Carbon-coated metal composite material and preparation method thereof

Abstract

The invention relates to the field of materials, and provides a carbon-coated metal composite material and a preparation method thereof. The method comprises the following steps: carrying out surface modification treatment on metal powder by using an organic solvent to obtain modified metal powder; carrying out carboxylation treatment on the carbon material to obtain a carboxylated carbon material; the modified metal powder and the carboxylated carbon material are put into an acoustic resonance ball-milling container, acoustic resonance ball-milling treatment is conducted in the argon atmosphere, and carbon-coated metal powder is obtained; and the carbon-coated metal powder is used for 3D printing forming, and the carbon-coated metal composite material is obtained. The method can effectively solve the problems that in the process of preparing the carbon-coated metal composite material at present, the metal material is prone to being seriously abraded and even broken, the carbon material is poor in dispersity and extremely prone to agglomeration in the metal material, a uniform, compact and thickness-controllable carbon material coating layer is difficult to form on the surface of the metal powder, and the service life of the carbon material is prolonged. Therefore, the mechanical property of the prepared carbon-coated metal composite material is directly influenced.

Description

Technical Field

[0001] This application relates to the field of materials, and more particularly to a carbon-coated metal composite material and its preparation method. Background Technology

[0002] In related technologies, carbon materials (such as carbon nanotubes and graphene) are commonly used as reinforcing materials to strengthen metal matrices. Although these carbon materials can significantly improve the hardness, strength, and tribological properties of metal materials, there are still problems in the preparation of carbon-coated metal composites, such as severe wear and even breakage of the metal materials. Furthermore, these carbon materials have poor dispersibility in metal materials and are extremely prone to agglomeration, making it difficult to form a uniform, dense, and controllable carbon coating layer on the surface of metal powder. This directly affects the mechanical properties of the prepared carbon-coated metal composites. Summary of the Invention

[0003] In view of the above-mentioned shortcomings in the existing technology, the purpose of this application is to provide a carbon-coated metal composite material and its preparation method, so as to solve the problems that the metal material is prone to severe wear and even breakage in the current process of preparing carbon-coated metal composite materials, and the carbon material has poor dispersibility in the metal material and is extremely easy to agglomerate, making it difficult to form a uniform, dense and controllable carbon coating layer on the surface of the metal powder, thereby directly affecting the mechanical properties of the obtained carbon-coated metal composite material.

[0004] To achieve the above-mentioned objectives, the technical solution adopted in this application is as follows:

[0005] In a first aspect, embodiments of this application provide a method for preparing a carbon-coated metal composite material, comprising:

[0006] Surface modification of metal powder is performed using organic solvents to obtain modified metal powder;

[0007] Carboxylation of carbon materials yields carboxylated carbon materials.

[0008] Modified metal powder and carboxylated carbon material are placed in an acoustic resonance ball mill container and subjected to acoustic resonance ball milling under an argon atmosphere to uniformly coat the surface of the modified metal powder with carboxylated carbon material to form a carbon coating layer, thereby obtaining carbon-coated metal powder.

[0009] Carbon-coated metal powder is used for 3D printing to obtain carbon-coated metal composite materials.

[0010] Secondly, embodiments of this application provide a carbon-coated metal composite material, which is prepared according to the preparation method of the carbon-coated metal composite material of the first aspect.

[0011] The beneficial effects of this application include at least the following:

[0012] By first modifying the surface of metal powder with organic solvents and then preparing carbon-coated metal powder using an acoustic resonant ball milling process, not only can the wear and even breakage of the metal powder be effectively reduced, but a thin film can also be formed on the surface of the metal powder. This film can minimize the increase of oxygen content on the surface of the metal powder, and it has an indirect promoting effect on the adsorption of carboxylated carbon materials on the surface of the metal powder. This helps to promote the adsorption of carboxylated carbon materials on the surface of the metal powder and to evenly distribute and wrap around the surface of the metal powder, thereby forming a uniform, dense, and controllable carbon coating layer on the surface of the metal powder, resulting in carbon-coated metal powder. This, in turn, is beneficial to improving the mechanical properties of carbon-coated metal composite materials made from the carbon-coated metal powder.

[0013] Furthermore, the preparation method of this application is simple, time-saving, and does not require sophisticated equipment, making it easy to promote and apply, and thus has broad market prospects. Attached Figure Description

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0015] Figure 1 This is a schematic diagram of the sample size for tensile strength testing of the carbon-coated alloy composite materials prepared in Examples 1 to 6 of this application. Detailed Implementation

[0016] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are only for explaining this application, but the implementation of this application is not limited thereto.

[0017] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art to which this application pertains. Unless otherwise specified, the experimental reagents used in the following embodiments are conventional biochemical reagents; the amounts of experimental reagents used are, unless otherwise specified, the amounts used in conventional experimental operations; and the experimental methods used are, unless otherwise specified, conventional methods.

[0018] Due to their low hardness, poor tribological properties, and severe adhesive and fretting wear, titanium alloys are limited in their application in high-tech fields such as aerospace and industrial manufacturing. Single titanium or titanium alloys can no longer meet the mechanical property requirements of key components in high-end applications. To further meet the application needs of lightweight, high-performance titanium materials in advanced equipment manufacturing, a trend towards composite materials is gradually emerging.

[0019] Traditional subtractive manufacturing methods, such as casting, forging, and machining, face a series of problems in the preparation and forming of high-performance metal components, including long manufacturing cycles, high costs, low material utilization, and difficulty in processing complex components. Therefore, additive manufacturing technology has become a new and effective approach for preparing composite materials.

[0020] However, traditional additive manufacturing processes still face many challenges. For example, in the process of preparing carbon-coated titanium alloy composites, the metal material is prone to severe wear and even breakage. Furthermore, the carbon material has poor dispersion in the metal material and is extremely easy to agglomerate, making it difficult to form a uniform, dense, and controllable carbon material coating layer on the surface of the metal powder. This directly affects the mechanical properties of the prepared carbon-coated titanium alloy composites.

