A multi-chamber graphite sagger, its preparation method and application
By using a combination of specific raw materials and coating materials in a multi-chamber graphite crucible, the problems of mechanical strength and thermal uniformity were solved, resulting in higher heat treatment efficiency and service life.
Patent Information
- Application Number
- CN202511124369.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-12
- Publication Date
- 2025-11-18
- Estimated Expiration
- 2045-08-12
AI Technical Summary
Existing multi-chamber graphite saggers suffer from poor oxidation resistance and mechanical strength, while the uneven thermal field between chambers leads to poor heat treatment results.
Using graphite, tungsten carbide, wood shavings and wood pulp as the main raw materials, the sagger matrix is prepared by low-temperature sintering and high-temperature sintering. Silicon carbide and high thermal conductivity materials are coated on the outer shell and partition surfaces to form a multi-layer coating to improve mechanical strength and thermal conductivity.
This improves the mechanical strength and temperature uniformity of the multi-chamber graphite sagger, extends its service life, and enhances the heat treatment effect.
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Figure CN120609209B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of graphite retort materials, and particularly relates to a multi-chamber graphite retort and a preparation method and application thereof. BACKGROUND
[0002] The multi-chamber graphite retort is designed with multiple independent or semi-independent chambers in a single retort to simultaneously carry multiple batches of materials or realize functions such as partitioned temperature control and atmosphere isolation. It is a graphite container for high-temperature heat treatment (such as lithium battery positive electrode material sintering, powder metallurgy, ceramic firing, etc.), and can generally withstand working temperatures above 1600 DEG C.
[0003] The main component of the existing multi-chamber graphite retort is graphite, which has high thermal conductivity, high temperature resistance and low thermal expansion coefficient, and is the first choice for materials that need to undergo rapid temperature reaction in high-temperature heat treatment. However, due to the defects of low hardness and high temperature oxidation of graphite, the oxidation resistance and mechanical strength of the multi-chamber graphite retort are generally poor, and there is also thermal field inhomogeneity between the chambers of the multi-chamber graphite retort, which will affect the sintering effect of the high-temperature heat treatment materials in the retort. SUMMARY
[0004] To solve the above problems, the application provides a multi-chamber graphite retort and a preparation method and application thereof. At least one aspect of the above technical problem is solved.
[0005] The application is implemented by the following technical solutions:
[0006] In a first aspect, the application provides a multi-chamber graphite retort, comprising a retort base body, an outer shell surface coating and a partition plate surface coating.
[0007] The retort base body comprises an outer base body and a partition plate base body.
[0008] The outer base body comprises the following raw materials by weight fraction:
[0009] 100 parts of graphite, 10-20 parts of tungsten carbide, 5-10 parts of wood shavings, and 12-18 parts of wood pulp.
[0010] The partition plate base body comprises the following raw materials by weight fraction: 100 parts of graphite, 10-20 parts of graphene oxide, 10-20 parts of carbon nanotubes, and 10-20 parts of a binder.
[0011] In a second aspect, the application provides a preparation method for the above multi-chamber graphite retort, comprising the following steps:
[0012] Preparation of the retort base body, the outer shell surface coating and the partition plate surface coating.
[0013] Thirdly, the present invention provides an application of the above-mentioned multi-chamber graphite sagger in the field of material sintering.
[0014] The multi-chamber graphite sagger, its preparation method, and its application provided by this invention have at least the following beneficial technical effects compared with the prior art:
[0015] (1) The multi-chamber graphite sagger provided by the present invention has tungsten carbide as the outer matrix material, which has high mechanical strength, thereby improving the mechanical strength of the outer matrix; wood pulp is used as a binder to adjust the viscosity and uniformity of the mixed slurry; wood shavings are used as raw materials for the preparation of carbon fibers, and carbon fibers are formed during calcination, thereby improving the mechanical strength of the outer matrix; in addition, wood pulp can also form carbon fibers during calcination, improving the mechanical strength of the outer matrix, and thus improving the mechanical strength of the multi-chamber graphite sagger.
[0016] (2) The multi-chamber graphite sagger provided by the present invention has a coating on the outer shell surface including silicon carbide. Silicon carbide has high mechanical strength (hardness, wear resistance and bending strength), which further improves the mechanical strength of the multi-chamber graphite sagger.
[0017] (3) The multi-chamber graphite sagger provided by the present invention has graphene oxide and carbon nanotubes in the partition matrix material, which have high thermal conductivity, can improve the thermal conductivity of the partition, thereby improving the temperature uniformity of each chamber in the multi-chamber graphite sagger.
[0018] (4) The multi-chamber graphite sagger provided by the present invention has a material with high thermal conductivity on the surface coating of the partition, which can further improve the thermal conductivity of the partition, thereby improving the temperature uniformity of each chamber in the multi-chamber graphite sagger.
[0019] (5) In the preparation method of the multi-chamber graphite sagger provided by the present invention, the calcination is divided into two steps: low-temperature sintering and high-temperature sintering. Low-temperature sintering is used to remove non-C substances in wood shavings and wood pulp. High-temperature sintering causes carbon in wood shavings and wood pulp to generate carbon fibers in situ, thereby improving the mechanical strength of the outer matrix and thus improving the service life of the multi-chamber graphite sagger. Attached Figure Description
[0020] To more clearly illustrate the technical solutions in the embodiments of this drawing or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this drawing. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.
[0021] Figure 1 This is a top view of the multi-chamber graphite sagger provided in an embodiment of the present invention.
