A siliconized graphite material, a siliconized graphite mold, and a method for manufacturing the same

Abstract

The application provides a siliconized graphite material, a siliconized graphite casting and a preparation method thereof, and relates to the technical field of nickel-based high-temperature alloy and titanium alloy casting. The siliconized graphite material comprises a porous graphite base and a silicon carbide layer wrapped on the surface of the porous graphite base. The porous graphite base has a hierarchical porous structure, and the hierarchical porous structure comprises closed pores and penetrating pores. The pore diameter of the closed pores is 0.001-0.05 mm. The penetrating pores penetrate through the porous graphite base and comprise first-level penetrating pores with a pore diameter of 0.03-0.2 mm and second-level penetrating pores with a pore diameter of 0.1-1 mm. The silicon carbide layer is uniformly wrapped on the outer surface of the multi-stage porous graphite base and the surface of the internal penetrating pores. The siliconized graphite material not only has good thermal stability and thermal conductivity, but also has good high-temperature oxidation resistance, good corrosion resistance, high mechanical strength, excellent air permeability and good dimensional stability.

Description

TECHNICAL FIELD

[0001] This application claims priority based on Chinese patent application No. "202411993089.6", filed on December 31, 2024, entitled "A graphite-based casting mold and its preparation method". All of these are incorporated herein by reference.

[0002] The present application belongs to the field of nickel-based superalloy and titanium alloy casting, and specifically relates to a siliconized graphite material, a siliconized graphite casting mold and a preparation method thereof. BACKGROUND

[0003] Nickel-based superalloy and titanium alloy have good comprehensive performance and are widely used in the fields of aviation, aerospace, ship, weapon, petrochemical industry, etc. With the rapid development of related fields, the demand for nickel-based superalloy and titanium alloy parts with complex cavities is increasing.

[0004] Casting process combines mold design and shape control technology, which can realize the overall forming of nickel-based superalloy and titanium alloy parts with complex structures. Graphite neither chemically reacts with nickel-based superalloy nor titanium alloy, and has good thermal conductivity and thermal stability, so it becomes one of the commonly used mold materials for casting. However, graphite material has poor high-temperature oxidation resistance and high brittleness. At the same time, due to the chilling effect and poor yielding of graphite, machined graphite casting mold is easy to cause many defects (such as cracks, cold shut, flow marks, etc.) on the surface of the casting, and the product quality is difficult to guarantee, which is not suitable for large-scale production of complex shape castings. For parts with complex structure and cavity, the shape control core also has a complex structure, so it is difficult to remove the traditional graphite core by conventional machining method. In addition, with the increase of the size of the casting, especially for large-scale complex thin-walled castings, the importance of gas permeability is particularly prominent. Therefore, a casting mold with excellent gas permeability is needed to ensure the smooth progress of the casting process. SUMMARY

[0005] In view of the deficiencies of the prior art, the present application provides a siliconized graphite material, a siliconized graphite casting mold and a preparation method thereof. The siliconized graphite material not only has good thermal stability and thermal conductivity, but also has good high-temperature oxidation resistance, good corrosion resistance, high mechanical strength, excellent gas permeability and good dimensional stability.

[0006] The specific technical solutions of the present application are as follows:

[0007] In a first aspect, the present application provides a siliconized graphite material, comprising a multi-stage porous graphite matrix and a silicon carbide layer wrapped on the surface of the multi-stage porous graphite matrix; the multi-stage porous graphite matrix has a hierarchical porous structure, the hierarchical porous structure comprises closed pores and penetrating pores, the closed pores are non-penetrating pores, the pore size of the closed pores is 0.001-0.05 mm, the penetrating pores penetrate through the multi-stage porous graphite matrix, the penetrating pores comprise first-stage penetrating pores and second-stage penetrating pores, the pore size of the first-stage penetrating pores is 0.03-0.2 mm, the pore size of the second-stage penetrating pores is 0.1-1 mm, and the silicon carbide layer is uniformly wrapped on the external surface of the multi-stage porous graphite matrix and the surface of the internal penetrating pores.