[0021] In view of this, embodiments of this application provide a method for preparing carbon-coated metal composite materials. This method involves first modifying the surface of metal powder with an organic solvent, and then preparing carbon-coated metal powder using an acoustic resonant ball milling process. This not only effectively reduces wear and even breakage of the metal powder, but also forms a thin film on the surface of the metal powder. This film can minimize the increase of oxygen content on the surface of the metal powder, and it has an indirect promoting effect on the adsorption of carboxylated carbon materials on the surface of the metal powder. This helps to promote the adsorption of carboxylated carbon materials on the surface of the metal powder and to uniformly distribute and wrap around the surface of the metal powder, thereby forming a uniform, dense, and controllable carbon coating layer on the surface of the metal powder, resulting in carbon-coated metal powder. This, in turn, is beneficial to improving the mechanical properties of the carbon-coated metal composite materials subsequently prepared using the carbon-coated metal powder.

[0022] In a first aspect, embodiments of this application provide a method for preparing a carbon-coated metal composite material, comprising:

[0023] S1. Surface modification treatment of metal powder is performed using organic solvents to obtain modified metal powder.

[0024] S2. Carboxylation treatment is performed on carbon materials to obtain carboxylated carbon materials.

[0025] S3. The modified metal powder and carboxylated carbon material are placed in an acoustic resonance ball mill container and subjected to acoustic resonance ball milling under an argon atmosphere to uniformly coat the surface of the modified metal powder with the carboxylated carbon material to form a carbon coating layer, thereby obtaining carbon-coated metal powder.

[0026] S4. Use carbon-coated metal powder for 3D printing to obtain carbon-coated metal composite material.

[0027] The preparation method provided in this application adopts acoustic resonance coating technology. Through mechanical resonance, the mixing field moves violently as a whole. At the same time, with the help of sound waves, a large number of microscopic acoustic mixing fields are formed in the modified metal powder and carboxylated carbon material, which fully fluidizes and mixes the modified metal powder and carboxylated carbon material, achieving global mixing and coating without dead angles. While the acoustic resonance is working, the random movement of the lightweight grinding ball can generate a strong shearing force, which can fully de-agglomerate and grind the difficult-to-disperse carboxylated carbon material. At the same time, it can effectively maintain the original state of the modified metal powder (such as spherical state), reduce the problem of severe wear or even breakage of the modified metal powder, and finally realize the rapid preparation of carbon-coated metal powder.

[0028] The preparation process of this application is simple, time-saving, and does not require high-end equipment. It is easy to promote and apply and has broad market prospects.

[0029] In some embodiments, in step S1 above, the organic solvent can be isopropanol. The carbon material is carbon nanotubes or graphene oxide.

[0030] When graphene oxide is selected as the carbon material, after coating is completed, a reducing agent (such as hydrazine, sodium borohydride, hydroiodic acid, etc.) is used to reduce the carboxylated carbon material coated on the surface of the modified metal powder to graphene, thus obtaining carbon-coated metal powder. This carbon-coated metal powder is a modified metal powder with a carbon coating layer composed of graphene wrapped on its surface.

[0031] In some embodiments, in step S1 above, the metal powder is spherical titanium alloy powder or spherical aluminum alloy powder; the particle size of the metal powder is 15-53 μm (e.g., it can be 15 μm, 20 μm, 30 μm, 40 μm, 50 μm, or 53 μm, etc.). For example, the spherical titanium alloy powder can be original atomized spherical TC4 alloy (i.e., titanium alloy Ti-6Al-4V, wherein the titanium content is approximately 90%, the aluminum content is approximately 6%, and the vanadium content is approximately 4%) powder.

[0032] Original atomized spherical TC4 alloy powder refers to TC4 metal powder that is spherical and has not undergone further processing (such as secondary ball milling, annealing, etc.) prepared by atomization process. Its particle shape is close to a perfect sphere and its surface is relatively smooth.

[0033] Due to titanium's strong chemical affinity for oxygen, oxygen can provide a significant strengthening effect, but it also reduces the ductility of titanium alloys. Oxygen also has a detrimental effect on toughness and notch sensitivity. Generally, during the process of coating carbon materials onto the surface of titanium alloy powder, oxidation aggravation is easily caused. However, in this embodiment, by first using an organic solvent to modify the surface of the titanium alloy powder, a thin film can be formed on the surface of the titanium alloy powder. This film has an indirect promoting effect on the adsorption of carboxylated carbon materials on the surface of the titanium alloy powder. This helps to promote the adsorption of carboxylated carbon materials on the surface of the titanium alloy powder and to uniformly distribute and wrap around the surface of the titanium alloy powder, thereby forming a uniform, dense, and controllable thickness carbon coating layer on the surface of the titanium alloy powder, resulting in carbon-coated titanium alloy powder.

[0034] In some embodiments, in step S2 above, the mass of the carboxylated carbon material used to coat the modified metal powder is 0.05% to 0.2% of the mass of the modified metal powder (for example, it can be 0.05%, 0.08%, 0.1%, 0.15%, or 0.2%, etc.).

[0035] The preparation method provided in this application, by employing an acoustic resonance ball milling process, can effectively solve the problem of agglomeration of carboxylated carbon materials (such as carboxylated carbon nanotubes) during the coating of modified metal powder. When the mass of the carboxylated carbon material used to coat the modified metal powder is 0.05% to 0.2% of the mass of the modified metal powder, a uniform, dense, and controllable carbon coating layer can be formed on the surface of the modified metal powder. This can reduce the amount of carbon material required for coating the metal powder and reduce material costs.

[0036] In some embodiments, in step S2 above, the conditions for the acoustic resonance ball milling treatment are: the grinding balls are zirconia balls with a diameter of 3-5 mm, the ball-to-material ratio is 2-5:1, the material filling ratio is 50%-80%, and the argon gas pressure inside the container is 10. -3 ~10MPa, vibration frequency of 50Hz~70Hz, amplitude of 8~15mm, and processing time of 10~30min.

