Porous graphite plate and preparation method thereof

Abstract

The invention relates to the technical field of semiconductor silicon carbide materials, in particular to a porous graphite plate which is prepared by uniformly mixing graphite powder, an adhesive, a pore forming agent and a dispersing agent, then putting the mixture into a mold, and carrying out hot isostatic pressing, roasting and purifying. The porous graphite plate prepared by the method is uniform in pore structure distribution; the preparation technology is simple, the period is short, the cost is low, and the pore structure and the pore size are controllable by adjusting technological parameters.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor silicon carbide materials, and in particular to a porous graphite plate and a preparation method thereof. Background Art

[0002] In recent years, with the rapid rise of new energy vehicles, photovoltaics, wind power, energy storage and other applications, the performance of traditional silicon devices has been far from meeting the needs of emerging applications. Therefore, major international semiconductor manufacturers have set their sights on the third-generation semiconductor material - silicon carbide.

[0003] At present, the PVT method is generally used to grow silicon carbide ingots, and the substrate is produced through multiple processes such as cutting, grinding and polishing. The cost of SiC substrates accounts for a high proportion, which is the link with the highest value share. The cost of substrates in silicon carbide devices accounts for 47%, which is a key link affecting the development of the silicon carbide industry. During the crystal growth process, SiC gas passes through a barrel made of PG graphite and grows into a crystal ingot in a crystal growth furnace. PG graphite regulates the growth rate and gas distribution of the crystal, directly affecting the rate and quality of crystal growth. It is the core consumable of crystal growth and one of the few production consumables that rely on imports. It is one of the key materials in the silicon carbide industry.

[0004] At present, the growth process of silicon carbide ingots has problems such as long growth cycle, low crystal length and consistency between ingots. Therefore, it is urgent to develop a porous graphite to regulate the crystal growth rate and gas distribution to meet the higher performance requirements of silicon carbide in the crystal growth process. Summary of the invention

[0005] In view of the above-mentioned shortcomings of the prior art, the present invention provides a porous graphite plate and a preparation method thereof, which has a simple preparation process, a short cycle, and low cost. By adjusting the process parameters, the pore structure and pore size can be controlled.

[0006] Technical Solution

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0008] The invention provides a porous graphite plate, which is prepared by uniformly mixing graphite powder, an adhesive, a pore-forming agent and a dispersant, and then putting the mixture into a mold, and performing hot isostatic pressing and calcining.

[0009] Furthermore, the adhesive is at least one or more of epoxy resin, phenolic resin, furfural resin, and coal tar.

[0010] Furthermore, the pore-forming agent is one or more of glass microspheres, plastic microspheres, biomass microspheres, and metal microspheres, and the particle size of the pore-forming agent is 50-500 μm; the particle size of the graphite powder is 50-500 μm.

[0011] Preferably, the particle size of the pore former is 50-120 μm; and the particle size of the graphite powder is 80-140 μm.

[0012] Furthermore, the dispersant is sodium citrate.

[0013] Furthermore, the weight ratio of the graphite powder, adhesive, pore-forming agent and dispersant is 1:(0.2-0.5):(0.5-1):(0.01-0.03).

[0014] Furthermore, in the hot isostatic pressing step, the isostatic pressing pressure is 2-10 MPa, the heating temperature is 100-200° C., and the isostatic pressing time is 10-24 h;

[0015] The calcination temperature is 2000-2500° C. and the calcination time is 120-240 hours.

[0016] Furthermore, when the weight ratio of the graphite powder, adhesive, pore-forming agent and dispersant is 1:0.2-0.4:0.5-0.8:0.01, and the particle size of the pore-forming agent is 50-120 μm and the particle size of the graphite powder is 80-140 μm, the pore size of the prepared porous graphite plate is 10-31 μm and the porosity is 35%-55%.

[0017] Preferably, the weight ratio of the graphite powder, adhesive, pore-forming agent and dispersant is 1:0.2:0.5:0.01, the particle size of the pore-forming agent is 100 μm and the particle size of the graphite powder is 80 μm.