[0008] The siliconized graphite material provided by the present application provides a rich pore size by adopting a multi-stage porous graphite matrix with a pore structure of different sizes. By controlling the number and distribution area of the closed pores with a pore size of 0.001-0.05 mm, the thermal conductivity of the local area of the material can be adjusted, and then the cooling speed of the local area of the casting during casting can be controlled, the temperature field of the casting is adjusted, the thermal stress defects of the casting are reduced, and the chilling effect of the siliconized graphite material is improved. By optimizing the distribution of the closed pores, the structural strength can also be improved, and the siliconized graphite material has sufficient resistance to metal liquid impact during the casting process. At the same time, the closed pores also provide a certain compression capacity for the siliconized graphite material, providing a certain space for the internal shrinkage of the casting during the cooling and solidification process, and improving the yielding property of the siliconized graphite material. The first penetrating pores with a pore size of 0.03-0.2 mm and the second penetrating pores with a pore size of 0.1-1 mm constitute effective gas channels, so that the siliconized graphite material has excellent gas permeability, which is beneficial to the smooth discharge of a large amount of gas (such as air, steam generated by water evaporation, etc.) generated after the high-temperature metal liquid is poured into the casting. The silicon carbide layer wrapped around the multi-stage porous graphite matrix can effectively prevent the erosion of the siliconized graphite material by the oxidizing atmosphere and / or high-temperature metal liquid during the casting process, and further improve the dimensional stability and mechanical strength thereof.

[0009] Further, the second-stage penetrating pores are prepared by an additive manufacturing technology. The additive manufacturing technology can adjust the pore size and distribution in the multi-stage porous graphite matrix according to the needs of the actual application scene, and the internal pore structure can be prepared at the same time during the graphite matrix molding process by the additive manufacturing technology, avoiding the risk of low strength of the graphite mold and easy damage in the prior art.

[0010] Further, the closed pores and the penetrating pores in the multi-level porous graphite matrix adopt at least one of parallel combination, series combination, modular combination, hierarchical combination and network combination. By adopting the above combination mode, the thermal conductivity, strength and the like of the local area of the siliconized graphite material can be adjusted by adjusting the distribution of the pores, so as to meet the needs of the casting in actual application.

[0011] Further, the parallel combination, the series combination, the modular combination, the hierarchical combination and the network combination are realized by adjusting the process of additive manufacturing, and the process includes at least one of model slicing processing mode, layer thickness, filler interval, filler mode, slurry extrusion speed, slurry extrusion pressure, extrusion head size, nozzle resolution, ink droplet size, inkjet pressure, laser power, spot size, scanning speed, printing path, temperature, humidity and protective gas.

[0012] In a possible implementation, the thickness of the silicon carbide layer is 0.05-5 mm. By controlling the thickness of the silicon carbide layer, the erosion of the siliconized graphite casting material by the oxidizing atmosphere and the high-temperature metal liquid in the casting process can be effectively prevented, and the dimensional stability and mechanical strength thereof are improved.

[0013] In a second aspect, the present application provides a siliconized graphite casting, and the material composition of the siliconized graphite casting includes the siliconized graphite material described above.

[0014] Further, the siliconized graphite casting includes a core, a shell, a casting assembly, an exhaust assembly and a guide assembly, and at least one of the core, the shell, the casting assembly and the exhaust assembly uses the siliconized graphite material according to any one of claims 1-5.

[0015] In a third aspect, the present application provides a preparation method of the siliconized graphite casting described above, including the following steps:

[0016] S1, modeling: according to the functional requirements of the siliconized graphite casting, the combination mode of the closed pores and the penetrating pores in the hierarchical porous structure is designed, and a three-dimensional model of the graphite matrix with the hierarchical porous structure is constructed;

[0017] S2, mixed raw material preparation: the carbon source, the binder, the additive and the solvent are fully mixed to form a mixed slurry; the mass ratio of the carbon source, the binder, the additive and the solvent is (60-90):(0-40):(0-10):(30-100);

[0018] S3, blank manufacturing: the three-dimensional model in step S1 is introduced into the control module of the additive manufacturing equipment, the mixed slurry in step S2 is added to the hopper of the additive manufacturing equipment, and three-dimensional printing is performed to obtain a blank of the multi-level porous graphite matrix;

[0019] S4, high temperature treatment: the green body of the multi-level porous graphite matrix in step S3 is sequentially subjected to carbonization treatment and graphitization treatment, then a silicon carbide layer is formed by siliconization treatment, and then optional silicon removal treatment is performed to obtain a siliconized graphite mold.

[0020] The preparation method of the siliconized graphite mold provided by the application can prepare a graphite-based mold with abundant pore diameters and controllable pore diameters and pore diameter distribution, and overcomes the problems of single pore diameter, uncontrollable pore diameter, uneven pore distribution and easy closed pores in the existing preparation method, thereby overcoming the problems of single function and low material transmission efficiency of the graphite-based mold. Moreover, the preparation method provided by the application is simple and controllable, and is conducive to large-scale industrial production.

