A graphite crucible with a silicon carbide coating

Abstract

The present invention discloses a graphite crucible with a silicon carbide coating, specifically relating to the technical field of crucibles, including a rotary positioning plate and a protective outer frame. The inner wall of the rotary positioning plate abuts against the outer surface of the crucible body. A protective coating is provided on the inner wall of the crucible body. The outer surface of the crucible body abuts against the outer surfaces of five limiting components, and the limiting components are arranged on the inner wall of a placement groove, and the placement groove is opened on the inner wall of the rotary positioning plate. Through the rotary positioning plate, teeth, gear, drive assembly, crucible body and protective outer frame, while the drive assembly works, it controls the rotation of the gear. At this time, the gear controls the rotation of the rotary positioning plate and the crucible body through the teeth. The crucible body is at an eccentric position on the rotary positioning plate, realizing that the crucible body is in full and uniform contact with the heat source during the rotation process, ensuring uniform heating of the crucible body, and significantly improving the service performance and service life of the crucible body.

Description

Technical Field

[0001] The present invention relates to the technical field of crucibles, and more specifically, the present invention relates to a graphite crucible with a silicon carbide coating. Background Art

[0002] Graphite crucibles have good thermal conductivity and high temperature resistance. During high-temperature use, they have a small coefficient of thermal expansion, certain anti-strain performance against rapid heating and cooling, strong corrosion resistance to acidic and alkaline solutions, and excellent chemical stability. In industrial sectors such as metallurgy, casting, machinery, and chemical engineering, they are widely used in the smelting of alloy tool steels and the melting of non-ferrous metals and their alloys, and have good technical and economic effects. When the existing crucibles are in use, the heat dissipation on their surfaces is relatively obvious during the heating process, resulting in unsatisfactory heating effects. Moreover, the bottom of the crucible is closest to the heat source, causing uneven heating of other edge positions of the crucible, or affecting the overall heating efficiency, which easily affects the service life of the crucible itself, and the heat resistance effect of the crucible itself is not ideal. Therefore, a graphite crucible with a silicon carbide coating is needed to solve the above problems. Summary of the Invention

[0003] In order to overcome the above-mentioned defects of the prior art, the present invention provides a graphite crucible with a silicon carbide coating. The technical problem to be solved by the present invention is: the heat dissipation on its surface is relatively obvious during the heating process, resulting in unsatisfactory heating effects, and the bottom of the crucible itself is closest to the heat source, causing uneven heating of other edge positions of the crucible, or affecting the overall heating efficiency, which easily affects the service life of the crucible itself, and the heat resistance effect of the crucible itself is not ideal.

[0004] To achieve the above object, the present invention provides the following technical solution: A graphite crucible with a silicon carbide coating, comprising a rotary positioning plate and a protective outer frame. The inner wall of the rotary positioning plate abuts against the outer surface of the crucible body. A protective coating is provided on the inner wall of the crucible body. The outer surface of the crucible body abuts against the outer surfaces of five limiting components. The limiting components are arranged on the inner wall of a placement groove, and the placement groove is opened on the inner wall of the rotary positioning plate. A number of teeth are provided on the outer surface of the rotary positioning plate, and the teeth are engaged with a gear. The lower surface of the gear is fixedly connected to the output shaft of a driving component, and the lower surface of the driving component is fixedly connected to the lower surface of the inner wall of a connection hole, and the connection hole is opened on the front surface of the protective outer frame.

[0005] As a further solution of the present invention: The limiting component includes a piston frame, the outer surface of the piston frame is fixedly connected to the inner wall of the placement groove, the inner wall of the piston frame is slidably connected to the outer surface of the piston plate, the outer surface of the piston plate is fixedly connected to one end of the piston rod, the other end of the piston rod is fixedly connected to the outer surface of the contact plate, the contact plate is lapped with the outer surface of the crucible body, and an elastic component is arranged on the outer surface of the piston rod, and both ends of the elastic component are fixedly connected to the outer surface of the piston plate and the inner wall of the piston frame respectively.

[0006] As a further solution of the present invention: A cover plate is arranged on the upper surface of the crucible body, the front surface of the protective outer frame is fixedly connected to the back surface of the extension frame, and the position of the extension frame corresponds to the position of the connection hole.

[0007] As a further solution of the present invention: A bearing is arranged on the outer surface of the rotary positioning plate, the bearing is arranged on the inner wall of the protective outer frame, and the protective coating is a silicon carbide coating.

