阅读说明：本技术 一种石墨烯增强铜基复合材料的制备方法 (Preparation method of graphene reinforced copper-based composite material ) 是由 战再吉 曹海要 王振春 田锭坤 张丹丹 于 2019-09-11 设计创作，主要内容包括：本发明公开了一种石墨烯增强铜基复合材料的制备方法,包括以下步骤：制备片状铜粉、石墨烯镀镍处理得到镀镍石墨烯；所述片状铜粉与镀镍石墨烯混合进行球磨处理得到混合粉末、在磁场下对所述混合粉末进行逆流旋转取向处理得到复合粉末压坯；所述复合粉末压坯烧结得到石墨烯增强铜基复合材料。本发明采用预先制备片状铜粉,同时对石墨烯进行镀镍处理,增加石墨烯的顺磁性；将片状铜粉和镀镍石墨烯混合粉末在磁场逆流旋转取向处理,热压烧结后制备出石墨烯定向增强铜基复合材料,提高了材料的力学及物理性能。(the invention discloses a preparation method of a graphene reinforced copper-based composite material, which comprises the following steps: preparing flake copper powder, and carrying out nickel plating treatment on graphene to obtain nickel-plated graphene; mixing the flaky copper powder and nickel-plated graphene, performing ball milling treatment to obtain mixed powder, and performing countercurrent rotation orientation treatment on the mixed powder under a magnetic field to obtain a composite powder compact; and sintering the composite powder pressed compact to obtain the graphene reinforced copper-based composite material. According to the method, flaky copper powder is prepared in advance, and meanwhile nickel plating treatment is carried out on graphene, so that paramagnetism of the graphene is increased; the sheet copper powder and nickel-plated graphene mixed powder is subjected to magnetic field countercurrent rotation orientation treatment, and the graphene oriented reinforced copper-based composite material is prepared after hot-pressing sintering, so that the mechanical and physical properties of the material are improved.)

1. the preparation method of the graphene reinforced copper-based composite material is characterized by comprising the following steps of:

Preparing flake copper powder;

Carrying out nickel plating treatment on the graphene to obtain nickel-plated graphene;

Performing ball milling treatment on the flaky copper powder and the nickel-plated graphene to obtain mixed powder;

Performing countercurrent rotation orientation treatment on the mixed powder under a magnetic field to obtain a composite powder compact;

and sintering the composite powder pressed compact to obtain the graphene directional reinforced copper-based composite material.

2. The preparation method of the graphene reinforced copper-based composite material according to claim 1, wherein the step of preparing the flake copper powder comprises the following steps:

Ball milling the copper powder to obtain sheet copper powder;

Drying and reducing the flaky copper powder to obtain reduced flaky powder;

and screening the particle size of the reduced flaky powder.

3. the preparation method of the graphene reinforced copper-based composite material according to claim 2, wherein the copper powder ball milling step comprises: putting the atomized spherical copper powder with the particle size of 45-109 mu m into a ball milling tank, and adding absolute ethyl alcohol as a process control agent for ball milling;

The ball-to-material ratio in the ball milling process is 10: 1, the ball milling speed is 250rpm, and the ball milling time is 10 h.

4. The preparation method of the graphene reinforced copper-based composite material according to claim 2, wherein the drying and reducing steps are as follows: carrying out vacuum drying on the flake copper powder obtained after ball milling at 60 ℃ for 12 h;

reducing the dried flake copper powder in a tubular reduction furnace by using hydrogen;

The reduction temperature is 400 ℃, and the reduction time is 3 h.

5. The preparation method of the graphene reinforced copper-based composite material according to claim 2, wherein the target particle size of the particle size screening is as follows:

sieving to obtain flake powder with particle size of 48-75 μm.

6. the preparation method of the graphene reinforced copper-based composite material according to claim 1, wherein the step of performing countercurrent rotational orientation treatment on the mixed powder under a magnetic field comprises the following steps:

Filling the mixed powder into a die;

placing the mold filled with the mixed powder in an external magnetic field for countercurrent rotation treatment;

Wherein, the radial direction of the mould is kept to be the same as or vertical to the direction of the magnetic field in the rotating treatment process.

7. The method for preparing the graphene reinforced copper-based composite material according to claim 6, wherein the mold comprises a mold die head and a mold cavity, and the mold die head is positioned inside the mold cavity; and the inside of the die cavity is processed with a rifling rib with the height of 2 mm;

The number of the rifling convex edges is three, the rifling convex edges are parallel to each other, the rifling convex edges are separated by 120 degrees in the cavity of the die, and the distance between the rifling convex edges and the cavity of the die is 40mm along the axial direction of the die.

