect. Therefore, the present invention adopts PECVD technology to grow graphene in situ on the surface of copper powder particles, with high deposition rate, uniform coating of graphene, large coating area, high bonding strength with copper particles, and difficult occurrence of graphene in composite powder. The separation from the copper powder greatly avoids the agglomeration of graphene, thereby effectively avoiding defects such as cracks caused by graphene agglomeration in the subsequent coating; and, in the preheating stage of PECVD, the temperature is raised to 500 ℃ and heat preservation can promote the refinement of the copper powder grains, which is beneficial to obtain a dense and uniform structure in the subsequent coating.

3. The present invention adopts the cold spraying technology, which can deposit the coating at a lower temperature (usually hundreds of degrees Celsius) and a higher deposition rate (usually the thickness of the coating deposition can reach millimeter level per minute), and the temperature of the spraying process is much lower Due to the melting point of copper, the mixed powder is less affected by heat, and no phase change occurs during the spraying process, which greatly suppresses the generation of thermal stress and thermal defects in the coating. It has excellent microstructure and mechanical properties. Between a few microns and tens of millimeters, and the prepared coating has high bonding strength with the substrate, thereby preparing a graphene-coated copper powder particle-reinforced copper matrix composite with excellent thermal, electrical, mechanical properties and wear resistance. coating.

Description of drawings

Fig. 1 is the Raman test result of the mixed powder prepared in step 2 in embodiment 1;

Fig. 2 is the physical picture of the PEEK substrate with graphene-coated copper powder particles reinforced copper-based composite coating prepared in Example 1.

Detailed ways

The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any reasonable combination among the specific embodiments.

Specific embodiment one: the preparation method of graphene-coated copper powder particle reinforced cold-sprayed copper-based composite coating in this embodiment is carried out according to the following steps:

Step 1. In a methane atmosphere, a graphene layer is grown in situ on the surface of the copper powder by plasma-enhanced chemical vapor deposition to obtain graphene-coated copper powder particles;

The plasma-enhanced chemical vapor deposition includes the following steps: firstly, spread the copper powder on the quartz plate, put it into a vacuum chamber, evacuate the vacuum until the pressure is below 40Pa, heat and dry for 10-30min, and then pass through methane When the air pressure returns to 1.01×10 ⁵ Pa, vacuumize again until the air pressure is below 40Pa, and feed methane to keep the air pressure at 40-66.7Pa; then heat the vacuum chamber at a heating rate of 10°C/min to 500°C Then keep warm for 10-30min, and then stop heating; let the temperature of the vacuum chamber drop naturally, and keep warm for 10-3000min when the temperature drops to 300°C; turn on the plasma exciter while keeping warm, and set the excitation power to 150-500W; The holding time is related to the thickness of graphene; wherein, the flow rate of methane is 1-50 sccm.

Step 2, using a ball mill to carry out low-energy ball milling of the graphene-coated copper powder particles and the copper powder, so that the graphene-coated copper powder particles are evenly distributed in the copper powder to obtain a mixed powder; the copper powder and the graphene-coated copper powder The mass ratio of particles is 1 to 3:1;

Step 3: Spray the mixed powder obtained in Step 2 on the substrate by cold spraying to obtain a graphene-coated copper powder particle-reinforced copper-based composite coating.

This embodiment has the following beneficial effects:

1. This embodiment adopts the combination of PECVD method and low-energy ball milling to obtain graphene-coated copper powder particles, which can effectively improve the bonding strength of graphene and copper powder, and make graphene evenly distributed in copper powder. The combination effect of graphene and copper particles is good and it is not easy to agglomerate, which is conducive to the preparation of graphene-coated copper powder particles reinforced copper-based composite coatings with excellent thermal, electrical, mechanical properties and wear resistance.

2. In this embodiment, plasma-enhanced chemical vapor deposition (PECVD) technology is used to grow graphene in situ on the surface of copper powder particles. Since the surface in contact with the gas can achieve film deposition, it is also good for complex geometric surfaces. film deposition effect. Therefore, this embodiment adopts PECVD technology to grow graphene in situ on the surface of copper powder particles, the deposition rate is high, the graphene coating is uniform, the coating area is large, and its bonding strength with copper particles is high, and graphite is not easy to occur in the composite powder. The separation of graphene and copper powder greatly avoids the agglomeration of graphene, thereby effectively avoiding defects such as cracks caused by graphene agglomeration in subsequent coatings; and, in the preheating stage of PECVD, the temperature is first raised to 500°C and heat preservation can promote the refinement of copper powder grains, which is conducive to obtaining a dense and uniform structure in subsequent coatings.