[0008] As a further solution of the present invention: The crucible body comprises raw materials with the following mass fractions: 20%-50% of coke, 15%-45% of flaky graphite, 30% of silicon carbide, and 5% of silicon powder.

[0009] As a further solution of the present invention: The preparation of the crucible body comprises the following steps:

[0010] S1. Put the raw materials of the above components into a crusher respectively to crush the raw materials. After crushing, the particle size of the raw materials is kept at 1-8 mm. Then put the crushed raw materials into the internal of the stirring equipment, and the stirring process lasts for 10 min to mix the raw materials evenly;

[0011] S2. Transfer the evenly mixed raw materials to a kneader for dry mixing and wet mixing. The temperature during the kneading process is controlled at 150°C - 175°C. After kneading, cool the obtained raw materials and transfer them to a molding machine;

[0012] S3. Put the semi-finished product obtained after molding into a dryer. The temperature during the drying process is 100°C, and the drying time is 24 h;

[0013] S4. Put the dried semi-finished product into a vacuum atmosphere furnace for firing. The firing temperature is controlled at 1150°C to obtain a finished graphite crucible;

[0014] S5. Immerse the finished graphite crucible in an inorganic material for densification treatment. The pressure during the immersion process is controlled at 0.35 MPa.

[0015] The molding temperature is controlled at 130°C - 140°C.

[0016] The beneficial effects of the present invention are as follows:

[0017] 1. The present invention controls the rotation of a gear while a driving assembly operates through a rotating positioning plate, teeth, a gear, the driving assembly, a crucible body, and a protective outer frame. At this time, the gear controls the rotation of the rotating positioning plate and the crucible body through the teeth. The crucible body is at an eccentric position on the rotating positioning plate, achieving full and uniform contact between the crucible body and the heat source during the rotation process of the crucible body, ensuring uniform heating of the crucible body, and significantly improving the service performance and service life of the crucible body.

[0018] 2. The present invention is provided with a piston frame, a piston plate, a piston rod, a contact plate, and an elastic assembly. When the crucible body is lowered, it will directly contact the contact plate. Subsequently, the crucible body presses the contact plate to move into the placement groove. At the same time, the gas inside the piston frame is compressed, increasing the pressure of the gas on the contact plate. After the crucible body is stably placed, a certain pressure is exerted on the crucible body by the contact plate, ensuring the smooth and stable placement of the crucible body, and making the positioning effect and efficiency of the crucible body relatively ideal.

[0019] 3. In the present invention, the raw materials of the crucible body include 50% silicon carbide and 15% flaky graphite. The content of silicon carbide is relatively high, reducing the weight loss rate of the crucible body and increasing the oxidation resistance. Silicon carbide has good oxidation resistance. Silicon carbide reacts with carbon monoxide to generate silicon oxide gas and solid carbon. The carbon is deposited on the surface of silicon carbide, and the overall volume shows an expansion, preventing oxygen from entering the interior and increasing the oxidation resistance. Moreover, the particle size of the raw materials during the processing process is maintained at 6 mm, making the heat resistance of the crucible body more ideal. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a three-dimensional structural schematic diagram of the present invention;

[0021] Figure 2 is a three-dimensional structural schematic diagram of the extension frame of the present invention;

[0022] Figure 3 is a three-dimensional structural schematic diagram of the rear view partial section of the protective outer frame of the present invention;

[0023] Figure 4 is a three-dimensional structural schematic diagram of the crucible body of the present invention;

[0024] Figure 5 is a three-dimensional sectional structural schematic diagram of the rotating positioning plate of the present invention;

[0025] Figure 6 is a three-dimensional sectional structural schematic diagram of the limiting assembly of the present invention;

[0026] In the figure: 1. Rotating positioning plate; 2. Protective outer frame; 3. Bearing; 4. Crucible body; 5. Protective coating; 6. Cover plate; 7. Placing groove; 8. Limiting component; 81. Piston frame; 82. Piston plate; 83. Piston rod; 84. Elastic component; 85. Contact plate; 9. Teeth; 10. Gear; 11. Driving component; 12. Connecting hole; 13. Extension frame. Detailed implementation mode

[0027] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0028] Embodiment 1:

