Metal powder composition and use thereof

Abstract

The application discloses a metal powder composition and application thereof. The metal powder composition comprises metal powder with a particle size of less than 250 microns and a binding material uniformly mixed with the metal powder; the content of the metal powder in the metal powder composition is more than 75 wt%, and the binding material contains a small amount of polymer material. The metal powder composition provided by the application is a flexible solid-phase material with plasticity, self-adhesion and arbitrary deformation, and has no dust and residue in use. When the metal powder composition is used for manufacturing a heat conducting pipe, the metal powder composition can be conveniently filled into a shell and a core rod, the filling amount is easy to accurately control, the metal powder composition will not flow out of the shell during a vibrating operation, and a capillary structure formed after sintering has the characteristics of high porosity and uniform pore size distribution, is firmly combined with a metal base, and a prepared heat conducting device has excellent heat conducting performance and high yield.

Description

Technical Field

[0001] This application specifically relates to a metal powder composition and its application, such as its application in the preparation of heat-conducting devices, and belongs to the field of metal materials technology. Background Technology

[0002] Heat pipe (also known as heat conduit) technology is widely used in aerospace, military, and radiator industries. It fully utilizes the principles of heat conduction and the rapid heat transfer properties of refrigerants, quickly transferring heat from a heat-generating object to the outside of the heat source, with a thermal conductivity exceeding that of any known metal. Generally, a heat pipe consists of a hollow cylindrical tube and a liquid working medium filled within it. Inside the cylindrical tube is a capillary wick, typically made of sintered copper powder. Current heat pipe manufacturing methods generally involve: inserting a mandrel into a copper tube, filling the space between the mandrel and the copper tube with copper powder and compacting it, then sintering the copper powder and the copper tube wall together at high temperature, removing the mandrel to obtain the component connected to the copper capillary wick on the copper wall, followed by subsequent processes such as water injection and vacuuming. However, the copper powder used is a dry powder, so the operation of filling the space between the mandrel and the copper tube and compacting it cannot be automated and easily causes dust pollution, seriously affecting the health of operators.

[0003] One existing solution is to mix copper powder with polymers to form a paste, which is then extruded into copper tubes. This method can reduce dust pollution, but the proportion of polymers in the copper paste needs to be at least 35 wt%, and an excessively high proportion of polymers will seriously affect the sintering of copper powder and copper tubes. Another solution is to mix copper powder with a certain amount of solvent to form a wet powder, which is then filled into copper tubes. However, this method cannot achieve automated production, and it is difficult to avoid wet powder residues in production equipment and non-working parts of the copper tubes, leading to a large waste of copper powder, equipment pollution, and less than ideal sintering of copper powder and copper tubes. Summary of the Invention

[0004] The main objective of this application is to provide a metal powder composition and its application to overcome the shortcomings of the prior art.

[0005] To achieve the aforementioned objective, the technical solution adopted in this application includes:

[0006] One aspect of this application provides a metal powder composition comprising:

[0007] Metal powder with a particle size of less than 250 μm, and

[0008] A polymeric material uniformly mixed with the metal powder;

[0009] Furthermore, the metal powder content in the metal powder composition is 75 wt% or more, and the metal powder composition is a flexible solid material with plasticity.

[0010] Another aspect of this application provides for the use of the metal powder composition, such as its use in the field of powder metallurgy.

[0011] Another aspect of this application provides a method for preparing a heat-conducting device, comprising:

[0012] The first step includes creating capillary structures within the shell; and

[0013] The second step includes sequentially performing the operations of injecting the working medium into the housing, evacuating the inner cavity of the housing, and sealing the housing.

[0014] The first step specifically includes:

[0015] Insert a mandrel into the inner cavity of the housing from one end opening, leaving a gap between the mandrel and the inner wall of the housing;

[0016] The metal powder composition is filled into the gap, and then sintered to form a capillary structure, and the capillary structure is bonded to the inner wall of the shell.

[0017] After the sintering is completed, the mandrel is removed.

[0018] Compared with the prior art, the advantages of this application include:

[0019] (1) The metal powder composition provided is a flexible solid material with plasticity, self-adhesion, and arbitrary deformation. It is dust-free and residue-free during use. Especially when used to make heat pipes, it can be easily filled between the shell and the core rod. The filling amount is easy to control precisely. It will not flow out of the shell during the vibration operation. The capillary structure formed after sintering has the characteristics of high porosity and uniform pore size distribution. Moreover, it is easy to remove the core rod without damaging the capillary structure.

