A preparation method of in-situ self-grown GNS / Cu composite foam reinforced copper-nickel-tin composite material

Abstract

This invention discloses a method for preparing in-situ self-grown GNS / Cu composite foam reinforced copper-nickel-tin composite material, belonging to the field of metal matrix composite material preparation technology. Based on copper foam, this invention prepares GNS / Cu composite foam using in-situ self-grown graphene (GNS) as the reinforcing phase. The in-situ self-growing method improves the interfacial bonding between the metal foam material and graphene, ensuring that the grown graphene uniformly coats the surface of the metal foam material, thereby improving its interfacial bonding performance. Subsequently, copper-nickel-tin powder is filled into the composite foam, further synergistically and significantly enhancing the electrical conductivity and mechanical properties of the composite material, which has important application value in the field of high-end conductive and wear-resistant components.

Description

Technical Field

[0001] This invention belongs to the field of metal matrix composite material preparation technology, and more specifically relates to a method for preparing an in-situ self-generated GNS / Cu composite foam reinforced copper-nickel-tin composite material. Background Technology

[0002] Copper-nickel-tin (Cu-Ni-Sn) alloys hold an irreplaceable position in fields such as precision electronic connectors, high-end bearings, turbine components, and marine engineering equipment due to their excellent strength, good wear resistance, corrosion resistance, stress relaxation resistance, and moderately high electrical and thermal conductivity. However, with the increasingly stringent performance requirements for key components in aerospace, high-speed rail transportation, and next-generation communication equipment, traditionally prepared Cu-Ni-Sn alloys face comprehensive performance bottlenecks. On the one hand, the potential for further strengthening through alloying and heat treatment is very limited, and there is an inherent inverse relationship between strength and conductivity; high strength is often accompanied by a significant decrease in conductivity. On the other hand, their wear resistance and resistance to arc erosion urgently need improvement when facing higher operating conditions.

[0003] To overcome this bottleneck, introducing high-performance second-phase reinforcements to prepare composite materials is a recognized effective approach. Among them, carbon nanomaterials, especially graphene nanosheets, are considered the "ultimate reinforcement" for metal matrix composites due to their theoretically ultra-high strength, excellent flexibility, and unparalleled electrical and thermal conductivity. Researchers have attempted to introduce graphene into matrices such as copper and aluminum through various methods, including powder metallurgy and stir casting. However, these traditional methods face two long-standing and unresolved core scientific challenges: First, the dispersion problem. Graphene nanosheets have a large specific surface area and high surface energy, making them prone to severe face-to-face aggregation in metal matrices. This not only fails to exert their nano-reinforcing effect but also becomes a source of microcracks, impairing material properties. Second, the interface problem. Graphene has poor wettability and low chemical compatibility with metal matrices (especially copper and nickel), often forming incoherent weak bonding interfaces. This leads to low load transfer efficiency and severely hinders the cross-interface transport of electrons and phonons, potentially causing the electrical and thermal conductivity of the composite material to be even lower than that of the matrix alloy.

[0004] Based on this, the present invention is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing in-situ self-grown GNS / Cu composite foam reinforced copper-nickel-tin composite material, thereby solving the problems existing in the prior art. This invention utilizes an in-situ synthesis method, taking advantage of the catalytic effect of copper powder, to allow graphene to grow directly on the surface of the copper foam, thus greatly improving its interfacial bonding performance. Subsequently, copper-nickel-tin powder is filled into the composite foam, further synergistically and significantly enhancing the comprehensive mechanical properties, electrical conductivity, and abrasion resistance of the composite material.

[0006] To achieve the above objectives, the present invention provides the following solution: One of the technical solutions of this invention is to provide a method for preparing in-situ self-generated GNS / Cu composite foam reinforced copper-nickel-tin composite material, comprising the following steps: Pre-sintered copper foam is impregnated in a mixture containing caramelized sucrose and iodide to obtain a precursor material; the precursor material is calcined to obtain graphene / Cu composite foam, i.e., GNS / Cu composite foam; copper-nickel-tin powder is filled into the pores of the GNS / Cu composite foam by vibration, and after sintering, the in-situ self-generated GNS / Cu composite foam reinforced copper-nickel-tin composite material is obtained.