8. the preparation method of the graphene reinforced copper-based composite material according to claim 6, wherein in the rotating treatment process, a die head of a mold is gradually compacted until the mold is taken out of a magnetic field after being completely compacted;

An oriented composite powder compact was obtained.

9. The preparation method of the graphene reinforced copper-based composite material according to claim 6, wherein in the rotating treatment process, the strength of the external magnetic field is 0.5-4.0T, the rotating speed of the graphite mold is 5-10rpm, and the rotating time is 8-10 min.

10. The preparation method of the graphene reinforced copper-based composite material according to claim 1, wherein the composite powder compact sintering adopts vacuum hot-pressing sintering, the sintering temperature is 700 ℃, the sintering time is 1h, the sintering pressure is 30MPa, and the vacuum degree is maintained at 1 x 10^-2pa or less.

Technical Field

The invention relates to the technical field of metal matrix composite materials, in particular to a preparation method of a graphene reinforced copper matrix composite material.

Background

metal Matrix Nanocomposites (MMNCs) are a new material consisting of nanoreinforcements added to a metal or alloy matrix by physical or chemical means. Compared with large-size reinforced materials, the nano reinforcement has the advantages of surface effect, small-size effect and macroscopic quantum tunneling effect, and shows unique physical, chemical and mechanical properties. The MMNCs can exert the synergistic effect of each component, has the excellent characteristics of the nano reinforcement and the metal matrix, such as high specific strength, high temperature resistance, corrosion resistance, good electric conduction and heat conduction performance and the like, and is widely applied to the high-technology fields of machinery, electronics, national defense and military industry and the like.

Graphene is a new dimensional material of the carbon nano family that was discovered following zero-dimensional fullerenes and one-dimensional graphene. It has a honeycomb crystal structure of two-dimensional hexagonal network rings, and the theoretical thickness of a single layer is about 0.35 nm. The graphene has ultrahigh elastic modulus and mechanical strength and excellent electric and heat conducting properties, and is an ideal composite material reinforcing phase. The tensile strength and the elastic modulus of the material are respectively as high as 130GPa and 1.1 TPa; the thermal conductivity at room temperature is about 5000W/(m.k), which is more than 10 times of that of common metals (such as copper, Ag, Au, and the like); conductivity of about 10⁶And (5) S/m. Due to the unique structure and performance of the graphene, when the graphene is used as a reinforcing phase to be compounded with a polymer, ceramic or metal material, the mechanical, electrical, thermal and other properties of the material can be improved under the condition of low content.

However, the existing graphene reinforced metal matrix composite materials are all isotropic materials, and in the actual use process of the materials, many materials pay attention to the mechanical or physical properties in a specific direction, such as a bar-shaped member load-bearing beam, a wheel shaft and the like, mainly emphasize the mechanical properties in the length direction, and because the bearing capacity of the materials in other directions is relatively small; similarly, for the existing graphene-reinforced functional composite material, although graphene itself is a good electric and heat conductor, the overall electric and heat conductivity is not significantly improved.

disclosure of Invention

The invention aims to provide a preparation method of a graphene reinforced copper-based composite material, so as to solve the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme:

A preparation method of a graphene reinforced copper-based composite material comprises the following steps:

preparing flake copper powder;

Carrying out nickel plating treatment on the graphene to obtain nickel-plated graphene;

Performing ball milling treatment on the flaky copper powder and the nickel-plated graphene to obtain mixed powder;

performing countercurrent rotation orientation treatment on the mixed powder under a magnetic field to obtain a composite powder compact;

And sintering the composite powder pressed compact to obtain the graphene directional reinforced copper-based composite material.

preferably, the step of preparing the flake copper powder comprises the following steps:

Ball milling the copper powder to obtain sheet copper powder;

drying and reducing the flaky copper powder to obtain reduced flaky powder;

And screening the particle size of the reduced flaky powder.

Preferably, the copper powder ball milling step is as follows: putting the atomized spherical copper powder with the particle size of 45-109 mu m into a ball milling tank, and adding absolute ethyl alcohol as a process control agent for ball milling;

the ball-to-material ratio in the ball milling process is 10: 1, the ball milling speed is 250rpm, and the ball milling time is 10 h.

Preferably, the step of drying and reducing comprises: carrying out vacuum drying on the flake copper powder obtained after ball milling at 60 ℃ for 12 h;

Reducing the dried flake copper powder in a tubular reduction furnace by using hydrogen;

The reduction temperature is 400 ℃, and the reduction time is 3h

Preferably, the particle size screening has the following target particle size:

sieving to obtain flake powder with particle size of 48-75 μm.

