Preparation method of large-size single crystal copper foil

Abstract

The invention discloses a preparation method of a large-size single crystal copper foil, which comprises the following steps: carrying out primary annealing treatment on the copper foil at a first temperature in a reducing atmosphere, then stretching the copper foil along a single direction until the total elongation is 0.1-1.0%, carrying out secondary annealing treatment on the copper foil at a second temperature in the reducing atmosphere, and then carrying out air cooling to obtain the large-size single crystal copper foil, wherein the first temperature is lower than the second temperature. According to the method, the annealing is combined with the uniaxial drawing process, and the large-size single crystal copper foil with the length exceeding 10 cm can be prepared according to specific requirements. The preparation method disclosed by the invention is low in preparation cost and simple and convenient to operate, and has good industrial production potential.

Description

Technical Field

[0001] The invention relates to the technical field of single crystal material preparation, and in particular to a method for preparing a large-size single crystal copper foil. Background Art

[0002] As an important metal substrate material, single crystal copper foil plays a pivotal role in the fields of materials science and nanotechnology. The preparation technology of single crystal copper foil is crucial for realizing high-performance electronic devices, energy storage systems, sensors, catalysts and other applications. The main properties of single crystal copper foil include its high electrical conductivity, high thermal conductivity, excellent mechanical properties and good chemical stability, which make it an ideal substrate for advanced material growth technologies such as chemical vapor deposition (CVD).

[0003] The traditional method of preparing single-crystal copper foil usually involves a high-temperature annealing process, which is not only energy-intensive but also may lead to microstructural defects in the material, such as grain boundaries, twins, and dislocations. These defects can reduce the catalytic performance of the copper foil and affect the growth quality of graphene. The preparation technology of single-crystal copper foil substrates is of great significance for promoting the scientific research and industrial application of graphene and other two-dimensional materials. With the continuous advancement of preparation technology and the development of new material systems, it is expected that higher quality and larger size graphene can be prepared in the future, providing a strong material foundation for various high-tech applications.

[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present invention, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0005] The object of the present invention is to provide a method for preparing a large-sized single-crystalline copper foil in view of the above-mentioned problems. The present invention first anneals the copper foil at a relatively low temperature in a reducing atmosphere, then stretches the copper foil in a single direction, and then performs a secondary annealing treatment at a relatively high temperature in a reducing atmosphere, so as to finally obtain a large-sized single-crystalline copper foil, thereby expanding the effective use area of ​​the single-crystalline copper foil, simplifying the preparation process, reducing the preparation cost, and overcoming the shortcomings of the existing preparation technology.

[0006] The technical solution adopted by the present invention is as follows: a method for preparing a large-size single-crystal copper foil, wherein the copper foil is subjected to a first annealing treatment at a first temperature in a reducing atmosphere (no pretreatment such as mechanical polishing of the copper foil is required), and then the copper foil is stretched in a single direction (the copper foil after the first annealing does not need to be cut or further processed, and can be directly subjected to uniaxial stretching), with a total elongation of 0.1-1.0%, and then the copper foil is subjected to a second annealing treatment at a second temperature in a reducing atmosphere, and then air-cooled to obtain a large-size single-crystal copper foil of centimeter level or above; wherein the first temperature is lower than the second temperature.

[0007] Further, the first temperature ranges from 300 to 900°C, for example, 300°C, 400°C, 500°C, 600°C, 800°C, 900°C, etc., and the second temperature ranges from 950 to 1100°C, for example, 950°C, 980°C, 1000°C, 1020°C, 1040°C, 1050°C, 1100°C, etc. Preferably, the first temperature ranges from 300 to 600°C, and the second temperature ranges from 950 to 1050°C, and more preferably, the first temperature ranges from 500 to 600°C, and the second temperature ranges from 1000 to 1040°C.

[0008] Furthermore, the total elongation is 0.1-1%, for example, 0.1%, 0.2%, 0.3%, 0.5%, 1% and the like.