3. This embodiment adopts cold spraying technology, which can deposit the coating at a lower temperature (usually hundreds of degrees Celsius) and a higher deposition rate (usually the thickness of the coating deposition can reach millimeter level per minute), and the temperature of the spraying process is far away. Lower than the melting point of copper, the mixed powder is less affected by heat, and no phase change occurs during the spraying process, which greatly suppresses the generation of thermal stress and thermal defects in the coating, and has excellent microstructure and mechanical properties. Between tens of microns and tens of millimeters, and the prepared coating has high bonding strength with the substrate, thereby preparing a graphene-coated copper powder particle reinforced copper substrate with excellent thermal, electrical, mechanical properties and wear resistance. Composite coating.

Embodiment 2: This embodiment differs from Embodiment 1 in that the purity of the copper powder in step 1 is 99.9%, the particles are spherical, the particle size is 40-60 μm, and the purity of methane gas is 99.99%.

Embodiment 3: The difference between this embodiment and Embodiment 1 or 2 is that the purity of the copper powder in step 2 is 99.9%, the particles are spherical, and the particle size is 40-60 μm.

Embodiment 4: This embodiment differs from Embodiment 1 to Embodiment 3 in that the ball mill described in step 2 is a planetary ball mill.

Embodiment 5: The difference between this embodiment and one of Embodiments 1 to 4 is that the plasma-enhanced chemical vapor deposition in step 1 includes the following steps: first, spread the copper powder on the quartz plate and put it into a vacuum chamber , evacuate until the air pressure is below 40Pa, heat and dry for 10min, then pass in methane until the air pressure returns to 1.01×10 ⁵ Pa, evacuate again until the air pressure is below 40Pa, and slowly pass in methane to maintain the air pressure at 40-66.7Pa ; Then heat the vacuum chamber at a heating rate of 10°C/min, heat it to 500°C and keep it warm for 10-30min, then stop heating; let the temperature of the vacuum chamber drop naturally, and keep it warm for 10-3000min when the temperature drops to 300°C; While keeping warm, turn on the plasma exciter, and the exciting power is set to 150-500W; the set holding time is related to the thickness of graphene; wherein, the flow rate of methane is 1-50 sccm.

Specific embodiment six: the difference between this embodiment and one of the specific embodiments one to five is that the plasma enhanced chemical vapor deposition in step 1 includes the following steps: first, spread the copper powder on the quartz plate and put it into a vacuum chamber , evacuate until the air pressure is below 40Pa, heat and dry for 10min, then pass in methane until the air pressure returns to 1.01×10 ⁵ Pa, evacuate again until the air pressure is below 40Pa, and slowly pass in methane to maintain the air pressure at 40-66.7Pa ; Then heat the vacuum chamber at a heating rate of 10°C/min, heat it to 500°C and keep it warm for 10 minutes, then stop heating; let the temperature of the vacuum chamber drop naturally, and keep it warm for 10-3000 minutes when the temperature drops to 300°C; Turn on the plasma exciter, and set the excitation power to 150-500W; the set holding time is related to the thickness of the graphene; wherein, the flow rate of methane is 1-50 sccm.

Embodiment 7: This embodiment differs from Embodiment 1 to Embodiment 6 in that the low-energy ball milling in step 2 includes the following steps: mixing copper powder and graphene-coated copper powder particles into a ball mill tank; vacuumizing , and then feed argon, the ball milling process is dry milling, the ball to material ratio is 8-12:1, the ball milling speed is 50-200r/min, the low energy ball milling is 4-10h,

Rotate in one direction, and stop for 10 minutes every 1 hour of ball milling to obtain a mixed powder, which is a copper composite powder with uniform distribution of graphene-coated copper powder particles.

Embodiment 8: The difference between this embodiment and one of Embodiments 1 to 7 is that the cold spraying in step 3 includes the following steps:

Ultrasonic cleaning of the substrate to be sprayed with absolute ethanol for 5-60 minutes, take it out and dry it, then perform sandblasting on the surface to be sprayed, and clean the surface to be sprayed with an air gun after treatment; put the mixed powder obtained in step 2 into the powder feeding In the container, fix the base material and use the spray gun to carry out cold spraying, using argon as the powder feeding gas, the cold spraying track is "S" shape, the line spacing of the spraying track is 1.5-3mm, and the spraying beam is 90° to the surface to be sprayed , The gun speed is 50-200mm/s, the vertical distance between the gun mouth and the surface to be sprayed is 10-50mm, the chamber pressure is 3-6MPa, and the chamber temperature is 700°C. According to the required coating thickness, the number of spraying times can be adjusted arbitrarily.