[0018] Preferably, the weight ratio of the graphite powder, adhesive, pore-forming agent and dispersant is 1:0.3:0.5:0.01, the particle size of the pore-forming agent is 80 μm and the particle size of the graphite powder is 100 μm.

[0019] Preferably, the weight ratio of the graphite powder, adhesive, pore-forming agent and dispersant is 1:0.2:0.6:0.01, the particle size of the pore-forming agent is 120 μm and the particle size of the graphite powder is 120 μm.

[0020] Preferably, the weight ratio of the graphite powder, adhesive, pore-forming agent and dispersant is 1:0.3:0.8:0.01, the particle size of the pore-forming agent is 50 μm and the particle size of the graphite powder is 140 μm.

[0021] Preferably, the weight ratio of the graphite powder, adhesive, pore-forming agent and dispersant is 1:0.4:0.7:0.01, the particle size of the pore-forming agent is 80 μm and the particle size of the graphite powder is 80 μm.

[0022] Preferably, the weight ratio of the graphite powder, adhesive, pore-forming agent and dispersant is 1:0.4:0.6:0.01, the particle size of the pore-forming agent is 100 μm and the particle size of the graphite powder is 100 μm.

[0023] Preferably, the weight ratio of the graphite powder, adhesive, pore-forming agent and dispersant is 1:0.2:0.7:0.01, the particle size of the pore-forming agent is 120 μm and the particle size of the graphite powder is 120 μm.

[0024] Preferably, the weight ratio of the graphite powder, adhesive, pore-forming agent and dispersant is 1:0.3:0.6:0.01, the particle size of the pore-forming agent is 50 μm and the particle size of the graphite powder is 140 μm.

[0025] A method for preparing a porous graphite plate comprises the following preparation steps:

[0026] (1) Preparation of graphite powder: Grinding block graphite into graphite powder by vertical roller mill;

[0027] (2) Mixing: kneading graphite powder, adhesive, pore former and dispersant in a kneading machine to make the materials uniform;

[0028] (3) Filling: Put the mixed material into the mold, close the mold and start vacuuming to extract the air;

[0029] (4) Hot isostatic pressing: Place the mold into a hot isostatic pressing device to solidify the material in the mold;

[0030] (5) Calcination: The solidified product is placed in a graphitization furnace and calcined under nitrogen protection to obtain a porous graphite blank;

[0031] (6) Machining: machining the graphitized porous graphite blank according to the test standard to obtain a porous graphite plate.

[0032] Furthermore, in step (2), the adhesive is at least one of epoxy resin, phenolic resin, furfural resin, and coal tar pitch; the pore-forming agent is at least one of glass microspheres, plastic microspheres, biomass microspheres, and metal microspheres, and the particle size of the pore-forming agent is 50-500 μm;

[0033] The mixing temperature is 25℃-50℃, the speed is 400-800r / min; the stirring time is 0.5-1h;

[0034] The weight ratio of the graphite powder, adhesive, pore former and dispersant is 1:(0.2-0.5):(0.5-1):(0.01-0.03).

[0035] Furthermore, in step (4), the isostatic pressing pressure is 2-10 MPa, the heating temperature is 100-200° C., and the isostatic pressing time is 10-24 h; in step (5), the roasting temperature is 2000-2500° C., and the time is 120-240 h.

[0036] Beneficial Effects

[0037] Compared with the known public technology, the technical solution provided by the present invention has the following beneficial effects:

[0038] (1) The present invention provides a method for preparing a porous graphite plate, wherein the porous graphite plate prepared by the method has a uniformly distributed pore structure; the preparation process of the present invention is simple, has a short cycle, and is low in cost; and by adjusting the process parameters, the pore structure and pore size can be controlled.

[0039] (2) In the process of preparing graphite plates, the pore-forming agent occupies a certain space in the green body. After sintering, the pore-forming agent leaves the matrix and forms pores to prepare porous graphite plates. In the process of silicon carbide crystal growth, porous graphite allows the raw material gas to reach the growth area evenly through its pore structure, and can remove other particulate impurities. The growth rate can be regulated by changing the porosity. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0041] Figure 1 This is a process flow chart for porous graphite;

[0042] Figure 2 This is a photo of the porous graphite surface. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] The present invention will be further described below in conjunction with the embodiments.

