Preparation method of nitrogen-doped carbon nanotube-reinforced high-conductivity copper-based composite material
The introduction of nitrogen doping on the surface of carbon nanotubes through plasma treatment and molecular-level blending processes has solved the problems of dispersion and bonding strength of carbon nanotubes in copper-based composite materials, and a nitrogen-doped carbon nanotube composite reinforced copper-based material with excellent mechanical and electrical properties was prepared.
Patent Information
- Application Number
- CN202310719391.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-06-16
- Publication Date
- 2025-08-19
- Estimated Expiration
- 2043-06-16
AI Technical Summary
In the prior art, carbon nanotubes have poor dispersion and weak interfacial bonding strength in copper-based composite materials, resulting in poor mechanical and electrical properties, and oxidation treatment reduces electrical conductivity.
Nitrogen-doped carbon nanotubes were introduced through plasma treatment, combined with molecular-level blending and discharge plasma sintering processes, the surface functional groups of carbon nanotubes were regulated, dispersibility and interface binding strength were improved, and nitrogen-doped carbon nanotube composite reinforced copper-based materials were prepared.
The uniform dispersion and strong interface combination of carbon nanotubes in the copper matrix are achieved, which improves the mechanical properties and electrical conductivity of the material and maintains excellent electrical properties.
Smart Images
Figure CN116727676B_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of metal matrix composite material preparation, and in particular relates to a method for preparing a nitrogen-doped carbon nanotube-reinforced high-conductivity copper matrix composite material. Background Art
[0002] Carbon nanotubes (CNTs) are considered an ideal reinforcement for composite materials due to their excellent mechanical, electrical, and thermal properties. Copper-based composites, due to their excellent electrical and thermal conductivity and corrosion resistance, are widely used in electronic devices, integrated circuit heat sinks, automotive rotors, and other fields. In the research of CNTs / Cu composites, how to leverage the respective advantages of CNTs and Cu to prepare CNTs / Cu composites with excellent mechanical and electrical properties has become a research hotspot in the field.
[0003] Currently, the application of CNTs in Cu-based composites faces the following challenges: First, due to their large aspect ratio and high specific surface area, CNTs easily agglomerate under the action of van der Waals forces, making them difficult to disperse in the metal matrix. Second, the interfacial wettability between CNTs and the Cu matrix is poor, and the interface bonding is mainly mechanical intercalation. This physical bonding method results in weak interfacial bonding strength of CNTs / Cu composites. Although the chemical bridging effect of oxygen generated by acidification of CNTs can improve the wettability between CNTs and Cu and enhance the interfacial bonding between CNTs and Cu, the presence of oxygen-containing functional groups greatly reduces the electrical conductivity of CNTs / Cu composites. Therefore, it is necessary to provide a feasible strategy to improve the interfacial bonding between CNTs and Cu matrix to meet the requirements of structural and functional integration. Summary of the Invention
[0004] In view of the above shortcomings of the prior art, the present invention provides a method for preparing a nitrogen-doped carbon nanotube-reinforced high-conductivity copper-based composite material.
[0005] To achieve the above object, the technical solution adopted by the present invention is:
[0006] A method for preparing a nitrogen-doped carbon nanotube-reinforced high-conductivity copper-based composite material comprises the following steps:
[0007] (1) introducing a mixed gas of N2 and Ar to subject the carbon nanotubes to plasma treatment, and then cooling the protective atmosphere to room temperature to obtain nitrogen-doped carbon nanotubes;
[0008] (2) nitrogen-doped carbon nanotubes were ultrasonically dispersed in water and then added to a copper acetate solution to prepare NCNTs / CuO composite powders by molecular-level blending;
[0009] (3) subjecting the NCNTs / CuO composite powder to a reduction annealing treatment in a reducing atmosphere of N2 and H2 to obtain a NCNTs / Cu composite powder;
[0010] (4) ball milling the NCNTs / Cu composite powder, drying it, and then performing reduction annealing treatment in a reducing atmosphere of N2 and H2 to obtain NCNTs / Cu composite powder;
[0011] (5) The NCNTs / Cu composite powder is subjected to spark plasma sintering to obtain nitrogen-doped carbon nanotube composite reinforced copper-based bulk material.