[0037] In some preferred embodiments, in step S2 above, the conditions for acoustic resonance ball milling are as follows: the grinding balls are zirconia balls with a diameter of 3-5 mm, the ball-to-material ratio is 2:1, the material filling ratio is 50%, the argon gas pressure in the acoustic resonance ball mill container (such as an acoustic resonance ball mill tank) is 3 MPa, the vibration frequency is 60 Hz, the amplitude is 10 mm, and the processing time is 15 min.

[0038] Using small, lightweight zirconia balls as grinding balls can avoid damage to the structure of carboxylated carbon materials (such as carboxylated carbon nanotubes) and sp. 3The study addresses issues such as hybridization, introduction of impurities, and interfacial reactions, thereby significantly improving the mechanical properties of carboxylated carbon nanotubes on modified metallic materials (such as modified titanium alloys).

[0039] In some embodiments, step S1 above includes: placing the metal powder in an organic solvent for ultrasonication, followed by filtration and vacuum drying to obtain modified metal powder, wherein the ultrasonication time is 10-60 min, and the vacuum drying temperature is 40-60°C for 3-5 hours.

[0040] In some implementations, step S2 above includes:

[0041] Carbon material is mixed with mixed acid and an oxidant is added. The mixture is then subjected to water bath and ultrasonic vibration at a temperature of 50–80°C to obtain a reactant. After removing the residual acid from the reactant, it is vacuum dried to obtain a carboxylated carbon material.

[0042] Furthermore, the volume ratio of carbon material to mixed acid is 3:1; the mixed acid includes concentrated sulfuric acid and concentrated nitric acid; the oxidant is potassium permanganate.

[0043] As an example, the carboxylated carbon material is carboxylated carbon nanotubes, and its preparation steps are as follows:

[0044] Carbon nanotubes were mixed with a mixed acid (including concentrated sulfuric acid and concentrated nitric acid) at a volume ratio of 3:1, and potassium permanganate was added as an oxidant. The mixture was then subjected to a water bath at a temperature of 50–80 °C and ultrasonic oscillation at a frequency of 20–60 kHz for 3–6 hours. After the reaction was completed, the reactants were obtained. The reactants were then diluted with a large amount of deionized water and filtered until the pH of the filtrate was close to 7 to remove residual acid. Finally, the reactants were vacuum dried at a temperature of 60–80 °C for 12–24 hours to obtain carboxylated carbon nanotubes.

[0045] By utilizing the oxidizing effect of strong acid systems, carboxyl (-COOH) and hydroxyl (-OH) functional groups can be introduced onto the surface of carbon materials. Since carbon materials (such as carbon nanotubes) are chemically relatively stable and have smooth surfaces, they are not conducive to interaction with other substances. Introducing carboxyl and hydroxyl functional groups onto the surface of carbon materials increases the number of active sites on the carbon nanotube surface. The oxygen atom in the carboxyl (-COOH) group has strong electronegativity, and the oxygen in the hydroxyl (-OH) group also carries a partial negative charge. These functional groups can interact physically or chemically with atoms on the surface of metal powder, such as through electrostatic interactions, hydrogen bonding, or the formation of chemical bonds. This allows carbon nanotubes to adhere tightly to the surface of the metal powder, achieving effective coating.

[0046] In some embodiments, in step S3 above, the parameters for 3D printing are set as follows: laser power of 180-220W, scanning speed of 500-1200mm / s, scanning spacing of 60-100μm, layer thickness of 20-40μm, and scanning strategy of rotating 67° layer by layer.

[0047] As an example, in step S3 above, the parameters for 3D printing can be set as follows: laser power of 200W, scanning speed of 1200mm / s, scanning spacing of 130μm, layer thickness of 30μm, and scanning strategy of rotating 67° layer by layer.

[0048] Secondly, embodiments of this application also provide a carbon-coated metal composite material, which is prepared according to the preparation method of the carbon-coated metal composite material of the first aspect described above.

[0049] The carbon-coated metal composite material prepared by the preparation method provided in the embodiments of this application maintains essentially the same plasticity, and the mechanical properties of the material are greatly improved.

[0050] This application has undergone multiple experiments, and some of the test results are presented here for reference to further describe the invention in detail. The following is a detailed description in conjunction with specific embodiments.

[0051] Example 1

[0052] This embodiment provides a carbon-coated titanium alloy composite material, the preparation steps of which are as follows:

[0053] (1) Take the original atomized spherical TC4 alloy powder and put it into a beaker. Add isopropanol to the beaker and sonicate for 30 minutes. Then filter it. The mass ratio of spherical TC4 alloy powder to isopropanol is 1:10. Place the filtered spherical TC4 alloy powder in a vacuum drying oven and set the vacuum drying temperature to 50°C. Bake for 3 hours to obtain dry and clean modified titanium alloy powder.

[0054] (2) Take commercial carbon nanotubes and put them into a beaker. Mix the carbon nanotubes with a mixed acid (including concentrated sulfuric acid and concentrated nitric acid) at a volume ratio of 3:1. Add potassium permanganate as an oxidant. Place the mixture in a water bath at 50°C and then perform ultrasonic oscillation at a frequency of 30kHz for 3 hours. After the reaction is complete, the reactant is obtained. Then, dilute the reactant with a large amount of deionized water and filter it until the pH of the filtrate is close to 7 to remove the residual acid in the reactant. Finally, vacuum dry the reactant at 60°C for 12 hours to obtain carboxylated carbon nanotubes.