[0022] The purpose, features, and advantages of this accompanying drawing will be further explained in conjunction with the embodiments and with reference to the accompanying drawing. Detailed Implementation
[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described and illustrated below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments provided by this invention without inventive effort are within the scope of protection of this invention.
[0024] Obviously, the following description is merely some examples or embodiments of the present invention. Those skilled in the art can apply the present invention to other similar scenarios without any inventive effort. Furthermore, it is understood that although the effort involved in such development may be complex and lengthy, for those skilled in the art related to the content disclosed in this invention, modifications to design, manufacturing, or production based on the technical content disclosed in this invention are merely conventional technical means and should not be construed as insufficient disclosure of the present invention.
[0025] However, there may be instances where unnecessary detailed descriptions are omitted. For example, detailed descriptions of well-known matters or repetitive descriptions of essentially the same structures may be omitted. This is to avoid making the following description unnecessarily lengthy and to facilitate understanding by those skilled in the art. Furthermore, the following description is provided to enable those skilled in the art to fully understand the invention and is not intended to limit the subject matter of the claims.
[0026] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions, and all technical features and optional technical features of the present invention can be combined with each other to form new technical solutions.
[0027] The first aspect of the present invention provides a multi-chamber graphite sagger, including a sagger base, a shell surface coating, and a partition surface coating;
[0028] The sagger base consists of an outer base and a partition base;
[0029] The outer matrix comprises the following raw materials in parts by weight:
[0030] 100 parts graphite, 10 to 20 parts tungsten carbide, 5 to 10 parts wood shavings, 12 to 18 parts wood pulp;
[0031] The partition matrix comprises the following raw materials in parts by weight: 100 parts graphite, 10 to 20 parts graphene oxide, 10 to 20 parts carbon nanotubes, and 10 to 20 parts binder.
[0032] The multi-chamber graphite sagger provided in this invention has tungsten carbide as the raw material for the outer matrix, which has high mechanical strength, thereby improving the mechanical strength of the outer matrix. Wood shavings, as the raw material for carbon fiber preparation, generate carbon fibers in situ during calcination, which can improve the mechanical strength of the outer matrix. Wood pulp is used as a binder to adjust the viscosity of the raw material. In addition, wood pulp can also generate carbon fibers, either wholly or partially, during calcination, further improving the mechanical strength of the outer matrix, and thus improving the mechanical strength of the multi-chamber graphite sagger.
[0033] In some embodiments, graphite includes at least one of artificial graphite and natural graphite.
[0034] In some embodiments, the graphitization degree of graphite is 90% to 100%.
[0035] In some embodiments, the average particle size of tungsten carbide is 50 nm to 80 nm. In this case, tungsten carbide enhances the mechanical strength of the outer matrix.
[0036] In some embodiments, the average particle size of the wood shavings is 0.01 mm to 0.1 mm. In this case, the carbon fibers obtained after sintering the wood shavings are short fibers and are uniformly distributed in the outer matrix, thereby effectively improving the mechanical strength of the outer matrix and thus improving the mechanical strength of the multi-chamber graphite sagger.
[0037] In some embodiments, the viscosity of the wood pulp is 700 mPa·s to 1000 mPa·s. In this case, the wood pulp acts as a binder to effectively bond other raw materials together.
[0038] In some embodiments, the material of the outer casing surface coating includes silicon carbide.
[0039] In some embodiments, the thickness of the coating on the outer shell surface is 100nm~200nm.
[0040] In some embodiments, the CAS number of graphene oxide is 2640657-49-2.
[0041] In some embodiments, the CAS number of the carbon nanotube is 1333-86-4.
[0042] In some embodiments, the binder in the raw material of the partition substrate includes at least one of polyvinyl alcohol and asphalt.
[0043] In some embodiments, the thickness of the coating on the partition surface is 70 μm to 100 μm. In some embodiments, the material of the partition surface coating includes at least one of boron nitride, graphene oxide, and carbon nanotubes. In this case, the partition surface coating materials all have high thermal conductivity, enabling rapid heat transfer within the partition and improving the temperature uniformity of each chamber in the multi-chamber graphite crucible.
[0044] In other embodiments, the material of the partition substrate is the same as that of the outer substrate.
[0045] A second aspect of this invention provides a method for preparing the above-mentioned multi-chamber graphite sagger, comprising the following steps:
[0046] S10. Prepare the sagger substrate, the outer shell surface coating, and the partition plate surface coating.
[0047] In some embodiments, in step S10 above, the sagger base includes an outer base and a partition base.
[0048] In some embodiments, in step S10 above, preparing the crucible substrate includes the following steps:
[0049] S101. The outer matrix mixture slurry and the partition matrix slurry are molded to obtain a sagger blank, which is then fired.
[0050] The outer matrix mixture contains graphite, tungsten carbide, wood shavings, and wood pulp.
[0051] In some embodiments, the preparation of the outer matrix mixture slurry in step S101 above includes the following steps:
[0052] S1011. Acidify wood shavings and mix them with primary pulp;
[0053] The primary pulp contains graphite, tungsten carbide, and wood pulp.
[0054] In the preparation of the above-mentioned mixed slurry, acidification of wood shavings can improve the mixing uniformity of wood shavings and primary slurry and prevent wood shavings from agglomerating.
[0055] In some embodiments, the step of acidifying the wood shavings in step S1011 above includes:
[0056] S10111. Dry wood shavings until the moisture content is below 10%.
[0057] S10112. Mix dried wood shavings with acid and acidify at 80℃~100℃.