[0012] The method of the present invention performs nitrogen doping on the surface of carbon nanotubes while maintaining the structural integrity of the carbon nanotubes. The nitrogen-doped carbon nanotubes not only improve their own dispersibility but also, when combined with a Cu-based material, enhance the wettability between Cu and the nitrogen-doped nanotubes due to changes in their surface properties, resulting in uniform dispersion of the nitrogen-doped nanotubes in the Cu matrix and improved interfacial bonding strength between the CNTs and the Cu matrix.
[0013] The present invention evenly disperses carbon nanotubes on a quartz plate to ensure that the carbon nanotubes are evenly spread and fluffy, and then places the quartz plate with the dispersed carbon nanotubes into a plasma treatment device for plasma treatment.
[0014] As a preferred embodiment of the present invention, the carbon nanotubes have a purity of 98%, an outer diameter of 20-50 nm, and a length of 10-50 μm.
[0015] As a preferred embodiment of the present invention, in step (1), the plasma treatment power is 150-250 W, the N2 flow rate is 60-90 sccm, and the Ar flow rate is 10-40 sccm.
[0016] The present invention regulates the content of nitrogen-containing functional groups on the carbon nanotube surface through plasma treatment, thereby controlling the properties of the nitrogen-doped carbon nanotubes and strengthening their interfacial bonding with the copper-based material. Furthermore, the nitrogen-doping treatment reduces backscattering from the Cu matrix surrounding the carbon nanotubes, thereby facilitating electron transfer at the interface between the carbon nanotubes and the Cu matrix. This results in a nitrogen-doped carbon nanotube-reinforced copper-based material with excellent mechanical and electrical properties.
[0017] Nitrogen-doped carbon nanotubes are referred to as NCNTs; NCNTs / CuO composite powder is nitrogen-doped carbon nanotube / CuO composite powder; NCNTs / Cu composite powder is nitrogen-doped carbon nanotube / Cu composite powder.
[0018] As a preferred embodiment of the present invention, the molecular-level blending method includes the following steps: adding nitrogen-doped carbon nanotubes to a copper acetate solution and stirring, then adding a sodium hydroxide solution and heating, and finally adding a glucose solution to react, and after the reaction is completed, washing and drying to obtain NCNTs / CuO composite powder.
[0019] As a preferred embodiment of the present invention, the volume fraction of Cu in the NCNTs / Cu composite powder is 97.5% to 99.5%, and the volume fraction of nitrogen-doped carbon nanotubes is 0.5% to 2.5%.
[0020] As a preferred embodiment of the present invention, the molar ratio of copper acetate, sodium hydroxide and glucose is 0.2:7:2.
[0021] As a preferred embodiment of the present invention, in step (3), the reduction annealing temperature is 250-350° C. and the time is 4-7 hours.
[0022] As a preferred embodiment of the present invention, in the step (4), the ball milling time is 2-3 hours, the rotation speed is 250-350 r / min; the reduction annealing temperature is 200-300° C., and the time is 3-6 hours.
[0023] As a preferred embodiment of the present invention, the spark plasma sintering has a heating rate of 120-200° C. / min, a temperature of 600-900° C., and a holding time of 5-20 min.
[0024] Compared with the prior art, the present invention has the following beneficial effects:
[0025] (1) The present invention adopts plasma treatment, molecular-level blending, plasma sintering and other processes to regulate the content of functional groups on the surface of nitrogen-doped carbon nanotubes without changing the structure of carbon nanotubes, thereby not only enhancing the dispersibility of carbon nanotubes but also enhancing the interfacial bonding strength with the Cu matrix. The obtained nitrogen-doped carbon nanotube composite reinforced copper-based material has not only excellent mechanical properties but also good electrical properties.
[0026] (2) The preparation method of the present invention is simple and easy to implement, and the method can be widely used in the composite of other metal-based materials and carbon nanotubes. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Figure 1 This is a process flow chart of the preparation method of the nitrogen-doped carbon nanotube-reinforced high-conductivity copper-based composite material of the present invention.