[0021] In a possible implementation, the combination mode in step S1 is parallel combination or hierarchical combination of the closed pores and the penetrating pores.

[0022] In a possible implementation, the preparation process of the mixed raw materials in step S2 further includes granulation, i.e., the mixed slurry is subjected to spheroidization granulation to obtain a mixed material. The spheroidization granulation can make the mixed raw materials carry more closed pores and first-level penetrating pores.

[0023] In a possible implementation, the carbon source in step S2 includes at least one of natural graphite powder, isostatic pressing graphite powder, graphite electrode powder, pitch coke, petroleum coke, metallurgical coke and carbon black.

[0024] In a possible implementation, the binder in step S2 includes at least one of epoxy resin, phenolic resin, furan resin, urea-formaldehyde resin, polyurethane, polyvinyl alcohol, polymethyl methacrylate and polyvinyl butyral.

[0025] In a possible implementation, the additive in step S2 includes at least one of a curing agent, a sintering aid, a dispersant and a diluent.

[0026] In a possible implementation, the solvent in step S2 includes at least one of water, methanol, ethanol, acetone, ethylene glycol, xylene, ethyl acetate and petroleum ether.

[0027] In a possible implementation, the three-dimensional printing in step S3 adopts any one of a slurry extrusion technology, a three-dimensional printing technology, a powder laser solidification technology, and a selective laser sintering technology.

[0028] In a possible implementation, the siliconization treatment in step S4 adopts any one of a chemical vapor infiltration method, a chemical vapor deposition method, a chemical vapor reaction method, and a liquid silicon infiltration method.

[0029] In a possible implementation, the silicon removal treatment in step S4 adopts a molten alkali silicon removal method or a high-temperature volatilization silicon removal method. Through the silicon removal treatment, the unreacted and excessive silicon present in the surface and / or the through hole of the mold after the siliconization treatment can be removed, the channel obstruction is prevented, and the air permeability of the mold is further improved.

[0030] On the basis of common knowledge in the art, the above-mentioned embodiments can be combined arbitrarily.

[0031] The reagents and raw materials used in the present application are commercially available.

[0032] The positive progress effect of the present application is that:

[0033] The siliconized graphite material provided by the present application has a pore structure with different sizes, provides a rich pore size, and through different combination strategies of closed pores and through holes, a siliconized graphite-based mold material meeting various functional requirements such as local regulation of thermal conductivity and local regulation of strength can be obtained. The siliconized graphite material has good high-temperature oxidation resistance and corrosion resistance, excellent air permeability, good dimensional stability, and good mechanical strength. The preparation method of the siliconized graphite mold provided by the present application is simple and controllable, and is conducive to large-scale industrialized production. DETAILED DESCRIPTION

[0034] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application are described in detail below. It should be noted that the following embodiments are only used to illustrate the implementation method and typical parameters of the present application, and are not used to limit the parameter range described in the present application, and the reasonable changes derived therefrom are still within the protection scope of the claims of the present application.

[0035] It should be noted that the endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. These ranges and values should be construed as having endpoints that are near the value that is stated. For ranges, the endpoints are determined with by adding or subtracting 1% from the upper and lower threshold of the given range. For probabilities, endpoints are determined to the nearest one-tenth. For single point values, the endpoint is the stated value.

[0036] Unless otherwise defined, all terms, symbols and other scientific terminology used herein are intended to have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. In some cases, terms with commonly understood meanings are defined herein for clarity and / or for the convenience of the reader. Such definitions are not intended to be limiting in scope unless otherwise expressly stated. The technical methods described or referenced herein are generally well known to those skilled in the art and are employed by conventional methods. Unless otherwise stated, the use of commercially available kits and reagents, instruments are carried out according to the protocols and parameters given by the manufacturer.

[0037] Embodiment 1

[0038] The embodiment provides a siliconized graphite material, which comprises a multi-stage porous graphite base and a silicon carbide layer wrapped on the surface of the multi-stage porous graphite base, the multi-stage porous graphite base is divided into three layers from inside to outside, wherein the inner layer and the outer layer are small-pore porous graphite, the small-pore porous graphite has closed pores with an average pore size of 0.003 mm and first-stage penetrating pores with an average pore size of 0.08 mm, and the middle layer is large-pore porous graphite, the large-pore porous graphite has, in addition to the closed pores with an average pore size of 0.003 mm and the first-stage penetrating pores with an average pore size of 0.08 mm, second-stage penetrating pores with a designed pore size of 1 mm, the second-stage penetrating pores in the large-pore porous graphite penetrate the multi-stage porous graphite base by communicating with the first-stage penetrating pores in the small-pore porous graphite, the silicon carbide layer is uniformly wrapped on the outer surface of the multi-stage porous graphite base and the surface of the internal penetrating pores, and the average thickness of the silicon carbide layer is 0.1 mm.