[0058] S10113. Water-washed acidified wood shavings to neutral.
[0059] S10114. Dry the washed wood shavings at 50℃~70℃ to obtain acidified wood shavings.
[0060] In some embodiments, in step S10111 above, the drying temperature is 50°C to 70°C.
[0061] In some embodiments, in step S10112 above, the acid includes at least one of dilute sulfuric acid, dilute phosphoric acid, and dilute nitric acid.
[0062] In some embodiments, the concentration of dilute sulfuric acid is 3% to 5%.
[0063] In some embodiments, the concentration of dilute phosphoric acid is 5% to 10%.
[0064] In some embodiments, the concentration of dilute nitric acid is 5% to 10%.
[0065] In some embodiments, in step S10112 above, the solid-liquid ratio of wood shavings to acid is 1:9~15.
[0066] In some embodiments, in step S10112 above, the acidification time is 1h to 6h.
[0067] In some embodiments, the acidification time of wood shavings with dilute sulfuric acid is 2h to 3h.
[0068] In some embodiments, the time for acidifying wood shavings with dilute phosphoric acid is 4h to 6h.
[0069] In some embodiments, the time for acidifying wood shavings with dilute nitric acid is 1 to 2 hours.
[0070] In some embodiments, in step S1011 above, the preparation of the primary pulp includes the following steps:
[0071] S10115. Tungsten carbide, graphite and wood pulp are ball-milled and mixed.
[0072] In some embodiments, in step S10115 above, the rotational speed of the ball mill is 150 rpm to 250 rpm.
[0073] In some embodiments, in step S10115 above, the ball-to-material ratio of the ball mill is (18~25):1.
[0074] In some embodiments, in step S10115 above, the ball milling time is 30 minutes or more.
[0075] In some embodiments, in step S10115 above, the ball milling time is 30 min to 120 min.
[0076] In some embodiments, in step S101 above, the partition matrix slurry is an outer matrix mixed slurry.
[0077] In other embodiments, in step S101 above, the partition matrix slurry contains graphite, graphene oxide, carbon nanotubes and a binder.
[0078] In some embodiments, the preparation of the partition matrix slurry in step S101 above includes the following steps:
[0079] S1012. Mix graphite, graphene oxide, carbon nanotubes and binder and ball mill.
[0080] In some embodiments, in step S1012 above, the rotational speed of the ball mill is 100 rpm to 150 rpm.
[0081] In some embodiments, in step S1012 above, the ball-to-material ratio of the ball mill is 1:(10~20).
[0082] In some embodiments, in step S1012 above, the ball milling time is 10 min to 20 min.
[0083] In some embodiments, in step S101 above, the compression molding pressure is 300MPa~400MPa.
[0084] In some embodiments, in step S101 above, the molding time is 20 min to 30 min.
[0085] In some embodiments, in step S101 above, calcination includes the following steps:
[0086] S1012. Under an inert atmosphere, the sagger blank is sintered at low temperature and then sintered at high temperature.
[0087] The above-mentioned sintering process is divided into two steps: low-temperature sintering and high-temperature sintering. Low-temperature sintering mainly removes non-carbon elements from wood shavings and wood pulp. High-temperature sintering causes carbon in wood shavings and wood pulp to form carbon fibers in situ, thereby improving the mechanical strength of the outer matrix and thus increasing the service life of the multi-chamber graphite sagger.
[0088] In some embodiments, in step S1012 above, the inert atmosphere includes at least one of nitrogen, argon, and helium.
[0089] In some embodiments, the low-temperature sintering step in step S1012 above includes:
[0090] S10121. Heat to 300℃~600℃ at a heating rate of 1℃ / min~2℃ / min and then hold at that temperature.
[0091] In this case, heating to a low temperature of 300℃~600℃ at a relatively low heating rate can first remove free moisture from the sagger blank, and the initial decomposition of organic matter in wood shavings and wood pulp removes non-carbon elements, forming a preliminary carbon fiber skeleton. In addition, the low heating rate keeps the molecular motion rate low, maintaining the structure of the sagger blank.
[0092] In some embodiments, in step S10121 above, the heat preservation time is 1h to 2h.
[0093] In some embodiments, the high-temperature sintering step in step S1012 above includes:
[0094] S10122. Heat to 1000℃~1500℃ at a heating rate of 60℃ / min~80℃ / min and then hold at that temperature.
[0095] In this case, the temperature is raised from a low temperature to a high temperature of 1000℃~1500℃ at a relatively high heating rate. The carbon fiber skeleton of wood shavings and wood pulp is further fiberized to form carbon fiber reinforcement, thereby improving the mechanical strength of the outer matrix and thus improving the mechanical strength of the multi-chamber graphite sagger.
[0096] In some embodiments, in step S10122 above, the heat preservation time is 1h to 2h.
[0097] In some embodiments, in step S10 above, preparing the outer shell surface coating includes the following steps:
[0098] S102. A silicon carbide slurry is sprayed onto the outer substrate surface using a cold spraying process, followed by laser remelting to obtain the outer shell surface coating.
[0099] Silicon carbide slurry contains silicon carbide and polyvinyl alcohol.
[0100] In the above steps for preparing the outer shell surface coating, the cold spraying method can achieve a coating thickness at the nanometer level. Laser remelting then forms chemical bonds between the silicon carbide and the carbon in the outer substrate, resulting in a tight bond between the outer shell surface coating and the outer substrate, making it less prone to peeling off. The silicon carbide slurry contains polyvinyl alcohol, which helps to reduce silicon carbide agglomeration and form micron-sized spheres, improving the slurry's fluidity and facilitating powder acceleration. Furthermore, polyvinyl alcohol temporarily binds the silicon carbide powder particles, improving the uniformity of powder feeding.
