Preparation method and application of nano-carbon material and metal-based composite powder

Abstract

The present invention belongs to the field of metal materials and processing technology, and particularly relates to a method for preparing a nano-carbon material and a metal-based composite powder and its application. The preparation method comprises the following process steps: nano-carbon material dispersion, gas-solid mixing, metal material melting, composite powder aerosol preparation, powder collection, etc. The process can prepare nano-carbon material and metal-based composite powder without significantly increasing the cost. The preparation method of the present invention can be scaled up and mass-produced, and has good application and promotion prospects.

Description

Technical Field

[0001] The present invention belongs to the field of metal materials and processing technology, and in particular relates to a method for preparing nano-carbon materials and metal-based composite powders, which can be used to prepare high-performance metal materials for aerospace, transportation, construction, electronics, etc. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention, and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] Nanocarbon materials refer to carbon materials with at least one dimension of the dispersed phase smaller than 100nm, including fullerene, carbon nanotubes, graphene, etc. Nanocarbon materials have superb mechanical properties (tensile strength of carbon nanotubes can reach 50-200GPa, elastic modulus exceeds 1TPa) and excellent electrical and thermal conductivity, and are excellent reinforcements for metal-based composite materials.

[0004] The difficulties in preparing nano-carbon material-metal matrix composites can be attributed to: the uniform dispersion of nano-carbon materials and the interface bonding problem between nano-carbon materials and metals. Since nano-carbon materials have a large specific surface area and high surface energy, they are very easy to agglomerate, so it is difficult to disperse them uniformly in the metal matrix. In addition, the lattices of carbon nanomaterials and metal matrices are quite different, and it is difficult for the two to form an effective interface bonding. Therefore, the performance of nano-carbon material-metal matrix composites is still far from the theoretical value.

[0005] Depending on the source of the reinforcement phase, the preparation methods of metal matrix composites can be divided into: in-situ synthesis method and external addition method.

[0006] In-situ synthesis is a method of generating a reinforcing phase in situ in a matrix through a chemical reaction. The reinforcing phase has a small size, stable thermodynamic properties, and high interface bonding strength. However, there are few in-situ synthesis systems, the reaction is difficult to control, and the application field is limited.

[0007] The addition method is a method of adding a prefabricated reinforcing phase to a molten or powdered matrix to improve performance. It is widely used in the preparation of bulk materials. Common processes include powder metallurgy, pressure infiltration, rheological casting, and stirring casting, among which the casting method has obvious cost advantages. Conventional nanocarbon material-metal matrix composite material casting is to add the nanocarbon material directly to the metal melt, stir and evenly disperse it to form a metal matrix composite melt, and then pour it into an ingot or casting. The density of nanocarbon material is about 1.2-1.6 g / cm 3, which is lighter than conventional metal structural materials. Directly adding and stirring it will easily cause it to segregate on the surface of the molten metal. One solution is to first prepare a high-content nano-carbon material-metal composite bulk material by mechanical ball milling / powder metallurgy, then add it to the molten metal in the form of a refiner, stir and pour to obtain a nano-carbon material-metal matrix composite ingot. This method requires multiple process steps such as atomization powder making, nano-carbon material dispersion, powder mixing, ball milling, powder metallurgy, hot compression, sintering, etc., and the cost is relatively high. Summary of the invention

[0008] In view of the problems of complex preparation process, high cost and poor stability of existing nano-carbon materials and metal-based composite materials, the present invention discloses a method for preparing a nano-carbon material and a metal-based composite powder material and its application. The powder preparation method avoids the complicated preparation process flow and obtains a nano-carbon material-metal-based composite material powder with uniform mixing and good interface bonding strength. The powder can be used in processes such as powder metallurgy, casting, and 3D printing of metal materials to improve the mechanical properties of the material.