[0007] Preferably, the preparation steps of the mixture include: dissolving sucrose in water to obtain a sucrose solution, heating and stirring to obtain a caramelized sucrose solution; diluting the caramelized sucrose solution with a dispersion composed of ethanol and water; adding iodide to the diluted solution and mixing to obtain the mixture; The iodide includes potassium iodide.

[0008] Potassium iodide is preferably used as the iodide in this invention, but other iodides containing iodide ions and not producing other impurities are also acceptable. Iodide ions can promote the formation of carbon quantum dots on the surface of caramelized sucrose.

[0009] Preferably, the heating and stirring temperature is 250°C; the concentration of caramelized sucrose in the diluted solution is 20~100 mg / mL; the mass ratio of sucrose to iodide is (13~40):1, more preferably (20~30):1, and even more preferably 26:1; and the volume ratio of ethanol to water is (1~4):1.

[0010] Preferably, the pre-sintering step of the copper foam includes: pre-sintering the copper foam in a mixed atmosphere of hydrogen and nitrogen to obtain the pre-sintered copper foam; the pre-sintering heating rate is 10℃ / min, the temperature is 300~500℃, and the holding time is 180min.

[0011] Preferably, the impregnation time is 24 hours; the calcination is carried out in a mixed atmosphere of hydrogen and argon, with a heating rate of 10°C / min, a temperature of 700~900°C, more preferably 750~850°C, more preferably 800°C, and a holding time of 10~30 minutes, more preferably 10 minutes.

[0012] Preferably, the copper-nickel-tin powder is Cu-15Ni-8Sn with a particle size ≥500 mesh.

[0013] Preferably, the specific steps for filling the pores of the GNS / Cu composite foam with copper-nickel-tin powder by vibration are as follows: the GNS / Cu composite foam is placed in a mold and wrapped with carbon paper, and copper-nickel-tin powder is filled into the pores of the GNS / Cu composite foam by vibration until the copper-nickel-tin powder no longer seeps into the pores; after filling, cold pressing is performed to obtain a composite block material; the pressure of the cold pressing is 15MPa, and the holding time is 5~10min.

[0014] Preferably, the sintering heating rate is 100°C / min, and the vacuum degree is <10. -3 Pa, temperature is 700~900℃, more preferably 750℃, and holding time is 5min.

[0015] The second technical solution of the present invention provides an in-situ self-generated GNS / Cu composite foam reinforced copper-nickel-tin composite material prepared by the above preparation method.

[0016] The third technical solution of the present invention provides the application of the above-mentioned in-situ self-generated GNS / Cu composite foam reinforced copper-nickel-tin composite material in the preparation of high-end conductive wear-resistant parts, wherein the high-end conductive wear-resistant parts include conductive wear-resistant parts used in fields such as precision electronic connectors, high-end bearings, turbine components and marine engineering equipment.

[0017] The technical principle of this invention is as follows: First, pretreated 3D network structured copper foam was selected as the reaction substrate to provide template support for subsequent graphene growth. Pre-sintering of the copper foam was performed to clean its surface, reduce surface oxides, and activate surface activity, creating favorable conditions for uniform adsorption of the carbon source and catalytic growth.

[0018] Secondly, the methods for introducing graphene as a reinforcing phase into graphene-reinforced metal matrix composites can be broadly categorized into two types: external addition and in-situ synthesis. In the external addition method, the high specific surface area and van der Waals forces lead to graphene agglomeration when pre-prepared graphene is introduced into the metal matrix. Furthermore, the unimproved wettability between metals such as copper and graphene is poor, generally resulting in mechanical bonding and thus weak interfacial bonding strength. This invention improves the interfacial bonding and coating state between graphene and copper foam through in-situ synthesis. Pretreated copper foam is immersed in a solution using caramelized sucrose as the carbon source and iodide (preferably potassium iodide) as the catalyst, allowing the carbon precursor to be fully adsorbed onto the surface of the copper foam. During subsequent calcination in a reducing atmosphere (H2 / Ar), the copper foam framework not only serves as a growth template but also provides a certain catalytic effect. Under suitable heating rates and temperatures (700~900℃), the adsorbed caramelized sucrose catalyzes the formation of carbon quantum dots on the copper surface, resulting in the in-situ growth of graphene (GNS). The advantages of this in-situ growth mechanism are as follows: First, the graphene synthesized by this method grows directly on the surface of copper foam through nucleation. The in-situ formed interface has good coherence, which is beneficial for optimizing the interfacial wetting properties and improving the interfacial strength, thereby achieving a breakthrough improvement in the overall performance of the composite material. Second, the growth process is limited and guided by the substrate morphology, and the graphene can be uniformly covered on the surface of the copper foam, effectively avoiding the agglomeration problem caused by later addition.

