Preparation method and application of single crystal metal material

Abstract

The invention belongs to the technical field of single crystal materials, and particularly relates to a preparation method and application of a single crystal metal material. The preparation method comprises the following steps that a metal material with the texture content being 80%-100% is annealed, and a single crystal metal material is obtained; in research, the inventor accidentally finds that when the texture content of the metal material reaches 80-100%, annealing is carried out, and due to the fact that the texture with the specific content is better in structure consistency and crystal grains are rearranged in the annealing process, the metal material can be converted into other textures in a relatively concentrated mode; atomic-scale optimization of impurity components and crystal structures can be achieved through annealing, crystals in the material are promoted to be more perfect, the surface roughness is lower, and the obtained single crystal metal material has excellent heat-conducting performance and electric-conducting performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of single crystal materials, and in particular relates to a preparation method and application of a single crystal metal material. Background Art

[0002] Single crystal metal materials (foils) exhibit excellent electrical conductivity, thermal management and mechanical properties due to their highly ordered lattice structure and extremely low defect density. They are ideal basic materials for promoting the performance improvement of high-tech products such as integrated circuit circuit boards and new energy battery collectors. Since 2017, when Liu's research group first prepared meter-sized single crystal Cu (111) foil using temperature gradient annealing technology, single crystal metal material research has quickly become a research hotspot in the field of materials science. In 2020, Wu et al. induced the preparation of A4-sized high-index crystal plane single crystal copper foil and nickel foil using original pre-oxidation treatment technology; in 2024, Su et al. successfully prepared decimeter-sized single crystal nickel foil using pre-strain energy engineering technology. Although single crystal metal material technology has made certain progress, it still faces many challenges in practical applications, especially in terms of large-scale and stable production. However, there is currently a lack of systematic understanding of the relationship between the microstructure characteristics of the raw materials and the single crystal effect after annealing, which makes it difficult to accurately predict and effectively control the single crystal transformation during the annealing process, seriously restricting the further promotion and application of the technology. The stability of materials produced by existing technologies cannot be guaranteed and cannot meet the requirements of large-scale production; and the thermal and electrical conductivity of the materials produced are poor, which has obvious limitations in practical applications. Summary of the Invention

[0003] Therefore, the technical problem to be solved by the present invention is to provide a preparation method and application of single crystal metal materials to address the defects of insufficient stability between batches of metal materials prepared by existing preparation methods and unsatisfactory thermal and electrical conductivity of the prepared materials.

[0004] To this end, the present invention provides the following technical solutions:

[0005] A first aspect of the present invention provides a method for preparing a single crystal metal material, wherein the preparation method comprises the following steps: annealing a metal material having a texture content of 80-100% to obtain a single crystal metal material.

[0006] In the present invention, a metal material with a texture content of 80-100% can be purchased or prepared directly. The inventors unexpectedly discovered that when the texture content of the metal material meets a specific range, it can form a single crystal material after annealing. Metal materials with a specific texture content range can be obtained by rolling the metal material or by pre-annealing after rolling. The source of the metal material is not limited and is relatively broad, including metal materials produced by casting, electrolysis, or rolling, thus having a wide range of applicability. The initial thickness of the metal material before rolling is 0.1-50 mm, and the initial length, width, and thickness can be selected according to requirements.

[0007] In the present invention, the texture content is tested by electron backscatter diffraction (EBSD), and the rolling surface, i.e., the surface formed when the rolling surface passes through the roller gap, is used as the test surface. Specifically, the test area is ≥3mm 2 , test step length ≤ 10μm.

[0008] In some alternative embodiments, the texture content of the metallic material is 90-100%.

[0009] In some optional embodiments, the metal material is face-centered cubic; in the present invention, face-centered cubic corresponds to FCC.

[0010] In some optional embodiments, the texture is cubic {100} <001> texture.