Preferably, the step of performing counter-current rotational orientation treatment on the mixed powder under a magnetic field comprises:

Filling the mixed powder into a die;

placing the mold filled with the mixed powder in an external magnetic field for countercurrent rotation treatment;

wherein, the radial direction of the mould is kept to be the same as or vertical to the direction of the magnetic field in the rotating treatment process.

preferably, the mold comprises a mold die head and a mold cavity, and the mold die head is positioned in the mold cavity; and the inside of the die cavity is processed with a rifling rib with the height of 2 mm;

The number of the rifling convex edges is three, the rifling convex edges are parallel to each other, the rifling convex edges are separated by 120 degrees in the cavity of the die, and the distance between the rifling convex edges and the cavity of the die is 40mm along the axial direction of the die.

preferably, in the rotating treatment process, the die head of the die is gradually compacted until the die is taken out of the magnetic field after being completely compacted;

An aligned composite powder compact was obtained.

preferably, in the rotating treatment process, the strength of the external magnetic field is 0.5-4.0T, the rotating speed of the graphite mold is 5-10rpm, and the rotating time is 8-10 min.

Preferably, the composite powder compact sintering adopts vacuum hot-pressing sintering, the sintering temperature is 700 ℃, the sintering time is 1h,

the sintering pressure is 30MPa, and the vacuum degree is maintained at 1X 10^-2pa or less.

Compared with the prior art, the invention has the beneficial effects that:

the method adopts the pre-prepared flake copper powder, and the flake copper powder is beneficial to the dispersion of graphene; meanwhile, nickel plating treatment is carried out on the graphene, and paramagnetism of the graphene is increased; and carrying out countercurrent rotation orientation treatment on the mixed powder of the flake copper powder and the nickel-plated graphene in a magnetic field, and carrying out hot-pressing sintering to prepare the graphene reinforced copper-based composite material. The plated nickel layer improves the paramagnetism of the graphene, and the nickel-plated graphene realizes directional arrangement in a magnetic field. The irregular graphene magnetized in the magnetic field treatment process is equivalent to a magnetic needle in a magnetic field, and the end part of the irregular graphene is high in coupling magnetization intensity and large in magnetic force; the middle position magnetization intensity is weak, and the magnetic force is small, so that the mutual magnetic adsorption between the graphene can be reduced, the original folded graphene can be pulled away, the performance of the original folded graphene can be more effectively exerted, and the mechanical and physical properties of the material are improved.

Drawings

FIG. 1 is a schematic view of a magnetic field orientation process according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of the overall structure of the mold according to the embodiment of the present invention;

FIG. 3 is a front cross-sectional view of a mold according to an embodiment of the invention;

FIG. 4 is a side cross-sectional view of a mold according to an embodiment of the invention;

FIG. 5 is a morphology diagram of graphene longitudinally arranged in a composite material after magnetic field orientation treatment in example 1 of the present invention;

FIG. 6 is a morphology diagram of graphene transversely arranged in a composite material after magnetic field orientation treatment in example 1 of the present invention;

FIG. 7 is a graph showing tensile strengths before and after magnetic field treatment in example 1 of the present invention;

FIG. 8 is a morphology diagram of graphene longitudinally arranged in a composite material after magnetic field orientation treatment in example 2 of the present invention;

FIG. 9 is a morphology diagram of graphene transversely arranged in a composite material after magnetic field orientation treatment in example 2 of the present invention;

FIG. 10 is a graph showing tensile strengths before and after magnetic field treatment in example 2 of the present invention.

Detailed Description

In order to enhance the understanding of the present invention, the present invention will be further described with reference to the following examples, which are only for the purpose of illustrating the present invention and are not to be construed as limiting the scope of the present invention.

the embodiment of the invention provides a preparation method of a graphene reinforced copper-based composite material, which comprises the following steps:

Preparing flake copper powder;

carrying out nickel plating treatment on the graphene to obtain nickel-plated graphene;

performing ball milling treatment on the flaky copper powder and the nickel-plated graphene to obtain mixed powder;

Performing countercurrent rotation orientation treatment on the mixed powder under a magnetic field to obtain a composite powder compact;

and sintering the composite powder pressed compact to obtain the graphene reinforced copper-based composite material.

