Method for preparing carbon nano tube aluminum alloy composite material through in-situ synthesis method

Abstract

The invention provides a method for preparing a carbon nanotube aluminum alloy composite material by an in-situ synthesis method, which comprises the following steps: S1, selection and pretreatment of an aluminum alloy carrier: selecting an aluminum alloy as the carrier, and pretreating the surface of the carrier; s2, loading a sodium-based catalyst; s3, carrying out zoned chemical vapor deposition in-situ growth; and S4, densification processing is conducted, specifically, densification processing is conducted on the carbon nano tube-aluminum alloy composite precursor, and the carbon nano tube-aluminum alloy composite material is obtained. The preparation method has the beneficial effects that the method is reasonable in process, and the prepared carbon nanotubes are uniform in dispersion, high in interface bonding strength and high in electrical conductivity and thermal conductivity; the growth density, length and tube diameter of the carbon nano tube can be effectively regulated and controlled, and the composite material can be customized as required.

Description

Technical Field

[0001] This invention relates to the field of metal composite material preparation technology, and more specifically, to a method for preparing carbon nanotube aluminum alloy composite materials by in-situ synthesis. Background Technology

[0002] Carbon nanomaterials refer to materials whose dispersed phase has at least one dimension smaller than 100 nm. Currently reported carbon nanomaterials include carbon nanofibers, graphene, and carbon nanospheres, while carbon nanotubes are recognized worldwide as the finest fibers. These materials, due to their excellent electrical conductivity and high mechanical properties, are considered ideal reinforcements for metal composites. However, traditional composite methods such as powder metallurgy and melt stirring suffer from global challenges, including carbon nanotube agglomeration, uneven dispersion, and weak interfacial bonding with the aluminum matrix, severely limiting their reinforcing effects.

[0003] In-situ synthesis, especially the growth of carbon nanotubes using the aluminum matrix itself as a catalyst support, can fundamentally solve the problems of dispersion and interfacial bonding. However, in current technologies, achieving uniform and efficient in-situ growth of carbon nanotubes directly on aluminum alloys still faces challenges, mainly due to: 1) the dense oxide film on the aluminum alloy surface hinders catalyst loading; 2) the difficulty in selecting and loading suitable catalysts; and 3) the matching problem between the carbon nanotube growth temperature and the thermal stability of the aluminum alloy.

[0004] To address the aforementioned technical problems, this invention discloses a method for preparing carbon nanotube aluminum alloy composite materials through in-situ synthesis. Summary of the Invention

[0005] The purpose of this invention is to address at least one of the aforementioned shortcomings of the prior art. For example, one objective of this invention is to provide a method for preparing carbon nanotube aluminum alloy composite materials through in-situ synthesis. This method is a reasonable process with uniform carbon nanotube dispersion and high interfacial bonding strength. The method involves pretreating the aluminum alloy support, loading a suitable sodium-based catalyst, and achieving low-temperature growth in a zoned temperature-controlled chemical vapor deposition system to ultimately obtain a carbon nanotube aluminum alloy composite material with excellent comprehensive performance.

[0006] To achieve the above objectives, the present invention provides a method for preparing carbon nanotube aluminum alloy composite materials by in-situ synthesis, comprising the following steps: S1. Selection and Pretreatment of Aluminum Alloy Carrier Aluminum alloy was selected as the carrier, and the surface of the carrier was pretreated. S2, Supported sodium-based catalyst The sodium-based catalyst precursor was uniformly loaded onto the surface of the pretreated support. The loaded carrier is dried at 80-120 degrees Celsius for 6-12 hours, and then calcined at 300-500 degrees Celsius for 1-2 hours in an inert atmosphere. S3, in-situ growth via zoned chemical vapor deposition Using a dual-temperature zone tube furnace, an aluminum alloy support loaded with a sodium-based catalyst is placed in a low-temperature growth zone. Under argon protection, the low-temperature growth zone is heated to the target growth temperature, and hydrogen is introduced and held for 20-60 minutes. The high-temperature zone is heated to 700-850℃, and then the carbon source gas and the carrier gas are introduced into a dual-temperature zone tube furnace. The carbon source gas is decomposed into active carbon species in the high-temperature zone, and then transported to the low-temperature zone by the carrier gas. Carbon nanotubes are precipitated and grown on the catalyst particles for 30-120 minutes to obtain carbon nanotube-aluminum alloy composite precursor. S4, Densification Processing The carbon nanotube-aluminum alloy composite precursor was densified to obtain a carbon nanotube-aluminum alloy composite material.

[0007] In a preferred embodiment of this solution, in step S3, the target growth temperature is 450-600℃; and / or in step S3, the hydrogen flow rate is 50-200 sccm; and / or in step S3, the carbon source gas is methane or acetylene; and / or in step S3, the carbon source gas flow rate is 20-100 sccm.