[0009] Furthermore, the reducing atmosphere is a mixed atmosphere of Ar and H2, wherein the volume fraction of H2 is 5-40%, for example, it can be 5%, 8%, 10%, 20%, 40%, etc., the gas flow rate is 20-100sccm, for example, it can be 20sccm, 40sccm, 60sccm, 80sccm, 100sccm, etc., and the gas flow rate of Ar is 300-700sccm, for example, it can be 300sccm, 400sccm, 500sccm, 600sccm, 700sccm, etc.

[0010] Furthermore, during the first annealing treatment, the annealing time is 10 min-24 h, for example, it can be 10 min, 30 min, 60 min, 1 h, 5 h, 12 h, 24 h, etc., and the annealing pressure is 0.1 Pa-101.325 kPa, for example, it can be 0.1 Pa, 10 Pa, 100 Pa, 1000 Pa, 101.325 kPa, etc.

[0011] Furthermore, during the second annealing treatment, for example, it can be 10 min, 30 min, 60 min, 1 h, 5 h, 12 h, 24 h, etc., the annealing pressure is 0.1 Pa-101.325 kPa, for example, it can be 0.1 Pa, 10 Pa, 100 Pa, 1000 Pa, 101.325 kPa, etc.

[0012] Furthermore, the copper foil used is commercial polycrystalline rolled copper foil.

[0013] Preferably, the method for preparing the large-size single crystal copper foil of the present invention comprises the following steps:

[0014] S1. Place the copper foil in a heating furnace, and perform the first annealing at 300-900°C (for example, 300°C, 500°C, 600°C, 900°C, etc.) in a mixed atmosphere of Ar and H2, keep the temperature for 10min-24h, the annealing pressure is 0.1Pa-101.325kPa (for example, 0.1Pa, 10Pa, 100Pa, 1000Pa, 101.325kPa, etc.), the Ar flow rate is 300-700sccm (for example, 300sccm, 400sccm, 500sccm, 600sccm, 700sccm, etc.), the H2 flow rate is 20-100sccm (for example, 20sccm, 40sccm, 60sccm, 80sccm, 100sccm, etc.), and then air-cool to room temperature and take out;

[0015] S2, stretching the copper foil annealed for the first time to a total elongation of 0.3-1%;

[0016] S3. Place the stretched copper foil in a heating furnace, and carry out a second annealing at 1040°C in a mixed atmosphere of Ar and H2, keep warm for 10min-24h, the annealing pressure is 0.1Pa-101.325kPa (for example, it can be 0.1Pa, 10Pa, 100Pa, 1000Pa, 101.325kPa, etc.), the Ar flow rate is 300-700sccm (for example, it can be 300sccm, 400sccm, 500sccm, 600sccm, 700sccm, etc.), the H2 flow rate is 20-100sccm (for example, it can be 20sccm, 40sccm, 60sccm, 80sccm, 100sccm, etc.), and then air-cool it to room temperature and take it out.

[0017] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0018] 1. The preparation method of the present invention is simple and easy, and can effectively reduce costs. The present invention can select a variety of commercial polycrystalline rolled copper foils, and there is no need to perform complex mechanical and polishing treatments on the copper foil in the early stage. The stretching process is also simple and easy, and no further treatment of the copper foil is required, which effectively reduces the preparation and production costs;

[0019] 2. The present invention can effectively control the size of the prepared single crystal, and the prepared single crystal substrate (copper foil) can be directly used in the growth process of two-dimensional materials, which is easy to expand to industrial production and shows broad commercial application potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the preparation process of the large-size single crystal copper foil of the present invention;

[0021] Figure 2 This is a photo of a large-sized single crystal copper foil obtained by stretching 0.3% in Example 1 of the present invention;

[0022] Figure 3 This is a photo of a large-sized single crystal copper foil obtained by stretching 0.5% in Example 2 of the present invention;

[0023] Figure 4 This is a photograph of the large-sized single crystal copper foil obtained by stretching 0.7% in Example 3 of the present invention. DETAILED DESCRIPTION

[0024] The present invention will be described in detail below in conjunction with the accompanying drawings.