[0055] (3) The carboxylated carbon nanotubes obtained in step (2) and the modified titanium alloy powder obtained in step (1) are placed in an acoustic resonance ball mill jar for acoustic resonance ball milling to uniformly coat the surface of the modified titanium alloy powder with carboxylated carbon material to form a carbon coating layer, thereby obtaining carbon-coated titanium alloy powder. The grinding balls are zirconia balls with a diameter of 3 mm, the ball-to-material ratio is 2:1, the material filling ratio is 50%, the argon gas pressure inside the jar is set to 1 MPa, the vibration frequency is 60 Hz, the amplitude is 10 mm, and the processing time is 15 minutes. The mass of the carboxylated carbon material used to coat the modified titanium alloy powder is 0.05% of the mass of the modified titanium alloy powder.

[0056] (4) First, using the SLM-150 selective laser melting equipment, the aluminum substrate is loaded into the forming chamber, and the carbon-coated titanium alloy powder obtained in step (3) above is loaded into the powder chamber; then, high-purity argon gas is introduced as a protective gas and the oxygen partial pressure in the selective laser melting equipment is less than 50ppm; then, a 3D printing task is established, and the powder thickness is set to 30μm, the laser power is 200W, the scanning speed is 1200mm / s, the scanning spacing is 100μm, and the scanning strategy is partitioned island scanning; finally, the powder laying system lays a layer of powder into the forming chamber, and the laser beam selectively melts and solidifies a layer of powder according to the slicing data of the three-dimensional model, and carbon-coated titanium alloy composite material is obtained by layer-by-layer melting and solidification.

[0057] Example 2

[0058] This embodiment provides a carbon-coated titanium alloy composite material, the preparation steps of which are as follows:

[0059] (1) Take the original atomized spherical TC4 alloy powder and put it into a beaker. Add isopropanol to the beaker and sonicate for 20 minutes. Then filter it. The mass ratio of spherical TC4 alloy powder to isopropanol is 1:10. Place the filtered spherical TC4 alloy powder in a vacuum drying oven and set the vacuum drying temperature to 40℃. Bake for 5 hours to obtain dry and clean modified titanium alloy powder.

[0060] (2) Take commercial carbon nanotubes and put them into a beaker. Mix the carbon nanotubes with a mixed acid (including concentrated sulfuric acid and concentrated nitric acid) at a volume ratio of 3:1. Add potassium permanganate as an oxidant. Place the mixture in a water bath at 60°C and then perform ultrasonic oscillation at a frequency of 30kHz for 4 hours. After the reaction is complete, the reactant is obtained. Then, dilute the reactant with a large amount of deionized water and filter it until the pH of the filtrate is close to 7 to remove the residual acid in the reactant. Finally, vacuum dry the reactant at 70°C for 15 hours to obtain carboxylated carbon nanotubes.

[0061] (3) The carboxylated carbon nanotubes obtained in step (2) and the modified titanium alloy powder obtained in step (1) are placed in an acoustic resonance ball mill jar for acoustic resonance ball milling to uniformly coat the surface of the modified titanium alloy powder with carboxylated carbon material to form a carbon coating layer, thereby obtaining carbon-coated titanium alloy powder. The grinding balls are zirconia balls with a diameter of 4 mm, the ball-to-material ratio is 2:1, the material filling ratio is 60%, the argon gas pressure inside the jar is set to 2 MPa, the vibration frequency is 65 Hz, the amplitude is 15 mm, and the processing time is 15 minutes. The mass of the carboxylated carbon material used to coat the modified titanium alloy powder is 0.08% of the mass of the modified titanium alloy powder.

[0062] (4) First, using the SLM-150 selective laser melting equipment, the aluminum substrate is loaded into the forming chamber, and the carbon-coated titanium alloy powder obtained in step (3) above is loaded into the powder chamber; then, high-purity argon gas is introduced as a protective gas and the oxygen partial pressure in the selective laser melting equipment is less than 50ppm; then, a 3D printing task is established, and the powder thickness is set to 30μm, the laser power is 200W, the scanning speed is 1200mm / s, the scanning spacing is 80μm, and the scanning strategy is partitioned island scanning; finally, the powder laying system lays a layer of powder into the forming chamber, and the laser beam selectively melts and solidifies a layer of powder according to the slicing data of the three-dimensional model, and carbon-coated titanium alloy composite material is obtained by layer-by-layer melting and solidification.

[0063] Example 3

[0064] This embodiment provides a carbon-coated titanium alloy composite material, the preparation steps of which are as follows:

[0065] (1) Take the original atomized spherical TC4 alloy powder and put it into a beaker. Add isopropanol to the beaker and sonicate for 60 minutes. Then filter it. The mass ratio of spherical TC4 alloy powder to isopropanol is 1:10. Place the filtered spherical TC4 alloy powder in a vacuum drying oven and set the vacuum drying temperature to 60℃. Bake for 4 hours to obtain dry and clean modified titanium alloy powder.

[0066] (2) Take commercial carbon nanotubes and put them into a beaker. Mix the carbon nanotubes with a mixed acid (including concentrated sulfuric acid and concentrated nitric acid) at a volume ratio of 3:1. Add potassium permanganate as an oxidant. Place the mixture in a water bath at 80°C and then perform ultrasonic oscillation at a frequency of 20kHz for 3 hours. After the reaction is complete, the reactant is obtained. Then, dilute the reactant with a large amount of deionized water and filter it until the pH of the filtrate is close to 7 to remove the residual acid in the reactant. Finally, vacuum dry the reactant at 60°C for 24 hours to obtain carboxylated carbon nanotubes.

[0067] (3) The carboxylated carbon nanotubes obtained in step (2) and the modified titanium alloy powder obtained in step (1) are placed in an acoustic resonance ball mill jar for acoustic resonance ball milling to uniformly coat the surface of the modified titanium alloy powder with carboxylated carbon material to form a carbon coating layer, thereby obtaining carbon-coated titanium alloy powder. The grinding balls are zirconia balls with a diameter of 4 mm, the ball-to-material ratio is 5:1, the material filling ratio is 80%, the argon gas pressure inside the jar is set to 3 MPa, the vibration frequency is 70 Hz, the amplitude is 15 mm, and the processing time is 30 minutes. The mass of the carboxylated carbon material used to coat the modified titanium alloy powder is 0.1% of the mass of the modified titanium alloy powder.