[0029] As Figures 1-6 shown, a graphite crucible with a silicon carbide coating includes a rotating positioning plate 1 and a protective outer frame 2. The inner wall of the rotating positioning plate 1 is lapped with the outer surface of the crucible body 4. A protective coating 5 is provided on the inner wall of the crucible body 4. The outer surface of the crucible body 4 is lapped with the outer surfaces of five limiting components 8. The limiting components 8 are arranged on the inner wall of the placing groove 7. The placing groove 7 is opened on the inner wall of the rotating positioning plate 1. A number of teeth 9 are provided on the outer surface of the rotating positioning plate 1. The teeth 9 are engaged with a gear 10. The lower surface of the gear 10 is fixedly connected to the output shaft of a driving component 11. The lower surface of the driving component 11 is fixedly connected to the lower surface of the inner wall of a connecting hole 12. The connecting hole 12 is opened on the front surface of the protective outer frame 2.

[0030] As Figure 5 and Figure 6 shown, the limiting component 8 includes a piston frame 81. The outer surface of the piston frame 81 is fixedly connected to the inner wall of the placing groove 7. The inner wall of the piston frame 81 is slidably connected to the outer surface of a piston plate 82. The outer surface of the piston plate 82 is fixedly connected to one end of a piston rod 83. The other end of the piston rod 83 is fixedly connected to the outer surface of a contact plate 85. The contact plate 85 is lapped with the outer surface of the crucible body 4. An elastic component 84 is provided on the outer surface of the piston rod 83. The two ends of the elastic component 84 are respectively fixedly connected to the outer surface of the piston plate 82 and the inner wall of the piston frame 81.

[0031] As Figure 1 shown, a cover plate 6 is provided on the upper surface of the crucible body 4. The front surface of the protective outer frame 2 is fixedly connected to the back surface of an extension frame 13. The position of the extension frame 13 corresponds to the position of the connecting hole 12.

[0032] As Figure 3 and Figure 4As shown, a bearing 3 is provided on the outer surface of the rotary positioning plate 1, and the bearing 3 is provided on the inner wall of the protective outer frame 2. The protective coating 5 is a silicon carbide coating.

[0033] The crucible body comprises raw materials with the following mass fractions: 20% silicon carbide, 45% flaky graphite, 30% coke, and 5% silicon powder.

[0034] The preparation of the crucible body comprises the following steps:

[0035] S1. Respectively put the raw materials of the above components into a pulverizer to pulverize the raw materials. After pulverization, the particle size of the raw materials remains at 6 mm. Subsequently, put the pulverized raw materials into the internal part of a stirring device, and keep the stirring process for 10 min to mix the raw materials evenly.

[0036] S2. Transfer the evenly mixed raw materials to a kneader for dry mixing and wet mixing. Control the temperature during the kneading process at 160 °C. After kneading, cool the obtained raw materials and transfer them to a molding machine.

[0037] S3. Put the semi-finished product obtained after molding into a dryer. The temperature during the drying process is 100 °C, and the drying time is 24 h.

[0038] S4. Put the dried semi-finished product into a vacuum atmosphere furnace for firing. Control the firing temperature at 1150 °C to obtain a finished graphite crucible.

[0039] S5. Immerse the finished graphite crucible with an inorganic material for densification treatment. Control the pressure during the immersion process at 0.35 MPa.

[0040] Control the molding temperature at 135 °C.

[0041] Example 2:

[0042] On the basis of Example 1, the crucible body comprises raw materials with the following mass fractions: 30% silicon carbide, 35% flaky graphite, 30% coke, and 5% silicon powder.

[0043] The preparation of the crucible body comprises the following steps:

[0044] S1. Respectively put the raw materials of the above components into a pulverizer to pulverize the raw materials. After pulverization, the particle size of the raw materials remains at 6 mm. Subsequently, put the pulverized raw materials into the internal part of a stirring device, and keep the stirring process for 10 min to mix the raw materials evenly.

[0045] S2. Transfer the evenly mixed raw materials to a kneader for dry mixing and wet mixing. Control the temperature during the kneading process at 160 °C. After kneading, cool the obtained raw materials and transfer them to a molding machine.

[0046] S3. Put the semi-finished product obtained after forming into a dryer, with the drying temperature at 100 °C and the drying time at 24 h;

[0047] S4. Put the dried semi-finished product into a vacuum atmosphere furnace for firing, with the firing temperature controlled at 1150 °C to obtain the finished graphite crucible;

[0048] S5. Immerse the finished graphite crucible with an inorganic material for densification treatment, with the pressure during the immersion process controlled at 0.35 MPa.

[0049] The forming temperature is controlled at 135 °C.