Embodiment 9: This embodiment differs from Embodiment 1 to Embodiment 8 in that the cold spraying in step 3 includes the following steps: ultrasonically clean the substrate to be sprayed with absolute ethanol for 5-60 minutes, take it out and dry it, and then Sand blast the surface to be sprayed, clean the surface to be sprayed with an air gun after treatment; put the mixed powder obtained in step 2 into the powder feeder, fix the base material and use a spray gun for cold spraying, using argon as the powder feed gas , the cold spraying trajectory is "S" shape, the line spacing of the spraying trajectory is 1.5mm, the spraying beam and the surface to be sprayed are at 90°, the gun speed is 100mm/s, the vertical distance between the gun mouth and the surface to be sprayed is 20mm, the chamber The air pressure is 3.5MPa, and the chamber temperature is 700°C.

Embodiment 10: This embodiment differs from Embodiment 1 to Embodiment 9 in that: in the graphene-coated copper powder particle reinforced copper-based composite coating obtained in step 3, graphene is 0.005-0.1wt of the total amount of metal %.

Example 1

The preparation method of the graphene-coated copper powder particle reinforced cold spray copper-based composite coating of this embodiment is carried out according to the following steps:

Step 1. In a methane atmosphere, a graphene layer is grown on the surface of the copper powder in situ by plasma-enhanced chemical vapor deposition to obtain graphene-coated copper powder particles; wherein, the purity of the copper powder is 99.9%, and the particles are Spherical, the particle size is 40μm, and the purity of methane gas is 99.99%.

The PECVD includes the following steps: flatten the copper powder on the quartz plate, put it into a vacuum chamber, evacuate it to a pressure of 35 Pa, heat and dry it for 10 minutes, and then inject methane until the pressure returns to 1.01×10 ⁵ Pa, Vacuum again until the air pressure reaches 35Pa, slowly introduce methane to maintain the air pressure at 40Pa; then heat the vacuum chamber at a heating rate of 10°C/min, heat it to 500°C and keep it for 10min, then stop heating; let the vacuum chamber temperature naturally Decline, when the temperature drops to 300°C, turn on the heater to keep warm; at the same time, turn on the plasma exciter, the excitation power is 200W, and the set holding time (that is, the graphene growth time) is 20min; wherein, the flow rate of methane Both are 30 sccm.

Step 2, using a planetary ball mill to carry out low-energy ball milling of the graphene-coated copper powder particles and the copper powder, so that the graphene-coated copper powder particles are evenly distributed in the copper powder to obtain a mixed powder; wherein the copper powder has a purity of 99.9%. The particles are spherical and have a diameter of 40 μm.

The low-energy ball milling comprises the steps of: mixing copper powder and graphene-coated copper powder particles at a mass ratio of 1:1 and then loading them into a ball milling tank; vacuuming, and then introducing argon gas, and the ball milling process is dry milling. Material ratio is 8:1, ball milling speed is 100r/min, low-energy ball milling 8h, unidirectional rotation, every ball milling 1h stops rotating 10min, obtains the copper composite powder that the graphene-coated copper powder particle is evenly distributed, and the drawing shown in Fig. 2 Mann tests showed that the obtained mixed powder had three characteristic peaks of graphene.

Step 3: Process the obtained mixed powder by cold spraying technology to obtain a graphene-coated copper powder particle-reinforced copper-based composite coating.

The cold spraying process includes the following steps: ultrasonically clean the PEEK base material with absolute ethanol for 10 minutes, take it out and dry it, then perform sandblasting on the surface to be sprayed, and clean the surface to be sprayed with an air gun after treatment; Put the mixed powder into the powder feeder, fix the PEEK base material and use the spray gun for cold spraying, using argon as the powder feeding gas, the cold spraying track is "S" shape, the line spacing of the spraying track is 1.5mm, and the spraying beam flow It is 90° to the surface to be sprayed, the gun speed is 100mm/s, the vertical distance between the gun mouth and the surface to be sprayed is 20mm, the chamber pressure is 3.5MPa, the chamber temperature is 700°C, and the spraying is repeated 10 times.

In the graphene-coated copper powder particle-reinforced cold-sprayed copper-based composite coating obtained in this example, graphene is 0.04%wt of the total amount of metal.