[0028] Figure 2TEM images of nitrogen-doped carbon nanotubes prepared in Example 1 and Comparative Example 1 of the present invention or untreated carbon nanotubes, wherein (a) is a TEM image of the untreated carbon nanotubes prepared in Comparative Example 1; (b) is a TEM image of the nitrogen-doped carbon nanotubes prepared in Example 1.
[0029] Figure 3 This is an X-ray photoelectron spectrum of the nitrogen-doped carbon nanotubes prepared in Example 1 of the present invention.
[0030] Figure 4 The engineering stress-strain curves obtained from the tensile test of the materials prepared in Examples 1, 2, 3 and Comparative Examples 1 and 5 of the present invention are shown. DETAILED DESCRIPTION
[0031] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.
[0032] Example 1
[0033] This embodiment provides a method for preparing a nitrogen-doped carbon nanotube-reinforced high-conductivity copper-based composite material, which specifically includes the following steps:
[0034] (1) 100 mg of carbon nanotubes were evenly dispersed on a quartz plate through a sieve to ensure that the carbon nanotubes were evenly spread and fluffy; the purity of the carbon nanotubes was 98%, the outer diameter was 20-50 nm, and the length was 10-50 μm.
[0035] (2) The quartz plate covered with carbon nanoparticles was placed in a tubular furnace with a plasma generator and placed close to the plasma emission source. A mixed gas of 90 sccm of N2 and 10 sccm of high-purity Ar was introduced. The CNTs were then treated with 250 W plasma for 25 minutes. After the treatment was completed, the furnace cover was opened and the temperature was lowered to room temperature in a protective atmosphere to obtain NCNTs.
[0036] (3) 36 mg of NCNTs were ultrasonically dispersed in 50 ml of water for 1 hour, then added to 0.2 ml of copper acetate solution and stirred, 7 mol of sodium hydroxide solution was added and heated, and finally 2 mol of glucose solution was added to react. After the reaction, the NCNTs / CuO composite powder was washed and dried to obtain the result.
[0037] (4) The NCNTs / CuO composite powder was placed in a tube furnace and heated and reduced at 350°C for 5 hours at a heating rate of 10°C / min. The reducing atmosphere was N2 and H2 with a total gas flow rate of 200 sccm, where the N2 to H2 flow ratio was 10:1, to obtain a composite powder.
[0038] (5) The composite powder was ball milled for 2 hours with a ball-to-material ratio of 10:1 and a rotation speed of 250 r / min, then filtered and dried, and finally heated in a tube furnace at 250 °C for 5 hours with a heating rate of 10 °C / min. The reducing atmosphere was N2 and H2 with a total gas flow rate of 200 sccm, where the N2 to H2 flow ratio was 10:1, to obtain NCNTs / Cu composite powder;
[0039] (6) The NCNTs / Cu composite powder was sintered by SPS with a heating rate of 100℃ / min, a sintering temperature of 700℃, and a holding time of 10min to obtain a nitrogen-doped carbon nanotube composite reinforced copper-based material.
[0040] The nitrogen-doped carbon nanotubes (NCNTs) sample obtained in step (2) was tested, and its microscopic morphology was as follows: Figure 2 As shown in the figure, Figure (a) is the morphology of carbon nanotubes taken by HRTEM, and Figure (b) is the morphology of nitrogen-doped carbon nanotubes taken by HRTEM. It can be seen from the figure that after plasma treatment, the surface of the nitrogen-doped carbon nanotubes presents a bamboo-like morphology along the tube wall, which is completely different from the tubular shape of the carbon nanotubes.
[0041] Through Figure 2 and Figure 3 The analysis of the test results such as XPS and TEM showed that in this embodiment, nitrogen-containing functional groups were successfully introduced on the surface of CNTs after plasma bombardment, and nitrogen-doped carbon nanotube composite reinforced copper-based materials were prepared by compounding them with pure Cu.