[0019] After obtaining the GNS / Cu composite foam, copper-nickel-tin (Cu-15Ni-8Sn) alloy powder was filled into it using a vibration-assisted method. Vibration helps the powder to be evenly distributed in the GNS / Cu foam, thereby improving the uniformity of the composite material composition after sintering. After filling, it was cold-pressed to form a pre-sintered block. Finally, it was subjected to spark plasma sintering (SPS) at a temperature of 700~900℃ for 5 minutes to allow diffusion bonding and partial metallurgical bonding to occur between the copper-nickel-tin powder particles and between the powder and the GNS / Cu framework, forming a highly dense composite material.

[0020] The present invention discloses the following technical effects: (1) The present invention optimizes the interfacial wetting properties by using an in-situ synthesis method, so that the in-situ grown graphene is evenly distributed on the surface of copper foam, thereby improving the interfacial bonding strength between copper foam and graphene.

[0021] (2) The present invention introduces three-dimensional graphene / copper (GNS / Cu) composite foam as a skeleton and fills it with copper-nickel-tin powder to prepare GNS / Cu composite foam reinforced copper-nickel-tin composite material with excellent electrical conductivity, mechanical properties and friction resistance, and is suitable for working environments with high requirements for metal conductivity and strength. Attached Figure Description

[0022] Figure 1This is a flowchart illustrating the preparation process of the in-situ self-generated GNS / Cu composite foam reinforced copper-nickel-tin composite material described in this invention. Figure 2 SEM images of in-situ self-grown GNS / Cu composite foam and pure copper foam prepared in Examples 1-4 and Comparative Examples 2-3, where (a)-(f) correspond to Examples 1-4 and Comparative Examples 2-3 respectively, and (g) is pure copper foam without graphene growth. Figure 3 The tensile stress-strain curves of the in-situ self-generated GNS / Cu composite foam reinforced copper-nickel-tin composite materials prepared in Examples 1-4 and Comparative Examples 1-3 are shown. Figure 4 The results show the micro Vickers hardness properties of the in-situ self-generated GNS / Cu composite foam reinforced copper-nickel-tin composite materials prepared in Examples 1-4 and Comparative Examples 1-3. Figure 5 The results show the electrical conductivity properties of the in-situ self-generated GNS / Cu composite foam reinforced copper-nickel-tin composite materials prepared in Examples 1-4 and Comparative Examples 1-3. Figure 6 The results show the tribological properties of the in-situ self-generated GNS / Cu composite foam reinforced copper-nickel-tin composite materials prepared in Examples 1-4 and Comparative Examples 1-3. Detailed Implementation

[0023] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0024] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0025] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0026] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0027] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0028] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0029] The copper foam used in the embodiments and comparative examples of this invention has a diameter of 28 mm, a height of 7 mm, a pore size of 0.1~1 mm, and a porosity of 95~98%.

[0030] Example 1 This embodiment provides a method for preparing in-situ self-generated GNS / Cu composite foam reinforced copper-nickel-tin composite material, including the following steps: (1) The foamed copper was placed in a horizontal tube furnace with an atmosphere of N2 and H2 (H2 volume percentage of 10%) and calcined. The temperature was set to 400℃, the heating rate was 10℃ / min, and the holding time was 180min. The pretreated foamed copper was then prepared for use.