[0101] In some embodiments, in step S102 above, the mass of polyvinyl alcohol in the silicon carbide slurry is 0.08% to 0.12% of the mass of silicon carbide.
[0102] In some embodiments, in step S102 above, the CAS number of polyvinyl alcohol is 9002-89-5.
[0103] In some embodiments, in step S102 above, the distance between the spray gun and the outer substrate in the cold spraying process is 30mm~40mm.
[0104] In some embodiments, in step S102 above, the spray angle of the spray gun in the cold spraying process is 90°.
[0105] In some embodiments, in step S102 above, the particle velocity in the cold spraying process is 1000m / s to 1200m / s.
[0106] In some embodiments, in step S102 above, the cold spraying process uses helium pressurization at a pressure of 2MPa to 5MPa.
[0107] In some embodiments, in step S102 above, the laser remelting power in the laser remelting process is 500W~600W.
[0108] In some embodiments, in step S102 above, the laser scanning speed in the laser remelting process is 5 mm / s to 10 mm / s.
[0109] In some embodiments, in step S10 above, preparing the coating on the partition surface includes the following steps:
[0110] S103. A coating is prepared on the surface of the partition substrate using a chemical vapor deposition process.
[0111] In some embodiments, in step S103 above, the boron source for preparing the boron nitride coating in the chemical vapor deposition process is trimethylboron [B(CH3)3].
[0112] In some embodiments, in step S103 above, the nitrogen source for preparing the boron nitride coating in the chemical vapor deposition process is ammonia.
[0113] In some embodiments, in step S103 above, the carbon source for preparing the graphene oxide coating in the chemical vapor deposition process is at least one of methane (CH4) and ethylene (C2H4).
[0114] The following description, in conjunction with specific embodiments, provides further details.
[0115] Example 1
[0116] Example 1 provides a multi-chamber graphite sagger, which is composed of a sagger base, an outer shell surface coating, and a partition plate surface coating;
[0117] The sagger base consists of an outer base and a partition base;
[0118] The outer matrix is composed of the following raw materials in parts by weight:
[0119] 100 parts artificial graphite, 10 parts tungsten carbide, 5 parts wood shavings, 12 parts wood pulp;
[0120] Among them, the graphitization degree of artificial graphite is 90%, the average particle size of tungsten carbide is 50nm, the average particle size of wood shavings is 0.01mm, and the viscosity of wood pulp is 700mPa·s.
[0121] The partition substrate is composed of the following raw materials in parts by weight:
[0122] 100 parts artificial graphite, 10 parts graphene oxide, 10 parts carbon nanotubes, 10 parts polyvinyl alcohol;
[0123] Among them, the degree of graphitization of artificial graphite is 90%, the CAS number of graphene oxide is 2640657-49-2, and the CAS number of carbon nanotubes is 1333-86-4.
[0124] The outer shell surface coating material is silicon carbide, with a thickness of 100nm;
[0125] The material of the coating on the surface of the partition is boron nitride, and the thickness is 70μm.
[0126] This embodiment also provides a method for preparing the multi-chamber graphite sagger provided in this embodiment, the steps of which are as follows:
[0127] E10. Preparation of external matrix mixture slurry
[0128] E101. Acidification of wood shavings:
[0129] (1) Dry the wood shavings at 50°C until the moisture content is less than 10%.
[0130] (2) Mix dried wood shavings with dilute phosphoric acid (solid-liquid ratio of 1:9) and acidify at 80°C for 4 hours.
[0131] (3) Wash the acidified wood shavings with water until they are neutral.
[0132] (4) Dry the washed wood shavings at 50°C to obtain acidified wood shavings.
[0133] E102. Preparation of primary slurry: Tungsten carbide, artificial graphite and wood pulp are ball-milled and mixed;
[0134] The ball milling speed was 150 rpm, the ball-to-material ratio was 20:1, and the milling time was 60 min.
[0135] E103. Preparation of outer matrix mixed slurry: Acidified wood shavings are mixed with primary pulp to obtain outer matrix mixed slurry.
[0136] E20. Preparation of partition plate matrix slurry
[0137] Artificial graphite, graphene oxide, carbon nanotubes, and polyvinyl alcohol were mixed and ball-milled; the ball milling speed was 120 rpm, the ball-to-material ratio was 1:15, and the time was 20 min.
[0138] E30. Compression molding: The sagger blank obtained by compression molding the outer matrix mixture slurry and the partition matrix slurry;
[0139] The compression molding pressure is 300 MPa, and the time is 20 minutes.
[0140] E30. Roasting
[0141] E301. Low-temperature sintering: Under a nitrogen atmosphere, the sagger blank is heated to 300℃ at a heating rate of 1℃ / min and then held for 2 hours.
[0142] E302. High-temperature sintering: Under a nitrogen atmosphere, the sagger blank is heated to 1000℃ at a heating rate of 80℃ / min and held for 2 hours to obtain the sagger matrix.
[0143] E40. Preparation of outer shell surface coating
[0144] E401. Preparation of silicon carbide slurry: Silicon carbide and polyvinyl alcohol are mixed to obtain silicon carbide slurry, wherein the mass of polyvinyl alcohol is 0.08% of the mass of silicon carbide, and the CAS number of polyvinyl alcohol is 9002-89-5.
