Graphene metal coating based on microforging and laser post-processing and preparation method

Abstract

This invention provides a graphene metal coating based on micro-forging and laser post-treatment, and its preparation method, belonging to the field of coating preparation technology. The method includes the following steps: surface pretreatment of the substrate material; coating the substrate material surface with a mixture of graphene nanosheets and metal powder to obtain a powder layer; micro-forging the substrate with the powder layer; and then performing laser post-treatment on the micro-forged sample. Before laser post-treatment, the substrate is preheated to 300°C. This invention, using the above-mentioned graphene metal coating based on micro-forging and laser post-treatment, achieves a corrosion-resistant coating that is firmly bonded to the substrate, structurally stable, and not easily detached through a three-step deposition-micro-forging-laser method.

Description

Technical Field

[0001] This invention belongs to the field of coating preparation technology, and in particular relates to a graphene metal coating based on micro-forging and laser post-processing and its preparation method. Background Technology

[0002] Corrosion-resistant coatings are a common method to improve the corrosion resistance of metal surfaces. Graphene, due to its excellent barrier properties and physical properties, is often used to prepare protective coatings for metal surfaces. Traditional coating preparation techniques (such as spraying, electroplating, and deposition) mainly rely on the natural settling of coating particles, but the resulting coatings often have insufficient adhesion to the substrate and are prone to peeling off from the surface.

[0003] Solution sedimentation is a preparation technique that utilizes the dispersion, sedimentation, and eventual formation of a dense coating by solid particles in a liquid medium. Metal powder and graphene nanosheets are uniformly dispersed in a mixture of specific organic solvents to form a stable suspension. By controlling the solution viscosity, it is ensured that the suspension can spread uniformly on a pre-treated substrate surface. Subsequently, at a specific heating temperature, the solvent gradually evaporates, and the metal powder and graphene nanosheets in the suspension, driven by gravity, capillary forces, and interparticle interactions, settle orderly and densely accumulate on the substrate surface, ultimately forming a solid powder coating layer with a predetermined thickness and uniformity.

[0004] Micro-forging is an advanced mechanical surface modification technology. Its core lies in using a high-frequency vibrating hard hammer to impact the target area. The micro-forging head repeatedly strikes the powder layer surface at a set impact frequency, stroke, and feed rate, subjecting the powder particles and matrix material to continuous impact loads at the microscale, thereby inducing intense plastic deformation. This plastic deformation promotes mechanical interlocking between powder particles and between powder particles and the matrix, ultimately achieving compaction and densification of the powder layer and significantly enhancing its bonding strength with the matrix.

[0005] Laser post-processing technology utilizes a high-energy laser beam to rapidly heat the surface of a material, achieving surface modification. The high-energy-density laser beam acts on the micro-forged surface, causing extremely thin areas of the powder layer and substrate surface to rapidly reach their melting points and melt. As the laser beam moves, the molten area solidifies rapidly within a very short time, forming a strong metallurgical interface between the powder layer and the substrate. This process effectively eliminates microscopic defects that may exist in mechanical bonding, further improving the bonding strength and overall density of the surface layer. Furthermore, preheating the substrate before laser treatment helps reduce the thermal stress gradient caused by rapid heating and cooling, thereby reducing the risk of surface layer cracking and ensuring the integrity of the treated surface. Summary of the Invention

[0006] The purpose of this invention is to provide a graphene metal coating based on micro-forging and laser post-treatment and its preparation method. Through a three-step method of deposition-micro-forging-laser treatment, a corrosion-resistant coating that is firmly bonded to the substrate, structurally stable, and not easily detached can be obtained.

[0007] To achieve the above objectives, this invention provides a method for preparing a graphene metal coating based on micro-forging and laser post-processing, comprising the following steps: Step 1: Perform surface pretreatment on the substrate material; Step 2: Mix graphene nanosheets and metal powder and coat them onto the surface of the substrate material to obtain a powder layer; the mass ratio of graphene nanosheets to metal powder is 1:100. Step 3: Hammer the substrate with the powder layer using a micro-forging method, and then perform laser post-treatment on the micro-forged sample. Before laser post-treatment, preheat the substrate to 270℃-330℃.

[0008] Preferably, the matrix material includes high-temperature nickel-based alloys, high-entropy alloys, and titanium alloys; The hardness of the metal powder is less than or equal to 450 HV, and the particle size is less than or equal to 20 μm.