[0031] (2) Dissolve 7.8g of sucrose in 70mL of deionized water, place it on a room temperature magnetic stirrer, and stir until the sucrose is completely dissolved to obtain a sucrose solution.

[0032] (3) Place the dissolved sucrose solution on a magnetic stirrer and heat it at 250°C. After 2 hours of heating and stirring, the solution gradually changes from colorless to light yellow, and finally turns into a brownish-yellow viscous liquid, which is caramelized sucrose solution.

[0033] (4) The obtained caramelized sucrose solution was diluted with a solvent obtained by mixing ethanol and deionized water at a volume ratio of 3:1 to obtain a caramelized sucrose solution with a concentration of 20 mg / mL. Then, 0.3 g of KI was added, and the mass ratio of sucrose to KI was 26:1. After stirring on a magnetic stirrer at room temperature for 1 h, the solution was observed to change from brownish-yellow to light yellow. Iodide ions can catalyze the conversion of sucrose to graphene. Finally, a mixed solution of graphene and sucrose was obtained.

[0034] (5) The pretreated copper foam is immersed in the mixed solution of graphene and sucrose prepared in step (4) for 24 hours. After treatment, copper foam precursor material is obtained.

[0035] (6) The obtained copper foam precursor material was placed in a tube sintering furnace under a mixed atmosphere of H2 and Ar (H2 volume ratio of 10%) for sintering. The sintering temperature was set to 700℃, the heating rate was 10℃ / min, and the holding time was 10min to obtain GNS / Cu composite foam.

[0036] (7) Place the obtained GNS / Cu composite foam in a graphite mold with a diameter of 30 mm and wrap it with carbon paper. Fill the pores of the composite foam with copper-nickel-tin powder (Cu-15Ni-8Sn, particle size 500 mesh) by vibration until the copper-nickel-tin powder no longer penetrates into the pores of the GNS / Cu composite foam. The loading of Cu-15Ni-8Sn powder is 90~95wt.%. After filling, cold press the foam with a tablet press at a pressure of 15MPa for a holding time of 5~10min.

[0037] (8) Place the cold-pressed material from step (7) into a spark plasma sintering furnace (SPS) for sintering at a temperature of 750°C, a holding time of 5 min, a heating rate of 100°C / min, and a vacuum degree of <10. -3 Pa, after sintering, yields GNS / Cu composite foam reinforced copper-nickel-tin composite material.

[0038] Example 2 This embodiment provides a method for preparing in-situ self-generated GNS / Cu composite foam reinforced copper-nickel-tin composite material, including the following steps: (1) The foamed copper was placed in a horizontal tube furnace with an atmosphere of N2 and H2 (H2 volume percentage of 10%) for calcination. The annealing temperature was set to 400℃, the heating rate was 10℃ / min, and the holding time was 180min. The pretreated foamed copper was then prepared for use.

[0039] (2) Dissolve 7.8g of sucrose in 70mL of deionized water, place it on a room temperature magnetic stirrer, and stir until the sucrose is completely dissolved to obtain a sucrose solution.

[0040] (3) Place the dissolved sucrose solution on a magnetic stirrer and heat it at 250°C. After 2 hours of heating and stirring, the solution gradually changes from colorless to light yellow, and finally turns into a brownish-yellow viscous liquid, which is caramelized sucrose solution.

[0041] (4) The obtained caramelized sucrose solution was diluted with a solvent obtained by mixing ethanol and deionized water at a volume ratio of 3:1 to obtain a caramelized sucrose solution with a concentration of 20 mg / mL. Then, 0.3 g of KI was added, and the mass ratio of sucrose to KI was 26:1. After stirring on a magnetic stirrer at room temperature for 1 h, the solution was observed to change from brownish-yellow to light yellow. Iodide ions can catalyze the conversion of sucrose to graphene. Finally, a mixed solution of graphene and sucrose was obtained.

[0042] (5) The pretreated copper foam is immersed in the mixed solution of graphene and sucrose prepared in step (4) for 24 hours. After treatment, copper foam precursor material is obtained.