[0020] (2) The preparation process of the provided heat-conducting device is simple and easy to operate, highly controllable, and can realize automated production. In particular, it can realize automated powder filling operation, which can greatly improve production efficiency. Moreover, the prepared heat-conducting device has excellent thermal conductivity and high yield. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figures 1a-1b Photographs of a copper powder composition in Example 1 in a static state and a lifted state are shown respectively;

[0023] Figure 2 This is a schematic diagram illustrating the fabrication process of a heat pipe in Example 1;

[0024] Figure 3 This is a schematic diagram of injecting a metal powder composition into the gap between a copper tube and a mandrel in Example 9. Detailed Implementation

[0025] In view of the shortcomings of the prior art, the inventors of this case, through long-term research and practice, have been able to propose the technical solution of this application, which will be described in more detail below.

[0026] Some embodiments of this application provide a metal powder composition comprising:

[0027] Metal powder with a particle size of less than 250 μm,

[0028] A binder material uniformly mixed with the metal powder;

[0029] Furthermore, the metal powder content in the metal powder composition is 75 wt% or more, and the metal powder composition is a flexible solid material with plasticity.

[0030] In one embodiment, the metal powder composition comprises 80 wt% to 95 wt% metal powder.

[0031] In one embodiment, the metal powder is regular spherical particles, irregularly shaped particles, or a combination thereof, wherein the spherical particles have a higher bonding strength with the substrate after sintering, and the irregular particles can form a capillary structure with a richer pore size distribution and higher porosity after sintering.

[0032] In one embodiment, the loose bulk density of the metal powder is 1.5 g / cm³. 3 ~2.5g / cm3.

[0033] In one embodiment, the particle size of the metal powder is 100 μm to 250 μm. Using metal powder within this particle size range allows for a higher metal powder content in the resulting metal powder composition while maintaining good plasticity and self-adhesion.

[0034] In one embodiment, the metal powder includes copper powder or copper alloy powder, but is not limited thereto.

[0035] Furthermore, the content of alloying elements in the copper alloy powder decreases from the particle surface to the interior, which helps to significantly reduce its sintering temperature and makes the bonding between metal powders and between the metal powder and the metal substrate stronger.

[0036] For example, the copper alloy powder contains a copper-tin alloy, wherein the tin content is 0.1wt% to 5wt%, preferably 0.5wt% to 3wt%.

[0037] For example, the copper alloy powder contains a copper-nickel alloy, wherein the nickel content is 0.1wt% to 5wt%, preferably 0.5wt% to 3wt%.

[0038] In one embodiment, the adhesive material comprises 2 wt% to 5 wt% nonionic soluble cellulose ether, 5 wt% to 10 wt% small molecule diol, 0.1 wt% to 1 wt% hydroquinone salt or its derivative, 0.2 wt% to 5 wt% corrosion inhibitor, and the remainder comprises solvent. In this application, if the amount of adhesive material is too high, the resulting metal powder composition will be in a paste or fluid form; if the amount of adhesive material is too low, the resulting metal powder composition will lose its plasticity. Furthermore, experiments have shown that the nonionic soluble cellulose ether, small molecule diol, hydroquinone salt or its derivative, corrosion inhibitor, and other components in the adhesive material are difficult to replace with other substances, and the proportions of each component cannot be arbitrarily adjusted; otherwise, the resulting metal composition will lose at least one of its properties: plasticity, flexibility, and solid phase.

[0039] Furthermore, the nonionic soluble cellulose ether includes, but is not limited to, hydroxyethyl cellulose, methyl cellulose, hydroxyethyl methyl cellulose (HEMC), hydroxypropyl methyl cellulose (HPMC), hydroxybutyl methyl cellulose (HBMC), ethyl methyl cellulose (EMC), carboxymethyl cellulose (CMMC), etc. In the metal powder composition of this application, the nonionic soluble cellulose ether can, on the one hand, bind the metal powders together to form deformable aggregates, and on the other hand, it also functions as a lubricant; for example, when the metal composition is extruded into a copper tube, it can significantly reduce friction.