[0008] In a preferred embodiment of this solution, in step S1, the aluminum alloy carrier is spherical or sheet-like aluminum alloy powder.

[0009] In a preferred embodiment of this solution, the pretreatment in step S1 specifically involves immersing the carrier in a 5-10% NaOH solution or dilute hydrochloric acid for 30-60 seconds to remove the inherent dense alumina film on the surface, followed by repeated washing with deionized water and anhydrous ethanol, and then rapid drying.

[0010] In a preferred embodiment of this scheme, step S2, which involves uniformly loading the sodium-based catalyst precursor onto the surface of the pretreated support, specifically involves mixing the pretreated support with solid sodium bisulfate monohydrate and stirring in an oil bath at 60-150 degrees Celsius to uniformly disperse the sodium salt on the surface of the support.

[0011] In a preferred embodiment of this solution, step S4 specifically involves: densifying the carbon nanotube-aluminum alloy composite precursor using spark plasma sintering, hot pressing sintering, or hot extrusion processes to obtain the carbon nanotube-aluminum alloy composite material.

[0012] In a preferred embodiment of this solution, step S4 specifically involves: loading the carbon nanotube-aluminum alloy composite precursor into a graphite carrier and hot-pressing it for 10-30 minutes at 500-580°C and 30-50MPa under vacuum or argon atmosphere protection.

[0013] In a preferred embodiment of this solution, in step S1, the aluminum alloy carrier is an aluminum alloy foil; and / or the pretreatment specifically involves: using low-speed dry or wet ball milling for 1-2 hours; and using mechanical force to break the oxide film to enhance surface roughness and active sites.

[0014] In a preferred embodiment of this solution, step S2, specifically loading the sodium-based catalyst precursor uniformly onto the surface of the pretreated support, involves immersing the pretreated support in a catalyst precursor solution and ultrasonically assisted impregnating it at room temperature for 2-4 hours. This ensures that the catalyst precursor is fully impregnated, permeated, and adsorbed.

[0015] In a preferred embodiment of this solution, step S4 specifically involves: using the carbon nanotube-aluminum alloy composite precursor directly as the carbon nanotube-aluminum alloy composite material, or densifying the carbon nanotube-aluminum alloy composite precursor by hot pressing and lamination to obtain the carbon nanotube-aluminum alloy composite material.

[0016] Compared with the prior art, the beneficial effects of the present invention include: (1) This scheme provides an in-situ synthesis method for preparing carbon nanotube aluminum alloy composite materials. The carrier and the matrix are unified. The aluminum alloy is directly used as the catalyst carrier. After the growth is completed, there is no need to separate them. The carrier is the matrix of the composite material. The process is simple. (2) This scheme innovates the catalyst by using a sodium-based catalyst, which avoids the residual pollution of traditional excessive metal catalysts. Furthermore, sodium is easy to remove in subsequent processing or can form beneficial compounds with aluminum, thus achieving low-temperature catalytic growth. (3) This scheme grows carbon nanotubes in different temperature zones, with the carbon source gas being pyrolyzed in the high-temperature zone and the carbon nanotubes being grown in the low-temperature zone; this scheme for growing carbon nanotubes in different temperature zones has the following advantages: A. Dispersion and interface improvement: In-situ growth fundamentally ensures the three-dimensional uniform distribution of carbon nanotubes in the aluminum matrix, and its "root-like" growth mode creates extremely strong interfacial bonding force and extremely high stress transfer efficiency. B. Tunable structure: By changing the catalyst concentration, CVD parameters such as temperature, time, and carbon source, the density, length, and diameter of the grown carbon nanotubes can be effectively controlled, enabling customized performance of composite processing. C. Superior performance: Compared with traditional methods, the composite material prepared by this method has higher strength, electrical conductivity and thermal conductivity at the same carbon nanotube content. Attached Figure Description

[0017] The above and other objects and / or features of the present invention will become clearer from the following description taken in conjunction with the accompanying drawings, in which: Figure 1 The accompanying images show comparative electron microscope (EM) images of Example 1 of the present invention; in the images, a and b are EEM images of 6061 aluminum powder; c and d are EEM images of 6061 after loading with a sodium-based catalyst; e and f are EEM scans of the carbon nanotube aluminum alloy powder composite material prepared.

[0018] Figure 2 Comparative electron microscope (EM) images of Example 2 of the present invention are shown; in the figures, a and b are EM images of 1060 aluminum foil; c and d are EM images of 1060 aluminum foil loaded with sodium-based catalyst; e and f are EM scan images of the prepared carbon nanotube aluminum alloy composite foil material. Detailed Implementation

[0019] The method of the present invention will be further described in detail below with reference to exemplary embodiments.