[0011] In the present invention, {100} represents a crystal plane family, <001> Indicates crystal orientation, cubic {100} <001> Texture content is defined as the orientation of the {100} plane parallel to the rolling surface, and <001> The area ratio of all grains parallel to the rolling direction and with an orientation difference of ≤15° is 80-100% for the rolled product. If it is less than 80%, a pre-annealing treatment may be performed to make {100} <001> The texture content is higher than 80%, which promotes the increase of cubic texture.

[0012] In some optional embodiments, the metal material includes at least one of nickel, copper, gold, aluminum, platinum, rhodium and silver.

[0013] In some optional embodiments, the metal material includes at least two of nickel, copper, gold, aluminum, platinum, rhodium and silver.

[0014] In some optional embodiments, the metal material is rolled to obtain a metal material having a texture content of 80-100%.

[0015] In some optional embodiments, the rolling temperature is 25-200°C.

[0016] In some optional embodiments, when the rolling deformation is ≥90%, the strain rate of each rolling pass is 0.1-850s -1 ; Optionally, the strain rate for each rolling pass is 300s -1 , 200s -1 , 100s -1 , 50s -1 , 20s -1 , 10s -1 , 5s -1 , 1s -1 Any value in .

[0017] In the present invention, rolling deformation refers to the absolute value of the deformation of the material during the rolling process; the testing method of rolling deformation (ε) is: ε = [(h0-h1) / h0] × 100%, where h0 is the initial thickness and h1 is the thickness of the rolled product. The strain rate is calculated as follows: Where V is the circumferential speed of the working roll, R is the radius of the working roll, and the strain rate in the present invention includes the strain rate of a single pass and the average strain rate of multiple passes. Rolling is completed when the thickness of the rolled product meets the requirements.

[0018] In some optional embodiments, when the rolling deformation is less than 90%, the strain rate of each rolling pass is 10-850s -1 ; Optionally, the strain rate for each rolling pass is 300s -1 , 200s -1 , 100s -1 , 50s -1 , 20s -1 Any value in .

[0019] In some optional embodiments, pre-annealing is further performed after rolling. It should be noted that when producing a metal material with a texture content of 80-100%, if the texture content of the metal material after rolling does not meet this requirement, pre-annealing is required to bring the texture content back to the required level. If the texture content of the metal material after rolling meets this requirement, pre-annealing may or may not be performed.

[0020] In some optional embodiments, the pre-annealing temperature is T1, 0.10T m ≤T1 ＜ T m ℃; time is 0.5-5h; optionally, 0.30T m ≤T1≤0.50T m , time is 1-3h.

[0021] In the present invention, T mis the melting point of the metal material. For a single metal, it is the melting point of the single metal; for a metal alloy, it is the solidus temperature. In the present invention, T m The first coefficient is rounded to two decimal places. For example, the melting point of nickel is 1455°C, and the actual pre-annealing temperature is 300°C. The coefficient = 300 / 1455≈0.21.

[0022] In some optional embodiments, the annealing temperature is T2, 0.70T m ≤T2 ＜ T m ℃, time is 1-24h.

[0023] In the present invention, T m The first coefficient is rounded to two decimal places.

[0024] In some optional embodiments, the annealing temperature is T2, 0.90T m ≤T2 ＜ T m ℃, time is 4-24h.

[0025] In the present invention, pre-annealing or annealing is independently performed under the protection of nitrogen or an inert gas (e.g., argon). For easily oxidized metals, in addition to the protective gas, a reducing gas (e.g., hydrogen) is also introduced. Typically, but not limited to, the volume ratio of argon to hydrogen is (5-9):(1-2). The gases can be mixed and introduced together, or one gas can be introduced separately and then the other gas. For simplicity of operation, it is generally selected to introduce them together after mixing. The flow rate of the gas is 50-200 sccm.

[0026] The second aspect of the present invention provides an application of a single crystal metal material obtained by the aforementioned preparation method in high-frequency communications, integrated circuits, quantum technology or new energy systems;

[0027] In some optional embodiments, the single crystal metal material is used in lithium batteries and the like.