[0045] The manufacturers and models of the raw materials in the embodiments and comparative examples are as follows:

[0046] Phenolic resin: KT-3640HC from Jiangmen Kunyi Resin Material Technology Co., Ltd.

[0047] Epoxy resin: EPON-1002F from Guangzhou Haoyun Chemical Co., Ltd.

[0048] Glass microspheres (particle size 100 μm): XL512 from Shanghai Xuyun New Materials Technology Co., Ltd.

[0049] Glass microspheres (particle size 50 μm): Shanghai Xuyun New Materials Technology Co., Ltd. XQ718;

[0050] Plastic microspheres: Shanghai Xuyun New Materials Technology Co., Ltd. XQ714;

[0051] Biomass microspheres: LP-3130 from Shanghai Dawu Plastics Co., Ltd.

[0052] (I) Embodiment

[0053] Embodiment 1:

[0054] A porous graphite plate, the preparation steps of which are as follows:

[0055] (1) Graphite powder, phenolic resin, glass microspheres, and sodium citrate were weighed in a mass ratio of 1:0.2:0.5:0.01, wherein the particle size of the graphite powder was 80 μm and the particle size of the glass microspheres was 100 μm. The graphite powder, phenolic resin, glass microspheres, and sodium citrate were kneaded in a kneading machine (mixing temperature of 35°C, speed of 600 r / min, stirring time of 1 h) to mix the materials evenly. After mixing evenly, the materials were placed in a mold. After the mold was closed, the air was extracted. The mold was then placed in an isostatic pressing device, and the materials in the container were evenly heated by a heating device. At the same time, nitrogen was injected into the container by a high-pressure pump. The temperature was raised to 100°C, and the pressure was raised to 10 MPa. The temperature and pressure were then maintained for 10 h, and the mold was demolded after cooling.

[0056] (2) The obtained porous graphite precursor is placed in a graphitization furnace, heated to 2000° C., calcined for 120 h under nitrogen protection, and then cooled to room temperature to obtain a porous graphite blank.

[0057] (3) The porous graphite blank is processed according to the test standard, and the pore size of the porous graphite plate obtained after processing can reach 25 μm and the porosity can reach 50%.

[0058] Embodiment 2:

[0059] A porous graphite plate, the preparation steps of which are as follows:

[0060] (1) Graphite powder, epoxy resin, plastic microspheres, and sodium citrate were weighed in a mass ratio of 1:0.3:0.5:0.01, wherein the particle size of the graphite powder was 100 μm, and the particle size of the plastic microspheres was 80 μm. The graphite powder, epoxy resin, plastic microspheres, and sodium citrate were kneaded by a kneading machine (mixing temperature of 35°C, speed of 600 r / min, stirring time of 1 h) to mix the materials evenly, and then put them into a mold. After the mold was closed, the air was extracted. Then the mold was placed in an isostatic pressing device, and the materials in the container were evenly heated by a heating device. At the same time, nitrogen was injected into the container by a high-pressure pump, and the temperature was raised to 100°C, and the pressure was raised to 10 MPa. Then, the temperature and pressure were kept for 10 h, and the mold was demolded after cooling.

[0061] (2) The obtained porous graphite precursor is placed in a graphitization furnace, heated to 2000° C., calcined for 120 h under nitrogen protection, and then cooled to room temperature to obtain a porous graphite blank.

[0062] (3) The porous graphite blank is processed according to the test standard, and the pore size of the obtained porous graphite plate reaches 20 μm and the porosity is 45%.

[0063] Embodiment 3:

[0064] A porous graphite plate, the preparation steps of which are as follows:

[0065] (1) Graphite powder, phenolic resin, biomass microspheres, and sodium citrate were weighed in a mass ratio of 1:0.2:0.6:0.01, wherein the particle size of the graphite powder was 120 μm, and the particle size of the biomass microspheres was 120 μm. The graphite powder, phenolic resin, biomass microspheres, and sodium citrate were kneaded by a kneading machine (mixing temperature of 35°C, speed of 600 r / min, stirring time of 1 h) to mix the materials evenly, and then put them into a mold. After the mold was closed, the air was extracted. Then the mold was placed in an isostatic pressing device, and the materials in the container were evenly heated by a heating device. At the same time, nitrogen was injected into the container by a high-pressure pump, and the temperature was raised to 100°C, and the pressure was raised to 10 MPa. Then, the temperature and pressure were kept for 10 h, and the mold was demolded after cooling.