[0039] The embodiment also provides a siliconized graphite mold for preparing a titanium alloy pipe, the mold shell and the mold core of the siliconized graphite mold are made of the siliconized graphite material provided by the embodiment, and the siliconized graphite mold is prepared by the following preparation method:

[0040] S1, modeling: according to the shape, size of the titanium alloy pipe to be prepared and the functional requirements of the siliconized graphite mold, a drawing of the siliconized graphite mold is designed and drawn, and then the designed drawing is constructed into a three-dimensional model;

[0041] S2, preparation of mixed material: the carbon source, the binder, the additive and the solvent are put into a stirrer in a mass ratio of 75:10:6:66 and are fully mixed to form a mixed slurry; wherein the carbon source is composed of isostatic pressing graphite powder and carbon black in a mass ratio of 1:1, the binder is polyvinyl alcohol, the additive is water-soluble sol, and the solvent is water;

[0042] S3, green body manufacturing: the three-dimensional model in step S1 is introduced into the slurry extrusion equipment, the mixed slurry in step S2 is loaded into the slurry extrusion equipment hopper, and the process conditions are set as follows: the model is sliced in an automatic mode, the layer thickness is 0.3 mm, the extrusion head diameter is 0.4 mm, the filler interval is 0.4 mm, and the working temperature is 45℃; the extruded filaments are deposited along the set path and solidified, the filaments and filaments form continuous pores with a diameter of 0.1 mm, and then the filaments are accumulated layer by layer to prepare a green body of a hierarchical porous graphite matrix;

[0043] S4, high temperature treatment: the green body of the hierarchical porous graphite matrix prepared in step S3 is sequentially subjected to carbonization treatment and graphitization treatment, and then a silicon carbide layer is deposited by chemical vapor deposition to obtain a siliconized graphite mold.

[0044] Example 2

[0045] The embodiment provides a siliconized graphite material, which comprises a hierarchical porous graphite matrix and a silicon carbide layer wrapped on the surface of the hierarchical porous graphite matrix, the hierarchical porous graphite matrix has a plurality of A-type regions and a plurality of B-type regions similar to a chessboard, the A-type regions and the B-type regions are alternately arranged, the A-type regions have closed pores with a pore diameter of 0.005 mm and first-level penetrating pores with a pore diameter of 0.05 mm, the B-type regions have closed pores with a pore diameter of 0.005 mm, first-level penetrating pores with a pore diameter of 0.05 mm and second-level penetrating pores with a pore diameter of 0.5 mm, and the distribution density of the second-level penetrating pores gradually increases from the center to the edge of the B-type regions; the silicon carbide layer uniformly wraps the outer surface of the hierarchical porous graphite matrix and the surface of the internal penetrating pores, and the average thickness of the silicon carbide layer is 0.2 mm.

[0046] The embodiment also provides a siliconized graphite mold for preparing a nickel-tungsten alloy concave plate, the mold shell, the mold core and the pouring assembly of the siliconized graphite mold are made of the siliconized graphite material provided by the embodiment, and the siliconized graphite mold is prepared by the following preparation method:

[0047] S1, modeling: according to the shape, size and functional requirements of the siliconized graphite mold of the nickel-tungsten alloy concave plate to be prepared, a drawing of the siliconized graphite mold is designed and drawn, and then the designed drawing is constructed into a three-dimensional model;

[0048] S2, preparation of mixed material: the carbon source, the binder, the additive and the solvent are put into a blender in a mass ratio of 85:30:8:96, and are fully mixed to form a mixed slurry, and then are subjected to spheroidization granulation to obtain the mixed material; wherein the carbon source is composed of natural graphite powder and petroleum coke in a mass ratio of 5:2, the binder is phenolic resin, the additive is an amine curing agent, and the solvent is ethanol;