the flake copper powder is prepared in advance, and is beneficial to dispersion of graphene; meanwhile, nickel plating treatment is carried out on the graphene, and paramagnetism of the graphene is increased; and carrying out countercurrent rotation orientation treatment on the mixed powder of the flake copper powder and the nickel-plated graphene in a magnetic field, and carrying out hot-pressing sintering to prepare the graphene reinforced copper-based composite material. The plated nickel layer improves the paramagnetism of the graphene, and the directional arrangement is realized in the magnetic field of the nickel-plated graphene. The irregular graphene magnetized in the magnetic field treatment process is equivalent to a magnetic needle in a magnetic field, and the end part of the irregular graphene is high in coupling magnetization intensity and large in magnetic force; the magnetization intensity of the middle position is weak, and the magnetic force is small, so that the mutual magnetic adsorption among the graphene can be reduced, the originally folded graphene can be pulled away, and the performance of the graphene can be more effectively exerted; the mechanical and physical properties of the material are improved.

in the implementation, the directional arrangement of the graphene in the matrix can be realized, and the mechanical and physical properties of the composite material along the graphene direction are obviously improved; the graphene direction is parallel to the required electric conduction or heat conduction direction, which is equivalent to introducing a convenient channel for electric conduction or heat conduction, and the electric conductivity or the heat conductivity in the direction can be obviously improved, so that the aim of directionally enhancing the electric conduction or the heat conduction is fulfilled.

In one embodiment, the preparation process of the flake copper powder comprises the steps of putting atomized spherical copper powder with the particle size of 45-109 microns into a ball milling tank, and adding absolute ethyl alcohol as a process control agent to avoid the excessive cold welding phenomenon of the copper powder in the ball milling process, wherein the ball-to-material ratio is 10: 1, ball milling at the rotation speed of 250rpm for 10h to obtain copper powder with different sheet diameter sizes, and vacuum drying the copper powder at 60 ℃ for 12h after ball milling. Then, reducing the dried powder in a tubular reduction furnace by using hydrogen, wherein the reduction temperature is 400 ℃, and the reduction time is 3 h; and screening the reduced flaky powder by using a 200-mesh 300-mesh sieve to obtain flaky powder with the particle size of 48-75 mu m to obtain the final flaky copper powder.

in the embodiment, the matrix metal powder is prepared into flaky particles in a mechanical ball milling mode, the flaky particles with high content are beneficial to dispersing graphene, and meanwhile, the van der waals force among the graphene can be effectively overcome by collision and shearing in the mechanical ball milling process, so that the graphene is more uniformly dispersed in the metal matrix, the surface energy of the graphene is reduced, and the agglomeration of the graphene is hindered; avoiding agglomeration in the mixing process, thereby improving the performance of the composite material.

in one embodiment, the graphene nickel plating treatment steps are as follows:

sensitizing graphene: and putting the graphene with the sheet diameter of 8-12 mu m into a proper amount of deionized water for ultrasonic treatment for 30min, so as to improve the dispersibility of the graphene in the solution. Then, SnCl was used₂·2H₂Hydrochloric acid solution of O (SnCl)₂·2H₂O10g/L + HCl 40mL/L), and then carrying out ultrasonic oscillation treatment for 30min, and then filtering and washing the mixed solution to be neutral by using deionized water.

Activating graphene: using PdCl₂hydrochloric acid solution (PdCl)₂0.5g/L + HCl 25mL/L) is activated, ultrasonic vibration is assisted for 30min, and then the mixed solution is filtered and washed to be neutral by deionized water.

the nickel plating process of the graphene is to sequentially mix NiSO₄Solution (20g/L), C₆H₅Na₃O₇·2H₂o solution (10g/L), NaH₂PO₂·H₂Adding an O solution (30g/L) into the activated graphene solution, and adding NH₃·H₂adjusting the pH value of the mixed solution by using the O solution, performing ultrasonic treatment for 30min at the reaction temperature of 35 +/-3 ℃ and the pH value of 8.5-9.5, filtering the mixed solution, and washing the mixed solution to be neutral by using deionized water. And finally, carrying out vacuum drying on the chemically nickel-plated graphene for 24 hours at the drying temperature of 60 ℃ to obtain nickel-plated graphene powder.

in one embodiment, the flake copper powder and the nickel-plated graphene are subjected to uniform ball milling treatment, the nickel-plated powder and the flake copper powder are placed into a ball milling tank and are subjected to ball milling for 4 hours at a ball milling rotation speed of 150rpm, and a nickel-graphene/copper composite powder, namely a mixed powder, is obtained.