[0066] (2) The obtained porous graphite precursor is placed in a graphitization furnace, heated to 2000° C., calcined for 120 h under nitrogen protection, and then cooled to room temperature to obtain a porous graphite blank.

[0067] (3) The porous graphite blank is processed according to the test standard, and the pore size of the porous graphite plate obtained after processing can reach 30 μm and the porosity is 45%.

[0068] Embodiment 4:

[0069] A porous graphite plate, the preparation steps of which are as follows:

[0070] (1) Graphite powder, epoxy resin, glass microspheres, and sodium citrate were weighed in a mass ratio of 1:0.3:0.8:0.01, wherein the particle size of the graphite powder was 140 μm, and the particle size of the glass microspheres was 50 μm. The graphite powder, epoxy resin, glass microspheres, and sodium citrate were kneaded in a kneading machine (mixing temperature of 35°C, speed of 600 r / min, stirring time of 1 h) to mix the materials evenly, and then put them into a mold. After the mold was closed, the air was extracted. Then the mold was placed in an isostatic pressing device, and the materials in the container were evenly heated by a heating device. At the same time, nitrogen was injected into the container by a high-pressure pump, and the temperature was raised to 100°C and the pressure was raised to 10 MPa. Then, the temperature and pressure were kept for 10 h, and the mold was demolded after cooling.

[0071] (2) The obtained porous graphite precursor is placed in a graphitization furnace, heated to 2000° C., calcined for 120 h under nitrogen protection, and then cooled to room temperature to obtain a porous graphite blank.

[0072] (3) The porous graphite is processed according to the test standard, and the obtained porous graphite has a pore diameter of 10 μm and a porosity of 40%.

[0073] Comparative Example 1:

[0074] A porous graphite plate, the preparation steps of which are as follows:

[0075] (1) Weigh graphite powder, glass microspheres, and sodium citrate in a mass ratio of 1:0.5:0.01, wherein the particle size of the graphite powder is 80 μm and the particle size of the glass microspheres is 100 μm. Mix the graphite powder, glass microspheres, and sodium citrate in a kneading machine (mixing temperature of 35°C, speed of 600 r / min, stirring time of 1 h) to mix the materials evenly, put them into a mold after mixing evenly, and evacuate the air after the mold is closed. Then place the mold in an isostatic pressing device, heat the materials in the container evenly through a heating device, and inject nitrogen into the container through a high-pressure pump. The temperature rises to 100°C, the pressure rises to 10 MPa, and then the temperature and pressure are maintained for 10 h, and the mold is demolded after cooling.

[0076] (2) The obtained graphite plate precursor is placed in a graphitization furnace, heated to 2000° C., calcined for 120 h under nitrogen protection, and then cooled to room temperature to obtain a graphite plate blank.

[0077] (3) The graphite plate blank is processed according to the test standard, and the pore size of the graphite plate obtained after processing can reach 20 μm and the porosity can reach 50%.

[0078] Comparative Example 2:

[0079] A porous graphite plate, the preparation steps of which are as follows:

[0080] (1) Weigh graphite powder, phenolic resin and sodium citrate in a mass ratio of 1:0.2:0.01, wherein the particle size of the graphite powder is 80 μm. Mix the graphite powder, phenolic resin and sodium citrate in a kneading machine (mixing temperature of 35°C, speed of 600 r / min, stirring time of 1 h) to mix the materials evenly, put them into a mold after mixing evenly, and extract the air after the mold is closed. Then place the mold in an isostatic pressing device, heat the materials in the container evenly through a heating device, and inject nitrogen into the container through a high-pressure pump. The temperature rises to 100°C and the pressure rises to 10 MPa. Then keep the temperature and pressure for 10 h, and demold after cooling.