[0040] Furthermore, the small molecule diols include, but are not limited to, ethylene glycol, 1,4-butanediol, or diethylene glycol.

[0041] Furthermore, the hydroquinone salt includes, but is not limited to, sodium resorcinol, sodium hydroquinone, or sodium catechol.

[0042] Furthermore, the corrosion inhibitor includes, but is not limited to, benzotriazole, aqueous rosin resin, or hydrogenated castor oil. The amount of benzotriazole in the adhesive material can be 0.2wt%-2wt%. The amount of aqueous rosin resin or hydrogenated castor oil in the adhesive material can be 0.5wt%-5wt%. The corrosion inhibitor can not only slow down or even eliminate the corrosion of metal powder by oxygen in the air, but also further improve the plasticity of the metal powder composition.

[0043] Furthermore, the solvent is a solvent that is easily volatile at the sintering temperature of the metal powder composition, such as carbitol or water, and is not limited thereto.

[0044] This application uses a small amount of nonionic soluble cellulose ether, small molecule diol, hydroquinone salt or its derivatives, and corrosion inhibitors, combined with a solvent as the main component to form an adhesive material. This adhesive material is then compounded with metal powder, which not only gives the metal powder composition characteristics similar to modeling clay, i.e., self-adhesive and deformable, but also gives it a very high metal content and a very low polymer content. Meanwhile, the remaining components are small molecule compounds and solvents, which are easily removed during the sintering process of the metal powder composition, thus effectively ensuring the bonding performance between metal particles and between metal particles and the metal substrate.

[0045] The metal powder composition of this application, when used, produces no dust or residue compared to pure metal powder, and is less prone to leakage. Furthermore, compared to copper paste and similar materials, the metal powder composition not only has a higher metal powder content but also leaves virtually no residue in areas other than the target area during use, preventing contamination of non-target areas. The dosage is easy to control precisely, and it has good gap-filling properties and is less prone to leakage. In addition, the metal powder composition, when used, can form a capillary structure with high porosity and uniform pore size distribution through simple sintering.

[0046] Some embodiments of this application provide the application of the metal powder composition in the preparation of heat-conducting devices, such as its application in the preparation of capillary structures within heat-conducting devices. The heat-conducting devices include, but are not limited to, heat pipes, heat spreaders, etc.

[0047] Some embodiments of this application provide a method for preparing a heat-conducting device, including:

[0048] The first step includes creating capillary structures within the shell; and

[0049] The second step includes sequentially performing the operations of injecting the working medium into the housing, evacuating the inner cavity of the housing, and sealing the housing.

[0050] The first step specifically includes:

[0051] Insert a mandrel into the inner cavity of the housing from one end opening, leaving a gap between the mandrel and the inner wall of the housing;

[0052] The metal powder composition is filled into the gap, and then sintered to form a capillary structure, and the capillary structure is bonded to the inner wall of the shell.

[0053] After the sintering is completed, the mandrel is removed.

[0054] In one embodiment, the first step specifically includes: filling the gap with the metal powder composition, then compacting or vibrating it, and then performing the sintering.

[0055] In one embodiment, the sintering includes: first sintering at 150-380°C for 10-30 min, then sintering at 400-600°C, and then sintering at 880-980°C; and the sintering is carried out in a non-oxidizing atmosphere.

[0056] Furthermore, the non-oxidizing atmosphere includes, but is not limited to, an atmosphere formed by any one or more combinations of nitrogen, hydrogen, and carbon monoxide.

[0057] The heat-conducting device preparation method provided in this application uses the aforementioned metal powder composition. When filling the gap between the shell and the core rod with the metal powder composition, the operation is simpler, the filling amount is easier to control precisely, and the compaction operation can be automated. The metal powder composition will not leak from the shell, there are no dead corners in the filling, and a capillary structure with relatively ideal quality can be obtained after simple sintering. The metal powder particles in the capillary structure are well bonded, and the capillary structure is firmly bonded to the inner wall of the shell. At the same time, the operation of removing the core rod after sintering is easy to perform and will not damage the capillary structure. This can effectively improve the heat conduction performance of the heat-conducting device and increase its yield.

[0058] Some embodiments of this application provide a heat-conducting device, which is manufactured by any of the aforementioned methods. The heat-conducting device includes, but is not limited to, heat pipes.

[0059] The technical solution of this application will be described in more detail below with reference to the accompanying drawings and several embodiments. However, it should be understood that the following embodiments are only for explaining and illustrating the technical solution of this application, and do not limit the scope of this application. Furthermore, unless otherwise specified, all raw materials used in the following embodiments are obtained from the market. The corresponding sintering equipment, vacuum equipment, etc., are also commonly used in the art. For example, the pure copper powder, copper-tin alloy powder, and copper-nickel alloy powder used in the following embodiments are all products of Suzhou Tongbaorui New Materials Co., Ltd., mainly consisting of irregularly shaped particles. The surface of the particles is mainly composed of tin and nickel, while the interior is mainly composed of copper.

[0060] The formulations of the metal powder compositions provided in Examples 1 to 9 are detailed in Tables 1 and 2.

[0061] Table 1. Formulations of the metal powder compositions in Examples 1 to 9

[0062]

[0063]

[0064] Table 2 shows the formulations of the adhesive materials used in Examples 1 through 9.

[0065]

[0066] Please see Figure 2 The method for fabricating a heat pipe using the metal powder composition in Example 1 includes the following steps:

[0067] S1. Provides a copper tube with one end open and a mandrel, the outer wall of which can be coated with an anti-stick coating commonly used in powder metallurgy.

[0068] S2. Insert one end of the mandrel into the copper tube, so that the mandrel and the copper tube are coaxially arranged, and leave a gap between the mandrel and the inner wall of the copper tube.

[0069] S3. Fill the gap with the metal powder composition and compact it;

[0070] S4. The metal powder composition filled in the copper tube is sintered. The sintering process includes three stages: first, sintering at 300°C for 15 minutes, then at 480°C for 40 minutes, and then at 960°C for 60 minutes. All three stages of sintering are carried out in a nitrogen atmosphere to form a capillary structure.

[0071] S5. After sintering, remove the core rod from the copper tube and inject water into the copper tube.

[0072] S6. Evacuate the copper tube and then seal the opening of the copper tube to form a heat pipe.

[0073] In step S4, after the mandrel is removed, the capillary structure is observed. It can be seen that the surface of the capillary structure is undamaged, the thickness is uniform throughout, and the pore size is mainly distributed in the range of 5-100 μm, with a porosity of approximately 55%. Furthermore, the surface of the inner wall of the copper tube is smooth except for the area covered by the capillary structure. In addition, after the semi-finished product obtained in step S4 is subjected to vibration testing according to the method of GB / T2423.10-2008, the capillary structure remains firmly bonded to the copper tube wall, without loosening or shedding powder.

[0074] The heat pipe in Example 2 was made in basically the same way as in Example 1. The difference is that in step S4, the sintering process includes: sintering at 150°C for 30 min, sintering at 400°C for 20 min, and then sintering at 960°C for 60 min. The sintering in these three stages is carried out in a hydrogen atmosphere to form a capillary structure.

[0075] The heat pipe in Example 3 was also made in basically the same way as in Example 1. The difference is that in step S4, the sintering process includes: sintering at 380°C for 10 min, sintering at 600°C for 60 min, and then sintering at 960°C for 40 min. The sintering of these three stages is carried out in a mixed atmosphere of hydrogen and nitrogen with a volume ratio of 1:1, thereby forming a capillary structure.

[0076] The heat pipe in Example 4 was made in basically the same way as in Example 1. The difference is that in step S4, the sintering process includes: sintering at 200°C for 20 min, sintering at 550°C for 30 min, and then sintering at 960°C for 30 min. The sintering in these three stages is carried out in a nitrogen atmosphere to form a capillary structure.

[0077] The heat pipe in Example 5 was made in basically the same way as in Example 1. The difference is that in step S4, the sintering process includes: sintering at 200°C for 20 min, sintering at 420°C for 30 min, and sintering at 880°C for 30 min. The sintering in these three stages is carried out in a nitrogen atmosphere to form a capillary structure.

[0078] The heat pipe in Example 6 was made in basically the same way as in Example 1. The difference is that in step S4, the sintering process includes: sintering at 180°C for 20 min, sintering at 450°C for 30 min, and then sintering at 900°C for 30 min. The sintering in these three stages is carried out in a CO atmosphere to form a capillary structure.

[0079] The heat pipe in Example 7 was made in basically the same way as in Example 1. The difference is that in step S4, the sintering process includes: sintering at 250°C for 20 min, sintering at 600°C for 30 min, and then sintering at 920°C for 30 min. The sintering in these three stages is carried out in a nitrogen atmosphere to form a capillary structure.

[0080] The heat pipe in Example 8 was made in basically the same way as in Example 1, except that in step S4, the sintering process included: sintering at 300°C for 15 min, sintering at 500°C for 35 min, and then sintering at 960°C for 25 min. All three sintering stages were carried out in a nitrogen atmosphere to form a capillary structure.

[0081] The heat pipe in Example 9 was fabricated using essentially the same method as in Example 1, with the difference being:

[0082] In step S3, refer to Figure 3 A feeding device is used to inject the metal powder composition into the gap between the mandrel and the inner wall of the copper tube. The feeding device can be a syringe or a similar structure; its outlet is aligned with the gap, and the metal powder composition is pushed through it, causing the composition to move in the direction indicated by the arrow and be injected into the gap. During this process, a pushing mechanism can be used to keep the mandrel fixed to the copper tube at all times. After filling with the metal powder composition, compaction or other operations can be performed.

[0083] In step S4, the sintering process includes: sintering at 200°C for 25 min, sintering at 480°C for 30 min, and sintering at 950°C for 35 min. All three sintering stages are carried out in a nitrogen atmosphere to form a capillary structure.

[0084] The heat pipes in Examples 2 to 9 were fabricated using the same method as in Example 1. The resulting capillary structures had no surface damage, with pore sizes mainly distributed in the range of 5-100 μm and porosity in the range of 50%-65%. Furthermore, the thickness of the capillary structure was uniform throughout. After vibration testing according to GB / T 2423.10-2008, the capillary structure remained firmly bonded to the copper pipe wall, without any loosening or powder shedding.

[0085] The composition of the metal powder compositions used in Comparative Examples 1 and 2 is detailed in Table 3. The metal powder composition in Comparative Example 1 is the same pure copper powder as in Example 1. The metal powder composition in Comparative Example 2 is copper paste produced by Suzhou Tongbaorui New Materials Co., Ltd., wherein the pure copper powder is the same as in Example 1, the binder is acrylic resin, and the solvent is turpentine.

[0086] Table 3 shows the formulations of the metal powder compositions provided in Comparative Examples 1 to 3.

[0087] Copper powder / ratio Adhesive / wt% Solvent / wt% Additives Comparative Example 1 Copper powder / 100% 0 0 0 Comparative Example 2 Copper powder / balance 10 20 2

[0088] The method for fabricating a heat pipe using a metal powder composition in Comparative Example 1 includes the following steps:

[0089] S1~S2: Same as in Example 1;

[0090] S3. Fill the gap with the metal powder composition and compact it. There is obvious dust during the compaction process.

[0091] S4. The metal powder composition filled in the copper tube is sintered at a temperature of 960°C for 40 minutes. The sintering of these three stages is carried out in a nitrogen atmosphere to form a capillary structure.

[0092] S5~S6: Same as in Example 1.

[0093] In Comparative Example 1, after the mandrel is removed in step S4, the capillary structure is observed. It can be seen that the pore size of the pores contained in the capillary structure is distributed in the range of 5-100μm, and the porosity is about 55%.

[0094] Because pure copper powder was used in Comparative Example 1, a large amount of dust was generated during the fabrication of the heat pipe. Furthermore, when transferring the heat pipe after the copper powder was filled, the copper powder easily flowed out from the filling port, resulting in a thinner capillary structure with uneven thickness in various places.

[0095] The method for fabricating a heat pipe using a metal powder composition in Comparative Example 2 includes the following steps:

[0096] S1~S2: Same as in Example 1;

[0097] S3. The metal powder composition is squeezed into the gap and allowed to stand to remove air bubbles;

[0098] S4. The metal powder composition filled in the copper tube is sintered. The sintering process includes three stages: first, sintering at 300°C for 15 minutes, then at 480°C for 40 minutes, and then at about 1000°C for 60 minutes. All three stages of sintering are carried out in a nitrogen atmosphere to form a capillary structure.

[0099] S5~S6: Same as in Example 1.

[0100] In Comparative Example 2, after the mandrel was removed in step S4, the capillary structure was observed. It was observed that the surface of the capillary structure showed some damage, and some copper powder detached from the inner wall of the copper tube after slight vibration. The pore size of the capillary structure ranged from 5 to 100 μm, with a porosity of approximately 65%. Simultaneously, some sintered copper powder was also sporadically distributed on the remaining areas of the inner wall of the copper tube, which may be due to some copper paste adhering to these areas during the filling process.

[0101] The copper paste used in Comparative Example 2 contains a large amount of polymer materials, resulting in poor sintering strength between copper powders and easy separation of copper powders from the inner wall of the copper tube.

[0102] It should be understood that the technical solution of this application is not limited to the specific implementation examples mentioned above. Any technical modifications made to the technical solution of this application without departing from the spirit and scope of protection of the claims shall fall within the scope of protection of this application.

Claims

1. A metal powder composition, characterized in that, include: 80wt%~95wt% metal powder, wherein the metal powder is irregularly shaped particles with a particle size of 100μm~250μm and a loose packing density of 1.5g / cm³. 3 ~2.5g / cm 3 It includes copper powder or copper alloy powder, wherein the content of alloying elements in the copper alloy powder decreases from the particle surface to the interior. The adhesive material is uniformly mixed with the metal powder, the adhesive material comprising 2wt%~5wt% nonionic soluble cellulose ether, 5wt%~10wt% small molecule diol, 0.1wt%~1wt% hydroquinone salt or its derivative, and 0.2wt%~5wt% corrosion inhibitor, the balance being solvent, the solvent including carbitol or water; Furthermore, the metal powder composition is a flexible solid material with plasticity.

2. The metal powder composition according to claim 1, characterized in that: The copper alloy powder contains a copper-tin alloy, wherein the tin content is 0.1wt% to 5wt%.

3. The metal powder composition according to claim 2, characterized in that: The tin content in the copper alloy powder is 0.5wt%~3wt%.

4. The metal powder composition according to claim 1, characterized in that: The copper alloy powder contains a copper-nickel alloy, wherein the nickel content is 0.1wt% to 5wt%.

5. The metal powder composition according to claim 4, characterized in that: The nickel content in the copper alloy powder is 0.5wt%~3wt%.

6. The metal powder composition according to claim 1, characterized in that: The nonionic soluble cellulose ethers include hydroxyethyl cellulose, methyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, hydroxybutyl methyl cellulose, ethyl methyl cellulose, or carboxymethyl cellulose.

7. The metal powder composition according to claim 1, characterized in that: The small molecule diols include ethylene glycol, 1,4-butanediol, or diethylene glycol.

8. The metal powder composition according to claim 1, characterized in that: The hydroquinone salts include sodium resorcinol, sodium hydroquinone, or sodium catechol.

9. The metal powder composition according to claim 1, characterized in that: The corrosion inhibitors include benzotriazole, waterborne rosin resin, or hydrogenated castor oil.

10. The use of the metal powder composition according to any one of claims 1-9 in the preparation of a heat-conducting device.

11. A method for preparing a heat-conducting device, comprising: The first step includes creating capillary structures within the shell; as well as The second step includes sequentially performing the operations of injecting the working medium into the housing, evacuating the inner cavity of the housing, and sealing the housing. The first step is characterized by including: Insert a mandrel into the inner cavity of the housing from one end opening, leaving a gap between the mandrel and the inner wall of the housing; The metal powder composition of any one of claims 1-9 is filled into the gap, and then sintered to form a capillary structure of the metal powder composition and to bind the capillary structure to the inner wall of the shell. After the sintering is completed, the mandrel is removed.

12. The preparation method according to claim 11, characterized in that, The first step specifically includes: filling the gap with the metal powder composition, then compacting or vibrating it, and then performing the sintering.

13. The preparation method according to claim 11, characterized in that, The sintering process includes: first sintering at 150~380℃ for 10~30 min, then sintering at 400~600℃, and finally sintering at 880~980℃; Furthermore, the sintering is carried out in a non-oxidizing atmosphere.

14. The preparation method according to claim 13, characterized in that: The non-oxidizing atmosphere includes an atmosphere formed by one or more combinations of nitrogen, hydrogen, and carbon monoxide.

15. A heat-conducting device, characterized in that, It is prepared by any one of claims 11-14.

16. The heat-conducting device according to claim 15, characterized in that: The heat-conducting device includes a heat pipe.

Images