[0009] In order to achieve the above object, the present invention adopts the following technical solution:

[0010] The first aspect of the present invention provides a method for preparing a nano-carbon material and a metal-based composite powder, comprising:

[0011] dispersing the nano-carbon material to obtain dispersed nano-carbon material;

[0012] Mixing the dispersed nano-carbon material with an inert gas to obtain a gas-nano-carbon material mixture;

[0013] The gas-nano carbon material mixture is used as cooling gas to powder the molten metal by aerosol method, and the powder is collected to obtain the product.

[0014] In view of the potential excellent performance and good application prospects of nano-carbon material-metal matrix composite materials, the present invention provides a low-cost design and manufacturing technology for the material, which is of great significance.

[0015] The design idea of ​​the present invention is to prepare nano-carbon material and metal-based composite powder through processes such as "dispersion", "mixing with gas to form a gas-solid mixture", "aerosol powder making", and "powder collection" of "nano-carbon material". Among them, "preparing a gas-solid mixture of nano-carbon material" is a key step. The nano-carbon material is fully dispersed by a suitable dispersion method, ensuring the generation of a fluidized gas-solid mixture of nano-carbon material in the subsequent preparation process, thereby promoting the cooling of the molten metal powder at a higher pressure and flow rate during the aerosol powder making process, and obtaining the preparation of nano-carbon material and metal-based composite powder with a core-shell structure or a core-shell / mosaic structure.

[0016] The second aspect of the present invention provides nano-carbon material and metal-based composite powder prepared by the above method.

[0017] The third aspect of the present invention provides the application of the above-mentioned nano-carbon material and metal-based composite powder in metallurgy and 3D printing.

[0018] Beneficial Effects of the Invention

[0019] (1) The nanocarbon material-metal matrix composite material prepared by the present invention can be evenly and dispersedly distributed in the metal matrix. Since the nanocarbon material is very easy to agglomerate and does not wet with metals, it is difficult to disperse it into the metal matrix, and the ball milling method is easy to destroy the structure of the nanocarbon material and affect the enhancement effect. The present invention cools the molten metal droplets by fluidizing the gas-solid mixture. During the rapid cooling process, the metal is very easy to wrap the nanocarbon material, thereby achieving good interface bonding strength, while not affecting the structural integrity of the nanocarbon material.

[0020] (2) The present invention combines nano-carbon material dispersion technology with aerosol powder preparation to achieve a short process and rapid preparation of nano-carbon material and metal-based composite powder. Traditionally, metal-based composite powders require steps such as preparation of metal powders and ball milling. On the one hand, the process is long, and on the other hand, one-dimensional and two-dimensional nano-carbon materials are prone to entanglement or breakage during the ball milling process, which changes the performance of the nano-carbon material and further affects its various properties.

[0021] (3) Compared with the water mist method, the aerosol method of the present invention has a clean interface between the nano-carbon material and the metal-based composite powder and no reaction products, so the powder quality is better.

[0022] In summary, the present invention mixes dispersed nano-carbon materials with gas (nitrogen or argon, etc.) to obtain a fluidized gas-solid mixture, and then powders the mixture through an aerosol method to obtain nano-carbon materials and metal-based composite powders. This method replaces the gas in the traditional method with a gas-solid mixture, and only requires adding a gas-solid mixing device to the front end of the existing aerosol powder making equipment to prepare nano-carbon materials and metal-based composite powders without significantly increasing costs. This process can be scaled up and mass-produced, and has good application and promotion prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0024] Figure 1 This is a flow chart for the preparation of nano-carbon materials and metal-based composite powders.

[0025] Figure 2 Schematic diagram of nanocarbon material and metal-based composite powder. DETAILED DESCRIPTION

[0026] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0027] A method for preparing a nano-carbon material and a metal-based composite powder material, the preparation method comprising the following process steps: nano-carbon material dispersion, gas-solid mixing, metal material melting, composite powder aerosol preparation, powder collection and the like.

[0028] The nano-carbon material is dispersed by subjecting the nano-carbon material to dispersion by mechanical stirring, ultrasonic treatment, electric field induction or surface modification.

[0029] The nano-carbon materials include zero-dimensional / one-dimensional / two-dimensional nano-carbon materials such as fullerene, carbon nanotube, and graphene.

[0030] The gas-solid mixing refers to mixing the dispersed nano-carbon material with nitrogen or argon to form a gas-nano-carbon material mixture.

[0031] The melting of the metal material refers to melting the metal in a vacuum induction heating furnace at a temperature of 50 to 300° C. above the melting point of the metal.

[0032] The metal includes metal materials such as Al, Zn, Mg, Cu, Fe, Ni, and Co.

[0033] The composite powder aerosol method refers to using a gas-solid mixture instead of conventional cooling gas to prepare nano-carbon material and metal-based composite powder by aerosol method. The concentration of the gas-solid mixture of nano-carbon material is: 1-100 mg / mm 3 ; Atomization pressure: 0.2~5.0MPa.

[0034] The powder collection refers to collecting the prepared nano-carbon material and metal-based composite powder by screening method and / or solvent method.

[0035] The invention provides a method for preparing composite powder of a nano-carbon material and a metal with a core-shell structure or a core-shell / inlaid structure.

[0036] The nano-carbon material and metal-based composite powder of the present invention can be used as a raw material for powder metallurgy and 3D printing, and can also be used as a refiner in the metal melting and casting process to improve the mechanical properties of the material.

[0037] The present invention will be further described in detail below in conjunction with specific embodiments. It should be noted that the specific embodiments are intended to explain the present invention rather than to limit it.

[0038] In the following examples, the power of ultrasound is 50 W and the frequency is 40 kHz.

[0039] The dispersed nanocarbon material and gas were mixed using a gas-solid mixing injector purchased from Shanghai Litang Environmental Protection Technology Co., Ltd.

[0040] Example 1

[0041] A method for preparing a carbon nanotube and aluminum composite powder material, the preparation process includes: dispersing carbon nanotubes, mixing carbon nanotubes with argon, melting metal aluminum, preparing composite powder by aerosol method, collecting powder and the like.

[0042] (1) Using ethanol as solvent, carbon nanotubes are dispersed by ultrasonic treatment; then, dispersed carbon nanotubes are obtained by vacuum heating and drying. The weight ratio of carbon nanotubes to ethanol is 1 / 100; the ultrasonic treatment time is 4 hours; and the vacuum heating and drying process is 60°C and 24 hours.

[0043] (2) Mix the dispersed carbon nanotubes with argon gas to form an argon-carbon nanotube mixture. The concentration of the gas-solid mixture of carbon nanotubes is about 10 mg / mm 3 .

[0044] (3) Pure aluminum was melted by vacuum induction heating at a temperature of 800°C. Carbon nanotube and aluminum composite powder was prepared by atomization. Argon-carbon nanotube gas-solid mixture was used instead of conventional cooling gas, and the atomization pressure was 0.7 MPa.

[0045] (4) Using ethanol as solvent, collecting the carbon nanotube and aluminum composite powder by precipitation and sieving. The separated carbon nanotube-ethanol mixture can be reused in step (1).

[0046] Example 2

[0047] A method for preparing a fullerene and zinc composite powder material, the preparation process comprising the steps of: fullerene dispersion, fullerene and nitrogen mixing, metal zinc melting, aerosol method preparation of composite powder, powder collection and the like.

[0048] (1) Using ethanol as solvent, fullerene is dispersed by ultrasonic treatment; then, dispersed carbon nanotubes are obtained by vacuum heating and drying. The weight ratio of fullerene / ethanol is 1 / 100; the ultrasonic treatment time is 2 hours; and the vacuum heating and drying process is 70°C and 24 hours.

[0049] (2) Mix the dispersed fullerene with nitrogen or the like to form a nitrogen-fullerene mixture. The concentration of the fullerene gas-solid mixture is about 5 mg / mm3 .