[0145] E402. A silicon carbide slurry is sprayed onto the outer substrate surface using a cold spraying process, followed by laser remelting to obtain the outer shell surface coating.
[0146] In the cold spraying process, helium gas is pressurized to a pressure of 3MPa; the distance between the spray gun and the outer substrate is 35mm; and the particle velocity is 1000m / s.
[0147] In the laser remelting process, the laser remelting power is 500W and the laser scanning speed is 5mm / s.
[0148] E50. Preparation of coating on partition surface
[0149] A partition surface coating was prepared on the surface of the partition substrate using chemical vapor deposition; a multi-chamber graphite sagger was obtained.
[0150] The boron source is trimethylboron [B(CH3)3], and the nitrogen source is ammonia.
[0151] Example 2
[0152] Example 2 provides a multi-chamber graphite sagger, which consists of a sagger base, an outer shell surface coating, and a partition plate surface coating;
[0153] The sagger base consists of an outer base and a partition base;
[0154] The outer matrix is composed of the following raw materials in parts by weight:
[0155] 100 parts artificial graphite, 15 parts tungsten carbide, 8 parts wood shavings, 13 parts wood pulp;
[0156] Among them, the graphitization degree of artificial graphite is 90%, the average particle size of tungsten carbide is 70nm, the average particle size of wood shavings is 0.09mm, and the viscosity of wood pulp is 886mPa·s.
[0157] The partition substrate is composed of the following raw materials in parts by weight:
[0158] 100 parts artificial graphite, 18 parts graphene oxide, 15 parts carbon nanotubes, 15 parts polyvinyl alcohol;
[0159] Among them, the degree of graphitization of artificial graphite is 90%, the CAS number of graphene oxide is 2640657-49-2, and the CAS number of carbon nanotubes is 1333-86-4.
[0160] The outer shell surface coating material is silicon carbide, with a thickness of 150nm;
[0161] The material of the coating on the partition surface is boron nitride, and the thickness is 80μm.
[0162] This embodiment also provides a method for preparing the multi-chamber graphite sagger provided in this embodiment. The steps are basically the same as those in Embodiment 1, except that:
[0163] E301. Low-temperature sintering: Under a nitrogen atmosphere, the sagger blank is heated to 400℃ at a heating rate of 2℃ / min and then held for 1.5h.
[0164] E302. High-temperature sintering: Under a nitrogen atmosphere, the sagger blank is heated to 1200℃ at a heating rate of 70℃ / min and held for 1 hour to obtain the sagger matrix.
[0165] Example 3
[0166] Example 3 provides a multi-chamber graphite sagger, which consists of a sagger base, an outer shell surface coating, and a partition surface coating;
[0167] The sagger base consists of an outer base and a partition base;
[0168] The outer matrix is composed of the following raw materials in parts by weight:
[0169] 100 parts artificial graphite, 20 parts tungsten carbide, 10 parts wood shavings, 18 parts wood pulp;
[0170] Among them, the graphitization degree of artificial graphite is 90%, the average particle size of tungsten carbide is 80nm, the average particle size of wood shavings is 0.05mm, and the viscosity of wood pulp is 912mPa·s.
[0171] The partition substrate is composed of the following raw materials in parts by weight:
[0172] 100 parts artificial graphite, 20 parts graphene oxide, 20 parts carbon nanotubes, 20 parts polyvinyl alcohol;
[0173] Among them, the degree of graphitization of artificial graphite is 90%, the CAS number of graphene oxide is 2640657-49-2, and the CAS number of carbon nanotubes is 1333-86-4.
[0174] The outer shell surface coating material is silicon carbide, with a thickness of 200nm;
[0175] The material of the coating on the surface of the partition is boron nitride, and the thickness is 100μm.
[0176] This embodiment also provides a method for preparing the multi-chamber graphite sagger provided in this embodiment. The steps are basically the same as those in Embodiment 1, except that:
[0177] E301. Low-temperature sintering: Under a nitrogen atmosphere, the sagger blank is heated to 600℃ at a heating rate of 2℃ / min and then held for 1 hour.
[0178] E302. High-temperature sintering: Under a nitrogen atmosphere, the sagger blank is heated to 1500℃ at a heating rate of 60℃ / min and held for 1 hour to obtain the sagger matrix.
[0179] Example 4
[0180] Example 4 provides a multi-chamber graphite sagger, which consists of a sagger base, an outer shell surface coating, and a partition plate surface coating;
[0181] The sagger base consists of an outer base and a partition base;
[0182] The outer matrix is composed of the following raw materials in parts by weight:
[0183] 100 parts artificial graphite, 10 parts tungsten carbide, 10 parts wood shavings, 18 parts wood pulp;
[0184] Among them, the graphitization degree of artificial graphite is 90%, the average particle size of tungsten carbide is 50nm, the average particle size of wood shavings is 0.01mm, and the viscosity of wood pulp is 700mPa·s.
[0185] The partition substrate is composed of the following raw materials in parts by weight:
[0186] 100 parts artificial graphite, 20 parts graphene oxide, 10 parts carbon nanotubes, 10 parts polyvinyl alcohol;
[0187] Among them, the degree of graphitization of artificial graphite is 90%, the CAS number of graphene oxide is 2640657-49-2, and the CAS number of carbon nanotubes is 1333-86-4.