[0028] The technical solution of the present invention has the following advantages:

[0029] 1. The present invention provides a method for preparing a single crystal metal material, wherein the preparation method comprises the following steps: annealing a metal material having a texture content of 80-100% to obtain a single crystal metal material; for a long time, the preparation of metal materials into single crystals has been accidental, resulting in unstable batch performance between the generated crystals. The inventors unexpectedly discovered in their research that when the texture content of the metal material reaches 80-100%, annealing is performed. Due to the specific content, the texture organization is more consistent, and the grains are rearranged during the annealing process, and can be relatively concentratedly transformed to other textures; annealing can achieve atomic-level optimization of impurity composition and crystal structure, promote more perfect crystals in the material and lower surface roughness, and the obtained single crystal metal material has excellent thermal conductivity and electrical conductivity; and the present invention is universal. Using this method, the stable preparation of meter-level single crystal metal materials has been successfully achieved; in addition, the present invention has a wide range of raw material sources and can adopt multiple channels to obtain materials, reducing the difficulty and cost of material acquisition; the preparation method is simple and the process requirements are low.

[0030] 2. The specific texture content of the metal material of the present invention can further improve the anisotropic properties of the material, so that it exhibits excellent thermal conductivity, electrical conductivity and surface properties (yield) in specific directions, thereby bringing higher application value, especially in high-precision manufacturing and electronic components.

[0031] 3. When the metal material of the present invention is a face-centered cubic lattice, it can further reduce internal stress, improve plasticity, and further optimize the processing performance of the material, so that it has better stability in extreme working environments.

[0032] 4. In the present invention, the metal is rolled to cause compressive strain in the metal, induce crystal orientation, reduce orientation differences, and optimize the crystal structure, providing a crystallographic basis for subsequent operations.

[0033] 5. The specific annealing conditions of the present invention can further achieve higher precision control at low temperatures, save energy and reduce the effects of oxidation or other pollution.

[0034] 6. The specific pre-annealing conditions of the present invention can further control the growth of grains and the evolution of texture, resulting in higher metal single crystal quality and more precise crystal orientation, thereby improving the overall performance of the material, especially in applications in high-frequency communications, integrated circuits, quantum technology or new energy systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0036] Figure 1 This is a picture of the cubic texture content of the nickel foil after pre-annealing in Example 1;

[0037] Figure 2 This is the EBSD image of the single crystal metal material of Example 1;

[0038] Figure 3 This is a picture of the cubic texture content of the copper foil after pre-annealing in Comparative Example 1;

[0039] Figure 4 This is the EBSD image of the single crystal metal material in Comparative Example 1. DETAILED DESCRIPTION

[0040] The following examples are provided for a better understanding of the present invention and are not intended to limit the best mode of implementation. They do not limit the content and scope of protection of the present invention. Any product identical or similar to the present invention obtained by anyone under the guidance of the present invention or by combining the features of the present invention with other prior arts shall fall within the scope of protection of the present invention.

[0041] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in this field can be used. If the manufacturer of the reagents or instruments is not specified, they are all commercially available conventional reagents.

[0042] Nickel plate: Purchased from Zhongke Jingyi (Dongguan) Materials Technology Co., Ltd., with a purity of 99.6%;

[0043] Copper plate: Purchased by Zhongke Jingyi (Dongguan) Materials Technology Co., Ltd., with a purity of 99.7%;

[0044] Gold plate: Purchased by Zhongke Jingyi (Dongguan) Materials Technology Co., Ltd., with a purity of 99.9%;

[0045] Silver plate: Purchased by Zhongke Jingyi (Dongguan) Materials Technology Co., Ltd., with a purity of 99.9%;

[0046] The rolling deformation in the examples and comparative examples is the average value of three tests;

[0047] According to international standards, the melting point of metal materials is 1455°C for nickel, 1084.62°C for copper, and 1064.18°C for gold.