[0009] Preferably, the thickness of the powder layer is 30±5 micrometers.

[0010] Preferably, when the powder layer is multi-layered, steps 2 and 3 are repeated.

[0011] Preferably, methods for coating graphene nanosheets and metal powder onto the surface of a substrate material include spin coating, titration, and brush coating.

[0012] Preferably, graphene nanosheets and metal powder are mixed and coated onto the surface of a substrate material using a solution sedimentation method, specifically: Large-sheet graphene nanosheets were mixed with anhydrous ethanol at a ratio of 15 mg: 2 ml, and dispersed using an ultrasonic oscillator to obtain the first mixed solution. Metal powder with a particle size of 0~20µm and glycerol were added to the first mixed solution to obtain the second mixed solution; the volume ratio of glycerol to ethanol in the solution was set to 8:2. Stir the second mixture solution. After stirring, use a pipette to draw up the second mixture solution and evenly drop it onto the surface of the pretreated substrate material. When the coated substrate material is dried at a constant temperature of 190~200℃ for 3~3.5 hours, a powder layer is formed.

[0013] Preferably, the process parameters for micro forging are as follows: the diameter D of the micro forging head is 4~5mm, the input voltage U is 16~18V, the stroke h is 1.0~1.2mm, the impact frequency is 90~100Hz, the step amount s is 0.1~0.15mm, and the feed speed v is 450~550mm / min.

[0014] Preferably, the laser post-processing parameters are: laser power P of 130~170W, spot diameter D of 1~1.5mm, scanning speed of 15~20mm / s, and interlayer width W of 0.25~0.3mm.

[0015] A graphene-metal coating based on micro-forging and laser post-processing, and the graphene-metal coating prepared by the same method.

[0016] Applications of graphene-metal coatings in aero-engines and marine applications.

[0017] Therefore, the present invention employs the above-mentioned graphene metal coating based on micro-forging and laser post-processing and its preparation method, with the following technical effects: This invention effectively solves the problem of powder adhesion by depositing a mixture of graphene and IN718 powder onto the substrate surface through micro-forging and combining it with laser treatment.

[0018] This invention achieves metallurgical bonding between the coating and the interface by optimizing laser post-processing parameters, which can suppress the formation of conductive networks in graphene and thus fully utilize its barrier properties.

[0019] This invention introduces a substrate preheating (300℃) process, which effectively reduces the temperature gradient, suppresses the generation of liquefaction cracks, and ensures the integrity of the surface layer.

[0020] This invention combines micro-forging additive manufacturing with laser post-processing to achieve the preparation of graphene / high-temperature alloy composite surface layers. Micro-forging enables powder deposition and initial strengthening, while laser processing achieves metallurgical bonding and crack suppression, forming a synergistic effect that significantly improves the corrosion resistance of the material, which is difficult to achieve with existing single technologies. Attached Figure Description

[0021] Figure 1 The preparation process for a graphene-high temperature alloy corrosion-resistant surface layer; Figure 2 An optical microscope image of the sample surface; Figure 2 (a) is Sub; Figure 2 (b) is Ni30; Figure 2 (c) is Gr30; Figure 2 (d) is Ni30-L; Figure 2 (e) is Gr30-L; Figure 3An optical microscope image of the sample cross-section; Figure 3 (a) is Ni30; Figure 3 (b) is Gr30; Figure 3 (c) is Ni30-L; Figure 3 (d) is Gr30-L; Figure 3 (e) is a magnified view of Gr30-L; Figure 4 The morphology of the micro-forged sample and the micro-forged surface layer sample; Figure 4 (a) is a micro-forged sample; Figure 4 (b) is Ni60; Figure 4 (c) is Gr60; Figure 5 The potentiodynamic polarization curve is shown. Figure 6 EIS impedance trend graph; Figure 6 (a) is a Bode plot; Figure 6 (b) is the Nyquist plot; Figure 7 The cross-sectional morphology of micro-forged surface layer samples with different deposition layers; Figure 7 (a) is Gr30-L-1; Figure 7 (b) is Gr30-L-3; Figure 7 (c) is Gr30L-6; Figure 8 EIS spectra of surface layer samples with different deposition layers; Figure 8 (a) is a Bode plot; Figure 8 (b) is the Nyquist plot; Figure 9 SEM surface morphology characterization images of surface layer samples with different micro-forging parameters; Figure 9 (a) is a SEM image of the surface morphology at 6V; Figure 9 (b) is a SEM image of the surface morphology at 18V; Figure 9 (c) is a SEM image of the surface morphology at 24V; Figure 10 EIS spectra of surface layer samples with different micro-forging parameters; Figure 10 (a) is a Bode plot; Figure 10 (b) is a magnified low-frequency Bode plot; Figure 11 EIS spectra of surface layer samples with different micro-forging parameters; Figure 11 (c) is the Nyquist plot; Figure 11 (d) is a magnified view of the Nyquist plot; Figure 12 Cross-sectional optical microscopy and electron microscopy images of surface layer samples with different laser powers: Figure 12 (a1~f1) are optical micrographs; Figure 12 (a2~f2) are electron microscope images; Figure 13 EBSD images of micro-forged surface layer samples with different laser powers; Figure 13 (a) is 150W; Figure 13 (b) is 170W; Figure 14 EIS spectra of surface layer samples with different laser powers; Figure 14 (a) is a Bode plot; Figure 14 (b) is the Nyquist plot. Detailed Implementation