Example 2

The preparation method of the graphene-coated copper powder particle reinforced cold spray copper-based composite coating of this embodiment is carried out according to the following steps:

Step 1. In a methane atmosphere, by plasma chemical vapor deposition (PECVD), a graphene layer is grown on the surface of the copper powder in situ to obtain graphene-coated copper powder particles; wherein, the purity of the copper powder is 99.9%, The particles are spherical, the particle size is 50 μm, and the purity of methane gas is 99.99%.

The PECVD includes the following steps: flatten the copper powder on the quartz plate, put it into a vacuum chamber, evacuate to 40 Pa, heat and dry for 20 minutes, and then inject methane until the pressure returns to 1.01×10 ⁵ Pa, Vacuum again until the air pressure reaches 40Pa, slowly feed methane to keep the air pressure at 66.7Pa; then heat the vacuum chamber at a heating rate of 10°C/min, heat it to 500°C and keep it for 15min, then stop heating; make the vacuum chamber temperature Naturally, when the temperature dropped to 300°C, the heater was turned on for heat preservation; at the same time, the plasma exciter was turned on, the excitation power was 250W, and the heat preservation time (that is, the graphene growth time) was set to 30min; The flow rates are all 50 sccm.

Step 2, using a planetary ball mill to carry out low-energy ball milling of the graphene-coated copper powder particles and the copper powder, so that the graphene-coated copper powder particles are evenly distributed in the copper powder to obtain a mixed powder; wherein the copper powder has a purity of 99.9%. The particles are spherical and have a diameter of 50 μm.

The low-energy ball milling comprises the steps of: mixing copper powder and graphene-coated copper powder particles in a mass ratio of 3:1 and then loading them into a ball milling tank; vacuuming, and then introducing argon gas, and the ball milling process is dry milling. The material ratio was 10:1, the ball milling speed was 200r/min, the low-energy ball milled for 4 hours, unidirectionally rotated, and the ball milled for 1 hour and stopped for 10 minutes to obtain a copper composite powder with uniform distribution of graphene-coated copper powder particles.

Step 3: Process the obtained mixed powder by cold spraying technology to obtain a graphene-coated copper powder particle-reinforced copper-based composite coating.

The processing process of the cold spraying technology includes the following steps: ultrasonically clean the PEEK substrate with absolute ethanol for 20 minutes, take it out and dry it, then perform sandblasting on the surface to be sprayed, and clean the surface to be sprayed with an air gun after treatment; Put the mixed powder into the powder feeder, fix the PEEK base material and use the spray gun to carry out cold spraying, using argon as the powder feeding gas, the cold spraying track is "S" shape, the line spacing of the spraying track is 2mm, the spraying beam flow and The surface to be sprayed is 90°, the gun speed is 200mm/s, the vertical distance between the gun mouth and the surface to be sprayed is 30mm, the chamber pressure is 4MPa, the chamber temperature is 700°C, and the spraying is repeated 20 times.

In the graphene-coated copper powder particle-reinforced cold-sprayed copper-based composite coating obtained in this embodiment, graphene is 0.025%wt of the total amount of metal.

Example 3

The preparation method of the graphene-coated copper powder particle reinforced cold spray copper-based composite coating of this embodiment is carried out according to the following steps:

Step 1. By plasma chemical vapor deposition, in a methane atmosphere, a graphene layer is grown on the surface of the copper powder in situ to obtain graphene-coated copper powder particles; wherein, the purity of the copper powder is 99.9%, and the particles are spherical , the particle size is 60μm, and the purity of methane gas is 99.99%.

The PECVD includes the following steps: flatten the copper powder on the quartz plate, put it into a vacuum chamber, evacuate it to a pressure of 35 Pa, heat and dry it for 15 minutes, and then inject methane until the pressure returns to 1.01×10 ⁵ Pa, Vacuum again until the air pressure reaches 35Pa, slowly introduce methane to keep the air pressure at 60Pa; then heat the vacuum chamber at a heating rate of 10°C/min, heat it to 500°C and keep it for 15min, then stop heating; let the vacuum chamber temperature naturally Decline, when the temperature drops to 300°C, turn on the heater for insulation; at the same time, turn on the plasma exciter, the excitation power is 225W, and the set holding time (ie graphene growth time) is 50min; wherein, the flow rate of methane Both are 40 sccm.