[0043] (6) The obtained copper foam precursor material was placed in a tube sintering furnace under a mixed atmosphere of H2 and Ar (H2 volume ratio of 10%) for sintering. The sintering temperature was set to 700℃, the heating rate was 10℃ / min, and the holding time was 10min to obtain GNS / Cu composite foam.

[0044] (7) Place the obtained GNS / Cu composite foam in a graphite mold with a diameter of 30 mm and wrap it with carbon paper. Fill the pores of the composite foam with copper-nickel-tin powder (Cu-15Ni-Sn, particle size 500 mesh) by vibration until the copper-nickel-tin powder no longer penetrates into the pores of the GNS / Cu composite foam. The loading of Cu-15Ni-8Sn powder is 90~95wt.%. After filling, cold press the foam with a tablet press at a pressure of 15MPa for a holding time of 5~10min.

[0045] (8) The material that has been cold-pressed in step (7) is placed in a spark plasma sintering furnace (SPS) for sintering at a temperature of 800℃, a holding time of 5 min, a heating rate of 100℃ / min, and a vacuum degree of <10. -3 Pa, after sintering, yields GNS / Cu composite foam reinforced copper-nickel-tin composite material.

[0046] Example 3 This embodiment provides a method for preparing in-situ self-generated GNS / Cu composite foam reinforced copper-nickel-tin composite material, including the following steps: (1) The foamed copper was placed in a horizontal tube furnace with an atmosphere of N2 and H2 (H2 volume percentage of 10%) and calcined. The temperature was set to 500℃, the heating rate was 10℃ / min, and the holding time was 180min. The pretreated foamed copper was then prepared for use.

[0047] (2) Dissolve 7.8g of sucrose in 70mL of deionized water, place it on a room temperature magnetic stirrer, and stir until the sucrose is completely dissolved to obtain a sucrose solution.

[0048] (3) Place the dissolved sucrose solution on a magnetic stirrer and heat it at 250°C. After 2 hours of heating and stirring, the solution gradually changes from colorless to light yellow, and finally turns into a brownish-yellow viscous liquid, which is caramelized sucrose solution.

[0049] (4) The obtained caramelized sucrose solution was diluted with a solvent obtained by mixing ethanol and deionized water at a volume ratio of 3:1 to obtain a caramelized sucrose solution with a concentration of 90 mg / mL. Then, 0.3 g of KI was added, and the mass ratio of sucrose to KI was 26:1. After stirring on a magnetic stirrer at room temperature for 1 h, the solution was observed to change from brownish-yellow to light yellow. Iodide ions can catalyze the conversion of sucrose to graphene. Finally, a mixed solution of graphene and sucrose was obtained.

[0050] (5) The pretreated copper foam is immersed in the mixed solution of graphene and sucrose prepared in step (4) for 24 hours. After treatment, copper foam precursor material is obtained.

[0051] (6) The obtained copper foam precursor material was placed in a tube sintering furnace under a mixed atmosphere of H2 and Ar (H2 volume ratio of 10%) for sintering. The sintering temperature was set to 700℃, the heating rate was 10℃ / min, and the holding time was 10min to obtain GNS / Cu composite foam.

[0052] (7) Place the obtained GNS / Cu composite foam in a graphite mold with a diameter of 30 mm and wrap it with carbon paper. Fill the pores of the composite foam with copper-nickel-tin powder (Cu-15Ni-Sn, particle size 500 mesh) by vibration until the copper-nickel-tin powder no longer penetrates into the pores of the GNS / Cu composite foam. The loading amount of Cu-15Ni-8Sn powder is 90~95wt.%. After filling, cold press the foam with a tablet press at a pressure of 15MPa for a holding time of 5~10min.

[0053] (8) Place the cold-pressed material from step (7) into a spark plasma sintering furnace (SPS) for sintering at a temperature of 750°C, a holding time of 5 min, a heating rate of 100°C / min, and a vacuum degree of <10. -3 Pa, after sintering, yields GNS / Cu composite foam reinforced copper-nickel-tin composite material.

[0054] Example 4 This embodiment provides a method for preparing in-situ self-generated GNS / Cu composite foam reinforced copper-nickel-tin composite material, including the following steps: (1) The foamed copper was placed in a horizontal tube furnace with an atmosphere of N2 and H2 (H2 volume percentage of 10%) and calcined. The temperature was set to 400℃, the heating rate was 10℃ / min, and the holding time was 180min. The pretreated foamed copper was then prepared for use.