[0048] Example 1

[0049] This embodiment provides a method for preparing a single crystal metal material, comprising the following steps:

[0050] A nickel plate with an initial size of 5m×120mm×2mm (length×width×thickness) was rolled at 25°C. When the rolling deformation was 97.5%, the strain rate was 30s. -1 , a rolled product was obtained, the thickness of the rolled product was 50 μm, and the {100} <001> The texture content is 10%; pre-annealing is performed, the pre-annealing gas includes argon and hydrogen, and the pre-annealing temperature is 450℃ (0.31T m ), time is 2h, pre-annealing product, the texture content picture of pre-annealing product is shown in Figure 1 Gray grains are cubic texture grains. The darker the color, the closer its orientation is to {100} <001> Orientation, as shown in the figure, {100} <001> The texture content is 93.4%; annealing is then performed, and the annealing gas includes argon and hydrogen, the volume ratio of argon and hydrogen is 5:1, and the gas flow rate is 100 sccm; during annealing, the temperature is 1400℃ (0.96T m ), the time is 6h, a single crystal metal material is obtained, and an EBSD test is performed to obtain an Inverse Pole Figure (IPF) diagram, as shown in the following figure: Figure 2 As shown, different grain orientations have different colors in the IPF diagram, while Figure 2 There is only one color in the image, which proves that there is only one grain.

[0051] Example 2

[0052] This embodiment provides a method for preparing a single crystal metal material, comprising the following steps:

[0053] A copper plate with an initial size of 100 mm × 300 mm × 0.2 mm (length × width × thickness) was rolled at 28°C. When the rolling deformation reached 87.5%, the strain rate was 300 s -1 , a rolled product was obtained, the thickness of the rolled product was 25 μm, and the {100} <001> The texture content is 13%; pre-annealing is performed, the pre-annealing gas includes argon and hydrogen, and the pre-annealing temperature is 300℃ (0.28T m), time is 2h, the {100} <001> The texture content is 98%; annealing is then performed, and the annealing gas includes argon and hydrogen, the volume ratio of argon and hydrogen is 5:1, and the gas flow rate is 100 sccm; during annealing, the temperature is 1035℃ (0.95T m ), the time is 4h, and a single crystal metal material is obtained.

[0054] Example 3

[0055] This embodiment provides a method for preparing a single crystal metal material, comprising the following steps:

[0056] A gold plate with an initial size of 0.5 m × 10 mm × 1 mm (length × width × thickness) was rolled at 27 ° C. When the rolling deformation was 96.0%, the strain rate was 200 s -1 , a rolled product was obtained, the thickness of the rolled product was 40 μm, and the {100} <001> The texture content is 99%; during annealing, the temperature is 1030℃ (0.97T m ), the time is 6h, and a single crystal metal material is obtained.

[0057] Example 4

[0058] This embodiment provides a method for preparing a single crystal metal material, comprising the following steps:

[0059] The method of Example 1 is different in that the pre-annealing conditions include: a temperature of 300°C (0.21T m ), time is 0.5h, after pre-annealing {100} <001> The texture content is 85%.

[0060] Example 5

[0061] This embodiment provides a method for preparing a single crystal metal material, comprising the following steps:

[0062] The method of Example 1 is different in that the annealing conditions include: a temperature of 1100°C (0.76T m ), time is 3h.

[0063] Comparative Example 1

[0064] This comparative example provides a method for preparing a single crystal metal material, comprising the following steps:

[0065] A copper plate with an initial size of 100 mm × 300 mm × 0.2 mm (length × width × thickness) was rolled at 25°C. When the rolling deformation was equal to 87.5%, the strain rate was 0.5 s -1, a rolled product was obtained, the thickness of the rolled product was 25 μm, and the {100} <001> The texture content is 5%; pre-annealing is performed, the pre-annealing gas includes argon and hydrogen, and the pre-annealing temperature is 300℃ (0.28T m ), annealing time is 2h, the texture content of the pre-annealing product is shown in the picture Figure 3 , as shown in the figure {100} <001> The texture content is 48%; annealing is then performed, and the annealing gas includes argon and hydrogen, the volume ratio of argon and hydrogen is 5:1, and the gas flow rate is 100 sccm; during annealing, the temperature is 1035℃ (0.95T m ), the time is 6h, and after annealing, a polycrystalline copper foil with an average grain size of 300μm and a roughness Ra of 30nm is obtained; EBSD test is performed to obtain the Inverse Pole Figure (IPF) diagram, as shown in the following figure: Figure 4 As shown, there are multiple colors in the figure, which proves that the comparative example has a polycrystalline structure.