[0025] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0026] Example 1

[0027] A method for preparing a large-size single crystal copper foil, such as Figure 1 As shown, the following steps are included:

[0028] S1. Place the commercial polycrystalline rolled copper foil in a heating furnace, perform the first annealing at 600°C in a mixed atmosphere of Ar and H2, keep the temperature for 60 minutes, the annealing pressure is 101.325 kPa, the Ar flow rate is 500 sccm, the H2 flow rate is 40 sccm, and then air-cool to room temperature and take out;

[0029] S2, stretching the copper foil annealed for the first time to a total elongation of 0.3%;

[0030] S3. Place the stretched copper foil in a heating furnace and perform a second annealing at 1040°C in a mixed atmosphere of Ar and H2 for 60 min (excluding 60 min of heating). The annealing pressure is 101.325 kPa, the Ar flow rate is 500 sccm, and the H2 flow rate is 40 sccm. Then, air cool to room temperature and take out to obtain a copper foil with an area of ​​2×10 cm 2 Single crystal copper foil substrate, such as Figure 2 As shown, metallographic examination shows that the single crystal copper foil has no microstructural defects such as grain boundaries, twins and dislocations.

[0031] Example 2

[0032] A method for preparing a large-size single crystal copper foil, such as Figure 1 As shown, the following steps are included:

[0033] S1. Place the commercial polycrystalline rolled copper foil in a heating furnace, perform the first annealing at 600°C in a mixed atmosphere of Ar and H2, keep the temperature for 60 minutes, the annealing pressure is 101.325 kPa, the Ar flow rate is 500 sccm, the H2 flow rate is 40 sccm, and then air-cool to room temperature and take out;

[0034] S2, stretching the copper foil annealed for the first time to a total elongation of 0.5%;

[0035] S3. Place the stretched copper foil in a heating furnace and perform a second annealing at 1040°C in a mixed atmosphere of Ar and H2 for 60 min (excluding 60 min of heating). The annealing pressure is 101.325 kPa, the Ar flow rate is 500 sccm, and the H2 flow rate is 40 sccm. Then, air cool to room temperature and take out to obtain a copper foil with an area of ​​2×10 cm 2 Single crystal copper foil substrate, such as Figure 3 As shown, metallographic examination shows that the single crystal copper foil has no microstructural defects such as grain boundaries, twins and dislocations.

[0036] Example 3

[0037] A method for preparing a large-size single crystal copper foil, such as Figure 1 As shown, the following steps are included:

[0038] S1. Place the commercial polycrystalline rolled copper foil in a heating furnace, perform the first annealing at 600°C in a mixed atmosphere of Ar and H2, keep the temperature for 60 minutes, the annealing pressure is 101.325 kPa, the Ar flow rate is 500 sccm, the H2 flow rate is 40 sccm, and then air-cool to room temperature and take out;

[0039] S2, stretching the copper foil annealed for the first time to a total elongation of 0.7%;

[0040] S3. Place the stretched copper foil in a heating furnace and perform a second annealing at 1040°C in a mixed atmosphere of Ar and H2 for 60 min (excluding 60 min of heating). The annealing pressure is 101.325 kPa, the Ar flow rate is 500 sccm, and the H2 flow rate is 40 sccm. Then, air cool to room temperature and take out to obtain a copper foil with an area of ​​2×5 cm 2 Single crystal copper foil substrate, such as Figure 4 As shown, metallographic examination shows that the single crystal copper foil has no microstructural defects such as grain boundaries, twins and dislocations.