[0042] Mechanical property testing results show that the nitrogen-doped carbon nanotube composite reinforced copper-based material has a tensile strength of 290 MPa and an elongation at break of 16%, significantly higher than pure copper (tensile strength of 224 MPa). This is due to the introduction of nitrogen-containing functional groups, which significantly improves the interfacial bonding between the nitrogen-doped carbon nanotubes and the Cu matrix, thereby significantly enhancing its load transfer capacity. At the same time, the nitrogen-doping treatment reduces the backscattering of the Cu matrix around the nitrogen-doped carbon nanotubes, allowing the nitrogen-doped carbon nanotube composite reinforced copper-based material to maintain excellent electrical conductivity of 94.3% IACS while improving its mechanical properties.
[0043] Example 2
[0044] This embodiment provides a method for preparing a nitrogen-doped carbon nanotube-reinforced high-conductivity copper-based composite material, which specifically includes the following steps:
[0045] (1) 100 mg of carbon nanotubes were evenly dispersed on a quartz plate through a sieve to ensure that the carbon nanotubes were evenly spread and fluffy; the purity of the carbon nanotubes was 98%, the outer diameter was 20-50 nm, and the length was 10-50 μm.
[0046] (2) The quartz plate covered with carbon nanoparticles was placed in a tubular furnace with a plasma generator and placed close to the plasma emission source. A mixed gas of 70 sccm of N2 and 30 sccm of high-purity Ar was introduced. The CNTs were then treated with 250 W plasma for 25 minutes. After the treatment was completed, the furnace cover was opened and the temperature was lowered to room temperature in a protective atmosphere to obtain NCNTs.
[0047] (3) 36 mg of NCNTs were ultrasonically dispersed in 50 ml of water for 1 hour, then added to 0.2 ml of copper acetate solution and stirred, 7 mol of sodium hydroxide solution was added and heated, and finally 2 mol of glucose solution was added to react. After the reaction, the NCNTs / CuO composite powder was washed and dried to obtain the result.
[0048] (4) The NCNTs / CuO composite powder was placed in a tube furnace and heated and reduced at 350°C for 5 hours at a heating rate of 10°C / min. The reducing atmosphere was N2 and H2 with a total gas flow rate of 200 sccm, where the N2 to H2 flow ratio was 10:1, to obtain a composite powder.
[0049] (5) The composite powder was ball milled for 2 hours with a ball-to-material ratio of 10:1 and a rotation speed of 250 r / min, then filtered and dried, and finally heated in a tube furnace at 250 °C for 5 hours with a heating rate of 10 °C / min. The reducing atmosphere was N2 and H2 with a total gas flow rate of 200 sccm, where the N2 to H2 flow ratio was 10:1, to obtain NCNTs / Cu composite powder;
[0050] (6) The NCNTs / Cu composite powder was sintered by SPS with a heating rate of 100℃ / min, a sintering temperature of 700℃, and a holding time of 10min to obtain a nitrogen-doped carbon nanotube composite reinforced copper-based material.
[0051] The obtained nitrogen-doped carbon nanotube composite reinforced copper-based material has a tensile strength of 282 MPa, an elongation at break of 23%, and an electrical conductivity of 94.5% IACS.
[0052] pass Figure 2 and 3 Analysis of XPS, TEM and other test results show that this embodiment successfully introduced nitrogen-containing functional groups on the surface of CNTs through plasma nitrogen doping treatment, and prepared NCNTs / Cu composite materials after compounding with copper powder. The mechanical properties test results show that the strength of the nitrogen-doped carbon nanotube composite reinforced copper-based material is significantly improved compared with pure copper prepared by the same method, and good plasticity is maintained. At the same time, it also has an electrical conductivity comparable to that of pure copper prepared by the same method.
[0053] Example 3
[0054] This embodiment provides a method for preparing a nitrogen-doped carbon nanotube-reinforced high-conductivity copper-based composite material, which specifically includes the following steps:
[0055] (1) 100 mg of carbon nanotubes were evenly dispersed on a quartz plate through a sieve to ensure that the carbon nanotubes were evenly spread and fluffy; the purity of the carbon nanotubes was 98%, the outer diameter was 20-50 nm, and the length was 10-50 μm.