[0022] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0023] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0024] Example 1 like Figure 1 As shown, a method for preparing a graphene metal coating based on micro-forging and laser post-processing includes the following steps: Step 1. Surface treatment of the substrate material The preparation process used an Inconel 718 high-temperature alloy sample with dimensions of 30mm × 20mm × 3mm as the matrix material. The matrix surface was first pretreated, including cleaning the surface with distilled water, and then grinding the matrix surface with P60 and P100 grit sandpaper.

[0025] Step 2. Powder layer deposition The powder layer was prepared by solution sedimentation. First, 15 mg of large-sheet graphene nanosheets were mixed with 2 ml of anhydrous ethanol and dispersed using an ultrasonic vibrator. Next, 1.5 g of Inconel 718 superalloy powder with a particle size of 0–20 µm and 8 ml of glycerol were added to the above mixed solution to prepare a mixed solution with a total volume of 10 ml. The concentration ratio of glycerol to ethanol in the solution was set to 8:2. This mixed solution was then placed on a magnetic stirrer and stirred at 450 rpm for 30 minutes. After stirring, 1.5 ml of the mixed solution was pipetted and uniformly drop-coated onto the surface of the pretreated Inconel 718 superalloy substrate. The coated sample was dried on a constant-temperature heating stage at 190 °C for 3 hours to form a powder layer with a thickness of approximately 30 µm.

[0026] Step 3. Micro-forging hammering The micro-forging hammering process utilizes a self-developed electromagnetic micro-forging device. This device mainly consists of a micro-forging head, a return spring, bearings, a punch, a coil, a limit block, a magnetic yoke, a permanent magnet, and a mounting base. An external AC power supply powers the coil, generating a strong magnetic field that causes the punch to undergo high-frequency reciprocating motion, which in turn drives the micro-forging head to mechanically impact the workpiece surface. The micro-forging device is mounted on a three-coordinate machine tool, and the movable platform moves along the X, Y, and Z directions under CNC programming control.

[0027] The micro-forging process parameters used in the experiment were as follows: micro-forging head diameter D = 5 mm, input voltage U = 18 V, stroke h = 1.2 mm, impact frequency = 100 Hz, step size s = 0.1 mm, and feed rate v = 500 mm / min. The processing area was 10 mm × 10 mm. The AC power for the micro-forging equipment was provided by a programmable power supply from ITECH Electronics, Inc., USA.

[0028] Step 4. Laser post-processing The micro-forged samples underwent laser post-processing. A 1000 WIPG fiber laser was used for post-processing, with a robotic arm controlling the laser to uniformly irradiate the workpiece surface along a preset trajectory. The laser processing parameters were set as follows: laser power P = 150 W, spot diameter D = 1 mm, scanning speed = 20 mm / s, and interlayer width W = 0.3 mm. The substrate was preheated to 300℃ before laser processing.

[0029] Coating performance characterization 1. Results from optical microscopy The surface morphology of the micro-forged nickel-based superalloy was characterized using an MB630 optical microscope. Figure 2 In the figures (a), (b), (c), (d), and (e), the original sample, Ni30, Gr30, Ni30-L, and Gr30-L, respectively, are shown. Here, 30 represents the desired surface layer thickness of 30 μm, Gr indicates the addition of graphene, and L represents laser post-treatment. The original sample shows numerous grinding marks on its surface. The micro-forged surface layer sample exhibits distinct lamellar material, approximately 50-100 µm in size, with a clearly observable thickness. Different lamellar layers overlap and compress, exhibiting an uneven, stepped structure. After laser treatment, the surface lamellars disappear, replaced by a smoother surface formed by the solidification of melted metal particles, with numerous black, round particles distributed within it.