[0020] Example 1 refer to Figure 1 As shown, this embodiment uses 6061 as a carrier to provide a method for preparing carbon nanotube aluminum alloy composite materials by in-situ synthesis, including the following steps: S1. Selection and Pretreatment of Aluminum Alloy Carrier 6061 aluminum alloy was selected as the carrier. The carrier was immersed in 8% NaOH solution or dilute hydrochloric acid for 40 seconds to remove the inherent dense alumina film on the surface. Then it was washed repeatedly with deionized water and anhydrous ethanol and dried quickly. S2, Supported sodium-based catalyst The carrier pretreated in step S1 is mixed with solid sodium bisulfate monohydrate and stirred in an oil bath at 100 degrees Celsius to make the sodium salt (Na2CO3) uniformly dispersed on the surface of the carrier. The loaded support was dried at 80-120 degrees Celsius for 9 hours, and then calcined at 400 degrees Celsius for 1.5 hours in an inert atmosphere to decompose the sodium salt and react with the aluminum surface to form catalytically active nano-sized sodium chlorate or other sodium-aluminum-oxide active sites. S3, in-situ growth via zoned chemical vapor deposition Using a dual-temperature zone tube furnace, an aluminum alloy support loaded with sodium-based catalyst was placed in the low-temperature growth zone. Under argon protection, the low-temperature growth zone was heated to the target growth temperature (550°C), and hydrogen gas (flow rate of 100 sccm) was introduced and kept at that temperature for 30 minutes to further activate the catalyst. The high-temperature zone is heated to 750°C. Then, the carbon source gas (acetylene, flow rate of 60 sccm) and the carrier gas are introduced into a dual-temperature zone tube furnace. The carbon source gas is decomposed into active carbon species in the high-temperature zone and then transported to the low-temperature zone by the carrier gas. Carbon nanotubes are precipitated and grown on the catalyst particles for 60 min to obtain a carbon nanotube-aluminum alloy composite precursor. S4, Densification Processing The carbon nanotube-aluminum alloy composite precursor was loaded into a graphite carrier and hot-pressed at 540°C and 40MPa for 20 minutes under vacuum or argon atmosphere protection to obtain the carbon nanotube-aluminum alloy composite material.

[0021] In this embodiment, a Na2CO3 catalyst was loaded, and acetylene was introduced for 60 minutes at a second temperature zone of 550 degrees and a first temperature zone of 750 degrees. The resulting composite powder (carbon nanotube aluminum alloy composite material) was subjected to 560 degrees / 40MPa, which was more than 50% higher than that of the base aluminum alloy.

[0022] Example 2 refer to Figure 2 As shown, this embodiment uses 1060 aluminum foil as a carrier to provide a method for in-situ synthesis of carbon nanotube aluminum alloy composite materials, including the following steps: A method for preparing carbon nanotube aluminum alloy composite materials by in-situ synthesis includes the following steps: S1. Selection and Pretreatment of Aluminum Alloy Carrier 1060 aluminum foil was selected as the carrier, and the oxide film was broken up by mechanical force to enhance the surface roughness and active sites by using a low-speed dry or wet ball mill for 1.5 hours. S2, Supported sodium-based catalyst The pretreated support was immersed in a sodium-based catalyst precursor solution and ultrasonically impregnated for 2-4 hours at room temperature to ensure that the catalyst precursor was fully impregnated and adsorbed with Na2CO3. The loaded support was dried at 100 degrees Celsius for 8 hours, and then calcined at 450 degrees Celsius for 1.5 hours in an inert atmosphere to decompose the sodium salt and react with the aluminum surface to form catalytically active nano-sized sodium chlorate or other sodium-aluminum-oxide active sites.

[0023] S3, in-situ growth via zoned chemical vapor deposition Using a dual-temperature zone tube furnace, an aluminum alloy support loaded with a sodium-based catalyst was placed in a low-temperature growth zone. Under argon protection, the low-temperature growth zone was heated to the target growth temperature (550°C), and hydrogen gas (flow rate of 120 sccm) was introduced and held at that temperature for 30 minutes to further activate the catalyst. The high-temperature zone was heated to 750°C. Then, carbon source gas (acetylene, flow rate 850 sccm) and carrier gas were introduced into a dual-temperature zone tube furnace. The carbon source gas was decomposed into active carbon species in the high-temperature zone and then transported to the low-temperature zone by the carrier gas. Carbon nanotubes were precipitated and grown on the catalyst particles for 60 min to obtain carbon nanotube-aluminum alloy composite precursor. S4, Densification Processing The carbon nanotube-aluminum alloy composite precursor was densified by hot pressing and lamination to obtain the carbon nanotube-aluminum alloy composite material.