[0066] Comparative Example 2

[0067] A nickel plate with an initial size of 5m×120mm×2mm (length×width×thickness) was rolled at 25°C. When the rolling deformation was 97.5%, the strain rate was 1s -1 , a rolled product was obtained, the thickness of the rolled product was 50 μm, and the {100} <001> The texture content is 2%; pre-annealing is performed, the pre-annealing gas includes argon and hydrogen, and the pre-annealing temperature is 350℃ (0.24T m ), time is 1h, the {100} <001> The texture content is 27%; annealing is then performed, and the annealing gas includes argon and hydrogen, the volume ratio of argon and hydrogen is 5:1, and the gas flow rate is 100 sccm; during annealing, the temperature is 1400℃ (0.96T m After annealing for 6 hours, a polycrystalline nickel foil with an average grain size of 500 μm and a roughness Ra of 36 nm was obtained.

[0068] Comparative Example 3

[0069] A gold plate with an initial size of 0.5 m × 10 mm × 1 mm (length × width × thickness) was rolled at 27 ° C. When the rolling deformation was 96.0%, the strain rate was 0.5 s -1 , a rolled product was obtained, the thickness of the rolled product was 40 μm, and the {100} <001> The texture content is 10%; pre-annealing is performed, the pre-annealing gas includes argon and hydrogen, and the pre-annealing temperature is 300℃ (0.28T m ), time is 1h, the {100} <001> The texture content is 38%, and the annealing temperature is 1030℃ (0.97Tm After annealing for 6 hours, a polycrystalline gold foil with an average grain size of 200 μm and a roughness Ra of 33 nm was obtained.

[0070] Test Case

[0071] Texture testing method: Electron backscatter diffraction was used, specifically using an Oxford Instruments Aztec 2.0 system equipped with an EBSD detector operating at 20 kV. EBSD data were analyzed using Aztec Crystal version 2.1 software. The area fraction of cubic texture (f c ) is calculated within a 15° directional error tolerance;

[0072] Yield test method: test 1,000 samples and observe them through a metallographic microscope. Samples without grain boundaries are judged to be single crystal samples. Use contact profilometry (step profiler) to test the roughness Ra. If Ra < 30nm, it is qualified. Record the percentage of qualified products in the total number of products to prove the stability between batches.

[0073] Thermal conductivity test method: Thermocouple method is used. The specific method is to select the single crystal metal material to be tested and ensure that its surface is flat to avoid affecting the measurement results; install thermocouples at two positions of the metal foil, usually one thermocouple is located on the side of the heating source and the other is located on the side of the metal foil away from the heating source, for measuring the temperature difference; heat the metal foil with a constant heat source (such as an electric heater or laser) to ensure that the heat flow is evenly transferred along the direction of the foil; measure the temperature difference between the two positions with the thermocouple and record the change of temperature over time; calculate the thermal conductivity of the metal foil according to the formula of thermal conductivity k, k = Q·D / A·ΔT, where Q is the heat flow (unit: W), k is the thermal conductivity (unit: W / m·K), and A is the heat conduction cross-sectional area (unit: m 2 ), ΔT is the temperature difference between the two points (unit: K), and D is the distance between the two points (unit: m);

[0074] Test method for conductive properties: The Van der Pauw method is used. The specific method is to take a square single crystal metal material with a side length of 1 cm for testing. The surface of the sample is clean to ensure that there are no pollutants or oxide layers to avoid affecting the test results. Four probes are placed at the four corners of the metal foil. A precision power supply is used to provide a constant current to the sample, and the probes are connected to the voltmeter through the current source. The external current source applies a constant current, and the voltage between the two middle probes is measured by the voltmeter. A known current is applied through the external power supply, usually in the microampere to milliampere level, to ensure that the current value is appropriate. According to Ohm's law and the Van der Pauw test method, the resistivity of the sample is ρ = 2πV / ln2I, where V is voltage and I is current. Then the conductivity σ = 1 / ρ, with units of S / m;

