阅读说明：本技术 单晶铜的制备方法 (Method for preparing single crystal copper ) 是由 邹定鑫 田圳 张振生 赵悦 俞大鹏 于 2021-01-20 设计创作，主要内容包括：本发明属于材料技术领域,具体涉及一种单晶铜的制备方法。本发明单晶铜的制备方法中,通过将多晶铜置于石墨容器中进行退火处理,利用石墨容器的限域空间作用,将退火处理过程中的石英渣、灰尘颗粒等各种杂质隔离在石墨容器的外面,从而避免上述杂质对所得单晶铜造成杂质污染,不仅大大提高了所得单晶铜的表面洁净度和制备效率,而且可以获得大尺寸的单晶铜,使所得单晶铜具有更优异的性能。本发明提供的制备方法操作简单,无需对多晶铜进行复杂多样的表面预处理,有利于实现单晶铜的工业化制备。(The invention belongs to the technical field of materials, and particularly relates to a preparation method of single crystal copper. According to the preparation method of the single crystal copper, polycrystalline copper is placed in the graphite container for annealing treatment, and various impurities such as quartz slag, dust particles and the like in the annealing treatment process are isolated outside the graphite container by utilizing the limited space effect of the graphite container, so that impurity pollution caused by the impurities to the obtained single crystal copper is avoided, the surface cleanliness and the preparation efficiency of the obtained single crystal copper are greatly improved, large-size single crystal copper can be obtained, and the obtained single crystal copper has more excellent performance. The preparation method provided by the invention is simple to operate, does not need to carry out complicated and diversified surface pretreatment on the polycrystalline copper, and is beneficial to realizing the industrial preparation of the single crystal copper.)

1. A preparation method of single crystal copper is characterized by comprising the following steps:

providing polycrystalline copper and a container, wherein at least one through hole is formed in the container;

and placing the polycrystalline copper in the container, and annealing to obtain the single crystal copper.

2. The method for producing single crystal copper according to claim 1, wherein the container comprises a container body and a top lid covering the container body, and the through hole is provided in a side wall of the container body.

3. The method for producing single crystal copper according to claim 2, wherein the container is made of graphite or metal.

4. The method for producing single-crystal copper according to claim 1, wherein the annealing treatment is annealing the container containing the polycrystalline copper at a temperature of 700 ℃ to 1000 ℃ for 1min to 200min in a mixed atmosphere of a protective gas and hydrogen gas.

5. The method for producing single crystal copper according to claim 4, wherein the time from the room temperature to 700 ℃ to 1000 ℃ is 50min to 60 min.

6. The method for producing single crystal copper according to claim 4, wherein the protective gas is introduced at a flow rate of 500sccm to 800 sccm; and/or

The protective gas is at least one of nitrogen and argon.

7. The method for producing single crystal copper according to claim 4, wherein the hydrogen gas is introduced at a flow rate of 1sccm to 600 sccm.

8. The method for producing single crystal copper according to any one of claims 1 to 7, wherein the surface cleanliness of the single crystal copper is 99% or more.

9. The method for producing single-crystal copper according to any one of claims 1 to 7, wherein the polycrystalline copper is a polycrystalline copper foil, and the single-crystal copper is a single-crystal copper foil.

10. The method for producing single crystal copper according to claim 9, wherein the thickness of the polycrystalline copper foil is 5 μm to 1000 μm; and/or

The purity of the polycrystalline copper foil is greater than or equal to 99%.

Technical Field

The invention belongs to the technical field of materials, and particularly relates to a preparation method of single crystal copper.

Background

Copper is one of the most commonly used metals in human society, and is widely used in the fields of electricity, light industry, machine manufacturing, building industry, defense industry, etc. due to its good electrical conductivity, thermal conductivity, ductility and corrosion resistance, and is second only to aluminum in the consumption of non-ferrous metal materials in China. Meanwhile, the copper has the characteristics of large reserves, high reutilization rate and the like, so that the cost of the copper is relatively low, and the copper is more suitable for large-scale application.