[0049] S3, green body manufacturing: the three-dimensional model in step S1 is imported into the powder laser solidification equipment, and the mixed material in step S2 is loaded into the equipment hopper. The process conditions adopted are: the model is sliced and layered manually, the layer thickness is 0.15 mm, the spot size is 0.2 mm, the laser power is 25 W, the laser scanning speed is 900 mm / s, the working temperature is 75 ℃, and N2 is filled as a protective gas in the operation space; during the green body manufacturing process, the center of the B region in the model to the edge of the B region, the laser filling interval gradually increases from 0.2 mm to 0.5 mm, so as to realize the step-by-step increase of the distribution density of the 0.5 mm second-level penetrating holes, and the green body of the multi-level porous graphite matrix is obtained;

[0050] S4, high temperature treatment: the green body of the multi-level porous graphite matrix prepared in step S3 is sequentially subjected to carbonization treatment and graphitization treatment, then a silicon carbide layer is prepared by using liquid silicon infiltration method, and then silicon removal treatment is performed by using high temperature volatilization method, so as to obtain a siliconized graphite mold.

[0051] Example 3

[0052] The embodiment provides a siliconized graphite material, which comprises a multi-level porous graphite matrix and a silicon carbide layer wrapped on the surface of the multi-level porous graphite matrix. The multi-level porous graphite matrix is divided into two layers from inside to outside. The outer layer has uniformly distributed closed pores and first-level penetrating holes. The average diameter of the closed pores is 0.001 mm, and the average diameter of the first-level penetrating holes is 0.03 mm. The inner layer has a network structure formed by the combination of a core framework and a network of ribs. The core framework has closed pores with an average pore size of 0.001 mm and first-level penetrating holes with an average pore size of 0.03 mm, which play a self-supporting role. The closed pores and the first-level penetrating holes are uniformly distributed on the framework. The ribs are wrapped around or connected to the core framework. In addition to the closed pores with an average pore size of 0.001 mm and the first-level penetrating holes with an average pore size of 0.03 mm, the ribs also have second-level penetrating holes with an average pore size of 0.8 mm. The closed pores, the first-level penetrating holes and the second-level penetrating holes are uniformly distributed on the ribs. The silicon carbide layer is uniformly wrapped on the outer surface of the multi-level porous graphite matrix and the surface of the internal penetrating holes. The average thickness of the silicon carbide layer is 0.1 mm.

[0053] The embodiment also provides a siliconized graphite mold for preparing a titanium-magnesium alloy space lattice foam structure component. The mold shell, the mold core, the pouring assembly, the exhaust assembly and the guide assembly of the siliconized graphite mold are all made of the siliconized graphite material provided in the embodiment, which is prepared by the following preparation method:

[0054] S1, modeling: according to the shape, size and functional requirements of the siliconized graphite mold of the titanium-magnesium alloy space lattice foam structure component to be prepared, a drawing of the siliconized graphite mold is designed and drawn, and then the designed drawing is constructed into a three-dimensional model.

[0055] S2, mixture preparation: the carbon source, the curing agent and the solvent are mixed in a mass ratio of 95:5:40 in a blender to form a mixed slurry, and then the mixed slurry is subjected to spheronization to obtain a mixture; wherein the carbon source is composed of pitch coke, graphite electrode powder and carbon black in a mass ratio of 5:1:3, the curing agent is p-toluenesulfonic acid, and the solvent is water;

[0056] S3, green body manufacturing: the three-dimensional model in step S1 is imported into a three-dimensional printing device, and the mixture in step S2 is loaded into a hopper of the device; the process conditions of three-dimensional printing are set as follows: the sprayed ink is furan resin, 1200 PDI inkjet resolution is used for the core skeleton area, and 400 PDI inkjet resolution is used for the rib area, to obtain a green body of a multi-level porous graphite matrix.

[0057] S4, high temperature treatment: the green body of the multi-level porous graphite matrix obtained in step S3 is sequentially subjected to carbonization treatment and graphitization treatment, then a silicon carbide layer is prepared by a chemical vapor infiltration method, and then a silicon removal treatment is performed by a molten alkali method, to obtain a siliconized graphite mold.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A siliconized graphite material characterized in that, The siliconized graphite material comprises a multi-level porous graphite matrix and a silicon carbide layer wrapped on the surface of the multi-level porous graphite matrix, the multi-level porous graphite matrix has a hierarchical porous structure, the hierarchical porous structure comprises closed pores and penetrating pores; the closed pores are used to improve the chilling effect, structural strength and yielding property of the siliconized graphite material; the penetrating pores are used to form effective gas channels, so that the siliconized graphite material has excellent gas permeability; the closed pores are non-penetrating pores, the aperture of the closed pores is 0.001-0.05 mm, the penetrating pores penetrate through the multi-level porous graphite matrix, the penetrating pores comprise first-level penetrating pores and second-level penetrating pores, the aperture of the first-level penetrating pores is 0.03-0.2 mm, the aperture of the second-level penetrating pores is 0.1-2 mm, and the silicon carbide layer is uniformly wrapped on the outer surface of the multi-level porous graphite matrix and the surface of the penetrating pores in the interior.