[0050] Example 3:

[0051] Based on Example 1, the crucible body includes raw materials with the following mass fractions: 40% silicon carbide, 25% flake graphite, 30% coke, and 5% silicon powder.

[0052] The preparation of the crucible body includes the following steps:

[0053] S1. Put the raw materials of the above components into a crusher respectively to crush the raw materials. After crushing, the particle size of the raw materials remains at 6 mm. Then put the crushed raw materials into the internal of a stirring device and stir for 10 min to mix the raw materials evenly;

[0054] S2. Transfer the evenly mixed raw materials to a kneader for dry mixing and wet mixing. The temperature during the kneading process is controlled at 160 °C. After kneading, cool the obtained raw materials and transfer them to a forming machine, with the forming temperature controlled at 135 °C;

[0055] S3. Put the semi-finished product obtained after forming into a dryer, with the drying temperature at 100 °C and the drying time at 24 h;

[0056] S4. Put the dried semi-finished product into a vacuum atmosphere furnace for firing, with the firing temperature controlled at 1150 °C to obtain the finished graphite crucible;

[0057] S5. Immerse the finished graphite crucible with an inorganic material for densification treatment, with the pressure during the immersion process controlled at 0.35 MPa.

[0058] Example 4:

[0059] Based on Example 1, the crucible body includes raw materials with the following mass fractions: 50% silicon carbide, 15% flake graphite, 30% coke, and 5% silicon powder.

[0060] The preparation of the crucible body includes the following steps:

[0061] S1. Put the raw materials of the above components into a crusher respectively to crush the raw materials. After crushing, the particle size of the raw materials is maintained at 6 mm. Subsequently, put the crushed raw materials into the stirring equipment, and the stirring process lasts for 10 min to mix the raw materials evenly.

[0062] S2. Transfer the evenly mixed raw materials to a kneader for dry mixing and wet mixing. The temperature during the kneading process is controlled at 160 °C. After kneading, cool the obtained raw materials and transfer them to a molding machine. The molding temperature is controlled at 135 °C.

[0063] S3. Put the semi-finished product obtained after molding into a dryer. The temperature during the drying process is 100 °C, and the drying time is 24 h.

[0064] S4. Put the dried semi-finished product into a vacuum atmosphere furnace for firing. The firing temperature is controlled at 1150 °C to obtain the finished graphite crucible.

[0065] S5. Immerse the finished graphite crucible in an inorganic material for densification treatment. The pressure during the immersion process is controlled at 0.35 MPa.

[0066] From Examples 1 - 4, the following table is obtained:

[0067]

[0068] Example 5:

[0069] On the basis of Example 1, the crucible body comprises raw materials with the following mass fractions: 50% silicon carbide, 15% flake graphite, 30% coke, and 5% silicon powder.

[0070] The preparation of the crucible body includes the following steps:

[0071] S1. Put the raw materials of the above components into a crusher respectively to crush the raw materials. After crushing, the particle size of the raw materials is maintained at 1 mm. Subsequently, put the crushed raw materials into the stirring equipment, and the stirring process lasts for 10 min to mix the raw materials evenly.

[0072] S2. Transfer the evenly mixed raw materials to a kneader for dry mixing and wet mixing. The temperature during the kneading process is controlled at 160 °C. After kneading, cool the obtained raw materials and transfer them to a molding machine.

[0073] S3. Put the semi-finished product obtained after molding into a dryer. The temperature during the drying process is 100 °C, and the drying time is 24 h.

[0074] S4. Put the dried semi-finished product into a vacuum atmosphere furnace for firing. The firing temperature is controlled at 1150 °C to obtain the finished graphite crucible.

[0075] S5. Immerse the finished graphite crucible in an inorganic material for densification treatment, and control the pressure during the immersion process at 0.35 MPa.

[0076] Control the forming temperature at 135 °C.

[0077] Example 6:

[0078] Based on Example 1, the crucible body comprises raw materials with the following mass fractions: 50% silicon carbide, 15% flake graphite, 30% coke, and 5% silicon powder.