Compared with polycrystalline copper, the single crystal copper has no limitation of grain boundaries, and has stronger performances in all aspects, such as higher conductivity, better mechanical properties, stronger corrosion resistance and the like. Therefore, single crystal copper has a wider application prospect than polycrystalline copper, and how to prepare single crystal copper also becomes one of the current research directions.

In the currently common preparation method of single crystal copper, the prepared single crystal copper is polluted by impurities in an annealing furnace, such as quartz slag, dust particles and the like, and the impurities can greatly influence the quality of the copper foil and even become heterogeneous nucleation points to promote the formation of grain boundaries. Therefore, how to eliminate the influence of impurities on the single crystal copper is an important problem for perfecting the preparation method of the single crystal copper.

Disclosure of Invention

The invention aims to provide a preparation method of single crystal copper, and aims to solve the technical problems that single crystal copper obtained by the existing preparation method of single crystal copper is high in impurity content and the like.

In order to achieve the above object, the present invention provides a method for preparing single crystal copper, comprising the steps of:

providing polycrystalline copper and a container, wherein at least one through hole is formed in the container;

and placing the polycrystalline copper in the container, and annealing to obtain the single crystal copper.

According to the preparation method of the single crystal copper, the polycrystalline copper is placed in the container for annealing treatment, and various impurities such as quartz slag, dust particles and the like in the annealing treatment process are isolated outside the container by utilizing the limited space effect of the container, so that impurity pollution caused by the impurities to the obtained single crystal copper is avoided, the surface cleanliness and the preparation efficiency of the obtained single crystal copper are greatly improved, the large-size single crystal copper can be obtained, and the obtained single crystal copper has more excellent performance. The preparation method provided by the invention is simple to operate, does not need to carry out complicated and diversified surface pretreatment on the polycrystalline copper, and is beneficial to realizing the industrial preparation of the single crystal copper.

As a preferable technical solution of the method for producing single crystal copper according to the present invention, the container includes a container body and a top cover covering the container body, and the through hole is provided in a side wall of the container body.

As a preferable technical scheme of the preparation method of the single crystal copper, the material of the container is graphite or metal.

As a preferable technical scheme of the preparation method of the single crystal copper, the annealing treatment is carried out in the mixed atmosphere of protective gas and hydrogen, the temperature is 700-1000 ℃, and the pressure is 1 multiplied by 10⁵And Pa annealing the graphite container containing the polycrystalline copper for 1-200 min.

As a further preferable technical scheme of the preparation method of the single crystal copper, the temperature rise rate is 10-20 ℃/min when the temperature rises from room temperature to 700-1000 ℃.

As a further preferable technical scheme of the preparation method of the single crystal copper, the protective gas is introduced at the flow rate of 500sccm-800 sccm.

In a more preferable embodiment of the method for producing single crystal copper according to the present invention, the protective gas is at least one selected from nitrogen and argon.

As a further preferable technical scheme of the preparation method of the single crystal copper, the introduction flow rate of the hydrogen is 1sccm-600 sccm.

As a preferable technical scheme of the preparation method of the single crystal copper, the surface cleanliness of the single crystal copper is more than or equal to 99%.

As a preferable technical scheme of the preparation method of the single crystal copper, the polycrystalline copper is a polycrystalline copper foil, and the single crystal copper is a single crystal copper foil.

As a preferable technical scheme of the preparation method of the single crystal copper, the thickness of the polycrystalline copper foil is 5-1000 μm, and the purity is more than or equal to 99%.

Drawings

FIG. 1 is a schematic view of a graphite container according to an embodiment of the present invention;

FIG. 2 is an optical micrograph of single-crystal copper obtained in example 1 of the present invention;

FIG. 3 is an optical micrograph of a single-crystal copper obtained according to a comparative example of the present invention;

FIG. 4 is a graph showing Electron Back Scattering Diffraction (EBSD) results of single-crystal copper obtained in example 1 of the present invention;

the reference numerals in fig. 1 are as follows:

10-a graphite container body; 20-a top cover; 30-through holes.