[0024] In this embodiment, 1060 aluminum foil is used as a carrier to support Na2CO3 catalyst. Acetylene is introduced for 60 minutes in the second temperature zone (550 degrees Celsius) and the first temperature zone (750 degrees Celsius) to grow the composite foil (carbon nanotube aluminum alloy composite material) with a uniform carbon nanotube forest on the surface. This material shows application potential in the fields of flexible conductors and sensors.

[0025] Although the present invention has been described above in conjunction with exemplary embodiments and accompanying drawings, those skilled in the art should understand that various modifications can be made to the above embodiments without departing from the spirit and scope of the claims.

Claims

1. A method for preparing carbon nanotube aluminum alloy composite materials by in-situ synthesis, characterized in that, Includes the following steps: S1. Selection and Pretreatment of Aluminum Alloy Carrier Aluminum alloy was selected as the carrier, and the surface of the carrier was pretreated. S2, Supported sodium-based catalyst The sodium-based catalyst precursor was uniformly loaded onto the surface of the pretreated support. The loaded carrier was dried at 80-120 degrees Celsius for 6-12 hours, and then calcined at 300-500 degrees Celsius for 1-2 hours in an inert atmosphere. S3, in-situ growth via zoned chemical vapor deposition Using a dual-temperature zone tube furnace, an aluminum alloy support loaded with a sodium-based catalyst is placed in a low-temperature growth zone. Under argon protection, the low-temperature growth zone is heated to the target growth temperature, and hydrogen is introduced and held for 20-60 minutes. The high-temperature zone is heated to 700-850℃, and then the carbon source gas and the carrier gas are introduced into a dual-temperature zone tube furnace. The carbon source gas is decomposed into active carbon species in the high-temperature zone, and then transported to the low-temperature zone by the carrier gas. Carbon nanotubes are precipitated and grown on the catalyst particles for 30-120 minutes to obtain carbon nanotube-aluminum alloy composite precursor. S4, Densification Processing The carbon nanotube-aluminum alloy composite precursor was densified to obtain a carbon nanotube-aluminum alloy composite material.

2. The method according to claim 1, characterized in that, In step S3, the target growth temperature is 450-600℃; and / or In step S3, the flow rate of the hydrogen gas is 50-200 sccm; and / or In step S3, the carbon source gas is methane or acetylene; and / or The flow rate of the carbon source gas is 20-100 sccm.

3. The method according to claim 1, characterized in that, In step S1, the aluminum alloy carrier is spherical or sheet-like aluminum alloy powder.

4. The method according to claim 3, characterized in that, In step S1, the preprocessing specifically includes: The carrier is immersed in 5-10% NaOH solution or dilute hydrochloric acid for 30-60 seconds to remove the inherent dense alumina film on the surface. It is then washed repeatedly with deionized water and anhydrous ethanol and dried quickly.

5. The method according to claim 3, characterized in that, In step S2, the process of uniformly loading the sodium-based catalyst precursor onto the surface of the pretreated support specifically involves: The pretreated carrier is mixed with solid sodium bisulfate monohydrate and stirred in an oil bath at 60-150 degrees Celsius to ensure that the sodium salt is evenly dispersed on the surface of the carrier.

6. The method according to claim 3, characterized in that, Step S4 specifically involves densifying the carbon nanotube-aluminum alloy composite precursor using spark plasma sintering, hot pressing sintering, or hot extrusion processes to obtain the carbon nanotube-aluminum alloy composite material.

7. The method according to claim 3, characterized in that, Step S4 specifically involves: The carbon nanotube-aluminum alloy composite precursor is loaded into a graphite carrier and hot-pressed for 10-30 minutes at 500-580℃ and 30-50MPa under vacuum or argon atmosphere protection.

8. The method according to claim 1, characterized in that, In step S1, the aluminum alloy carrier is an aluminum alloy foil; and / or The pretreatment specifically involves: low-speed dry or wet ball milling for 1-2 hours.

9. The method according to claim 1, characterized in that, In step S2, the process of uniformly loading the sodium-based catalyst precursor onto the surface of the pretreated support specifically involves immersing the pretreated support in a catalyst precursor solution and ultrasonically assisted impregnating it for 2-4 hours at room temperature.

10. The method according to claim 1, characterized in that, Specifically, step S4 involves: using the carbon nanotube-aluminum alloy composite precursor directly as the carbon nanotube-aluminum alloy composite material, or densifying the carbon nanotube-aluminum alloy composite precursor through hot pressing lamination to obtain the carbon nanotube-aluminum alloy composite material.

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