2. The siliconized graphite material of claim 1, wherein, The second-level penetrating pores are prepared by an additive manufacturing technology.

3. The siliconized graphite material of claim 2, wherein, In the multi-level porous graphite matrix, the closed pores and the penetrating pores adopt at least one of parallel combination, series combination, modular combination, hierarchical combination and network combination.

4. The siliconized graphite material of claim 3, wherein, The parallel combination, the series combination, the modular combination, the hierarchical combination and the network combination are realized by adjusting a process of the additive manufacturing technology, and the process comprises at least one of model slicing processing mode, layer thickness, filler interval, filler mode, slurry extrusion speed, slurry extrusion pressure, extrusion head size, nozzle resolution, ink droplet size, inkjet pressure, laser power, spot size, scanning speed, printing path, temperature, humidity and protective gas.

5. The siliconized graphite material of claim 1, wherein, The thickness of the silicon carbide layer is 0.05-5 mm.

6. A siliconized graphite mold, characterized by, The material composition of the siliconized graphite mold comprises the siliconized graphite material in any one of claims 1-5.

7. The siliconized graphite mold of claim 6, wherein, The siliconized graphite mold comprises a core, a shell, a casting assembly, an exhaust assembly and a guide assembly, and at least one of the core, the shell, the casting assembly, the exhaust assembly and the guide assembly uses the siliconized graphite material in any one of claims 1-5.

8. A method of producing a siliconized graphite mold according to claim 6 or 7, characterized by, The method comprises the following steps: S1, modeling: according to the functional requirements of the siliconized graphite mold, the combination mode of the closed pores and the penetrating pores in the hierarchical porous structure is designed, and a three-dimensional model of the graphite matrix with the hierarchical porous structure is constructed; S2, mixed raw material preparation: the carbon source, the binder, the additive and the solvent are fully mixed to form a mixed slurry; the mass ratio of the carbon source, the binder, the additive and the solvent is (60-90):(0-40):(0-10):(30-100); S3, blank manufacturing: the three-dimensional model in step S1 is imported into the control module of the additive manufacturing equipment, the mixed slurry in step S2 is added into the hopper of the additive manufacturing equipment, and three-dimensional printing is performed to obtain a blank of the multi-level porous graphite matrix; S4, high-temperature treatment: after the blank of the multi-level porous graphite matrix in step S3 is sequentially subjected to carbonization treatment and graphitization treatment, a silicon carbide layer is formed through siliconization treatment, and then selective desiliconization treatment is performed to obtain a siliconized graphite mold.

9. The method for preparing a siliconized graphite casting mold according to claim 8, characterized in that, The combination mode of step S1 is parallel combination or hierarchical combination of the closed hole and the penetrating hole.

10. The method for preparing a siliconized graphite casting mold according to claim 8, characterized in that, The preparation process of the mixed raw material of step S2 further includes granulation, i.e. the mixed slurry is subjected to spheroidization granulation to obtain a mixture; And / or, the carbon source of step S2 includes at least one of natural graphite powder, isostatic pressing graphite powder, graphite electrode powder, pitch coke, petroleum coke, metallurgical coke and carbon black; And / or, the binder of step S2 includes at least one of epoxy resin, phenolic resin, furan resin, urea-formaldehyde resin, polyurethane, polyvinyl alcohol, polymethyl methacrylate and polyvinyl butyral; And / or, the additive of step S2 includes at least one of curing agent, sintering aid, dispersant and diluent; And / or, the solvent of step S2 includes at least one of water, methanol, ethanol, acetone, ethylene glycol, xylene, ethyl acetate and petroleum ether; And / or, the three-dimensional printing of step S3 adopts any one of slurry extrusion technology, three-dimensional printing technology, powder laser solidification technology and selective laser sintering technology; And / or, the siliconization treatment of step S4 adopts any one of chemical vapor infiltration method, chemical vapor deposition method, chemical vapor reaction method and liquid silicon infiltration method; And / or, the silicon removal treatment of step S4 adopts molten alkali silicon removal method or high temperature volatilization silicon removal method.