[0055] (2) Dissolve 7.8g of sucrose in 70mL of deionized water, place it on a room temperature magnetic stirrer, and stir until the sucrose is completely dissolved to obtain a sucrose solution.

[0056] (3) Place the dissolved sucrose solution on a magnetic stirrer and heat it at 250°C. After 2 hours of heating and stirring, the solution gradually changes from colorless to light yellow, and finally turns into a brownish-yellow viscous liquid, which is caramelized sucrose solution.

[0057] (4) The obtained caramelized sucrose solution was diluted with a solvent obtained by mixing ethanol and deionized water at a volume ratio of 3:1 to obtain a caramelized sucrose solution with a concentration of 20 mg / mL. Then, 0.3 g of KI was added, and the mass ratio of sucrose to KI was 26:1. After stirring on a magnetic stirrer at room temperature for 1 h, the solution was observed to change from brownish-yellow to light yellow. Iodide ions can catalyze the conversion of sucrose to graphene. Finally, a mixed solution of graphene and sucrose was obtained.

[0058] (5) The pretreated copper foam is immersed in the mixed solution of graphene and sucrose prepared in step (4) for 24 hours. After treatment, copper foam precursor material is obtained.

[0059] (6) The obtained copper foam precursor material was placed in a tube sintering furnace under a mixed atmosphere of H2 and Ar (H2 volume ratio of 10%) for sintering. The sintering temperature was set to 800℃, the heating rate was 10℃ / min, and the holding time was 10min to obtain GNS / Cu composite foam.

[0060] (7) Place the obtained GNS / Cu composite foam in a graphite mold with a diameter of 30 mm and wrap it with carbon paper. Fill the pores of the composite foam with copper-nickel-tin powder (Cu-15Ni-Sn, particle size 500 mesh) by vibration until the copper-nickel-tin powder no longer penetrates into the pores of the GNS / Cu composite foam. The loading amount of Cu-15Ni-8Sn powder is 90~95wt.%. After filling, cold press the foam with a tablet press at a pressure of 15MPa for a holding time of 5~10min.

[0061] (8) Place the cold-pressed material from step (7) into a spark plasma sintering furnace (SPS) for sintering at a temperature of 750°C, a holding time of 5 min, a heating rate of 100°C / min, and a vacuum degree of <10. -3 Pa, after sintering, yields GNS / Cu composite foam reinforced copper-nickel-tin composite material.

[0062] Comparative Example 1 Similar to Example 1, except that the in-situ grown graphene was omitted. Graphene (purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.) was uniformly mixed with Cu-15Ni-8Sn powder and then filled into copper foam. Subsequently, non-in-situ grown GNS / Cu foam reinforced copper-nickel-tin composite material was prepared by SPS sintering.

[0063] Comparative Example 2 Same as Example 1, except that in step (6), when the obtained copper foam precursor material is sintered in a tube sintering furnace under a mixed atmosphere of H2 and Ar (H2 volume ratio of 10%), the sintering temperature is 950℃.

[0064] Comparative Example 3 Same as Example 1, except that in step (8), the material that was cold-pressed in step (7) is placed in a spark plasma sintering furnace (SPS) for sintering at a temperature of 650°C and a holding time of 10 min.

[0065] Performance testing: The microstructures of the in-situ grown GNS / Cu foam and pure copper foam prepared in Examples 1-4 and Comparative Examples 2-3 are as follows: Figure 2 As shown. It can be observed that compared to pure copper foam without graphene growth ( Figure 2 (g) The graphene wrinkles on the surface of the in-situ grown GNS / Cu foam prepared in Examples 1-4 and Comparative Example 3 are uniformly distributed and structurally complete. Figure 2 (a)~(d), (f)), this is one of the typical microscopic morphological characteristics of successfully grown graphene. However, in Comparative Example 2, due to excessively high growth temperature, the graphene wrinkles were coarser and showed localized damage. Figure 2 (e) This structural defect is detrimental to the improvement of the overall performance of composite materials.