[0068] (4) First, using the SLM-150 selective laser melting equipment, the aluminum substrate is loaded into the forming chamber, and the carbon-coated titanium alloy powder obtained in step (3) above is loaded into the powder chamber; then, high-purity argon gas is introduced as a protective gas and the oxygen partial pressure in the selective laser melting equipment is less than 50ppm; then, a 3D printing task is established, and the powder thickness is set to 30μm, the laser power is 200W, the scanning speed is 1200mm / s, the scanning spacing is 60μm, and the scanning strategy is partitioned island scanning; finally, the powder laying system lays a layer of powder into the forming chamber, and the laser beam selectively melts and solidifies a layer of powder according to the slicing data of the three-dimensional model, and carbon-coated titanium alloy composite material is obtained by layer-by-layer melting and solidification.

[0069] Example 4

[0070] This embodiment provides a carbon-coated aluminum alloy composite material, the preparation steps of which are as follows:

[0071] (1) Take spherical aluminum alloy powder and put it into a beaker. Add isopropanol to the beaker and sonicate for 60 minutes. Then filter it. The mass ratio of spherical aluminum alloy powder to isopropanol is 1:10. Place the filtered spherical aluminum alloy powder in a vacuum drying oven and set the vacuum drying temperature to 50°C. Bake for 3 hours to obtain dry and clean modified aluminum alloy powder.

[0072] (2) Take commercial carbon nanotubes and put them into a beaker. Mix the carbon nanotubes with a mixed acid (including concentrated sulfuric acid and concentrated nitric acid) at a volume ratio of 3:1. Add potassium permanganate as an oxidant. Place the mixture in a water bath at 70°C and then perform ultrasonic oscillation at a frequency of 50kHz for 3 hours. After the reaction is complete, the reactant is obtained. Then, dilute the reactant with a large amount of deionized water and filter it until the pH of the filtrate is close to 7 to remove the residual acid in the reactant. Finally, vacuum dry the reactant at 60°C for 18 hours to obtain carboxylated carbon nanotubes.

[0073] (3) The carboxylated carbon nanotubes obtained in step (2) and the modified aluminum alloy powder obtained in step (1) are placed in an acoustic resonance ball mill jar for acoustic resonance ball milling to uniformly coat the surface of the modified aluminum alloy powder with carboxylated carbon material to form a carbon coating layer, thereby obtaining carbon-coated aluminum alloy powder. The grinding balls are zirconia balls with a diameter of 4 mm, the ball-to-material ratio is 5:1, the material filling ratio is 80%, the argon gas pressure inside the jar is set to 5 MPa, the vibration frequency is 70 Hz, the amplitude is 15 mm, and the processing time is 30 minutes. The mass of the carboxylated carbon material used to coat the modified aluminum alloy powder is 0.2% of the mass of the modified aluminum alloy powder.

[0074] (4) First, using the SLM-150 selective laser melting equipment, the aluminum substrate is loaded into the forming chamber, and the carbon-coated aluminum alloy powder obtained in step (3) above is loaded into the powder chamber; then, high-purity argon gas is introduced as a protective gas and the oxygen partial pressure in the selective laser melting equipment is less than 50ppm; then, a 3D printing task is established, and the powder thickness is set to 30μm, the laser power is 200W, the scanning speed is 1200mm / s, the scanning interval is 60μm, and the scanning strategy is partitioned island scanning; finally, the powder laying system lays a layer of powder into the forming chamber, and the laser beam selectively melts and solidifies a layer of powder according to the slicing data of the three-dimensional model, and carbon-coated aluminum alloy composite material is obtained by layer-by-layer melting and solidification.

[0075] Example 5

[0076] This embodiment provides a carbon-coated titanium alloy composite material, the preparation steps of which are as follows:

[0077] (1) Take the original atomized spherical TC4 alloy powder and put it into a beaker. Add isopropanol to the beaker and sonicate for 30 minutes. Then filter it. The mass ratio of spherical TC4 alloy powder to isopropanol is 1:10. Place the filtered spherical TC4 alloy powder in a vacuum drying oven and set the vacuum drying temperature to 50°C. Bake for 3 hours to obtain dry and clean modified titanium alloy powder.

[0078] (2) Place graphene oxide in a beaker, mix graphene oxide with mixed acid (including concentrated sulfuric acid and concentrated nitric acid) at a volume ratio of 3:1, add potassium permanganate as an oxidant, and perform water bath at 50°C and ultrasonic oscillation at 30kHz for 3 hours. After the reaction is completed, the reactant is obtained. Then, the reactant is diluted with a large amount of deionized water and filtered until the pH of the filtrate is close to 7 to remove residual acid in the reactant. Finally, the reactant is vacuum dried at 60°C for 12 hours to obtain carboxylated graphene.

[0079] (3) The carboxylated graphene obtained in step (2) and the modified titanium alloy powder obtained in step (1) are placed in an acoustic resonance ball mill jar for acoustic resonance ball milling treatment, so that the carboxylated graphene is uniformly coated on the surface of the modified titanium alloy powder to form a carbon coating layer. Then, the carbon coating layer is reduced using a reducing agent (hydroiodic acid) to obtain carbon-coated titanium alloy powder. The grinding balls are zirconia balls with a diameter of 3 mm, the ball-to-material ratio is 2:1, the material filling ratio is 50%, the argon gas pressure in the jar is set to 3 MPa, the vibration frequency is 60 Hz, the amplitude is 10 mm, and the processing time is 15 minutes. The mass of the carboxylated carbon material used to coat the modified titanium alloy powder is 0.05% of the mass of the modified titanium alloy powder.