Step 2, using a planetary ball mill to carry out low-energy ball milling of the graphene-coated copper powder particles and the copper powder, so that the graphene-coated copper powder particles are evenly distributed in the copper powder to obtain a mixed powder; wherein the copper powder has a purity of 99.9%. The particles are spherical and have a particle size of 60 μm.

The low-energy ball milling comprises the steps of: mixing the copper powder and the graphene-coated copper powder particles in a mass ratio of 2:1 and then putting them into a ball milling tank; vacuuming, and then introducing argon gas, and the ball milling process is dry milling. The material ratio was 12:1, the ball milling speed was 150r/min, the low-energy ball milled for 6 hours, unidirectionally rotated, and the ball milled for 1 hour and stopped for 10 minutes to obtain a copper composite powder with evenly distributed graphene-coated copper powder particles.

Step 3: Process the obtained mixed powder by cold spraying technology to obtain a graphene-coated copper powder particle-reinforced copper-based composite coating.

The processing process of the cold spraying technology includes the following steps: ultrasonically clean the PEEK substrate with absolute ethanol for 15 minutes, take it out and dry it, then perform sandblasting on the surface to be sprayed, and clean the surface to be sprayed with an air gun after treatment; Put the mixed powder into the powder feeder, fix the PEEK base material and use the spray gun to carry out cold spraying, using argon as the powder feeding gas, the cold spraying track is "S" shape, the line spacing of the spraying track is 2mm, the spraying beam flow and The surface to be sprayed is 90°, the gun speed is 150mm/s, the vertical distance between the gun mouth and the surface to be sprayed is 25mm, the chamber pressure is 3.8MPa, the chamber temperature is 700°C, and the spraying is repeated 15 times.

In the graphene-coated copper powder particle-reinforced cold-sprayed copper-based composite coating obtained in this example, graphene is 0.045%wt of the total amount of metal.

Claims (9)

1. A preparation method of a graphene coated copper powder particle reinforced cold spray copper-based composite coating is characterized by comprising the following steps: the preparation method of the graphene coated copper powder particle reinforced cold spray copper-based composite coating comprises the following steps:

firstly, in a methane atmosphere, adopting a plasma enhanced chemical vapor deposition method to grow a graphene layer on the surface of copper powder in situ to obtain graphene coated copper powder particles;

the plasma enhanced chemical vapor deposition comprises the following steps: firstly, copper powder is spread on a quartz plate, and is placed in a vacuum chamber, vacuumized until the air pressure is below 40Pa, heated and dried for 10-30min, and then methane is introduced until the air pressure is recovered to 1.01X10 ⁵ Pa, vacuumizing again until the air pressure is lower than 40Pa, and introducing methane to maintain the air pressure at 40-66.7Pa; then heating the vacuum chamber at a heating rate of 10 ℃/min, keeping the temperature for 10-30min after heating to 500 ℃, and stopping heating; naturally lowering the temperature of the vacuum chamber, and preserving the temperature for 10-3000min when the temperature is lowered to 300 ℃; the plasma exciter is started while the temperature is maintained, and the exciting power is set to be 150-500W; the set heat preservation time is related to the thickness of the graphene; wherein the flow rate of methane is 1-50sccm;

secondly, carrying out low-energy ball milling on the graphene coated copper powder particles and the copper powder by utilizing a ball mill, so that the graphene coated copper powder particles are uniformly distributed in the copper powder, and obtaining mixed powder; the mass ratio of the copper powder to the graphene coated copper powder particles is 1-3:1;

the low-energy ball milling comprises the following steps: mixing copper powder and graphene coated copper powder particles, and then filling the mixture into a ball milling tank; vacuumizing, then introducing argon, performing dry grinding in a ball-milling process, wherein the ball-material ratio is 8-12:1, the ball-milling rotating speed is 50-200r/min, the low-energy ball milling is performed for 4-10 hours, the ball milling is performed for 1 hour in a unidirectional rotation manner, and stopping the rotation for 10 minutes to obtain mixed powder, namely copper composite powder with uniformly distributed graphene coated copper powder particles;

and thirdly, spraying the mixed powder obtained in the second step on a substrate by adopting cold spraying to obtain the graphene coated copper powder particle reinforced copper-based composite coating.

2. The method for preparing the graphene-coated copper powder particle-reinforced cold spray copper-based composite coating, according to claim 1, is characterized in that: in the first step, the purity of the copper powder is 99.9%, the particles are spherical, the particle size is 40-60 mu m, and the purity of methane gas is 99.99%.