[0056] (2) The quartz plate covered with carbon nanoparticles was placed in a tubular furnace with a plasma generator and placed close to the plasma emission source. A mixed gas of 60 sccm of N2 and 40 sccm of high-purity Ar was introduced. The CNTs were then treated with 250W plasma for 25 minutes. After the treatment was completed, the furnace cover was opened and the temperature was lowered to room temperature in a protective atmosphere to obtain NCNTs.
[0057] (3) 36 mg of NCNTs were ultrasonically dispersed in 50 ml of water for 1 hour, then added to 0.2 ml of copper acetate solution and stirred, 7 mol of sodium hydroxide solution was added and heated, and finally 2 mol of glucose solution was added to react. After the reaction, the NCNTs / CuO composite powder was washed and dried to obtain the result.
[0058] (4) The NCNTs / CuO composite powder was placed in a tube furnace and heated and reduced at 350°C for 5 hours at a heating rate of 10°C / min. The reducing atmosphere was N2 and H2 with a total gas flow rate of 200 sccm, where the N2 to H2 flow ratio was 10:1, to obtain a composite powder.
[0059] (5) The composite powder was ball milled for 2 hours with a ball-to-material ratio of 10:1 and a rotation speed of 250 r / min, then filtered and dried, and finally heated in a tube furnace at 250 °C for 5 hours with a heating rate of 10 °C / min. The reducing atmosphere was N2 and H2 with a total gas flow rate of 200 sccm, where the N2 to H2 flow ratio was 10:1, to obtain NCNTs / Cu composite powder;
[0060] (6) The NCNTs / Cu composite powder was sintered by SPS with a heating rate of 100℃ / min, a sintering temperature of 700℃, and a holding time of 10min to obtain a nitrogen-doped carbon nanotube composite reinforced copper-based material.
[0061] The obtained nitrogen-doped carbon nanotube composite reinforced copper-based material has a tensile strength of 273 MPa, an elongation at break of 24%, and an electrical conductivity of 94.7% IACS.
[0062] pass Figure 2 and Figure 3Analysis of XPS, TEM and other test results showed that nitrogen-containing functional groups were successfully introduced on the surface of CNTs through plasma nitrogen doping treatment, and nitrogen-doped carbon nanotube composite reinforced copper-based materials were prepared after compounding with copper powder. The mechanical properties test results showed that the nitrogen-doped carbon nanotube composite reinforced copper-based materials maintained excellent electrical conductivity while achieving improved mechanical properties.
[0063] Example 4
[0064] This embodiment provides a method for preparing a nitrogen-doped carbon nanotube-reinforced high-conductivity copper-based composite material, which specifically includes the following steps:
[0065] (1) 100 mg of carbon nanotubes were evenly dispersed on a quartz plate through a sieve to ensure that the carbon nanotubes were evenly spread and fluffy; the purity of the carbon nanotubes was 98%, the outer diameter was 20-50 nm, and the length was 10-50 μm.
[0066] (2) The quartz plate covered with carbon nanoparticles was placed in a tubular furnace with a plasma generator and placed close to the plasma emission source. A mixed gas of 60 sccm of N2 and 40 sccm of high-purity Ar was introduced. The CNTs were then treated with 150W plasma for 25 minutes. After the treatment was completed, the furnace cover was opened and the temperature was lowered to room temperature in a protective atmosphere to obtain NCNTs.
[0067] (3) 12 mg of NCNTs were ultrasonically dispersed in 50 ml of water for 1 hour, then added to 0.2 ml of copper acetate solution and stirred, 7 mol of sodium hydroxide solution was added and heated, and finally 2 mol of glucose solution was added to react. After the reaction, the NCNTs / CuO composite powder was washed and dried to obtain the result.
[0068] (4) The NCNTs / CuO composite powder was placed in a tube furnace for heating reduction treatment at 250°C for 7 hours with a heating rate of 10°C / min. The reducing atmosphere was N2 and H2 with a total gas flow rate of 200 sccm, where the N2 to H2 flow ratio was 10:1, to obtain a composite powder.