[0050] (3) Pure zinc was melted by vacuum induction heating at a temperature of 650°C. Fullerene and zinc composite powder was prepared by atomization. A nitrogen-fullerene gas-solid mixture was used instead of the conventional cooling gas, and the atomization pressure was 0.8 MPa.

[0051] (4) Using ethanol as solvent, collecting the fullerene and zinc composite powder by precipitation and sieving. The separated fullerene-ethanol mixture can be reused in step (1).

[0052] Comparative Example 1

[0053] A method for preparing a carbon nanotube and aluminum composite powder material, the preparation process comprising the steps of carbon nanotube dispersion, carbon nanotube-aluminum powder ball milling and the like.

[0054] The difference from Example 1 is that the composite powder is prepared by ball milling carbon nanotubes and gas atomized aluminum powder. The ball-to-material ratio is 5:1; the ball mill speed is 150 r / min; and the ball milling time is 10 h.

[0055] Comparative Example 2

[0056] A method for preparing a fullerene and zinc composite powder material, the preparation process comprising the steps of: fullerene dispersion, fullerene-ethanol solution mixing, metal zinc melting, preparing composite powder by water mist method, powder collection and the like.

[0057] The difference from Example 2 is that the composite powder is prepared by a water mist method.

[0058] The mechanical properties of 6061 aluminum alloy extruded bars prepared by using the composite powders prepared in Examples 1 and 2 and Comparative Examples 1 and 2 as aluminum alloy refiners are shown in Table 1. The mechanical property test method is performed in accordance with GB T 228.1-2010.

[0059] Table 1 Mechanical properties of 6061 aluminum alloy extruded bars prepared with different refiners

[0060]

[0061]

[0062] From the effects of the powders of the embodiments and comparative examples as aluminum alloy refiners in Table 1, it can be seen that the powder prepared by the present invention can significantly improve the mechanical properties of the material. This is because the nano-carbon material prepared by the present invention has good bonding strength with the metal cross section and no obvious agglomeration occurs. However, during the preparation of the composite powder in the comparative example, problems occurred in the dispersibility, structure or interface bonding of the nano-carbon material, resulting in no obvious performance improvement when it was added as a refiner to the 6061 aluminum alloy.

[0063] In summary, the present invention provides a method for preparing nano-carbon material and metal-based composite powder. The process can be scaled up and mass-produced, and has good application and promotion prospects.

[0064] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a nano-carbon material and a metal-based composite powder, characterized in that: include: dispersing the nano-carbon material to obtain dispersed nano-carbon material; Mixing the dispersed nano-carbon material with an inert gas to obtain a gas-nano-carbon material mixture; The gas-nano carbon material mixture is used as cooling gas to powderize the molten metal by aerosol method, and the powder is collected to obtain; The dispersion method is to use ethanol as a solvent and disperse by ultrasonic treatment; then, obtain the dispersed nano-carbon material by vacuum heating and drying; The power of ultrasound was 50W and the frequency was 40kHz; The nanocarbon material is at least one of fullerene, carbon nanotube and graphene; Atomization pressure is 0.7 or 0.8 MPa; The method of collecting the powder is screening and / or solvent collection; The concentration of the gas-solid mixture of the nanocarbon material is 1-100 mg / mm 3 .

2. The method for preparing the nano-carbon material and metal-based composite powder according to claim 1, characterized in that: When the molten metal melts the metal material, its melting temperature is 50 to 300° C. above the melting point of the metal.

3. The method for preparing the nano-carbon material and metal-based composite powder according to claim 2, characterized in that: The metal is at least one of Al, Zn, Mg, Cu, Fe, Ni and Co.

4. A nano-carbon material and metal-based composite powder prepared by the method according to any one of claims 1 to 3.

5. Application of the nano-carbon material and metal-based composite powder according to claim 4 in metallurgy and 3D printing.

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