[0030] like Figure 3As shown, in the cross-sectional morphology characterization, after the sample was mounted, polished, and etched, the cross-sectional image was clearly observed to be divided into a dark area (resin) on the left, a micro-forged surface layer area in the middle, and an Inconel 718 alloy substrate area on the right by two dividing lines. The metallographic morphology of the surface layer area is significantly different from that of the substrate, exhibiting finer grain size and higher grain density, with obvious stacking traces and fine grain boundaries between grains. No defects such as pores and gaps were observed in the cross-sectional morphology, indicating that the surface layer prepared by this method has high density and strong adhesion.

[0031] 2. Scanning electron microscopy (SEM) results To further observe the microstructure and perform elemental analysis of the micro-forged surface layer samples, lanthanum hexaboride scanning electron microscopy was used for characterization. Figure 4 As shown in the figure, the results indicate that micro-forging has a surface strengthening and smoothing effect on the substrate. Some pits with diameters of 30µm to 50µm are visible on the substrate surface, which is the effect of mechanical hammering. The surface layer sample exhibits numerous "scale-like" and "layered" structures with sizes ranging from 20µm to 60µm. These structures overlap and interweave, forming an uneven microstructure. Notably, the surface of the sample with added graphene is smoother and flatter than that without graphene, indicating that graphene can enhance adhesion and is beneficial for smoothing the micro-forged surface layer sample.

[0032] 3. Potentiodynamic polarization analysis The corrosion resistance test of the micro-forged surface layer was conducted in a 3.5% (w / w) NaCl solution to simulate a seawater environment. Figure 5 As shown, Tafel analysis revealed significant differences in corrosion potential among different samples obtained using the Tafel extrapolation method. The results indicate that the micro-forged surface layer samples showed a substantial improvement over the original samples, with corrosion resistance increasing with increasing surface layer thickness and the introduction of laser post-treatment. The thicker surface layer provides better barrier properties, and laser post-treatment promotes powder layer remelting and metallurgical bonding, forming ultrafine grains, further enhancing the surface layer's corrosion resistance.

[0033] 4. Electrochemical Impedance Spectroscopy (EIS) Analysis like Figure 6 As shown in the EIS spectra, the low-frequency impedance of the original sample is lower than that of the micro-forged sample. The low-frequency impedance of the micro-forged sample is an order of magnitude higher than that of the substrate. Laser post-treatment further significantly improves the low-frequency impedance of the coating, effectively enhancing the corrosion resistance of the original sample. The curves of each sample are incomplete semicircles, without a Warburg impedance region, indicating a capacitive arc, suggesting that the corrosion process is dominated by capacitance. A larger arc radius indicates better corrosion resistance; all samples exhibit larger arc radii.

[0034] Example 2: Comparison of different number of layers Steps 1, 2, and 3 of the preparation process are the same as in Example 1. Since the multi-layer surface layer sample in this example can be prepared by repeating the powder spreading, micro-forging, and laser processing steps after the previous single-layer preparation process, steps 2, 3, and 4 are repeated. To investigate the effect of the number of surface layers on corrosion resistance, three sets of parameters were set for experiments: single-layer, three-layer, and six-layer. The three sets of samples were named Gr30-L-1, Gr30-L-3, and Gr30-L-6, respectively. The three sets of surface layer samples were characterized using a metallographic microscope. (REF _Ref220498785 \h \) MERGEFORMAT Figure 7 The cross-sectional morphology of three groups of samples with different numbers of layers is shown. From Figure 7 The boundary between the surface layer and the substrate can be clearly observed. The grains within the layer are very fine and the grain boundaries are dense. The thickness of a single surface layer was measured to be 30 mm. about.

[0035] The protective effect of surface layers with different numbers of layers on the substrate was analyzed using electrochemical impedance spectroscopy (EIS). The EIS results are shown in REF_Ref220498805. MERGEFORMAT Figure 8 As shown, from REF _Ref220498805 \h \ MERGEFORMAT Figure 8 As can be seen from the Bode plot in (a), the Gr60-L-6 sample has the highest impedance |Z| value at the lowest frequency of 0.01Hz, with a magnitude of 146898. The other two samples were quite similar; the Gr60-L-3 sample had a |Z| value of 89384 at its lowest frequency of 0.01Hz. The Gr60-L-1 sample has a |Z| value of 102102 at its lowest frequency of 0.01 Hz. REF _Ref220498805 \h \ MERGEFORMAT Figure 8 Similar conclusions can be drawn from the Nyquist plot in (b): the Gr60-L-6 sample has the largest semicircular radius, followed by the Gr60-L-3 sample, and the Gr60-L-1 sample has the smallest.

[0036] Example 3: Comparison of different high-frequency micro-forging process parameters The preparation steps are the same as in Example 1. Among these, the parameters of micro-forging, a core step in the surface layer preparation process, have a significant impact on the corrosion resistance of the surface layer. Therefore, this example selects voltages of 6V, 18V, and 24V to investigate the effect of voltage parameters on the surface layer preparation. The surface morphology of the micro-forged surface layer at different voltages was observed using scanning electron microscopy, as shown below. Figure 9 As shown, the 6V sample surface showed no lamellar structure, only some pits. Combined with the observed significant powder splattering during the experiment, it can be inferred that the lower voltage resulted in lower impact energy, and the impact of the micro-forging head was insufficient to achieve good bonding between the powder and the matrix, thus only providing a hammering effect on the matrix. In contrast, the 18V sample clearly showed the presence of numerous lamellar structures, indicating that sufficient impact energy could deform the powder and bond it to the matrix. The 24V sample, in addition to some lamellar structures, also exhibited numerous pits on its surface. This is because excessive impact energy would cause defects on the powder layer surface.

[0037] The corrosion resistance of surface layer samples with different micro-forging parameters was analyzed. The corrosion resistance of surface layers with different micro-forging parameters was analyzed by electrochemical impedance spectroscopy (EIS). The EIS results are as follows: Figure 10 and Figure 11 As shown, from Figure 10 (a) and Figure 10 As can be seen from the Bode plot in (b), the impedance |Z| of the two samples with an 18V voltage is the largest at the lowest frequency of 0.01Hz, with a value of 350000. and 370,000 The voltage level is significantly higher than that of other samples; while the other samples are not significantly different, with |Z| values ​​all around 50000 at the lowest frequency of 0.01Hz. nearby. Figure 11 (c) and Figure 11 Similar conclusions can be drawn from the Nyquist plot in (d). The 18V sample exhibits a significantly larger semi-circular radius than other samples, indicating that it has the best corrosion resistance. Conversely, the 24V sample performs worse than the matrix, suggesting that excessively large micro-forging parameters have a detrimental effect on corrosion resistance. In summary, the micro-forging parameters should not be too large or too small. Based on the experimental results, a voltage of 18V and a stroke of 1.2mm are the optimal parameters.

[0038] Example 4: Comparison of different laser post-processing parameters The preparation steps are the same as in Example 1. Since the parameters of laser post-treatment also significantly affect the corrosion resistance of the surface layer, the main parameters influencing the laser post-treatment effect are laser power P, spot diameter D, and scanning speed V. Therefore, in this example, the spot diameter D = 1 mm and the scanning speed V = 20 mm / s are fixed. The laser power P is changed to alter the laser's energy input. Laser power parameters of P = 120 W, 130 W, 140 W, 150 W, 160 W, and 170 W are set to ensure a surface energy density of 10 J / mm². 2 Left and right, cross-sectional optical micrographs and electron micrographs of surface layer samples with different laser powers, as shown in the figure. Figure 12 As shown.

[0039] To further investigate the grain refinement and growth within surface layer samples with different power levels, EBSD analysis was performed using a TESCAN GAIA3 scanning electron microscope to characterize the grain size. The results are as follows: Figure 13 As shown in the diagram, comparing the IPF and grain boundary diagrams of the 150W and 170W samples reveals that the surface layer of the 150W sample consists entirely of fine equiaxed crystals with diameters ranging from 0 to 10 μm. In contrast, the 170W sample, while containing equiaxed crystals at the bottom, exhibits coarse columnar crystals growing vertically near the surface, with grain sizes around 50 to 100 μm. This is consistent with observations under cross-sectional light microscopy and electron microscopy, demonstrating that excessively high laser power leads to grain growth in the surface layer, while low laser power, due to lower temperatures and higher cooling rates, inhibits grain growth, thus preventing it. However, excessively low laser power (such as 120W) is insufficient for grain refinement in laser post-processing. Therefore, in practical operation, the laser power needs to be controlled within a suitable range around 150W.

[0040] Corrosion resistance of surface layer samples with different laser post-processing parameters was analyzed. The corrosion resistance of surface layers with different laser powers was analyzed by electrochemical impedance spectroscopy (EIS). The EIS results are shown below. Figure 14 As shown, from Figure 14 As can be seen from the Bode plot in (a), the impedance |Z| of the two samples with a power of 150W is the largest at the lowest frequency of 0.01Hz, with a value of 2e6. and 6e5 The value of |Z| is around 2e5, significantly higher than that of other samples; while the other samples are not significantly different, with |Z| being around 2e5 at the lowest frequency of 0.01Hz. nearby. Figure 14 A similar conclusion can be drawn from the Nyquist plot in (b): the 150W power sample has the largest semi-circular radius, indicating that it has the best corrosion resistance.

[0041] Therefore, the present invention adopts the above-mentioned graphene metal coating and preparation method based on micro-forging and laser post-treatment. Through the three-step method of deposition-micro-forging-laser, a corrosion-resistant coating that is firmly bonded to the substrate, structurally stable, and not easy to fall off can be obtained.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a graphene metal coating based on micro-forging and laser post-processing, characterized in that, Includes the following steps: Step 1: Perform surface pretreatment on the substrate material; Step 2: Mix graphene nanosheets and metal powder and coat them onto the surface of the substrate material to obtain a powder layer; the mass ratio of graphene nanosheets to metal powder is 1:

100. Step 3: Hammer the substrate with the powder layer using a micro-forging method, and then perform laser post-treatment on the micro-forged sample. Before laser post-treatment, preheat the substrate to 270℃-330℃.

2. The method for preparing a graphene metal coating based on micro-forging and laser post-processing according to claim 1, characterized in that, The matrix materials include high-temperature nickel-based alloys, high-entropy alloys, and titanium alloys; The hardness of the metal powder is less than or equal to 450 HV, and the particle size is less than or equal to 20 μm.

3. The method for preparing a graphene metal coating based on micro-forging and laser post-processing according to claim 1, characterized in that, The thickness of the powder layer is 30±5 micrometers.

4. The method for preparing a graphene metal coating based on micro-forging and laser post-processing according to claim 1, characterized in that, When the powder layer is multi-layered, repeat steps 2 and 3.

5. The method for preparing a graphene metal coating based on micro-forging and laser post-processing according to claim 1, characterized in that, Methods for coating graphene nanosheets and metal powders onto the surface of a substrate material include spin coating, titration, and brush coating.

6. The method for preparing a graphene metal coating based on micro-forging and laser post-processing according to claim 1, characterized in that, The solution sedimentation method is used to coat graphene nanosheets and metal powder onto the surface of a substrate material. Specifically: Large-sheet graphene nanosheets were mixed with anhydrous ethanol at a ratio of 15 mg: 2 ml, and dispersed using an ultrasonic oscillator to obtain the first mixed solution. Metal powder with a particle size of 0~20µm and glycerol were added to the first mixed solution to obtain the second mixed solution; the volume ratio of glycerol to ethanol in the second mixed solution was set to 8:

2. Stir the second mixture solution. After stirring, use a pipette to draw up the second mixture solution and evenly drop it onto the surface of the pretreated substrate material. When the coated substrate material is dried at a constant temperature of 190-200°C for 3-3.5 hours, a powder layer is formed.

7. The method for preparing a graphene metal coating based on micro-forging and laser post-processing according to claim 1, characterized in that, The process parameters for micro forging are as follows: the diameter D of the micro forging head is 4~5mm, the input voltage U is 16~18V, the stroke h is 1.0~1.2mm, the impact frequency is 90~100Hz, the step amount s is 0.1~0.15mm, and the feed speed v is 450~550mm / min.

8. The method for preparing a graphene metal coating based on micro-forging and laser post-processing according to claim 1, characterized in that, The laser post-processing parameters are as follows: laser power P is 130~170W, spot diameter D is 1~1.5mm, scanning speed is 15~20mm / s, and interlayer width W is 0.25~0.3mm.

9. The graphene metal coating prepared by the method for preparing graphene metal coating based on micro-forging and laser post-processing according to claim 1.

10. The application of the graphene-metal coating as described in claim 9 in aero-engines and marine applications.

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