[0069] (5) The composite powder was ball milled for 3 hours with a ball-to-material ratio of 10:1 and a rotation speed of 350 r / min, then filtered and dried, and finally heated in a tube furnace for reduction treatment at 300 °C for 3 hours with a heating rate of 10 °C / min. The reducing atmosphere was N2 and H2 with a total gas flow rate of 200 sccm, where the N2 to H2 flow ratio was 10:1, to obtain NCNTs / Cu composite powder;
[0070] (6) The NCNTs / Cu composite powder was sintered by SPS with a heating rate of 200℃ / min, a sintering temperature of 900℃, and a holding time of 5min to obtain a nitrogen-doped carbon nanotube composite reinforced copper-based material.
[0071] The obtained nitrogen-doped carbon nanotube composite reinforced copper-based material has a tensile strength of 269 MPa, an elongation at break of 28%, and an electrical conductivity of 95.2% IACS.
[0072] Example 5
[0073] This embodiment provides a method for preparing a nitrogen-doped carbon nanotube-reinforced high-conductivity copper-based composite material, which specifically includes the following steps:
[0074] (1) 100 mg of carbon nanotubes were evenly dispersed on a quartz plate through a sieve to ensure that the carbon nanotubes were evenly spread and fluffy; the purity of the carbon nanotubes was 98%, the outer diameter was 20-50 nm, and the length was 10-50 μm.
[0075] (2) The quartz plate covered with carbon nanoparticles was placed in a tubular furnace with a plasma generator and placed close to the plasma emission source. A mixed gas of 60 sccm of N2 and 40 sccm of high-purity Ar was introduced. The CNTs were then treated with 200 W plasma for 25 min. After the treatment was completed, the furnace cover was opened and the temperature was lowered to room temperature in a protective atmosphere to obtain NCNTs.
[0076] (3) 60 mg of NCNTs were ultrasonically dispersed in 50 ml of water for 1 hour, then added to 0.2 ml of copper acetate solution and stirred, 7 mol of sodium hydroxide solution was added and heated, and finally 2 mol of glucose solution was added to react. After the reaction, the NCNTs / CuO composite powder was washed and dried to obtain the result.
[0077] (4) The NCNTs / CuO composite powder was placed in a tube furnace for heating reduction treatment at 300°C for 4 hours with a heating rate of 10°C / min. The reducing atmosphere was N2 and H2 with a total gas flow rate of 200 sccm, where the N2 to H2 flow ratio was 10:1, to obtain a composite powder.
[0078] (5) The composite powder was ball milled for 2 hours with a ball-to-material ratio of 10:1 and a rotation speed of 300 r / min, then filtered and dried, and finally heated in a tube furnace for reduction treatment at 250 °C for 6 hours with a heating rate of 10 °C / min. The reducing atmosphere was N2 and H2 with a total gas flow rate of 200 sccm, where the N2 to H2 flow ratio was 10:1, to obtain NCNTs / Cu composite powder;
[0079] (6) The NCNTs / Cu composite powder was sintered by SPS with a heating rate of 150℃ / min, a sintering temperature of 600℃, and a holding time of 20min to obtain a nitrogen-doped carbon nanotube composite reinforced copper-based material.
[0080] The obtained nitrogen-doped carbon nanotube composite reinforced copper-based material has a tensile strength of 263 MPa, an elongation at break of 15%, and an electrical conductivity of 91.2% IACS.
[0081] Comparative Example 1
[0082] This comparative example provides a method for preparing a carbon nanotube composite reinforced copper-based material, which specifically includes the following steps:
[0083] (1) 36 mg of carbon nanotubes were ultrasonically dispersed in 50 ml of water for 1 hour, then added to 0.2 ml of copper acetate solution and stirred, 7 mol of sodium hydroxide solution was added and heated, and finally 2 mol of glucose solution was added to react. After the reaction, the CNTs / CuO composite powder was washed and dried to obtain the result.
[0084] (2) The CNTs / CuO composite powder was placed in a tube furnace and subjected to a heating reduction treatment at 350°C for 5 hours at a heating rate of 10°C / min. The reducing atmosphere was N2 and H2 with a total gas flow rate of 200 sccm, where the N2 to H2 flow ratio was 10:1, to obtain a composite powder.