[0079] The preparation of the crucible body includes the following steps:

[0080] S1. Put the raw materials of the above components into a crusher respectively to crush the raw materials. After crushing, the particle size of the raw materials remains at 3 mm. Then put the crushed raw materials into the stirring equipment, and keep the stirring process for 10 minutes to mix the raw materials evenly;

[0081] S2. Transfer the evenly mixed raw materials to a kneader for dry mixing and wet mixing. Control the temperature during the kneading process at 160 °C. After kneading, cool the obtained raw materials and transfer them to a molding machine;

[0082] S3. Put the semi-finished product obtained after molding into a dryer. The temperature during the drying process is 100 °C, and the drying time is 24 h;

[0083] S4. Put the dried semi-finished product into a vacuum atmosphere furnace for firing. Control the firing temperature at 1150 °C to obtain the finished graphite crucible;

[0084] S5. Immerse the finished graphite crucible in an inorganic material for densification treatment, and control the pressure during the immersion process at 0.35 MPa.

[0085] Control the forming temperature at 135 °C.

[0086] Example 7:

[0087] Based on Example 1, the crucible body comprises raw materials with the following mass fractions: 50% silicon carbide, 15% flake graphite, 30% coke, and 5% silicon powder.

[0088] The preparation of the crucible body includes the following steps:

[0089] S1. Put the raw materials of the above components into a crusher respectively to crush the raw materials. After crushing, the particle size of the raw materials remains at 6 mm. Then put the crushed raw materials into the stirring equipment, and keep the stirring process for 10 minutes to mix the raw materials evenly;

[0090] S2. Transfer the uniformly mixed raw materials to a kneader for dry mixing and wet mixing. Control the temperature during the kneading process at 160°C. After kneading, cool the obtained raw materials and transfer them to a molding machine.

[0091] S3. Place the semi-finished product obtained after molding into a dryer. The temperature during the drying process is 100°C, and the drying time is 24 hours.

[0092] S4. Place the dried semi-finished product into a vacuum atmosphere furnace for firing. Control the firing temperature at 1150°C to obtain the finished graphite crucible.

[0093] S5. Immerse the finished graphite crucible in an inorganic material for densification treatment. Control the pressure during the immersion process at 0.35 MPa.

[0094] Control the molding temperature at 135°C.

[0095] Example 8:

[0096] Based on Example 1, the crucible body comprises raw materials with the following mass fractions: 50% silicon carbide, 15% flake graphite, 30% coke, and 5% silicon powder.

[0097] The preparation of the crucible body includes the following steps:

[0098] S1. Put the raw materials of each component into a crusher respectively to crush the raw materials. After crushing, keep the particle size of the raw materials at 8 mm. Then put the crushed raw materials into the internal part of a stirring device and stir for 10 minutes to mix the raw materials uniformly.

[0099] S2. Transfer the uniformly mixed raw materials to a kneader for dry mixing and wet mixing. Control the temperature during the kneading process at 160°C. After kneading, cool the obtained raw materials and transfer them to a molding machine, and control the molding temperature at 135°C.

[0100] S3. Place the semi-finished product obtained after molding into a dryer. The temperature during the drying process is 100°C, and the drying time is 24 hours.

[0101] S4. Place the dried semi-finished product into a vacuum atmosphere furnace for firing. Control the firing temperature at 1150°C to obtain the finished graphite crucible.

[0102] S5. Immerse the finished graphite crucible in an inorganic material for densification treatment. Control the pressure during the immersion process at 0.35 MPa.

[0103] From Examples 5 - 8, the following table is obtained:

[0104]

[0105] In summary, in the present invention:

[0106] In the present invention, through a rotating positioning plate, teeth, a gear, a driving assembly, a crucible body, and a protective outer frame, while the driving assembly operates, the rotation of the gear is controlled. At this time, the gear controls the rotation of the rotating positioning plate and the crucible body through the teeth. The crucible body is at an eccentric position on the rotating positioning plate, realizing full and uniform contact between the crucible body and the heat source during the rotation process of the crucible body, ensuring uniform heating of the crucible body, and significantly improving the service performance and service life of the crucible body.

[0107] In the present invention, by providing a piston frame, a piston plate, a piston rod, a contact plate, and an elastic component, when the crucible body is lowered, it will directly contact the contact plate. Subsequently, the crucible body presses the contact plate and moves it into the placement groove. At the same time, the gas inside the piston frame is compressed, increasing the pressure of the air pressure on the contact plate, realizing that a certain pressure is applied to the crucible body by the contact plate after the crucible body is stably placed, ensuring the smooth and stable placement of the crucible body, and making the positioning effect and efficiency of the crucible body relatively ideal.