Detailed Description

In order to make the objects, technical solutions and technical effects of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described, and the embodiments described below are a part of the embodiments of the present invention, but not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art without any inventive step in connection with the embodiments of the present invention shall fall within the scope of protection of the present invention. Those whose specific conditions are not specified in the examples are carried out according to conventional conditions or conditions recommended by the manufacturer; the reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

In the description of the present invention, the term "and/or" describing an association relationship of associated objects means that there may be three relationships, for example, a and/or B, may mean: a is present alone, A and B are present simultaneously, and B is present alone. Wherein A and B can be singular or plural. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship.

In the description of the present invention, "at least one" means one or more, "a plurality" means two or more. "at least one of the following" or similar expressions refer to any combination of these items, including any combination of the singular or plural items. For example, "at least one (a), b, or c", or "at least one (a), b, and c", may each represent: a. b, c, a-b (i.e. a and b), a-c, b-c, or a-b-c, wherein a, b, and c can be single or multiple respectively.

It should be understood that the weight of the related components mentioned in the embodiments of the present invention may not only refer to the specific content of each component, but also represent the proportional relationship of the weight among the components, and therefore, it is within the scope of the disclosure that the content of the related components is scaled up or down according to the embodiments of the present invention. Specifically, the weight described in the embodiments of the present invention may be a unit of mass known in the chemical field such as μ g, mg, g, kg, etc.

In addition, unless the context clearly uses otherwise, an expression of a word in the singular is to be understood as including the plural of the word. The terms "comprises" or "comprising" are intended to specify the presence of stated features, quantities, steps, operations, elements, portions, or combinations thereof, but are not intended to preclude the presence or addition of one or more other features, quantities, steps, operations, elements, portions, or combinations thereof.

The embodiment of the invention provides a preparation method of single crystal copper, which comprises the following steps:

s1, providing polycrystalline copper and a container, wherein the container is provided with at least one through hole;

and S2, placing the polycrystalline copper into a container, and annealing to obtain the single crystal copper.

According to the preparation method of the single crystal copper provided by the embodiment of the invention, the polycrystalline copper is placed in the container for annealing treatment, and various impurities such as quartz slag, dust particles and the like in the annealing treatment process are isolated outside the container by utilizing the limited space effect of the container, so that impurity pollution to the obtained single crystal copper caused by the impurities is avoided, the surface cleanliness and the preparation efficiency of the obtained single crystal copper are greatly improved, and the large-size single crystal copper can be obtained, so that the obtained single crystal copper has more excellent performance. The preparation method provided by the embodiment of the invention is simple to operate, does not need to carry out complicated and diversified surface pretreatment on polycrystalline copper, and is beneficial to realizing the industrial preparation of single crystal copper.

Specifically, in S1, polycrystalline copper is used as a raw material for preparing single crystal copper, and in some embodiments, the polycrystalline copper is a polycrystalline copper foil. The polycrystalline copper foil is a commercial copper foil, has the advantages of easily available raw materials and low cost, and is beneficial to reducing the production cost of the single crystal copper.

Further, a polycrystalline copper foil having a thickness of 5 μm to 1000 μm is selected. If the thickness of the polycrystalline copper foil is too thin, micro-melting can occur during annealing treatment, and the polycrystalline copper foil is adhered in a graphite container; if the thickness of the polycrystalline copper foil is too thick, a higher energy is required for the annealing treatment, and even a problem arises in that it is difficult to obtain single crystal copper by annealing.

Further, a polycrystalline copper foil having a purity of 99% or more is selected. By selecting the high-purity polycrystalline copper foil, impurities in the copper foil can be reduced, and the high-purity single crystal copper foil can be obtained.