[0081] (2) The obtained graphite plate precursor is placed in a graphitization furnace, heated to 2000° C., calcined for 120 h under nitrogen protection, and then cooled to room temperature to obtain a porous graphite blank.

[0082] (3) The graphite sheet blank is processed according to the test standard, and the porous graphite obtained after processing has a pore size of up to 2 μm and a porosity of up to 10%.

[0083] Comparative Example 3:

[0084] A porous graphite plate, the preparation steps of which are as follows:

[0085] (1) Graphite powder, phenolic resin and glass microspheres were weighed in a mass ratio of 1:0.2:0.5, wherein the particle size of the graphite powder was 80 μm and the particle size of the glass microspheres was 100 μm. The graphite powder, phenolic resin, glass microspheres and sodium citrate were kneaded in a kneading machine (mixing temperature was 35°C, speed was 600 r / min, stirring time was 1 h) to mix the materials evenly, and then put them into a mold. After the mold was closed, the air was extracted. Then the mold was placed in an isostatic pressing device, and the materials in the container were evenly heated by a heating device. At the same time, nitrogen was injected into the container by a high-pressure pump, and the temperature was raised to 100°C and the pressure was raised to 10 MPa. Then the temperature and pressure were kept for 10 h, and the mold was demolded after cooling.

[0086] (2) The obtained porous graphite precursor is placed in a graphitization furnace, heated to 2000° C., calcined for 120 h under nitrogen protection, and then cooled to room temperature to obtain a porous graphite blank.

[0087] (3) The porous graphite blank is processed according to the test standard, and the pore diameter of the porous graphite obtained after processing can reach 25 μm and the porosity can reach 48%.

[0088] Comparative Example 4:

[0089] A porous graphite plate, the preparation steps of which are as follows:

[0090] (1) Graphite powder, phenolic resin, glass microspheres, and sodium citrate were weighed in a mass ratio of 1:0.4:0.7:0.01, wherein the particle size of the graphite powder was 80 μm, and the particle size of the glass microspheres was 80 μm. The graphite powder, phenolic resin, glass microspheres, and sodium citrate were kneaded by a kneading machine (mixing temperature of 35°C, speed of 600 r / min, stirring time of 1 h) to mix the materials evenly, and then put them into a mold. After the mold was closed, the air was extracted. Then the mold was placed in an isostatic pressing device, and the materials in the container were evenly heated by a heating device. At the same time, nitrogen was injected into the container by a high-pressure pump, and the temperature was raised to 100°C and the pressure was raised to 10 MPa. Then, the temperature and pressure were maintained for 10 h, and the mold was demolded after cooling.

[0091] (2) The obtained porous graphite precursor is placed in a graphitization furnace, heated to 2000° C., calcined for 120 h under nitrogen protection, and then cooled to room temperature to obtain a porous graphite blank.

[0092] (3) The porous graphite blank is processed according to the test standard, and the pore diameter of the porous graphite obtained after processing can reach 20 μm and the porosity can reach 40%.

[0093] Comparative Example 5:

[0094] A porous graphite plate, the preparation steps of which are as follows:

[0095] (1) Weigh graphite powder, epoxy resin, plastic microspheres, and sodium citrate in a mass ratio of 1:0.4:0.6:0.01, wherein the particle size of the graphite powder is 100 μm, and the particle size of the plastic microspheres is 100 μm. Mix the graphite powder, epoxy resin, plastic microspheres, and sodium citrate in a kneading machine (mixing temperature of 35°C, speed of 600 r / min, stirring time of 1 h) to mix the materials evenly, put them into a mold after mixing evenly, and extract the air from the mold after the mold is closed. Then place the mold in an isostatic pressing device, heat the materials in the container evenly through a heating device, and inject nitrogen into the container through a high-pressure pump. The temperature rises to 100°C, the pressure rises to 10 MPa, and then the temperature and pressure are maintained for 10 h, and the mold is demolded after cooling.

[0096] (2) The obtained porous graphite precursor is placed in a graphitization furnace, heated to 2000° C., calcined for 120 h under nitrogen protection, and then cooled to room temperature to obtain a porous graphite blank.