[0066] The tensile properties of the in-situ grown GNS / Cu foam reinforced copper-nickel-tin composites prepared in Examples 1-4 and Comparative Examples 2-3, and the externally added GNS / Cu foam reinforced copper-nickel-tin composites prepared in Comparative Example 1 are as follows: Figure 3 As shown, it can be seen that compared with Comparative Example 1 (external graphene method), Examples 1-4 prepared by in-situ growth method are superior in terms of yield strength, tensile strength, and elongation. This is due to the advantages of in-situ growth. On the one hand, graphene can be grown in-situ using copper foam as a template to form a continuous and interconnected three-dimensional network structure, achieving uniform reinforcement in three-dimensional space. On the other hand, the in-situ grown graphene forms a good interfacial bond with the copper foam skeleton, which can more effectively transfer stress to the matrix through the interface when bearing load, thereby effectively transferring the load and alleviating local stress concentration. In addition, in-situ growth can improve the graphene agglomeration problem, which is beneficial to the uniformity of the composite material composition. In contrast, the performance of samples prepared outside the process parameter range described in this invention (Comparative Examples 2-3) is significantly lower than that of Examples 1-4. Specifically, in Comparative Example 2, the temperature at which graphene was grown in situ on copper foam was too high, resulting in an increase in graphene structural defects and a decrease in the reinforcing effect; while in Comparative Example 3, the sintering temperature of SPS was too low, resulting in insufficient densification of the composite material and defects such as residual micropores, which had an adverse effect on mechanical and physical properties.

[0067] The micro Vickers hardness of the in-situ grown GNS / Cu foam reinforced copper-nickel-tin composite materials prepared in Examples 1-4 and Comparative Examples 2-3, and the externally added GNS / Cu foam reinforced copper-nickel-tin composite material prepared in Comparative Example 1, are as follows: Figure 4 As shown in the figure, hardness is a material's ability to resist localized deformation. For most metallic materials, there is an approximate direct proportionality between hardness and tensile strength. The hardness graph shows that, compared to Comparative Example 1 prepared by the graphene-added method, Examples 1-4 prepared by the in-situ growth method all exhibit higher microhardness, consistent with the tensile property trend results. In contrast, when the preparation process was outside the required range, the microVickers hardness of the samples deteriorated significantly. Specifically, compared to the sample prepared in Example 4, the Vickers hardness of the samples prepared in Comparative Examples 2-3 decreased by 14% and 19%, respectively.

[0068] The electrical conductivity properties of the in-situ grown GNS / Cu foam reinforced copper-nickel-tin composite materials prepared in Examples 1-4 and Comparative Examples 2-3, and the externally added GNS / Cu foam reinforced copper-nickel-tin composite material prepared in Comparative Example 1 are as follows: Figure 5 As shown, the conductivity of Examples 1-4 (in-situ growth method) is generally better than that of Comparative Example 1 (external graphene method), and is significantly higher than that of Comparative Examples 2-3 prepared outside the process requirements. Furthermore, compared to pure Cu15Ni8Sn alloy, the conductivity of Examples 1-4 within the process parameter range of this invention is improved, with a maximum increase of 29.9%. Unlike externally added graphene, which is isolated and aggregated in the matrix, the in-situ grown graphene forms an interconnected three-dimensional conductive network with copper foam as the framework, constructing a high-speed electron transport channel and mitigating electron scattering losses introduced by the graphene / matrix interface to a certain extent. Simultaneously, the good interface formed between the in-situ grown graphene and the copper foam facilitates efficient electron transport between the reinforcing phase and the matrix, thereby improving conductivity. In contrast, Comparative Example 2 suffers from increased structural defects due to excessively high graphene growth temperature, compromising its intrinsic high conductivity; Comparative Example 3 suffers from insufficient densification and residual micropores due to excessively low SPS sintering temperature, significantly increasing electron scattering centers. These factors resulted in the conductivity of Comparative Examples 2-3 being significantly inferior to that of Examples 1-4.