[0188] The outer shell surface coating material is silicon carbide, with a thickness of 180nm;
[0189] The material of the coating on the surface of the partition is boron nitride, and the thickness is 90μm.
[0190] This embodiment also provides a method for preparing the multi-chamber graphite sagger provided in this embodiment. The steps are basically the same as those in Embodiment 1, except that:
[0191] E301. Low-temperature sintering: Under a nitrogen atmosphere, the sagger blank is heated to 500℃ at a heating rate of 1℃ / min and then held for 2 hours.
[0192] E302. High-temperature sintering: Under a nitrogen atmosphere, the sagger blank is heated to 1500℃ at a heating rate of 70℃ / min and held for 2 hours to obtain the sagger matrix.
[0193] Example 5
[0194] Example 5 provides a multi-chamber graphite sagger, which consists of a sagger base, an outer shell surface coating, and a partition plate surface coating;
[0195] The sagger base consists of an outer base and a partition base;
[0196] The outer matrix is composed of the following raw materials in parts by weight:
[0197] 100 parts artificial graphite, 10 parts wood shavings, 12 parts wood pulp;
[0198] Among them, the graphitization degree of artificial graphite is 90%, the average particle size of tungsten carbide is 50nm, the average particle size of wood shavings is 0.1mm, and the viscosity of wood pulp is 1000mPa·s.
[0199] The partition substrate is composed of the following raw materials in parts by weight:
[0200] 100 parts artificial graphite, 12 parts graphene oxide, 18 parts carbon nanotubes, 15 parts polyvinyl alcohol;
[0201] Among them, the degree of graphitization of artificial graphite is 90%, the CAS number of graphene oxide is 2640657-49-2, and the CAS number of carbon nanotubes is 1333-86-4.
[0202] The outer shell surface coating material is silicon carbide, with a thickness of 100nm;
[0203] The material of the coating on the surface of the partition is boron nitride, and the thickness is 70μm.
[0204] This embodiment also provides a method for preparing the multi-chamber graphite sagger provided in this embodiment. The steps are basically the same as those in Embodiment 1, except that:
[0205] E402. A silicon carbide slurry is sprayed onto the outer substrate surface using a cold spraying process, followed by laser remelting to obtain the outer shell surface coating.
[0206] In the cold spraying process, helium gas is pressurized to a pressure of 5 MPa; the distance between the spray gun and the outer substrate is 40 mm; and the particle velocity is 1200 m / s.
[0207] In the laser remelting process, the laser remelting power is 600W and the laser scanning speed is 10mm / s.
[0208] Example 6
[0209] Example 6 provides a multi-chamber graphite sagger, which consists of a sagger base, an outer shell surface coating, and a partition surface coating;
[0210] The sagger base consists of an outer base and a partition base;
[0211] The outer matrix is composed of the following raw materials in parts by weight:
[0212] 100 parts artificial graphite, 20 parts tungsten carbide, 5 parts wood shavings, 17 parts wood pulp;
[0213] Among them, the graphitization degree of artificial graphite is 90%, the average particle size of tungsten carbide is 70nm, the average particle size of wood shavings is 0.05mm, and the viscosity of wood pulp is 738mPa·s.
[0214] The partition substrate is composed of the following raw materials in parts by weight:
[0215] 100 parts artificial graphite, 10 parts graphene oxide, 20 parts carbon nanotubes, 20 parts polyvinyl alcohol;
[0216] Among them, the degree of graphitization of artificial graphite is 90%, the CAS number of graphene oxide is 2640657-49-2, and the CAS number of carbon nanotubes is 1333-86-4.
[0217] The outer shell surface coating material is silicon carbide, with a thickness of 200nm;
[0218] The material of the coating on the surface of the partition is boron nitride, and the thickness is 100μm.
[0219] This embodiment also provides a method for preparing the multi-chamber graphite sagger provided in this embodiment. The steps are basically the same as those in Embodiment 1, except that:
[0220] E402. A silicon carbide slurry is sprayed onto the outer substrate surface using a cold spraying process, followed by laser remelting to obtain the outer shell surface coating.
[0221] In the cold spraying process, helium gas is pressurized to a pressure of 2MPa; the distance between the spray gun and the outer substrate is 30mm; and the particle velocity is 1000m / s.
[0222] In the laser remelting process, the laser remelting power is 600W and the laser scanning speed is 10mm / s.
[0223] Example 7
[0224] Example 7 provides a multi-chamber graphite sagger, which consists of a sagger base, an outer shell surface coating, and a partition plate surface coating;
[0225] The sagger base consists of an outer base and a partition base;
[0226] Both the outer matrix and the partition matrix are composed of the following raw materials:
[0227] 100 parts artificial graphite, 10 parts tungsten carbide, 5 parts wood shavings, 12 parts wood pulp;
[0228] Among them, the degree of graphitization of artificial graphite is 90%, the average particle size of tungsten carbide is 50 nm, the average particle size of wood shavings is 0.01 mm, and the viscosity of wood pulp is 700 mPa·s.
[0229] The materials and thicknesses of the outer shell surface coating and the partition surface coating are the same as in Example 1.
[0230] Comparative Example 1
[0231] Comparative Example 1 provides a multi-chamber graphite sagger, which is composed of a sagger base, an outer shell surface coating, and a partition surface coating;
[0232] The sagger base consists of an outer base and a partition base;
[0233] The outer matrix is composed of the following raw materials in parts by weight:
[0234] 100 parts artificial graphite, 10 parts tungsten carbide, 5 parts wood shavings, 12 parts wood pulp;
[0235] Among them, the graphitization degree of artificial graphite is 90%, the average particle size of tungsten carbide is 50nm, the average particle size of wood shavings is 0.01mm, and the viscosity of wood pulp is 712mPa·s.