The container, which is used for containing polycrystalline copper in the embodiment of the invention, is used as a carrier of the polycrystalline copper, and can isolate various impurities outside the container so as to improve the purity of the obtained single crystal copper. Meanwhile, at least one through hole is formed in the container, so that gas can enter the container to finish annealing in the annealing process. The shape of the container according to the embodiments of the present invention is not particularly critical, and any container that can accommodate polycrystalline copper (e.g., polycrystalline copper foil) is suitable for the embodiments of the present invention. The structure of the container provided by one embodiment is described below with reference to fig. 1: as shown in fig. 1, the container includes a container body 10, and a top cover 20 covering the container body 10, and a through hole 30 is provided at a sidewall of the container body 10. When in use, the polycrystalline copper is placed in the accommodating space of the container body 10, and then annealed after the top cover 20 is covered. The container with the structure is divided into two parts, namely a container body 10 and a top cover 20 on one hand, so that polycrystalline copper is very convenient to place in the container during the preparation process; on the other hand, through-hole 30 sets up the lateral wall at vessel 10, rather than the bottom of top cap 20 or vessel 10, this mode of setting up is favorable to making gas fully to get into the inside of container in the annealing process, avoids falling into the inside problem of container because of impurity such as quartz slag that exists when setting up top cap 20, is favorable to further promoting the purity of single crystal copper. In some embodiments, the material of the container is selected from metal or graphite. The metal container is preferably made of ultrahigh-purity and high-temperature-resistant metal materials (including alloys), impurities in the ultrahigh-purity metal materials can be prevented from being introduced into the single crystal copper, and the high-temperature-resistant metal materials can be prevented from being melted under the high-temperature condition of chemical vapor deposition reaction to influence the preparation of the single crystal copper; graphite containers are preferably graphite cartridges, as graphite cartridges are commercially available. It should be noted that, if the graphite box is purchased without the through hole, at least one through hole is manually provided. The embodiment of the invention has no special requirement on the diameter of the through hole and can be adjusted according to the actual situation.

In some embodiments, by selecting a container with a larger accommodating space so that the container can accommodate polycrystalline copper with the width direction dimension of 1cm-30cm and the length direction of 5cm-50cm, large-size single crystal copper with the width direction dimension of 1cm-30cm and the length direction of 5cm-50cm can be obtained at one time. The width and length are listed here, and are not limited to the size of the polycrystalline copper raw material and the size of the single crystal copper product, and the single crystal copper with any size can be prepared as the size of the container and the size of the equipment (such as chemical vapor deposition equipment) for annealing treatment allow.

In S2, the polycrystalline copper is placed in a container, and then the container is annealed, and the polycrystalline copper placed in the container is also annealed to obtain single crystal copper. In some embodiments, when the polycrystalline copper is a polycrystalline copper foil, the polycrystalline copper foil is preferably placed in the container in a flat state in order to sufficiently anneal the polycrystalline copper foil.

In some embodiments, the annealing treatment is in an annealing apparatus, and the annealing atmosphere in the annealing apparatus is a mixed atmosphere of a protective gas and hydrogen gas, and the container containing the polycrystalline copper is annealed at a temperature of 700 ℃ to 1000 ℃ for 1min under normal pressure. By annealing the single crystal copper at the annealing temperature, the annealing pressure and the annealing time in the mixed atmosphere, the surface cleanliness and the purity of the obtained single crystal copper can be further improved. The hydrogen is used as etching gas, so that nucleation points with poor quality in the polycrystalline copper can be etched, the nucleation density of the copper is effectively reduced, and the single crystal copper is ensured to be obtained; meanwhile, the hydrogen also has a reduction effect, so that the oxide on the surface of polycrystalline copper (such as polycrystalline copper foil) can be reduced into a copper simple substance, the preparation of single crystal copper can be realized under the condition that the polycrystalline copper is not subjected to any pretreatment, and the preparation process is obviously simplified. In some embodiments, the annealing apparatus is a chemical vapor deposition apparatus. Specifically, typical but non-limiting annealing temperatures are 700 deg.C, 750 deg.C, 800 deg.C, 850 deg.C, 900 deg.C, 950 deg.C, 1000 deg.C.

Further, the time for annealing treatment at 700-1000 ℃ is 1-200 min, preferably 30-120 min. If the annealing time is too short, single crystal copper cannot be obtained; if the annealing time is too long, unnecessary energy consumption is easily caused, which is not beneficial to improving the production efficiency. Specifically, typical but non-limiting annealing treatment times are 1min, 5min, 10min, 20min, 30min, 40min, 50min, 60min, 70min, 80min, 90min, 100min, 110min, 120min, 130min, 140min, 150min, 160min, 170min, 180min, 190min, 200 min.