[0075] In metal materials, electrical conductivity is usually expressed in % IACS (International Annealed Copper Standard). The electrical conductivity of annealed pure copper is 5.8×10 7 S / m is defined as 100% IACS. To convert the conductivity unit S / m to % IACS, we need to compare the conductivity of the actual material with the conductivity of copper. That is, the conductivity of the metal material is σ (unit: S / m), and its conductivity σ material Relative to the electrical conductivity of copper σ Cu (100% IACS) can be expressed as % IACS = (σ material / σ Cu )×100%;

[0076] The test data is shown in Table 1;

[0077] Table 1

[0078]

[0079]

[0080] IACS standard: 100% IACS is based on the electrical conductivity of annealed pure copper (99.999% Cu) at 20°C (58.0MS / m). Exceeding 100% IACS means the material has a higher electrical conductivity than pure copper, which usually requires extremely low impurity content and a special microstructure.

[0081] In the present invention, the initial thermal and electrical conductivity vary significantly due to the specific composition of the materials themselves. Therefore, only comparisons between materials of the same type are meaningful. For example, Example 1 is compared with Comparative Example 2, Example 2 is compared with Comparative Example 1, and Example 3 is compared with Comparative Example 3.

[0082] In Example 3, the thermal conductivity of pure gold is about 317 W / m·K. However, in the present invention, due to the successful preparation of single crystal material, the thermal conductivity reaches 332 W / m·K, which is an increase of 3-10%.

[0083] In the present invention, Example 1 is compared with Comparative Example 2, Example 2 with Comparative Example 1, and Example 3 with Comparative Example 3. The electron conduction process is affected by crystal defects, grain boundaries, and impurities. In single crystal materials, due to the absence of grain boundaries, electron migration is not easily scattered, resulting in relatively high electrical conductivity. During heat conduction, the lack of grain boundaries can minimize heat generation and make heat transfer more efficient. The atomic arrangement in single crystal materials is regular, and the transfer of heat in the crystal is almost unimpeded, resulting in high thermal conductivity.

[0084] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A method for preparing a single crystal metal material, characterized in that: The preparation method comprises the following steps: annealing a metal material with a texture content of 80-100% to obtain a single crystal metal material.

2. The preparation method according to claim 1, characterized in that The texture content of the metallic material is 90-100%.

3. The preparation method according to claim 1 or 2, characterized in that The metal material is face-centered cubic; And / or, the texture is cubic {100} <001> texture.

4. The preparation method according to claim 3, characterized in that The metal material includes at least one of nickel, copper, gold, aluminum, platinum, rhodium and silver; Optionally, the metal material includes at least two of nickel, copper, gold, aluminum, platinum, rhodium and silver.

5. The preparation method according to claim 1, characterized in that Rolling the metal material to obtain a metal material having a texture content of 80-100%; Optionally, the rolling temperature is 25-200°C; Optionally, when the rolling deformation is ≥90%, the strain rate of each rolling pass is 0.1-850s -1 ; Optionally, when the rolling deformation is less than 90%, the strain rate of each rolling pass is 10-850s -1 .

6. The preparation method according to claim 5, characterized in that Pre-annealing is also included after rolling.

7. The preparation method according to claim 6, characterized in that The pre-annealing temperature is T1, 0.10T m ≤T1 ＜ T m ℃; time is 0.5-5h; Optionally, 0.30T m ≤T1≤0.50T m , time is 1-3h.

8. The preparation method according to any one of claims 1 to 7, characterized in that The annealing temperature is T2, 0.70T m ≤T2 ＜ T m ℃, time is 1-24h.

9. The preparation method according to claim 8, characterized in that The annealing temperature is T2, 0.90T m ≤T2 ＜ T m ℃, time is 4-24h.

10. Application of a single crystal metal material prepared by the preparation method according to any one of claims 1 to 9 in high-frequency communications, integrated circuits, quantum technology or new energy systems; Preferably, the single crystal metal material is used in lithium batteries and the like.

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