[0069] The friction coefficients of the in-situ grown GNS / Cu foam reinforced copper-nickel-tin composite materials prepared in Examples 1-4 and Comparative Examples 2-3, and the externally added GNS / Cu foam reinforced copper-nickel-tin composite material prepared in Comparative Example 1 are as follows: Figure 6As shown, the friction coefficients of Examples 1-4 (in-situ growth method) are generally lower than those of Comparative Example 1 (external graphene method), and are significantly lower than those of Comparative Examples 2-3 prepared outside the process parameter range of this invention. This indicates that the introduction of graphene effectively plays a lubricating role. Among them, the samples prepared by the in-situ growth method have the lowest friction coefficient and the most significant friction reduction effect, which also shows that the external graphene method has inherent limitations in achieving uniform dispersion and effective lubrication. When deviating from the process range, Comparative Example 2 suffers from increased structural defects due to excessively high graphene growth temperature, which weakens its intrinsic lubrication ability; Comparative Example 3 suffers from insufficient densification and residual micropores due to excessively low sintering temperature. During the friction process, these pores become wear debris accumulation points and stress concentration sources, exacerbating wear damage. These factors lead to a significant increase in the friction coefficients of both examples.

[0070] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0071] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing an in-situ self-generated GNS / Cu composite foam reinforced copper-nickel-tin composite material, characterized in that, Includes the following steps: Pre-sintered copper foam is impregnated in a mixture containing caramelized sucrose and iodide to obtain a precursor material; the precursor material is calcined to obtain graphene / Cu composite foam, i.e., GNS / Cu composite foam; copper-nickel-tin powder is filled into the pores of the GNS / Cu composite foam by vibration, and after sintering, the in-situ self-generated GNS / Cu composite foam reinforced copper-nickel-tin composite material is obtained.

2. The preparation method according to claim 1, characterized in that, The preparation steps of the mixture include: dissolving sucrose in water to obtain a sucrose solution, heating and stirring to obtain a caramelized sucrose solution; diluting the caramelized sucrose solution with a dispersion composed of ethanol and water; adding iodide to the diluted solution and mixing to obtain the mixture; The iodide includes potassium iodide.

3. The preparation method according to claim 2, characterized in that, The concentration of caramelized sucrose in the diluted solution is 20~100 mg / mL; the mass ratio of sucrose to iodide is (13~40):1; and the volume ratio of ethanol to water is (1~4):

1.

4. The preparation method according to claim 1, characterized in that, The pre-sintering step of copper foam includes: pre-sintering copper foam in a mixed atmosphere of hydrogen and nitrogen to obtain the pre-sintered copper foam; the heating rate of the pre-sintering is 10℃ / min, the temperature is 300~500℃, and the holding time is 180min.

5. The preparation method according to claim 1, characterized in that, The impregnation time is 24 hours; the calcination is carried out in a mixed atmosphere of hydrogen and argon, with a heating rate of 10℃ / min, a temperature of 700~900℃, and a holding time of 10~30 minutes.

6. The preparation method according to claim 1, characterized in that, The copper-nickel-tin powder is Cu-15Ni-8Sn with a particle size ≥500 mesh.

7. The preparation method according to claim 1, characterized in that, The specific steps for filling the pores of the GNS / Cu composite foam with copper-nickel-tin powder by vibration are as follows: the GNS / Cu composite foam is placed in a mold and wrapped with carbon paper, and copper-nickel-tin powder is filled into the pores of the GNS / Cu composite foam by vibration until the copper-nickel-tin powder no longer seeps into the pores; after filling, cold pressing is performed to obtain a composite block material; the pressure of the cold pressing is 15MPa, and the holding time is 5~10min.

8. The preparation method according to claim 1, characterized in that, The sintering heating rate is 100℃ / min, and the vacuum degree is <10. -3 Pa, temperature 700~900℃, holding time 5min.

9. The in-situ self-generated GNS / Cu composite foam reinforced copper-nickel-tin composite material prepared by the preparation method according to any one of claims 1 to 8.

10. The application of the in-situ self-generated GNS / Cu composite foam reinforced copper-nickel-tin composite material as described in claim 9 in the preparation of high-end conductive and wear-resistant components.

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