[0080] (4) First, using the SLM-150 selective laser melting equipment, the aluminum substrate is loaded into the forming chamber, and the carbon-coated titanium alloy powder obtained in step (3) above is loaded into the powder chamber; then, high-purity argon gas is introduced as a protective gas and the oxygen partial pressure in the selective laser melting equipment is less than 50ppm; then, a 3D printing task is established, and the powder thickness is set to 30μm, the laser power is 200W, the scanning speed is 1200mm / s, the scanning spacing is 100μm, and the scanning strategy is partitioned island scanning; finally, the powder laying system lays a layer of powder into the forming chamber, and the laser beam selectively melts and solidifies a layer of powder according to the slicing data of the three-dimensional model, and carbon-coated titanium alloy composite material is obtained by layer-by-layer melting and solidification.

[0081] Example 6

[0082] This embodiment provides a carbon-coated titanium alloy composite material, the preparation steps of which are as follows:

[0083] (1) Take the original atomized spherical TC4 alloy powder and put it into a beaker. Add isopropanol to the beaker and sonicate for 30 minutes. Then filter it. The mass ratio of spherical TC4 alloy powder to isopropanol is 1:10. Place the filtered spherical TC4 alloy powder in a vacuum drying oven and set the vacuum drying temperature to 50°C. Bake for 3 hours to obtain dry and clean modified titanium alloy powder.

[0084] (2) Place graphene oxide in a beaker, mix graphene oxide with mixed acid (including concentrated sulfuric acid and concentrated nitric acid) at a volume ratio of 3:1, add potassium permanganate as an oxidant, and perform water bath at 50°C and ultrasonic oscillation at 30kHz for 3 hours. After the reaction is completed, the reactant is obtained. Then, the reactant is diluted with a large amount of deionized water and filtered until the pH of the filtrate is close to 7 to remove residual acid in the reactant. Finally, the reactant is vacuum dried at 60°C for 12 hours to obtain carboxylated graphene.

[0085] (3) The carboxylated graphene obtained in step (2) and the modified titanium alloy powder obtained in step (1) are placed in an acoustic resonance ball mill jar for acoustic resonance ball milling to uniformly coat the surface of the modified titanium alloy powder with carboxylated graphene to form a carbon coating layer, thereby obtaining carbon-coated titanium alloy powder. The grinding balls are zirconia balls with a diameter of 3 mm, the ball-to-material ratio is 2:1, the material filling ratio is 50%, the argon gas pressure inside the jar is set to 3 MPa, the vibration frequency is 60 Hz, the amplitude is 10 mm, and the processing time is 15 minutes. The mass of the carboxylated carbon material used to coat the modified titanium alloy powder is 0.05% of the mass of the modified titanium alloy powder.

[0086] (4) First, using the SLM-150 selective laser melting equipment, the aluminum substrate is loaded into the forming chamber, and the carbon-coated titanium alloy powder obtained in step (3) above is loaded into the powder chamber; then, high-purity argon gas is introduced as a protective gas and the oxygen partial pressure in the selective laser melting equipment is less than 50ppm; then, a 3D printing task is established, and the powder thickness is set to 30μm, the laser power is 200W, the scanning speed is 1200mm / s, the scanning spacing is 100μm, and the scanning strategy is partitioned island scanning; finally, the powder laying system lays a layer of powder into the forming chamber, and the laser beam selectively melts and solidifies a layer of powder according to the slicing data of the three-dimensional model, and carbon-coated titanium alloy composite material is obtained by layer-by-layer melting and solidification.

[0087] The carbon-coated alloy composite materials prepared in Examples 1 to 6 were subjected to the following performance tests, and the test results are shown in Table 1.

[0088] Test metrics and test methods:

[0089] 1) Tensile Strength: The tensile strength of the SLM (Selective Laser Melting) shaped specimens was tested using an Instron 5980 electronic universal testing machine. First, before testing, the printed dumbbell-shaped SLM specimens were smoothed with 800# sandpaper. The specimen dimensions are as follows: Figure 1 As shown. The sample size was determined according to ISO 6892–1:2019 standard for tensile testing of metallic materials. To ensure the accuracy of the experimental measurement, a 5KN range sensor was selected, and the tensile rate was set to 0.5mm / min. After inputting the specified parameters in the Bluehill3 software, data points can be automatically collected and tensile curves can be generated. Based on the tensile curves, the software can automatically calculate the tensile strength of the SLM formed part. The tensile strength of the test sample can be calculated according to formula (1).

[0090]

[0091] In equation (1), σ bF represents the tensile strength of the tested sample, expressed in MPa. b S0 represents the maximum tensile stress, in N; S0 represents the cross-sectional area of ​​the test sample, in mm2. 2 .

[0092] 2) Elongation: Refer to the relevant test methods in GB / T228.1-2021 "Metallic materials - Tensile testing - Part 1: Test method at room temperature".

[0093] 3) Coating amount: The mass of carbon material used to coat the modified titanium alloy powder.

[0094] Table 1. Performance test results of carbon-coated alloy composite materials prepared in each embodiment.

[0095]

[0096]

[0097] Please refer to Table 1 above. The comparison results of Examples 1-4 show that when the coating amount of carboxylated carbon material (carboxylated carbon nanotubes) is 0.05%-0.1%, the tensile strength of the prepared carbon-coated alloy composite material can reach 1150-1280 MPa, and the elongation can reach 9.5%-12%. When the coating amount of carboxylated carbon material (carboxylated carbon nanotubes) continues to increase to 0.2%, the tensile strength and elongation of the prepared carbon-coated alloy composite material both decrease significantly. It is evident that the agglomeration problem of carboxylated carbon materials (such as carboxylated carbon nanotubes) during the coating of modified metal powder can be effectively solved by adopting the acoustic resonance ball milling process. When the mass of the carboxylated carbon material used to coat the modified metal powder is 0.05% to 0.2% of the mass of the modified metal powder, a uniform, dense carbon coating layer with controllable thickness can be formed on the surface of the modified metal powder. This can reduce the amount of carbon material required for coating the metal powder and reduce material costs.

[0098] The comparison results of Examples 1, 5-6 show that the carbon-coated alloy composite material prepared by coating modified metal powder with carboxylated carbon nanotubes and carboxylated graphene can achieve a tensile strength of over 1150 MPa and an elongation of over 9.8%.

[0099] Experiment 1: Investigating the effect of vibration frequency in acoustic resonance ball milling process on the coating effect of modified metal powder.

[0100] Based on Example 1 above, with other raw materials and process conditions kept unchanged, only the vibration frequencies in step (3) of Example 1 were changed to 40Hz, 50Hz, 60Hz, 70Hz, and 80Hz, respectively, and carbon-coated titanium alloy powders were prepared under the above conditions. The mass (i.e., coating amount) of carboxylated carbon material used to coat the modified titanium alloy powder in each test group was tested according to the above test method, and the test results are shown in Table 2.

[0101] Table 2. Coating amount of carboxylated carbon material used for coating modified titanium alloy powder

[0102]

[0103]

[0104] As shown in Table 2 above, as the vibration frequency gradually increases, the mass of the carboxylated carbon material used to coat the modified titanium alloy powder also gradually increases. Therefore, the mass (i.e., coating amount) of the carboxylated carbon material used to coat the modified titanium alloy powder can be flexibly controlled by adjusting the vibration frequency of the acoustic resonance ball milling process.

[0105] Experiment 2: Investigating the effect of processing time in acoustic resonance ball milling on the coating effect of modified metal powder.

[0106] Based on Example 1 above, with other raw materials and process conditions kept unchanged, only the processing time in step (3) of Example 1 was changed to 5 min, 10 min, 20 min, 30 min, and 40 min, respectively, and carbon-coated titanium alloy powder was prepared under the above conditions. The mass (i.e., coating amount) of carboxylated carbon material used to coat the modified titanium alloy powder in each test group was tested according to the above test method, and the test results are shown in Table 3.

[0107] Table 3. Coating amount of carboxylated carbon material used for coating modified titanium alloy powder

[0108]

[0109] As shown in Table 3, the coating amount of carboxylated carbon material used to coat modified titanium alloy powder increases with the increase of the treatment time of acoustic resonance ball milling. Therefore, the coating amount of carboxylated carbon material used to coat modified titanium alloy powder can be flexibly controlled by adjusting the treatment time of acoustic resonance ball milling.

[0110] Experiment 3: Investigating the effect of vacuum drying temperature on the surface modification of metal powders.

[0111] Based on Example 1 above, with other raw materials and process conditions kept unchanged, only the vacuum drying temperature in step (1) of Example 1 was changed to 30℃, 40℃, 50℃, 60℃, and 70℃, respectively, and modified titanium alloy powder was prepared under the above conditions. The oxygen content of the prepared modified titanium alloy powder was tested, and the test results are shown in Table 4.

[0112] Test method:

[0113] Start the ON-3000 oxygen and nitrogen analyzer from NACK & SCNOQU, enter the analysis software interface, input the sample name, and read the weighing data. Add the test sample to the sampler of the ON-3000 oxygen and nitrogen analyzer, along with a certain amount of flux to ensure complete combustion. Click the "Add Sample" button on the analysis software interface, and the instrument will automatically inject the sample. First, the test sample enters the degassing stage to remove adsorbed gases from the sample surface. Then, an oxidation reaction occurs in a pulse furnace at high temperature (>3000℃), generating gases such as CO2, N2, and H2. The gas signals and gas release curves are then captured by an infrared sensor to calculate the oxygen, nitrogen, and hydrogen contents. Finally, the software will automatically output the oxygen, nitrogen, and hydrogen contents.

[0114] Table 4 Oxygen content of modified titanium alloy powder

[0115]

[0116] Table 4 shows that the oxygen content of the modified titanium alloy powder increases slightly when the vacuum drying temperature is below 40℃. When the vacuum drying temperature is between 40℃ and 70℃, the oxygen content of the modified titanium alloy powder is between 800 ppm and 860 ppm. The lowest oxygen content, 800 ppm, is found when the vacuum drying temperature is 60℃. This indicates that the vacuum drying temperature has a significant impact on the oxygen content of the modified titanium alloy powder. Controlling the vacuum drying temperature within the range of 40℃ to 70℃ is beneficial for reducing the oxygen content on the surface of the metal powder.

[0117] Experiment 4: Investigating the effect of carboxylation process conditions on the degree of carboxylation of carbon materials.

[0118] Experiment ①: This experiment is basically the same as Example 1 above, except that: in step (2), commercial carbon nanotubes are placed in a beaker, and carbon nanotubes are mixed with concentrated sulfuric acid at a volume ratio of 3:1. Potassium permanganate is added as an oxidant, and the mixture is placed in a water bath at a temperature of 50°C and subjected to ultrasonic oscillation at a frequency of 30kHz for 3 hours. After the reaction is completed, the reactant is obtained. Then, a large amount of deionized water is used to dilute the reactant and filter it until the pH value of the filtrate is close to 7 to remove the residual acid in the reactant. Finally, the reactant is vacuum dried at a temperature of 60°C for 12 hours to obtain carboxylated carbon nanotubes.

[0119] Experiment ②: This experiment is basically the same as Example 1 above, except that: in step (2), commercial carbon nanotubes are placed in a beaker, and carbon nanotubes are mixed with concentrated nitric acid at a volume ratio of 3:1. Potassium permanganate is added as an oxidant, and the mixture is placed in a water bath at a temperature of 50°C and subjected to ultrasonic oscillation at a frequency of 30kHz for 3 hours. After the reaction is completed, the reactant is obtained. Then, a large amount of deionized water is used to dilute the reactant and filter it until the pH value of the filtrate is close to 7 to remove the residual acid in the reactant. Finally, the reactant is vacuum dried at a temperature of 60°C for 12 hours to obtain carboxylated carbon nanotubes.