[0085] (3) The composite powder was ball-milled for 2 hours with a ball-to-material ratio of 10:1 and a rotation speed of 250 r / min, then filtered and dried, and finally subjected to a heating reduction treatment in a tube furnace at 250 °C for 5 hours with a heating rate of 10 °C / min. The reducing atmosphere was N2 and H2 with a total gas flow rate of 200 sccm, wherein the flow ratio of N2 to H2 was 10:1, to obtain CNTs / Cu composite powder;
[0086] (4) The CNTs / Cu composite powder was sintered by SPS with a heating rate of 100℃ / min, a sintering temperature of 700℃, and a holding time of 10min to obtain a carbon nanotube composite reinforced copper-based material.
[0087] The obtained nanotube composite reinforced copper-based material has a tensile strength of 241 MPa, an elongation at break of 10%, and an electrical conductivity of 89.3% IACS.
[0088] Comparative Example 2
[0089] The only difference between the preparation method of a nitrogen-doped carbon nanotube-reinforced high-conductive copper-based composite material in this comparative example and that in Example 1 is that in step (2), 100 sccm of N2 is introduced, and high-purity Ar is not introduced.
[0090] The obtained nitrogen-doped carbon nanotube composite reinforced copper-based material has a tensile strength of 255 MPa, an elongation at break of 22%, and an electrical conductivity of 92.9% IACS.
[0091] Due to the presence of a small amount of Ar, the dissociation of N2 during plasma treatment can be promoted, thereby increasing the N content incorporated into CNTs. Without the introduction of Ar, the N content incorporated into CNTs is less, resulting in its performance being worse than that of the example sample.
[0092] Comparative Example 3
[0093] The only difference between the preparation method of a nitrogen-doped carbon nanotube-reinforced high-conductive copper-based composite material in this comparative example and that in Example 1 is that in step (2), a mixed gas of 50 sccm of N2 and 50 sccm of high-purity Ar is introduced.
[0094] The obtained nitrogen-doped carbon nanotube composite reinforced copper-based material has a tensile strength of 251 MPa, an elongation at break of 25%, and an electrical conductivity of 93.3% IACS.
[0095] Due to the excessive amount of Ar introduced, Ar is a protective gas and its state is very stable. In the presence of a large amount of Ar, the plasma cannot ionize N2, resulting in a low content of N incorporated into CNTs, and the ideal enhancement effect cannot be achieved, resulting in its performance being worse than that of the example sample.
[0096] Comparative Example 4
[0097] The only difference between the preparation method of a nitrogen-doped carbon nanotube-reinforced high-conductive copper-based composite material in this comparative example and that in Example 1 is that in step (2), 100 sccm of high-purity Ar is introduced, and N2 is not introduced.
[0098] The obtained nitrogen-doped carbon nanotube composite reinforced copper-based material has a tensile strength of 245 MPa, an elongation at break of 13%, and an electrical conductivity of 89.1% IACS.
[0099] Since only Ar was introduced without the presence of a nitrogen source, no N was incorporated into the CNTs, resulting in a low interfacial bonding strength between the CNTs and the Cu matrix. At the same time, the mechanical and electrical properties of the CNT composite reinforced copper-based material decreased.
[0100] Comparative Example 5
[0101] This comparative example provides a method for preparing a copper-based material, comprising the following steps:
[0102] (1) Stir 0.2 ml of copper acetate solution evenly, add 7 mol of sodium hydroxide solution and heat, and finally add 2 mol of glucose solution to react. After the reaction is completed, wash and dry the CuO powder.
[0103] (4) The CuO powder was placed in a tube furnace and subjected to a heating reduction treatment at 350°C for 5 hours at a heating rate of 10°C / min. The reducing atmosphere was N2 and H2 with a total gas flow rate of 200 sccm, wherein the flow ratio of N2 to H2 was 10:1, to obtain Cu powder.