The method adopts the steps of preparing flaky copper powder in advance, and simultaneously carrying out pretreatment on graphene to increase the paramagnetism of the graphene; and carrying out countercurrent rotation orientation treatment on the mixed powder in a magnetic field, and carrying out hot-pressing sintering to prepare the graphene reinforced copper-based composite material.

Firstly, the graphene is pretreated to prevent the graphene from agglomerating and improve the dispersity of the graphene; meanwhile, the matrix metal powder is prepared into flaky particles in a mechanical ball milling mode, the flaky particles with high content are beneficial to dispersing the two-dimensional graphene with a certain sheet diameter ratio, and meanwhile, the collision and shearing in the mechanical ball milling process can effectively overcome the van der Waals force between graphene sheet layers, so that the graphene is more uniformly dispersed in the metal matrix, and the agglomeration of the graphene is hindered; avoiding agglomeration in the mixing process, thereby improving the performance of the composite material.

In one embodiment, the step of performing counter-current rotational orientation treatment on the mixed powder under a magnetic field comprises:

Filling the mixed powder into a die;

placing the die filled with the mixed powder in an external magnetic field for rotating treatment;

Wherein, the radial direction of the mould is kept to be the same as or vertical to the direction of the magnetic field in the rotating treatment process. And in the rotating process, keeping the radial direction of the graphite die to be the same as the direction of the magnetic field to obtain a transverse pressed blank, and keeping the axial direction of the graphite die to be the same as the direction of the magnetic field to obtain a longitudinal pressed blank.

Specifically, as shown in fig. 1, the countercurrent spin orientation treatment process of graphene under a magnetic field is to load the loosely packed nickel-graphene/copper composite powder into a mold, and at this time, the graphene on the surface layer of the mixed powder is only subjected to a small pressure and is in a "free movement" state; and (3) placing the mold in an external strong magnetic field with the strength of 0.5-4.0T, rotating the mold at the speed of 5-10rpm for 8-10min, always keeping the radial direction of the mold to be the same as the direction of the magnetic field, and deflecting the graphene on the surface layer to the direction of the magnetic field under the action of the strong magnetic field. And the pressure and friction force applied to the graphene in the inner layer are gradually increased along with the increase of the depth, so that the graphene in the deep layer can only slightly rotate or cannot rotate. In order to ensure that all the graphene is directionally arranged, the die is rotated in a specific direction in a magnetic field, the surface layer of the composite powder flows downwards due to gravity, the inner layer of the subsurface layer is exposed and changed into a new surface layer, and the graphene in the new surface layer begins to deflect under the action of the magnetic field. At this time, the graphite in the original surface layer is buried in the mixed powder in a certain orientation; through multiple countercurrent rotations, graphene can be distributed in the mixed powder along the direction of a magnetic field; and (3) gradually compacting the die head to control the powder flowability in the rotating process of the die, and taking the die out of the magnetic field after the die is completely compacted, so that the longitudinally-arranged composite powder compact is obtained, and the transverse compact process is shown in fig. 1 (c). By the same method, if the radial direction of the die is always kept perpendicular to the direction of the magnetic field during the magnetization process, the directionally arranged transverse composite powder compact can be obtained, and the obtained longitudinal compact process is shown in fig. 1 (d).

In the above embodiments, as shown in fig. 2 to 4, the mold includes a mold die head 1 and a mold cavity 2, and the mold die head 1 is located inside the mold cavity 2; and the mould cavity 2 is internally processed with a rifling rib with the height of 2 mm; the number of the rifling convex edges is three, the rifling convex edges are parallel to each other, the rifling convex edges are separated by 120 degrees in the cavity of the die, and the distance between the rifling convex edges and the cavity of the die is 40mm along the axial direction of the die. In the powder mixing process, the rifling ridges obstruct the free fluid movement of the powder, so that the mixing is more uniform.

in one embodiment, the mixed powder sintering process is to perform hot-pressing sintering on the nickel-graphene/copper composite powder after magnetic field treatment, wherein the sintering temperature is 700 ℃, the sintering time is 1h, the sintering pressure is 30MPa, and the vacuum degree is kept at 1 × 10^-2And Pa below, obtaining a graphene directionally reinforced metal matrix composite material sample.

According to the embodiment of the invention, the graphene in the graphene reinforced copper-based composite material prepared by magnetic field treatment is uniformly dispersed and directionally arranged, and compared with a material which is not subjected to magnetic field orientation treatment under the same condition, the electrical property and the mechanical property of the composite material in the magnetic field direction are improved by the magnetic field orientation treatment.

the following is a detailed description by way of specific examples: