Method and system for preparing three-dimensional reticulated through-hole graphite

Abstract

This invention provides a method and system for preparing three-dimensional mesh-like porous graphite, comprising: preparing a mesh-like metal skeleton using an additive manufacturing process; mixing graphite carbon aggregate and a binder, filling the mesh-like metal skeleton, pressing and molding, and then calcining; and electrolyzing the graphite product containing the mesh-like metal skeleton to remove the mesh-like metal skeleton, thereby obtaining a graphite body containing mesh-like porous structures. This invention can prepare a graphite body with a mesh-like porous distribution, the distribution of which is controlled by the mesh-like metal skeleton.

Description

Technical Field

[0001] This invention relates to the technical field of graphite preparation, specifically to a method and system for preparing three-dimensional mesh-like porous graphite. Background Technology

[0002] Graphite, an allotrope of carbon, is heat-resistant and possesses excellent electrical and thermal conductivity, as well as self-lubricating properties. It can be used in refractory materials, conductive materials, electrode materials for EDM and electrochemical machining, wear-resistant lubricants, mold materials, and more. The manufacturing process for graphite products can include raw material crushing, purification, mixing, kneading, molding, calcination, impregnation, and graphitization. This process can be adjusted based on the specific needs of the graphite product and the availability of raw materials. Graphite products that have not yet been impregnated after calcination have micropores. This porous graphite can store lubricating oil, resulting in bearings with excellent lubrication performance. Impregnation of this microporous graphite, depending on the impregnating material, can produce graphite products of various composite materials, such as resin-impregnated graphite, silver-impregnated graphite, and siliconized graphite. However, because graphite micropores include both open and closed forms, and there is no large-scale interconnection between the micropores, the impregnation depth is limited, making it difficult to produce thick impregnated graphite.

[0003] To prepare large-sized impregnated graphite, researchers analyzed the effects of particle size and calcination temperature on the pore distribution of graphite and optimized the process to obtain the desired porous graphite. However, it remains difficult to overcome the limitations of graphite impregnation size. Therefore, it is necessary to design a porous graphite that can meet the requirements of large-sized impregnation and provide a corresponding preparation process.

[0004] Therefore, a new technical solution needs to be proposed. Summary of the Invention

[0005] In view of the deficiencies in the prior art, the purpose of this invention is to provide a method and system for preparing three-dimensional mesh-like porous graphite.

[0006] According to the present invention, a method for preparing three-dimensional mesh porous graphite includes the following steps:

[0007] Step S1: Fabricate a three-dimensional mesh metal skeleton using additive manufacturing processes;

[0008] Step S2: Mix carbon aggregate and binder, fill the mixture into a mesh metal skeleton, and press it to form a graphite raw product.

[0009] Step S3: Electrolyze the graphite green product containing the three-dimensional mesh metal skeleton to remove the metal skeleton and obtain the graphite green product containing the three-dimensional mesh through holes.

[0010] Step S4: The graphite raw product with the metal skeleton removed is subjected to calcination and graphitization treatment to obtain a graphite product containing a combination of three-dimensional network pores and micropores.

[0011] Preferably, the binder in step S2 is asphalt or resin;

[0012] The pressing and molding method is either molding or isostatic pressing.

[0013] Preferably, the diameter of the three-dimensional mesh through-holes in step S3 is 0.1-2 mm;

[0014] The distribution configuration of the three-dimensional mesh through holes is controlled by a metal skeleton, and the metal skeleton configuration includes three-dimensional vertical cross type, three-dimensional spiral type, and three-dimensional ring array.

[0015] Preferably, in step S3:

[0016] The graphite raw material and the cathode tool are placed in the electrolyte, with a gap between them filled with the electrolyte. The graphite raw material is connected to the positive terminal of the power supply, and the cathode tool is connected to the negative terminal. After the power is turned on, the metal in the graphite raw material is electrolytically corroded. The electrolysis ends after the metal is completely removed.

[0017] In the electrolytic reaction system, graphite acts only as a conductor and does not undergo electrochemical reactions; the metal in the graphite acts as the anode, and is electrolytically corroded to generate metal ions that enter the electrolyte, leaving through-holes in the graphite mass. The electrolyte fills these through-holes, prompting the remaining metal to continue to be electrolytically removed; when the metal is completely removed, the electrolysis of water occurs.

[0018] Preferably, in step S4:

[0019] After electrolysis, the metal skeleton in the graphite raw product is corroded and removed, leaving three-dimensional macroscopic channels; after calcination, the graphite product has microscopic pores; the three-dimensional macroscopic channels and microscopic pores are connected to form a three-dimensional porous graphite product.

[0020] The present invention also provides a system for preparing three-dimensional mesh porous graphite, the system comprising the following modules:

[0021] Module M1: A three-dimensional mesh metal skeleton is fabricated using additive manufacturing processes;

[0022] Module M2: The carbon aggregate and binder are mixed and kneaded, the mixture is filled into a mesh metal skeleton, and then pressed to form a graphite raw product.

[0023] Module M3: Electrolytically treats graphite raw products containing a three-dimensional mesh metal skeleton to remove the metal skeleton and obtain graphite raw products containing three-dimensional mesh through holes;

[0024] Module M4: The graphite raw product with the metal skeleton removed is subjected to calcination and graphitization treatment to obtain a graphite product containing a combination of three-dimensional network through holes and micro-pores.

[0025] Preferably, the binder in module M2 is asphalt or resin;

[0026] The compression molding system is either a molding method or an isostatic pressing method.

[0027] Preferably, the diameter of the three-dimensional mesh through-holes in module M3 is 0.1-2 mm;

[0028] The distribution configuration of the three-dimensional mesh through holes is controlled by a metal skeleton, and the metal skeleton configuration includes three-dimensional vertical cross type, three-dimensional spiral type, and three-dimensional ring array.

[0029] Preferably, in module M3:

[0030] The graphite raw material and the cathode tool are placed in the electrolyte, with a gap between them filled with the electrolyte. The graphite raw material is connected to the positive terminal of the power supply, and the cathode tool is connected to the negative terminal. After the power is turned on, the metal in the graphite raw material is electrolytically corroded. The electrolysis ends after the metal is completely removed.

[0031] In the electrolytic reaction system, graphite acts only as a conductor and does not undergo electrochemical reactions; the metal in the graphite acts as the anode, and is electrolytically corroded to generate metal ions that enter the electrolyte, leaving through-holes in the graphite mass. The electrolyte fills these through-holes, prompting the remaining metal to continue to be electrolytically removed; when the metal is completely removed, the electrolysis of water occurs.

[0032] Preferably, in module M4:

[0033] After electrolysis, the metal skeleton in the graphite raw product is corroded and removed, leaving three-dimensional macroscopic channels; after calcination, the graphite product has microscopic pores; the three-dimensional macroscopic channels and microscopic pores are connected to form a three-dimensional porous graphite product.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] 1. This invention prepares three-dimensional mesh-distributed porous graphite by electrolytic metal skeleton. The distribution state of the graphite pores is controlled by the metal skeleton configuration. The metal skeleton is prepared by additive manufacturing process. Therefore, it is relatively convenient to prepare mesh-distributed porous graphite with different configurations, and the production flexibility is high.

[0036] 2. The three-dimensional network-distributed porous graphite prepared by this invention provides liquid penetration channels for subsequent impregnation processes. The combination of the three-dimensional macroscopic pores left after metal corrosion and the microscopic pores after graphite calcination improves the impregnation depth of graphite. Attached Figure Description

[0037] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0038] Figure 1 This is a schematic diagram of a three-dimensional vertically intersecting metal skeleton.

[0039] Figure 2 This is a schematic diagram of a three-dimensional vertically intersecting metal skeleton.

[0040] Figure 3 This is a schematic diagram of a three-dimensional ring-shaped metal skeleton;

[0041] Figure 4 This is a schematic diagram of a three-dimensional spiral metal skeleton.

[0042] Figure 5 A schematic diagram of porous graphite with a three-dimensional network distribution;

[0043] Figure 6 A schematic diagram of an electrolytic processing system for graphite raw materials containing a metal framework;

[0044] Figure 7 This is a flowchart illustrating the principle of the present invention.

[0045] in:

[0046] Graphite raw materials 1, power supply 3

[0047] Cathode tool 2 Electrolyte container 4

[0048] Electrolyte 5 Detailed Implementation

[0049] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0050] Example 1:

[0051] Reference Figure 7 According to the present invention, a method for preparing three-dimensional mesh porous graphite includes the following steps:

[0052] Step S1: Fabricate a three-dimensional mesh metal skeleton using additive manufacturing processes;

[0053] Step S2: Mix carbon aggregate and binder, fill the mixture into a mesh metal skeleton, and press to obtain graphite raw product; the binder is asphalt or resin; the pressing method is molding or isostatic pressing.

[0054] Step S3: Electrolyze the graphite green product containing a three-dimensional mesh metal skeleton to remove the metal skeleton, obtaining a graphite green product containing three-dimensional mesh through-holes; the diameter of the three-dimensional mesh through-holes is 0.1-2 mm; the distribution configuration of the three-dimensional mesh through-holes is controlled by the metal skeleton, and the metal skeleton configuration includes three-dimensional vertical cross type, three-dimensional spiral type, and three-dimensional ring array; place the graphite green product and cathode tool in the electrolyte, with a gap between the graphite green product and the cathode tool, which is filled with electrolyte; connect the graphite green product to the positive terminal of the power supply, and the cathode tool to the negative terminal of the power supply. After the power is turned on, the metal in the graphite green product is electrolytically corroded; the electrolysis ends after the metal is completely removed; in the electrolytic reaction system, graphite only acts as a conductor and does not undergo electrochemical reaction; the metal in the graphite acts as the anode, is electrolytically corroded to generate metal ions that enter the electrolyte, leaving through-holes in the graphite body. The electrolyte fills the through-holes, promoting the continued electrolytic removal of the remaining metal; when the metal is completely removed, the electrolysis reaction of water occurs.

[0055] Step S4: The graphite raw product with the metal skeleton removed is subjected to calcination and graphitization treatment to obtain a graphite product containing a combination of three-dimensional network through holes and micro-pores; after electrolysis, the metal skeleton in the graphite raw product is corroded and removed, leaving three-dimensional macro channels; after calcination, the graphite product has micro-pores; the three-dimensional macro channels are connected with the micro-pores to form a three-dimensional porous graphite product.

[0056] The present invention also provides a preparation system for three-dimensional mesh-like porous graphite. The preparation system for three-dimensional mesh-like porous graphite can be implemented by executing the process steps of the preparation method for three-dimensional mesh-like porous graphite. That is, those skilled in the art can understand the preparation method for three-dimensional mesh-like porous graphite as a preferred embodiment of the preparation system for three-dimensional mesh-like porous graphite.

[0057] Example 2:

[0058] The present invention also provides a system for preparing three-dimensional mesh porous graphite, the system comprising the following modules:

[0059] Module M1: A three-dimensional mesh metal skeleton is fabricated using additive manufacturing processes;

[0060] Module M2: Carbon aggregate and binder are mixed and kneaded, the mixture is filled into a mesh metal skeleton, and then pressed to obtain graphite raw products; the binder is asphalt or resin; the pressing system is molding or isostatic pressing.

[0061] Module M3: Electrolytically treats a graphite green product containing a three-dimensional mesh metal skeleton to remove the metal skeleton, resulting in a graphite green product containing three-dimensional mesh through-holes. The diameter of the three-dimensional mesh through-holes is 0.1-2 mm. The distribution configuration of the three-dimensional mesh through-holes is controlled by the metal skeleton, which includes three-dimensional vertical cross-shaped, three-dimensional spiral, and three-dimensional ring array. The graphite green product and cathode tool are placed in an electrolyte with a gap between them, which is filled with electrolyte. The graphite green product is connected to the positive terminal of a power supply, and the cathode tool is connected to the negative terminal. After the power is turned on, the metal in the graphite green product is electrolytically corroded. Electrolysis ends after the metal is completely removed. In the electrolytic reaction system, graphite only acts as a conductor and does not undergo electrochemical reaction. The metal in the graphite acts as the anode, and is electrolytically corroded to generate metal ions that enter the electrolyte, leaving through-holes in the graphite body. The electrolyte fills these through-holes, promoting the continued electrolytic removal of the remaining metal. When the metal is completely removed, an electrolytic reaction of water occurs.

[0062] Module M4: The graphite raw product with the metal skeleton removed is subjected to calcination and graphitization treatment to obtain a graphite product containing a combination of three-dimensional network through holes and micro-pores; after electrolysis, the metal skeleton in the graphite raw product is corroded and removed, leaving three-dimensional macro channels; after calcination, the graphite product has micro-pores; the three-dimensional macro channels and micro-pores are connected to form a three-dimensional porous graphite product.

[0063] Example 3:

[0064] This invention provides a method for preparing three-dimensional mesh-like porous graphite, comprising: preparing a mesh-like metal skeleton using an additive manufacturing process; mixing graphite carbon aggregate and a binder, filling the mesh-like metal skeleton, pressing and molding, and then calcining; and electrolyzing the graphite product containing the mesh-like metal skeleton to remove the mesh-like metal skeleton, thereby obtaining a graphite body containing mesh-like porous structures. This invention can prepare a graphite body with a mesh-like porous distribution, the distribution of which is controlled by the mesh-like metal skeleton.

[0065] A method for preparing three-dimensional mesh porous graphite according to the present invention includes:

[0066] Reference Figure 1 , Figure 2 , Figure 3 , Figure 4 A three-dimensional mesh metal skeleton was prepared using additive manufacturing. Carbon aggregate and binder were mixed, and the mixture was filled into the mesh metal skeleton and pressed to obtain a graphite green product. The graphite green product containing the three-dimensional mesh metal skeleton was then subjected to electrolytic treatment to remove the metal skeleton, yielding a graphite green product containing three-dimensional mesh through-holes. (Refer to...) Figure 5The graphite raw material with the metal skeleton removed is subjected to calcination and graphitization treatment to obtain a graphite product containing a combination of three-dimensional network macroscopic through-pores and microscopic pores.

[0067] The binder is asphalt or resin; the pressing method is molding or isostatic pressing; the diameter of the graphite pores is 0.1-2 mm; the graphite pressing temperature is lower than the metal melting point; the distribution configuration of the graphite three-dimensional network pores is controlled by a metal skeleton, preferably, the metal skeleton configuration includes a three-dimensional vertical cross type, a three-dimensional spiral type, and a three-dimensional ring array; the graphite green product and the cathode tool are placed in the electrolyte, with a certain gap between the graphite green product and the cathode tool, and this gap is filled with electrolyte; the graphite green product is connected to the positive terminal of the power supply, and the cathode tool is connected to the negative terminal of the power supply. After the power is turned on, the metal in the graphite green product is electrolytically corroded; the electrolysis ends after the metal is completely removed.

[0068] Reference Figure 6 In the electrolytic reaction system, graphite acts only as a conductor and does not undergo electrochemical reactions. The metal in the graphite acts as the anode, and is electrolytically corroded to generate metal ions that enter the electrolyte, leaving through-pores in the graphite mass. The electrolyte fills these through-pores, prompting the remaining metal to continue to be electrolytically removed. When the metal is completely removed, an electrolytic reaction of water occurs. After electrolysis, the metal skeleton in the graphite product is corroded away, leaving macroscopic three-dimensional channels. After calcination, the graphite product contains a large number of micropores. The three-dimensional macroscopic channels are connected to the micropores to form a three-dimensional porous graphite product.

[0069] A method for preparing three-dimensional mesh porous graphite according to the present invention includes:

[0070] A three-dimensional mesh-like metal skeleton was fabricated using additive manufacturing technology. The metal used was 316L stainless steel, and the skeleton was composed of 0.5mm diameter wires. The skeleton had a three-dimensional, vertically intersecting structure. Figure 1 and Figure 2 As shown, the parallel metal wires are spaced 5 mm apart.

[0071] Petroleum coke particles are selected as carbon aggregate and asphalt is selected as binder. The carbon aggregate and binder are mixed and kneaded. After kneading, the dry powder of the mixture is filled into a metal mesh skeleton and pressed into shape using an isostatic pressing process with a molding pressure of 50-200MPa to obtain graphite raw products.

[0072] Electrolytic treatment is performed on a graphite raw product containing a three-dimensional network metal skeleton. The graphite raw product 1 and the cathode tool 2 are placed in an electrolyte 5, which is a 10% sodium chloride solution. The electrolyte 5 is located in an electrolyte container 4, and there is a certain gap between the graphite raw product 1 and the cathode tool 2, which is filled with electrolyte 5. The graphite raw product 1 is connected to the positive terminal of a power supply 3, and the cathode tool 2 is connected to the negative terminal of the power supply 3. The power supply voltage is 15-30V. After the power supply 3 is turned on, the metal in the graphite raw product is electrolytically corroded. After the metal is completely removed, the electrolysis is stopped, and a graphite raw product containing three-dimensional network pores is obtained.

[0073] The raw graphite product with its metal skeleton removed is subjected to calcination and graphitization treatment. The calcination temperature is no higher than 1200℃, and the graphitization temperature is 2400℃. After calcination, the binder pitch gradually cokes, forming micropores. After graphitization treatment, a porous graphite product combining three-dimensional network macroscopic through-pores and micropores is obtained.

[0074] Those skilled in the art can understand this embodiment as a more specific description of Embodiment 1 and Embodiment 2.

[0075] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0076] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A method for preparing three-dimensional mesh-like porous graphite, characterized in that, The method includes the following steps: Step S1: Fabricate a three-dimensional mesh metal skeleton using additive manufacturing processes; Step S2: Mix carbon aggregate and binder, fill the mixture into a mesh metal skeleton, and press it to form a graphite raw product. Step S3: Electrolyze the graphite green product containing the three-dimensional mesh metal skeleton to remove the metal skeleton and obtain the graphite green product containing the three-dimensional mesh through holes. Step S4: The graphite raw product with the metal skeleton removed is subjected to calcination and graphitization treatment to obtain a graphite product containing a combination of three-dimensional network pores and micropores; The diameter of the three-dimensional mesh through-holes in step S3 is 0.1-2 mm; The distribution configuration of the three-dimensional mesh through holes is controlled by a metal skeleton, and the metal skeleton configuration includes three-dimensional vertical intersecting type, three-dimensional spiral type, and three-dimensional ring array; In step S3: The graphite raw material and the cathode tool are placed in the electrolyte, with a gap between them filled with the electrolyte. The graphite raw material is connected to the positive terminal of the power supply, and the cathode tool is connected to the negative terminal. After the power is turned on, the metal in the graphite raw material is electrolytically corroded. The electrolysis ends after the metal is completely removed. In the electrolytic reaction system, graphite acts only as a conductor and does not undergo electrochemical reactions. The metal within the graphite acts as the anode, being electrolytically corroded to generate metal ions that enter the electrolyte, leaving pores in the graphite mass. The electrolyte fills these pores, prompting the continued electrolytic removal of any remaining metal. When the metal is completely removed, the electrolysis of water occurs. In step S4: After electrolysis, the metal skeleton in the graphite raw product is corroded and removed, leaving three-dimensional macroscopic channels; after calcination, the graphite product has microscopic pores; the three-dimensional macroscopic channels are connected with the microscopic pores to form a three-dimensional porous graphite product. The binder in step S2 is asphalt or resin; The pressing and molding method is either molding or isostatic pressing.

2. A system for preparing three-dimensional mesh-like porous graphite, characterized in that, The system includes the following modules: Module M1: A three-dimensional mesh metal skeleton is fabricated using additive manufacturing processes; Module M2: The carbon aggregate and binder are mixed and kneaded, the mixture is filled into a mesh metal skeleton, and then pressed to form a graphite raw product. Module M3: Electrolytically treats graphite raw products containing a three-dimensional mesh metal skeleton to remove the metal skeleton and obtain graphite raw products containing three-dimensional mesh through holes; Module M4: Calcination and graphitization are performed on the graphite raw material after the metal skeleton has been removed to obtain a graphite product containing a combination of three-dimensional network pores and micropores; The diameter of the three-dimensional mesh through-holes in module M3 is 0.1-2 mm; The distribution configuration of the three-dimensional mesh through holes is controlled by a metal skeleton, and the metal skeleton configuration includes three-dimensional vertical intersecting type, three-dimensional spiral type, and three-dimensional ring array; In module M3: The graphite raw material and the cathode tool are placed in the electrolyte, with a gap between them filled with the electrolyte. The graphite raw material is connected to the positive terminal of the power supply, and the cathode tool is connected to the negative terminal. After the power is turned on, the metal in the graphite raw material is electrolytically corroded. The electrolysis ends after the metal is completely removed. In the electrolytic reaction system, graphite acts only as a conductor and does not undergo electrochemical reactions; the metal in the graphite acts as the anode, and is electrolytically corroded to generate metal ions that enter the electrolyte, leaving through-holes in the graphite mass. The electrolyte fills these through-holes, prompting the remaining metal to continue to be electrolytically removed; when the metal is completely removed, the electrolysis of water occurs. The binder in module M2 is asphalt or resin; The compression molding system is either a molding method or an isostatic pressing method.

3. The preparation system for three-dimensional mesh porous graphite according to claim 2, characterized in that, In module M4: After electrolysis, the metal skeleton in the graphite raw product is corroded and removed, leaving three-dimensional macroscopic channels; after calcination, the graphite product has microscopic pores; the three-dimensional macroscopic channels and microscopic pores are connected to form a three-dimensional porous graphite product.

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