[0097] (3) The porous graphite blank is processed according to the test standard, and the pore size of the porous graphite plate obtained after processing reaches 30 μm and the porosity is 45%.

[0098] Comparative Example 6:

[0099] A porous graphite plate, the preparation steps of which are as follows:

[0100] (1) Graphite powder, phenolic resin, biomass microspheres, and sodium citrate were weighed in a mass ratio of 1:0.2:0.7:0.01, wherein the particle size of the graphite powder was 120 μm, and the particle size of the biomass microspheres was 120 μm. The graphite powder, phenolic resin, biomass microspheres, and sodium citrate were kneaded by a kneading machine (mixing temperature of 35°C, speed of 600 r / min, stirring time of 1 h) to mix the materials evenly, and then put them into a mold. After the mold was closed, the air was extracted. Then the mold was placed in an isostatic pressing device, and the materials in the container were evenly heated by a heating device. At the same time, nitrogen was injected into the container by a high-pressure pump, and the temperature was raised to 100°C, and the pressure was raised to 10 MPa. Then, the temperature and pressure were kept for 10 h, and the mold was demolded after cooling.

[0101] (2) The obtained porous graphite precursor is placed in a graphitization furnace, heated to 2000° C., calcined for 120 h under nitrogen protection, and then cooled to room temperature to obtain a porous graphite blank.

[0102] (3) The porous graphite blank is processed according to the test standard, and the pore size of the porous graphite plate obtained after processing can reach 31 μm and the porosity is 55%.

[0103] Comparative Example 7:

[0104] A porous graphite plate, the preparation steps of which are as follows:

[0105] (1) Graphite powder, epoxy resin, glass microspheres, and sodium citrate were weighed in a mass ratio of 1:0.3:0.6:0.01, wherein the particle size of the graphite powder was 140 μm, and the particle size of the glass microspheres was 50 μm. The graphite powder, epoxy resin, glass microspheres, and sodium citrate were kneaded in a kneading machine (mixing temperature of 35°C, speed of 600 r / min, stirring time of 1 h) to mix the materials evenly, and then put them into a mold. After the mold was closed, the air was extracted. The mold was then placed in an isostatic pressing device, and the materials in the container were evenly heated by a heating device. At the same time, nitrogen was injected into the container by a high-pressure pump, and the temperature was raised to 100°C, and the pressure was raised to 10 MPa. Then, the temperature and pressure were maintained for 10 h, and the mold was demolded after cooling.

[0106] (2) The obtained porous graphite precursor is placed in a graphitization furnace, heated to 2000° C., calcined for 120 h under nitrogen protection, and then cooled to room temperature to obtain a porous graphite blank.

[0107] (3) The porous graphite blank is processed according to the test standard, and the porous graphite plate obtained after processing has a pore diameter of 10 μm and a porosity of 35%.

[0108] (II) Performance test

[0109] Pore ​​size test method or standard: Test according to GB / T 21650.1-2008 / ISO15901-1:2005 "Determination of pore size distribution and porosity of solid materials by mercury intrusion and gas adsorption method";

[0110] Porosity test method or standard: Test according to GB / T 21650.1-2008 / ISO15901-1:2005 "Determination of pore size distribution and porosity of solid materials by mercury intrusion and gas adsorption method"

[0111] Pore ​​size distribution uniformity determination method or standard: Use the pressure pump method to determine the pore size distribution uniformity through the pore size distribution curve

[0112] Pore ​​size / μm Porosity / % Pore ​​size distribution uniformity Example 1 25μm 50％ Uniform distribution Example 2 20μm 45％ More uniform distribution Example 3 30μm 45％ More uniform distribution Example 4 10μm 40％ More uniform distribution Comparative Example 1 20μm 50％ More uniform distribution Comparative Example 2 2μm 10％ Uneven distribution Comparative Example 3 25μm 48％ Uneven distribution Comparative Example 4 20μm 40％ More uniform distribution Comparative Example 5 30μm 45％ More uniform distribution Comparative Example 6 31μm 55％ More uniform distribution Comparative Example 7 10μm 35％ More uniform distribution

[0113] It can be seen from Example 1 and Comparative Examples 1-3 that without adding phenolic resin, the prepared graphite plate has serious powder shedding; without adding glass microspheres, the prepared graphite plate has a smaller pore size of 2 μm and a porosity of 10%; without adding sodium citrate, the prepared porous graphite plate has an uneven pore size distribution and resin agglomeration.