[0120] Experiment ③: This experiment is basically the same as Example 1 above, except that: in step (2), commercial carbon nanotubes are placed in a beaker, and the carbon nanotubes are mixed with a mixed acid (including concentrated sulfuric acid and concentrated nitric acid) at a volume ratio of 1:3. Potassium permanganate is added as an oxidant. The mixture is placed in a water bath at a temperature of 50°C and subjected to ultrasonic oscillation at a frequency of 30kHz for 3 hours. After the reaction is completed, the reactants are obtained. Then, a large amount of deionized water is used to dilute the reactants and filter them until the pH value of the filtrate is close to 7 to remove the residual acid in the reactants. Finally, the reactants are vacuum dried at a temperature of 60°C for 12 hours to obtain carboxylated carbon nanotubes.

[0121] Experiment 4. This experiment is basically the same as Example 1 above, except that: in step (2), commercial carbon nanotubes are placed in a beaker and the carbon nanotubes are mixed with a mixed acid (including concentrated sulfuric acid and concentrated nitric acid) at a volume ratio of 3:1. The mixture is placed in a water bath at a temperature of 50°C and subjected to ultrasonic oscillation at a frequency of 30kHz for 3 hours. After the reaction is completed, the reactant is obtained. Then, a large amount of deionized water is used to dilute the reactant and filter it until the pH value of the filtrate is close to 7 to remove the residual acid in the reactant. Finally, the reactant is vacuum dried at a temperature of 60°C for 12 hours to obtain carboxylated carbon nanotubes.

[0122] The carboxylated carbon nanotubes prepared in experiments ① to ④ above were subjected to the following performance tests, and the test results are shown in Table 5.

[0123] Test method:

[0124] Degree of carboxylation: Using XPS testing, the proportion of oxygen in carboxyl groups is quantitatively calculated by analyzing the surface elemental composition and chemical state. The surface carboxyl group ratio is calculated by the peak area ratio (carboxyl oxygen / total oxygen).

[0125] Table 5 shows the degree of carboxylation of carboxylated carbon nanotubes obtained in experiments ① to ④.

[0126] Test sample Experiment ① Experiment ② Experiment ③ Experiment 4 Degree of carboxylation 10％ 15％ 30％ 12％

[0127] Table 5 shows that the degree of carboxylation of the carboxylated carbon nanotubes obtained in Experiment ① using concentrated sulfuric acid alone, Experiment ② using concentrated sulfuric acid alone, and Experiment ④ using a mixed acid of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 3:1, without the addition of an oxidant (potassium permanganate), were significantly lower than that obtained in Experiment ③ using a mixed acid of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 1:3, and with the addition of an oxidant (potassium permanganate). It is evident that the type and volume ratio of the mixed acid, as well as the addition of an oxidant, have a significant impact on the degree of carboxylation of carboxylated carbon nanotubes. In this application, the carboxylation process described in Experiment ③ is preferred for preparing carboxylated carbon nanotubes.

[0128] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. A method for preparing a carbon-coated metal composite material, characterized in that, include: Surface modification of metal powder is performed using organic solvents to obtain modified metal powder; Carboxylation of carbon materials yields carboxylated carbon materials. The modified metal powder and carboxylated carbon material are placed in an acoustic resonance ball mill container and subjected to acoustic resonance ball milling under an argon atmosphere to uniformly coat the surface of the modified metal powder with the carboxylated carbon material to form a carbon coating layer, thereby obtaining carbon-coated metal powder. The carbon-coated metal powder is used for 3D printing to obtain a carbon-coated metal composite material.

2. The method for preparing carbon-coated metal composite material according to claim 1, characterized in that, The organic solvent is isopropanol; the carbon material is carbon nanotubes or graphene oxide.

3. The method for preparing carbon-coated metal composite material according to claim 1, characterized in that, The metal powder is spherical titanium alloy powder or spherical aluminum alloy powder; the particle size of the metal powder is 15-53 μm.

4. The method for preparing carbon-coated metal composite material according to claim 1, characterized in that, The mass of the carboxylated carbon material used to coat the modified metal powder is 0.05% to 0.2% of the mass of the modified metal powder.

5. The method for preparing carbon-coated metal composite material according to claim 1, characterized in that, In the step of placing the modified metal powder and carboxylated carbon material into an acoustic resonance ball mill container and performing acoustic resonance ball milling under an argon atmosphere to obtain carbon-coated metal powder, the vibration frequency of the acoustic resonance ball milling is 50Hz to 70Hz, and the processing time is 10 to 30 minutes.

6. The method for preparing carbon-coated metal composite material according to claim 1, characterized in that, Surface modification of metal powder using organic solvents yields modified metal powder, including: Metal powder is placed in an organic solvent and sonicated, then filtered and vacuum dried to obtain modified metal powder. The sonication time is 10-60 min, and the vacuum drying temperature is 40-60℃ for 3-5 hours.

7. The method for preparing carbon-coated metal composite material according to claim 1, characterized in that, Carboxylation of carbon materials yields carboxylated carbon materials, including: Carbon materials are mixed with mixed acids and an oxidant is added. The mixture is then subjected to a water bath and ultrasonic vibration at a temperature of 50–80°C to obtain the reactants. After removing residual acid from the reactants, vacuum drying is performed to obtain carboxylated carbon material.

8. The method for preparing carbon-coated metal composite material according to claim 7, characterized in that, The volume ratio of the carbon material to the mixed acid is 3:1; the mixed acid includes concentrated sulfuric acid and concentrated nitric acid; the oxidant is potassium permanganate.

9. The method for preparing carbon-coated metal composite material according to claim 1, characterized in that, In the step of using the carbon-coated metal powder to 3D print and obtain a carbon-coated metal composite material, the 3D printing parameters are set as follows: laser power of 180-220W, scanning speed of 500-1200mm / s, scanning spacing of 60-100μm, layer thickness of 20-40μm, and scanning strategy of rotating 67° layer by layer.

10. A carbon-coated metal composite material, characterized in that, The carbon-coated metal composite material is prepared by the method for preparing carbon-coated metal composite materials according to any one of claims 1 to 9.

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