METHOD FOR CLONAL-GROWTH OF SINGLE-CRYSTAL METAL

Abstract

A method for clonal-growth of a single-crystal metal, including: using copper as an example, placing an existing small-sized single-crystal copper foil with a plane of any index on a copper foil that needs to be single-crystallized, and performing annealing to obtain, by cloning, a large-area (in meters) single-crystal copper foil with the same surface index as that of the parent facet. The method solves the difficult problem of large-area single-crystal copper foil preparation. By performing annealing, a parent single-crystal copper foil with a very small size (˜0.25 cm.sup.2) can be cloned to produce a large-area (˜700 cm.sup.2) single-crystal copper foil, which is an increase in area of about 3000 times.

Claims

1. A method for clonal growth of single-crystal metal, which comprises the following steps: providing a first single-crystal copper foil and a first polycrystal copper foil; placing the first single-crystal copper foil on the first polycrystal copper foil; and annealing to transform the first polycrystal copper foil into a large-sized second single-crystal copper foil the same surface index as the first single-crystal copper foil by cloning with the small-sized first single-crystal copper foil as a clone matrix.

2. The method according to claim 1, which comprises the following steps: (1) using a single-crystal copper foil with any facet as the clone matrix; (2) cutting the clone matrix into a small triangle shape as the first single-crystal copper foil, and placing it on the first polycrystal copper foil that needs to be single-crystallized; (3) placing the stacked first polycrystal copper foil and first single-crystal copper foil in a heating furnace, introducing Ar gas at a flow rate of 300 sccm or more, and then raising the temperature for 60-100 minutes; (4) introducing H.sub.2 gas at a flow rate of 10-500 sccm when the temperature is raised to 1010-1050° C., while remaining the Ar flow rate unchanged; and annealing for 120 min-300 min; and (5) turning off the power supply of the heating furnace after the annealing is finished, and cooling to room temperature naturally with Ar gas and H.sub.2 gas as protective gases; the first polycrystal copper foil has been transformed into the second single-crystal copper foil with the same surface index as that of the first single-crystal copper foil, that is, the clonal growth process of the single-crystal copper foil is completed.

3. The method according to claim 2, wherein the facets of the clone matrix include Cu(111), Cu(110), Cu(211), Cu(345), Cu(346), Cu(335), Cu(236), Cu(124), Cu(553), Cu(122), Cu(255), or Cu(256).

4. The method according to claim 2, wherein the shape of the small triangle is a right triangle whose hypotenuse is from 1 cm to 5 cm.

5. The method according to claim 2, wherein in step (2), when the first single-crystal copper foil is placed on the first polycrystal copper foil, a flattening process is performed so that the first single-crystal copper foil is in sufficient contact with the first polycrystal copper foil.

6. The method according to claim 2, wherein the size of the first polycrystal copper foil is 39 cm*18 cm or more.

7. The method according to claim 1, wherein the annealing time is adjusted to ensure that the facet of the second single-crystal copper foil is consistent with the facet of the first single-crystal copper foil.

8. The method according to claim 1, wherein the area of the first single-crystal copper foil is 1%-50% of that of the first polycrystal copper foil.

9. A single-crystal copper foil which is the second single-crystal copper foil prepared by the method according to claim 1.

10. The single-crystal copper foil according to claim 9, wherein the size of the single-crystal copper foil is 39 cm*18 cm or more.

11. A single-crystal copper foil which is the second single-crystal copper foil prepared by the method according to claim 2.

12. A single-crystal copper foil which is the second single-crystal copper foil prepared by the method according to claim 3.

13. A single-crystal copper foil which is the second single-crystal copper foil prepared by the method according to claim 4.

14. A single-crystal copper foil which is the second single-crystal copper foil prepared by the method according to claim 5.

15. A single-crystal copper foil which is the second single-crystal copper foil prepared by the method according to claim 6.

16. A single-crystal copper foil which is the second single-crystal copper foil prepared by the method according to claim 7.

17. A single-crystal copper foil which is the second single-crystal copper foil prepared by the method according to claim 8.

18. The single-crystal copper foil according to claim 11, wherein the size of the single-crystal copper foil is 39 cm*18 cm or more.

19. The single-crystal copper foil according to claim 12, wherein the size of the single-crystal copper foil is 39 cm*18 cm or more.

20. The single-crystal copper foil according to claim 13, wherein the size of the single-crystal copper foil is 39 cm*18 cm or more.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG. 1 is a schematic diagram of using a single-crystal copper with any surface index (Cu(xyz)) as a matrix to transform an underlying polycrystal copper foil into a single-crystal copper foil with the same surface index (Cu(xyz)) by cloning during an annealing process in a tube furnace.