[0104] (5) The Cu powder was ball-milled for 2 h with a ball-to-material ratio of 10:1 and a rotation speed of 250 r / min, then filtered and dried, and finally subjected to a heat reduction treatment at 250 °C in a tube furnace for 5 h with a heating rate of 10 °C / min. The reducing atmosphere was N2 and H2 with a total gas flow rate of 200 sccm, where the N2 to H2 flow ratio was 10:1, to obtain pure Cu powder;
[0105] (6) The pure Cu powder was sintered by SPS with a heating rate of 100℃ / min, a sintering temperature of 700℃, and a holding time of 10min to obtain a bulk copper-based material.
[0106] The obtained copper-based material has a tensile strength of 224 MPa, an elongation at break of 36%, and an electrical conductivity of 95.9% IACS.
[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.
Claims
1. A method for preparing a nitrogen-doped carbon nanotube-reinforced high-conductivity copper-based composite material, characterized in that: The following steps are involved: (1) introducing a mixed gas of N2 and Ar to subject the carbon nanotubes to plasma treatment, and then cooling the protective atmosphere to room temperature to obtain nitrogen-doped carbon nanotubes; the flow rate of N2 is 60-90 sccm, the flow rate of Ar is 10-40 sccm, and the plasma treatment power is 150-250 W; (2) nitrogen-doped carbon nanotubes were ultrasonically dispersed in water and then added to a copper acetate solution to prepare NCNTs / CuO composite powders by molecular-level blending; (3) subjecting the NCNTs / CuO composite powder to a reduction annealing treatment in a reducing atmosphere of N2 and H2 to obtain a NCNTs / Cu composite powder; (4) ball milling the composite powder, drying it, and then performing reduction annealing treatment in a reducing atmosphere of N2 and H2 to obtain NCNTs / Cu composite powder; (5) The NCNTs / Cu composite powder is subjected to spark plasma sintering to obtain nitrogen-doped carbon nanotube-reinforced copper-based composite bulk material.
2. The method for preparing the nitrogen-doped carbon nanotube-reinforced high-conductivity copper-based composite material according to claim 1, wherein: The carbon nanotubes have a purity of more than 98%, an outer diameter of 20-50 nm, and a length of 10-50 μm.
3. The method for preparing the nitrogen-doped carbon nanotube-reinforced high-conductivity copper-based composite material according to claim 1, wherein: In the step (3), the volume fraction of Cu in the NCNTs / Cu composite powder is 97.5% to 99.5%, and the volume fraction of the nitrogen-doped carbon nanotubes is 0.5% to 2.5%.
4. The method for preparing the nitrogen-doped carbon nanotube-reinforced high-conductivity copper-based composite material according to claim 1, wherein: The molecular-level blending method comprises the following steps: adding NCNTs to a copper acetate solution and stirring, then adding a sodium hydroxide solution and heating, and finally adding a glucose solution to react, and after the reaction is completed, washing and drying to obtain NCNTs / CuO composite powder.
5. The method for preparing the nitrogen-doped carbon nanotube-reinforced high-conductivity copper-based composite material according to claim 4, wherein: The molar ratio of the copper acetate, sodium hydroxide and glucose is 0.2:7:
2.
6. The method for preparing the nitrogen-doped carbon nanotube-reinforced high-conductivity copper-based composite material according to claim 1, wherein: In the step (3), the reduction annealing temperature is 250-350° C. and the time is 4-7 hours.
7. The method for preparing the nitrogen-doped carbon nanotube-reinforced high-conductivity copper-based composite material according to claim 1, wherein: In the step (4), the ball milling time is 2-3 hours, the rotation speed is 250-350 r / min; the reduction annealing temperature is 200-300° C., and the time is 3-6 hours.
8. The method for preparing the nitrogen-doped carbon nanotube-reinforced high-conductivity copper-based composite material according to claim 1, wherein: The heating rate of spark plasma sintering is 120-200°C / min, the temperature is 600-900°C, and the holding time is 5-20min.
Citation Information
Patent Citations
Method for formation of nitrogen doped single-walled carbon nanotube
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Loaded graphene / metallic compound-contained electrode preparation method based on hollow cathode plasma reduction and nitridation
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