[0236] The partition substrate is composed of the following raw materials in parts by weight:
[0237] 100 parts artificial graphite, 10 parts graphene oxide, 10 parts carbon nanotubes, 10 parts polyvinyl alcohol;
[0238] Among them, the degree of graphitization of artificial graphite is 90%, the CAS number of graphene oxide is 2640657-49-2, and the CAS number of carbon nanotubes is 1333-86-4.
[0239] The outer shell surface coating material is silicon carbide, with a thickness of 100nm;
[0240] The material of the coating on the surface of the partition is boron nitride, and the thickness is 70μm.
[0241] This comparative example also provides a method for preparing a multi-chamber graphite sagger, the steps of which are basically the same as those in Example 1, except that:
[0242] Step E30. The roasting process is as follows:
[0243] Under a nitrogen atmosphere, the sagger blank is heated to 1000℃ at a heating rate of 10℃ / min and held for 2 hours to obtain a multi-chamber graphite sagger.
[0244] Comparative Example 2
[0245] Comparative Example 2 provides a multi-chamber graphite sagger, which consists of an outer shell and partitions;
[0246] The outer shell is composed of the following parts by weight of raw materials:
[0247] 100 parts artificial graphite, 20 parts tungsten carbide, 12 parts wood pulp;
[0248] Among them, the degree of graphitization of artificial graphite is 90%, the average particle size of tungsten carbide is 50 nm, and the viscosity of wood pulp is 700 mPa·s.
[0249] The partition is composed of the following parts by weight of raw materials:
[0250] 100 parts artificial graphite and 10 parts polyvinyl alcohol;
[0251] Among them, the degree of graphitization of artificial graphite is 90%, the CAS number of graphene oxide is 2640657-49-2, and the CAS number of carbon nanotubes is 1333-86-4.
[0252] This comparative example provides a method for preparing a multi-chamber graphite sagger, the steps of which are as follows:
[0253] D10. Preparation of shell mixing slurry
[0254] Tungsten carbide, artificial graphite, and wood pulp were ball-milled and mixed.
[0255] The ball milling speed was 150 rpm, the ball-to-material ratio was 20:1, and the milling time was 120 min.
[0256] D20. Preparation of partition slurry
[0257] Artificial graphite and polyvinyl alcohol were mixed and ball-milled; the ball milling speed was 150 rpm, the ball-to-material ratio was 1:20, and the time was 10 min.
[0258] D30. Compression molding: The sagger blank obtained by compression molding the outer shell mixture slurry and the partition slurry;
[0259] The compression molding pressure is 300 MPa, and the time is 20 minutes.
[0260] D30. Calcination
[0261] D301. Low-temperature sintering: Under a nitrogen atmosphere, the sagger blank is heated to 300℃ at a heating rate of 1℃ / min and then held for 2 hours.
[0262] D302. High-temperature sintering: Under a nitrogen atmosphere, the sagger blank is heated to 1000℃ at a heating rate of 80℃ / min and held for 2 hours to obtain a multi-chamber graphite sagger.
[0263] Comparative Example 3
[0264] Comparative Example 3 provides a multi-chamber graphite sagger, which consists of an outer shell and partitions;
[0265] The outer shell is composed of the following parts by weight of raw materials:
[0266] 100 parts artificial graphite, 5 parts wood shavings, 12 parts wood pulp;
[0267] Among them, the graphitization degree of artificial graphite is 90%, the average particle size of wood shavings is 0.01 mm, and the viscosity of wood pulp is 700 mPa·s.
[0268] The partition is composed of the following parts by weight of raw materials:
[0269] 100 parts artificial graphite, 10 parts graphene oxide, 10 parts carbon nanotubes, 10 parts polyvinyl alcohol;
[0270] Among them, the degree of graphitization of artificial graphite is 90%, the CAS number of graphene oxide is 2640657-49-2, and the CAS number of carbon nanotubes is 1333-86-4.
[0271] To verify the advancement of the multi-chamber graphite sagger and its preparation method provided in the embodiments of the present invention, the multi-chamber graphite saggers provided in the embodiments of the present invention and the comparative examples were experimentally tested for bending strength at 1000℃, lithium battery sintering life, oxidation weight loss at 1000℃, and thermal conductivity of the separator. The results are shown in Table 1 below.
[0272] Table 1
[0273]
[0274] In the above table:
[0275] (1) As can be seen from the comparison of the bending strength of Examples 1-7 and Comparative Example 1, the bending strength of Comparative Example 1 is significantly reduced. This is because the preparation method of the multi-chamber graphite sagger provided in the embodiments of the present invention adopts a sintering method of low-temperature sintering followed by high-temperature sintering during sintering, which allows wood shavings and wood pulp to generate carbon fibers in situ. Tungsten carbide also has high mechanical strength. The combination of the two can significantly improve the mechanical strength of the outer matrix, thereby improving the mechanical strength of the multi-chamber graphite sagger. In contrast, in Comparative Example 1, since the preparation of the multi-chamber graphite sagger did not involve low-temperature sintering followed by high-temperature sintering, the wood shavings and wood pulp could not generate carbon fibers in situ, resulting in very low mechanical strength of the multi-chamber graphite sagger.