Further, in the annealing treatment process, the temperature is raised from the room temperature to 700-1000 ℃ for 50-60 min. Specifically, typical but non-limiting temperature rise times are 50min, 51min, 52min, 53min, 54min, 55min, 56min, 57min, 58min, 59min, 60 min.

Furthermore, the flow rate of protective gas in the annealing atmosphere is 500sccm-800 sccm. In some embodiments, the protective gas is selected from nitrogen and/or argon. Specifically, the protective gas is typically, but not limited to, flowed at a flow rate of 500sccm, 550sccm, 600sccm, 650sccm, 700sccm, 750sccm, 800 sccm.

Further, in the annealing atmosphere, the flow rate of hydrogen gas is 1sccm to 600sccm, preferably 30sccm to 100 sccm. Under the introduction flow, the hydrogen can be fully and uniformly distributed in the annealing equipment, thereby playing the roles of reduction and etching. If the flow rate is too low, the polycrystalline copper will not be completely crystallized; if the flow rate is too high, the etching capability of hydrogen is stronger, which may cause the problem that the obtained single crystal copper is also etched. Specifically, hydrogen gas is typically, but not limited to, introduced at a flow rate of 1sccm, 5sccm, 10sccm, 15sccm, 20sccm, 25sccm, 30sccm, 35sccm, 40sccm, 45sccm, 50sccm, 55sccm, 60sccm, 65sccm, 70sccm, 75sccm, 80sccm, 85sccm, 90sccm, 95sccm, 100sccm, 150sccm, 200sccm, 250sccm, 300sccm, 350sccm, 400sccm, 450sccm, 500sccm, 550sccm, 600 sccm.

In the embodiment of the invention, the container is adopted, and the side wall of the container body is provided with at least one through hole, and the surface cleanliness of the single crystal copper obtained by annealing treatment is more than or equal to 99 percent, and belongs to ultra-clean single crystal copper. The method can also be used for preparing the single crystal copper foil with the Cu (111) crystal face, is most suitable for the growth of two-dimensional material graphene, and has good application prospect.

In order to make the above implementation details and operations of the present invention clearly understood by those skilled in the art and to make the progress of the method for preparing single crystal copper according to the embodiment of the present invention obvious, the above technical solution is illustrated by the following examples.

Example 1

The embodiment provides a preparation method of a single crystal copper foil, which comprises the following steps:

(11) flatly placing the polycrystalline copper foil with the width dimension of 20cm and the length dimension of 40cm in a graphite box (a plurality of through holes are formed in the side wall of the graphite box), placing the polycrystalline copper foil in chemical vapor deposition equipment, and introducing protective gas, wherein the flow of the protective gas is 600sccm, the working pressure is normal pressure, and the protective gas is Ar;

(12) introducing protective gas, heating to 1000 deg.C for 60min, and introducing H₂Gas, H₂The flow rate is 100 sccm;

(13) keeping the temperature constant, and carrying out annealing treatment for 30min to obtain the ultra-clean single crystal copper foil after the annealing is finished, wherein the width dimension of the single crystal copper foil is 20cm, the length dimension is 40cm, and the cleanliness is 99.7%.

Example 2

The embodiment provides a preparation method of a single crystal copper foil, which comprises the following steps:

(21) flatly placing the polycrystalline copper foil with the width dimension of 20cm and the length dimension of 40cm in a graphite box (the graphite box is consistent with the embodiment 1), placing the polycrystalline copper foil in chemical vapor deposition equipment, and introducing protective gas, wherein the flow rate of the protective gas is 600sccm, the working pressure is normal pressure, and the protective gas is Ar;

(22) introducing protective gas, heating to 800 deg.C for 60min, introducing H₂Gas, H₂The flow rate is 100 sccm;

(23) keeping the temperature constant, and carrying out annealing treatment for 50min to obtain the ultra-clean single crystal copper foil after the annealing is finished, wherein the width dimension of the single crystal copper foil is 20cm, the length dimension is 40cm, and the cleanliness is 99.5%.