[0114] It can be seen from Examples 1-4 and Comparative Examples 4-7 that when the weight ratio of raw graphite powder, adhesive, pore-forming agent, and sodium citrate is in the range of 1:0.2-0.4:0.5-0.8:0.01, and the particle size of the pore-forming agent is 50-120 μm and the particle size of the graphite powder is 80-140 μm, a graphite plate with a pore size range of 10-31 μm and a porosity of 35%-55% can be prepared.

[0115] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of the present invention.

Claims

1. A porous graphite plate, characterized in that: The method is prepared by uniformly mixing graphite powder, adhesive, pore-forming agent and dispersant, and then putting the mixture into a mold, and performing hot isostatic pressing and calcining.

2. A porous graphite plate and a method for preparing the same according to claim 1, characterized in that: The adhesive is at least one or more of epoxy resin, phenolic resin, furfural resin and coal tar.

3. A porous graphite plate and a method for preparing the same according to claim 1, characterized in that: The pore-forming agent is one or more of glass microspheres, plastic microspheres, biomass microspheres, and metal microspheres, and the particle size of the pore-forming agent is 50-500 μm; the particle size of the graphite powder is 50-500 μm.

4. A porous graphite plate according to claim 1, characterized in that: The dispersant is sodium citrate.

5. A porous graphite plate according to claim 1, characterized in that: The weight ratio of the graphite powder, adhesive, pore former and dispersant is 1:(0.2-0.5):(0.5-1):(0.01-0.03).

6. A porous graphite plate and a method for preparing the same according to claim 1, characterized in that: In the hot isostatic pressing step, the isostatic pressing pressure is 2-10 MPa, the heating temperature is 100-200° C., and the isostatic pressing time is 10-24 h; The calcination temperature is 2000-2500° C. and the calcination time is 120-240 hours.

7. A porous graphite plate according to claim 1, characterized in that: When the weight ratio of the graphite powder, adhesive, pore former and dispersant is 1:0.2-0.4:0.5-0.8:0.01, and the particle size of the pore former is 50-120 μm and the particle size of the graphite powder is 80-140 μm, the pore size of the prepared porous graphite plate is 10-31 μm and the porosity is 35%-55%.

8. A method for preparing a porous graphite plate as claimed in any one of claims 1 to 7, characterized in that: It comprises the following preparation steps: (1) Preparation of graphite powder: Grinding block graphite into graphite powder by vertical roller mill; (2) Mixing: kneading graphite powder, adhesive, pore former and dispersant in a kneading machine to make the materials uniform; (3) Filling: Put the mixed material into the mold, close the mold and start vacuuming to extract the air; (4) Hot isostatic pressing: Place the mold into a hot isostatic pressing device to solidify the material in the mold; (5) Calcination: The solidified product is placed in a graphitization furnace and calcined under nitrogen protection to obtain a porous graphite blank; (6) Machining: machining the graphitized porous graphite blank according to the test standard to obtain a porous graphite plate.

9. The method for preparing a porous graphite plate according to claim 8, characterized in that: In step (2), the adhesive is at least one of epoxy resin, phenolic resin, furfural resin, and coal tar pitch; the pore-forming agent is at least one of glass microspheres, plastic microspheres, biomass microspheres, and metal microspheres, and the particle size of the pore-forming agent is 50-500 μm; The mixing temperature is 25℃-50℃, the speed is 400-800r / min; the stirring time is 0.5-1h; The weight ratio of the graphite powder, adhesive, pore former and dispersant is 1:(0.2-0.5):(0.5-1):(0.01-0.03).

10. The method for preparing a porous graphite plate according to claim 8, characterized in that: In step (4), the isostatic pressing pressure is 2-10 MPa, the heating temperature is 100-200° C., and the isostatic pressing time is 10-24 h; in step (5), the roasting temperature is 2000-2500° C., and the time is 120-240 h.

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