[0276] (2) As can be seen from the lithium battery sintering life and oxidation weight loss at 1000℃ data of Examples 1-7 and Comparative Examples 1-3, the multi-chamber graphite sagger provided in the embodiments of the present invention has excellent lithium battery sintering life and very low oxidation weight loss rate. This is because the multi-chamber graphite sagger provided in the embodiments of the present invention contains a shell surface coating and a partition surface coating with a material having high chemical stability, thereby giving the multi-chamber graphite sagger provided in the embodiments of the present invention high high temperature resistance and oxidation resistance.
[0277] (3) Based on the thermal conductivity data of Example 1 and Comparative Example 2, although the matrix raw material composition is the same, the thermal conductivity of the partition of the multi-chamber graphite sagger prepared in Comparative Example 2 is significantly reduced. This is because the raw material of the partition matrix in the multi-chamber graphite sagger provided in the present invention contains graphene oxide and carbon nanotubes with high thermal conductivity, and also contains a shell surface coating and a partition surface coating with high thermal conductivity, thereby improving the thermal conductivity of the partition and thus improving the uniformity of the thermal field between the chambers.
[0278] It should be noted that the present invention is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments that have the same structure and perform the same effects as the technical concept within the scope of the present invention are included within the scope of the present invention. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of the present invention, are also included within the scope of the present invention.
Claims
1. A multi-chamber graphite sagger, characterized in that, This includes the sagger base, the outer shell surface coating, and the partition plate surface coating; The sagger base includes an outer base and a partition base; The outer matrix comprises the following raw materials in parts by weight: 100 parts graphite, 10 to 20 parts tungsten carbide, 5 to 10 parts wood shavings, 12 to 18 parts wood pulp; The partition substrate comprises the following raw materials in parts by weight: 100 parts graphite, 10 to 20 parts graphene oxide, 10 to 20 parts carbon nanotubes, and 10 to 20 parts binder.
2. The multi-chamber graphite sagger according to claim 1, characterized in that, At least one of the following conditions (1) to (5) must be satisfied: (1) The graphite includes at least one of artificial graphite and natural graphite; (2) The graphitization degree of the graphite is 90%~100%; (3) The average particle size of the tungsten carbide is 50 nm to 80 nm; (4) The average particle size of the wood shavings is 0.01 mm to 0.1 mm; (5) The viscosity of the wood pulp is 700 mPa·s to 1000 mPa·s.
3. The multi-chamber graphite sagger according to claim 1 or 2, characterized in that, At least one of the following conditions (1) to (4) must be satisfied: (1) The material of the outer shell surface coating includes silicon carbide; (2) The thickness of the coating on the outer shell surface is 100nm~200nm; (3) The material of the coating on the surface of the partition includes at least one of boron nitride, graphene oxide, and carbon nanotubes; (4) The thickness of the coating on the surface of the partition is 70μm~100μm.
4. A method for preparing a multi-chamber graphite sagger as described in any one of claims 1 to 3, characterized in that, Includes the following steps: Prepare the sagger substrate, the outer shell surface coating, and the partition plate surface coating.
5. The method for preparing a multi-chamber graphite sagger according to claim 4, characterized in that, The preparation of the sagger substrate includes the following steps: The outer matrix mixture slurry and the partition matrix slurry are molded together to obtain a sagger blank, which is then fired. The outer matrix mixture contains graphite, tungsten carbide, wood shavings, and wood pulp.
6. The method for preparing a multi-chamber graphite sagger according to claim 5, characterized in that, At least one of the following conditions (1) to (5) must be satisfied: (1) The pressure of the compression molding is 300MPa~400MPa; (2) The molding time is 20 min to 30 min; (3) The roasting includes the following steps: The sagger blank is sintered at low temperature and then at high temperature under an inert atmosphere. (4) The preparation of the outer shell surface coating includes the following steps: A silicon carbide slurry is sprayed onto the outer substrate surface using a cold spraying process, followed by laser remelting to obtain the outer shell surface coating. The silicon carbide slurry contains silicon carbide and polyvinyl alcohol; (5) The preparation of the coating on the partition surface includes the following steps: A surface coating for the partition plate is prepared on the surface of the partition plate substrate using a chemical vapor deposition process.
7. The method for preparing a multi-chamber graphite sagger according to claim 6, characterized in that, At least one of the following conditions (1) to (4) must be satisfied: (1) In the silicon carbide slurry, the mass of polyvinyl alcohol is 0.08%~0.12% of the mass of silicon carbide; (2) In the cold spraying process, the distance between the spray gun and the outer substrate is 30mm~40mm; (3) In the cold spraying process, the particle velocity is 1000m / s~1200m / s; (4) In the laser remelting process, the power of the laser remelting is 500W~600W.
8. The method for preparing a multi-chamber graphite sagger according to claim 6 or 7, characterized in that, At least one of the following conditions (1) to (2) must be satisfied: (1) The low-temperature sintering step includes: Heat to 300℃~600℃ at a heating rate of 1℃ / min~2℃ / min and then hold at that temperature; (2) The high-temperature sintering step includes: Heating to 1000℃~1500℃ at a heating rate of 60℃ / min~80℃ / min and then holding at that temperature.
9. The method for preparing a multi-chamber graphite sagger according to claim 8, characterized in that, At least one of the following conditions (1) to (2) must be satisfied: (1) In the low-temperature sintering, the holding time is 1h~2h; (2) In the high-temperature sintering, the holding time is 1h~2h.
10. The application of a multi-chamber graphite sagger as described in any one of claims 1 to 3 in the field of material sintering.
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