[0108] In the present invention, the raw material of the crucible body contains 50% silicon carbide and 15% flaky graphite. The content of silicon carbide is relatively high, the weight loss rate of the crucible body is reduced, and the antioxidant performance is increased. Silicon carbide has good antioxidant performance. Silicon carbide reacts with carbon monoxide to generate silicon oxide gas and solid carbon. The carbon is deposited on the surface of silicon carbide, and the overall volume shows an expansion, preventing oxygen from entering the interior, increasing the antioxidant property, and the particle size of the raw material during the processing process is maintained at 6 mm, making the heat resistance performance of the crucible body more ideal.

[0109] Finally, several points should be noted: First, in the description of the present application, it should be noted that unless otherwise specified and defined, the terms "installation", "connection", and "connection" should be understood in a broad sense. It can be a mechanical connection or an electrical connection, or it can be the communication inside two components. It can be directly connected. "Up", "down", "left", "right", etc. are only used to represent relative position relationships. When the absolute position of the described object changes, the relative position relationship may change;

[0110] Second: In the attached drawings of the disclosed embodiments of the present invention, only the structures related to the disclosed embodiments of the present invention are involved. Other structures can refer to the general design. Without conflict, the same embodiment and different embodiments of the present invention can be combined with each other;

[0111] Finally: The above are only the preferred embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A graphite crucible with a silicon carbide coating, comprising a rotary positioning plate (1) and a protective outer frame (2), characterized in that: The inner wall of the rotating positioning plate (1) is lapped with the outer surface of the crucible body (4). A protective coating (5) is provided on the inner wall of the crucible body (4). The outer surface of the crucible body (4) is lapped with the outer surfaces of five limiting components (8). The limiting components (8) are arranged on the inner wall of the placement groove (7). The placement groove (7) is opened on the inner wall of the rotating positioning plate (1). A number of teeth (9) are provided on the outer surface of the rotating positioning plate (1). The teeth (9) are engaged with a gear (10). The lower surface of the gear (10) is fixedly connected to the output shaft of the driving component (11). The lower surface of the driving component (11) is fixedly connected to the lower surface of the inner wall of the connection hole (12). The connection hole (12) is opened on the front surface of the protective outer frame (2); The limiting component (8) includes a piston frame (81). The outer surface of the piston frame (81) is fixedly connected to the inner wall of the placement groove (7). The inner wall of the piston frame (81) is slidably connected to the outer surface of a piston plate (82). The outer surface of the piston plate (82) is fixedly connected to one end of a piston rod (83). The other end of the piston rod (83) is fixedly connected to the outer surface of a contact plate (85). The contact plate (85) is lapped with the outer surface of the crucible body (4). An elastic component (84) is provided on the outer surface of the piston rod (83). The two ends of the elastic component (84) are respectively fixedly connected to the outer surface of the piston plate (82) and the inner wall of the piston frame (81); A cover plate (6) is provided on the upper surface of the crucible body (4). The front surface of the protective outer frame (2) is fixedly connected to the back surface of an extension frame (13). The position of the extension frame (13) corresponds to the position of the connection hole (12); A bearing (3) is provided on the outer surface of the rotating positioning plate (1). The bearing (3) is arranged on the inner wall of the protective outer frame (2). The protective coating (5) is a silicon carbide coating; The crucible body comprises raw materials with the following mass fractions: 20%-50% of silicon carbide, 15%-45% of flaky graphite, 30% of coke, and 5% of silicon powder.

2. The graphite crucible with a silicon carbide coating according to claim 1, wherein: The preparation of the crucible body comprises the following steps: S1. Put the raw materials of the above components into a crusher respectively to crush the raw materials. After crushing, the particle size of the raw materials is kept at 1-8 mm. Then put the crushed raw materials into the internal of a stirring device and stir for 10 min to mix the raw materials evenly; S2. Transfer the evenly mixed raw materials to a kneader for dry mixing and wet mixing. The temperature during the kneading process is controlled at 150°C - 175°C. After kneading, cool the obtained raw materials and transfer them to a molding machine; S3. Put the semi-finished product obtained after molding into a dryer. The temperature during the drying process is 100°C and the drying time is 24 h; S4. Put the dried semi-finished product into a vacuum atmosphere furnace for firing. The firing temperature is controlled at 1150°C to obtain a finished graphite crucible; S5. Immerse the finished graphite crucible with an inorganic material for densification treatment. The pressure during the immersion process is controlled at 0.35 MPa.

3. The graphite crucible with a silicon carbide coating according to claim 2, wherein: The molding temperature is controlled at 130°C - 140°C.

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