[0041] Example 4

[0042] A method for preparing a large-size single crystal copper foil, such as Figure 1 As shown, the following steps are included:

[0043] S1. Place the commercial polycrystalline rolled copper foil in a heating furnace, perform the first annealing at 500°C in a mixed atmosphere of Ar and H2 for 80 minutes, the annealing pressure is 101.325 kPa, the Ar flow rate is 500 sccm, the H2 flow rate is 40 sccm, and then air-cool to room temperature and take out;

[0044] S2, stretching the copper foil annealed for the first time to a total elongation of 0.3%;

[0045] S3. Place the stretched copper foil in a heating furnace and perform a second annealing at 1020°C in a mixed atmosphere of Ar and H2 for 80 min. The annealing pressure is 101.325 kPa, the Ar flow rate is 500 sccm, and the H2 flow rate is 40 sccm. Then, air cool to room temperature and take out to obtain a copper foil with an area of ​​2×10 cm 2 The single crystal copper foil substrate has no microstructural defects such as grain boundaries, twins and dislocations through metallographic detection.

[0046] Through the above examples, the size of the single crystal copper foil can be directly controlled according to the total elongation of the stretching. Under the same conditions, a smaller total elongation will be able to obtain a larger single crystal copper foil. At the same time, due to the limitation of the experimental equipment, it is impossible to prepare a single crystal with a larger length and width in the example. Those skilled in the art can use the present invention to improve the experimental conditions to obtain a larger single crystal copper foil.

[0047] Comparative Example 1

[0048] Comparative Example 1 is the same as Example 1, except that the copper foil annealed for the first time is stretched along the rolling direction with a total elongation of 1.2%.

[0049] Test results: The single crystal copper foil substrate was tested by metallographic examination, and microstructural defects such as dislocations and cracks were found inside the copper foil.

[0050] Comparative Example 2

[0051] Comparative Example 2 is the same as Example 1, except that the first annealing temperature is 900°C.

[0052] Test results: Metallographic examination of the obtained single crystal copper foil substrate showed that there were grain boundary and twin microstructure defects inside the copper foil.

[0053] Comparative Example 3

[0054] Comparative Example 3 is the same as Example 1, except that the first annealing temperature is the same as the second annealing temperature, both of which are 1040°C.

[0055] Test results: Metallographic examination of the obtained single crystal copper foil substrate showed that there were obvious microstructural defects such as dislocation and twins inside the copper foil.

[0056] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a large-size single crystal copper foil, characterized in that: The steps include: S1, placing the copper foil in a heating furnace, performing a first annealing at a first temperature in a reducing mixed atmosphere, and keeping the temperature for a certain time, maintaining a certain annealing pressure, and then air-cooling to room temperature and taking it out; S2, stretching the copper foil annealed for the first time to a certain elongation; S3, placing the stretched copper foil in a heating furnace, annealing it for the second time at the second temperature in a reducing mixed atmosphere, keeping it warm for a certain time, maintaining a certain annealing pressure, and then air-cooling it to room temperature and taking it out, wherein the first temperature is lower than the second temperature.

2. The preparation method according to claim 1, characterized in that The first temperature ranges from 300-900°C.

3. The preparation method according to claim 1, characterized in that: During the first annealing treatment, the annealing time is 10 min-24 h, and the annealing pressure is 0.1 Pa-101.325 kPa.

4. The preparation method according to claim 1, characterized in that: The reducing atmosphere in the first annealing is a mixed atmosphere of Ar and H2, wherein the volume fraction of H2 is 5-40%, the gas flow rate is 20-100 sccm, and the gas flow rate of Ar is 300-700 sccm.

5. The preparation method according to claim 1, characterized in that: The total elongation is 0.1-1%.

6. The preparation method according to claim 1, characterized in that: The second temperature ranges from 950 to 1100° C., the annealing time is from 10 min to 24 h, and the annealing pressure is from 0.1 Pa to 101.325 kPa.

7. The preparation method according to claim 1, characterized in that: The reducing atmosphere in the second annealing is a mixed atmosphere of Ar and H2, wherein the volume fraction of H2 is 5-40%, the gas flow rate is 20-100 sccm, and the gas flow rate of Ar is 300-700 sccm.

8. The preparation method according to claim 1, characterized in that: The copper foil used is commercial polycrystalline rolled copper foil.

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