[0018] FIG. 2 takes Cu(211) surface as an example and shows a process of obtaining single-crystal Cu(211) by cloning. In FIG. 2a of the process, a triangle with a hypotenuse of 2 cm is used as a matrix and a polycrystal copper foil with a size of 9 cm*5 cm is taken as an example, and 98% of the whole polycrystal copper foil in FIG. 2c is converted to Cu(211) after 180 minutes of annealing treatment. FIG. 2b shows that a part of the polycrystal copper foil in FIG. 2b is converted to Cu(211) after 90 minutes of annealing treatment.

[0019] FIG. 3a is the EBSD result of Cu(211) matrix, and FIG. 3b is the EBSD result of Cu(211) induced after cloning.

[0020] FIG. 4 shows a large-area single-crystal Cu(211) obtained after the cloning is completed.

DETAILED DESCRIPTION OF THE INVENTION

[0021] The present disclosure will be further described in detail below in conjunction with specific examples, but the inventive method is not limited to the following examples.

[0022] In the following examples, the methods are conventional methods unless otherwise specified; and the raw materials can be obtained commercially unless otherwise specified.

[0023] Example 1: A method for clonal growth of single-crystal metal, including the following steps:

(1) using a single-crystal copper foil with any facet as a clone matrix; here single-crystal Cu(211) was used;
(2) cutting the obtained matrix into a standard small right-angled triangle shape with a hypotenuse size of 2 cm, and placing it on a polycrystal copper foil with a size of 9 cm*5 cm that needed to be single-crystallized;
(3) placing the copper foil in a tube furnace, introducing Ar gas at a flow rate of 800 sccm, and then starting to raise the temperature, wherein the temperature raising process lasted for 80 minutes;
(4) introducing H.sub.2 gas at a flow rate of 50 sccm when the temperature was raised to 1030° C., while remaining the Ar flow rate unchanged; and then annealing, wherein the annealing process lasted for 90 minutes; and
(5) turning off the power supply of the heating furnace after the annealing was finished, and cooling to room temperature naturally with Ar gas and H.sub.2 gas as protective gases.

[0024] The single-crystal copper foil prepared by cloning in this experiment was shown in FIG. 2(b). It can be seen that a facet consistent with that of the matrix was cloned around the single-crystal Cu(211) after annealing for 90 minutes. Different colors represented different facets. Therefore, it was known that we obtained the Cu(211) surface consistent with that of the matrix by cloning, which extended to ¼ of the area of the whole copper foil.

[0025] Example 2: A method for clonal growth of single-crystal metal, including the following steps:

(1) using a single-crystal copper foil with any facet as a clone matrix; here single-crystal Cu(211) was used;
(2) cutting the obtained matrix into a standard small right-angled triangle shape with a hypotenuse size of 2 cm, and placing it on a polycrystal copper foil with a size of 9 cm*5 cm that needed to be single-crystallized;
(3) placing the copper foil in a tube furnace, introducing Ar gas at a flow rate of 800 sccm, and then starting to raise the temperature, wherein the temperature raising process lasted for 80 minutes;
(4) introducing H.sub.2 gas at a flow rate of 50 sccm when the temperature was raised to 1030° C., while remaining the Ar flow rate unchanged; and then annealing, wherein the annealing process lasted for 180 minutes; and
(5) turning off the power supply of the heating furnace after the annealing was finished, and cooling to room temperature naturally with Ar gas and H.sub.2 gas as protective gases.

[0026] The single-crystal copper foil prepared by cloning in this experiment was shown in FIG. 2(c). It can be seen that after annealing for 180 minutes, we obtained the Cu(211) surface consistent with that of the matrix by cloning, which extended to greater than 98% of the area of the whole copper foil.

[0027] Example 3: A method for clonal growth of single-crystal metal, including the following steps:

(1) using a single-crystal copper foil with any facet as a clone matrix; here single-crystal Cu(211) was used;
(2) cutting the obtained matrix into a standard small right-angled triangle shape with a hypotenuse size of 1 cm, and placing it on to polycrystal copper foil with a size of 39 cm*18 cm that needed to be single-crystallized;
(3) placing the copper foil in a tube furnace, introducing Ar gas at a flow rate of 800 sccm, and then starting to raise the temperature, wherein the temperature raising process lasted for 80 minutes;
(4) introducing H.sub.2 gas at a flow rate of 50 sccm when the temperature was raised to 1030° C., while remaining the Ar flow rate unchanged; and then annealing, wherein the annealing process lasted for 300 minutes; and
(5) turning off the power supply of the heating furnace after the annealing was finished, and cooling to room temperature naturally with Ar gas and H.sub.2 gas as protective gases.

[0028] The single-crystal copper foil prepared by cloning in this experimental was shown in FIG. 4. FIG. 3(a) showed the EBSD of the clone matrix, and FIG. 3(b) was the EBSD of the large single-crystal copper induced. Both EBSD's proved to be single-crystal Cu(211), which also confirmed the reliability of the single-crystal cloning method. It can be seen that we obtained the Cu(211) surface consistent with that of the matrix by cloning, i.e., a large-area (meter-level) single-crystal copper foil was prepared.