3. The method for preparing the graphene-coated copper powder particle-reinforced cold spray copper-based composite coating, according to claim 1, is characterized in that: in the second step, the purity of the copper powder is 99.9%, the particles are spherical, and the particle size is 40-60 mu m.

4. The method for preparing the graphene-coated copper powder particle-reinforced cold spray copper-based composite coating, according to claim 1, is characterized in that: in the second step, the ball mill is a planetary ball mill.

5. The method for preparing the graphene-coated copper powder particle-reinforced cold spray copper-based composite coating, according to claim 1, is characterized in that: the plasma enhanced chemical vapor deposition in the first step comprises the following steps:

firstly, copper powder is spread on a quartz plate, and is placed in a vacuum chamber, vacuumized to the air pressure below 40Pa, heated and dried for 10min, and then methane is introduced until the air pressure is recovered to 1.01X10 ⁵ Pa, vacuumizing again until the air pressure is below 40Pa, and slowly introducing methane to maintain the air pressure at 40-66.7Pa; then heating the vacuum chamber at a heating rate of 10 ℃/min, keeping the temperature for 10-30min after heating to 500 ℃, and stopping heating; naturally lowering the temperature of the vacuum chamber, and preserving the temperature for 10-3000min when the temperature is lowered to 300 ℃; the plasma exciter is started while the temperature is maintained, and the exciting power is set to be 150-500W; the flow rate of methane is 1-50sccm.

6. The method for preparing the graphene-coated copper powder particle-reinforced cold spray copper-based composite coating, according to claim 1, is characterized in that: the plasma enhanced chemical vapor deposition in the first step comprises the following steps:

firstly, copper powder is spread on a quartz plate, and is placed in a vacuum chamber, vacuumized to the air pressure below 40Pa, heated and dried for 10min, and then methane is introduced until the air pressure is recovered to 1.01X10 ⁵ Pa, vacuumizing again until the air pressure is below 40Pa, and slowly introducing methane to maintain the air pressure at 40-66.7Pa; then heating the vacuum chamber at a heating rate of 10 ℃/min, keeping the temperature for 10min after heating to 500 ℃, and stopping heating; naturally lowering the temperature of the vacuum chamber, and keeping when the temperature is lowered to 300 DEG CThe temperature is 10-3000min; the plasma exciter is started while the temperature is maintained, and the exciting power is set to be 150-500W; the flow rate of methane is 1-50sccm.

7. The method for preparing the graphene-coated copper powder particle-reinforced cold spray copper-based composite coating, according to claim 1, is characterized in that: the cold spraying in the third step comprises the following steps:

ultrasonically cleaning a substrate to be sprayed with absolute ethyl alcohol for 5-60min, taking out, drying, performing sand blasting on the surface to be sprayed, and cleaning the surface to be sprayed with an air gun after the treatment; loading the mixed powder obtained in the second step into a powder feeder, fixing a substrate, then carrying out cold spraying by using a spray gun, adopting argon as powder feeding gas, wherein a cold spraying track is S-shaped, the row spacing of the spraying track is 1.5-3mm, the spraying beam current and the surface to be sprayed are 90 degrees, the gun speed is 50-200mm/S, the vertical distance between a gun muzzle and the surface to be sprayed is 10-50mm, the chamber air pressure is 3-6MPa, and the chamber temperature is 700 ℃.

8. The method for preparing the graphene-coated copper powder particle-reinforced cold spray copper-based composite coating according to claim 7, wherein the method comprises the following steps: the cold spraying in the third step comprises the following steps:

ultrasonically cleaning a substrate to be sprayed with absolute ethyl alcohol for 5-60min, taking out, drying, performing sand blasting on the surface to be sprayed, and cleaning the surface to be sprayed with an air gun after the treatment; and (3) loading the mixed powder obtained in the step two into a powder feeder, fixing a substrate, then carrying out cold spraying by using a spray gun, adopting argon gas as powder feeding gas, wherein a cold spraying track is S-shaped, the row spacing of the spraying track is 1.5mm, the spraying beam current and the surface to be sprayed are 90 degrees, the gun speed is 100mm/S, the vertical distance between a gun opening and the surface to be sprayed is 20mm, the chamber air pressure is 3.5MPa, and the chamber temperature is 700 ℃.

9. The method for preparing the graphene-coated copper powder particle-reinforced cold spray copper-based composite coating, according to claim 1, is characterized in that: in the graphene coated copper powder particle reinforced copper-based composite coating obtained in the step three, the graphene accounts for 0.005-0.1wt% of the total metal.