Example 3

The embodiment provides a preparation method of a single crystal copper foil, which comprises the following steps:

(31) flatly placing the polycrystalline copper foil with the width dimension of 20cm and the length dimension of 40cm in a graphite box (the graphite box is consistent with the embodiment 1), placing the polycrystalline copper foil in chemical vapor deposition equipment, and introducing protective gas, wherein the flow rate of the protective gas is 600sccm, the working pressure is normal pressure, and the protective gas is Ar;

(32) introducing protective gas, heating to 1000 deg.C for 60min, and introducing H₂Gas, H₂The flow rate is 50 sccm;

(33) keeping the temperature constant, and carrying out annealing treatment for 60min to obtain the ultra-clean single crystal copper foil after the annealing is finished, wherein the width dimension of the single crystal copper foil is 20cm, the length dimension is 40cm, and the cleanliness is 99.6%.

Example 4

The embodiment provides a preparation method of a single crystal copper foil, which comprises the following steps:

(41) flatly placing the polycrystalline copper foil with the width dimension of 20cm and the length dimension of 40cm in a graphite box (the graphite box is consistent with the embodiment 1), placing the polycrystalline copper foil in chemical vapor deposition equipment, and introducing protective gas, wherein the flow rate of the protective gas is 600sccm, the working pressure is normal pressure, and the protective gas is Ar;

(42) introducing protective gas, heating to 800 deg.C for 60min, introducing H₂Gas, H₂The flow rate is 30 sccm;

(43) keeping the temperature constant, and carrying out annealing treatment for 120min to obtain the ultra-clean single crystal copper foil after the annealing is finished, wherein the width dimension of the single crystal copper foil is 20cm, the length dimension is 40cm, and the cleanliness is 99.4%.

Comparative example

The comparative example provides a preparation method of a single crystal copper foil, comprising the following steps:

(51) flatly placing the polycrystalline copper foil with the width dimension of 20cm and the length dimension of 40cm on a quartz plate, placing the polycrystalline copper foil into chemical vapor deposition equipment, and introducing protective gas, wherein the flow of the protective gas is 600sccm, the working pressure is normal pressure, and the protective gas is Ar;

(52) introducing protective gas, heating to 1000 deg.C for 60min, and introducing H₂Gas, H₂The flow rate is 100 sccm;

(53) keeping the temperature constant, and carrying out annealing treatment for 30min to obtain the ultra-clean single crystal copper foil after the annealing is finished, wherein the width dimension of the single crystal copper foil is 20cm, the length dimension is 40cm, and the cleanliness is 55%.

Examples of the experiments

The single crystal copper foils obtained in examples 1 to 4 and comparative example were observed by an optical microscope, the single crystal copper foil obtained in example 1 is shown in FIG. 2, and the single crystal copper foils obtained in examples 2 to 4 are substantially the same as in FIG. 2, but not limited thereto; the single crystal copper foil obtained by the comparative example is shown in FIG. 3.

As can be seen from the comparison between FIG. 2 and FIG. 3, the surfaces of the single crystal copper foils obtained in examples 1 to 4 are clean and free of contamination, while the surfaces of the single crystal copper foils obtained in the comparative examples have more impurities such as quartz slag, amorphous carbon contaminants and the like, which are not favorable for post-treatment and application.

The results of Electron Back Scattering Diffraction (EBSD) of the single crystal copper foil obtained in example 1 are shown in fig. 4, and the results of Electron Back Scattering Diffraction (EBSD) of the single crystal copper foils obtained in examples 2 to 4 are substantially the same as those of fig. 4, but they are not listed.

As can be seen from fig. 4, 9 points were randomly selected from the surface of the single-crystal copper foil obtained in example 1, and the electron backscatter diffraction patterns thereof were all blue (not shown), the color agreement indicates that the foil was single-crystal, and the blue color indicates that the crystal plane index was Cu (111).

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.