Silicon carbide raw material synthesis furnace

Abstract

This invention provides a silicon carbide raw material synthesis furnace, belonging to the field of silicon carbide synthesis technology. The silicon carbide raw material synthesis furnace includes a body and a crucible located inside the body. The body has a vertically arranged column inside, and a rotating shaft is coaxially arranged inside the column. The rotating shaft can rotate within the column. An end face gear is arranged on the rotating shaft, and a third gear meshes with the end face gear. A horizontal column is arranged on the third gear, perpendicular to the rotating shaft. A fixing member is arranged at the end of the horizontal column away from the rotating shaft, which is used to fix the crucible. The body is provided with a drive structure to drive the rotating shaft to rotate in both directions. Through the first transmission structure, the crucible can be repeatedly oscillated, thereby turning the raw material inside the crucible and making the raw material more evenly heated.

Description

Technical Field

[0001] This invention belongs to the field of silicon carbide synthesis technology, specifically relating to a silicon carbide raw material synthesis furnace. Background Technology

[0002] The silicon carbide vertical induction synthesis furnace mainly uses high-frequency induction heating. High-purity carbon powder and high-purity silicon powder, along with a certain amount of high-purity additives, are uniformly mixed in a molar ratio and placed in a high-purity graphite crucible 6. In a clean environment, high-purity argon, nitrogen, hydrogen, and other gases are introduced. The furnace gradually completes the processes of heating, holding, replacing argon, nitrogen, hydrogen, or other atmospheric gases, and cooling in a set manner, so that the carbon powder and silicon powder are synthesized into high-purity silicon carbide raw materials.

[0003] Chinese patent CN112516916A discloses an ultra-high vacuum silicon carbide raw material synthesis furnace system, including a furnace chamber. The furnace chamber is a cylindrical vertical double-layer water-cooled structure. A furnace cover is installed on the furnace chamber. The furnace cover is also a double-layer water-cooled structure. An infrared temperature measuring component is located at the top of the furnace cover. The furnace cover can be raised, lowered, and opened by an electric lift. The furnace chamber is connected to a molecular pump through a gate valve and a pump extraction bend pipe to form the main extraction pipeline of the system. The furnace chamber is also connected to a mechanical pump through an angle valve and a bellows to form the side extraction pipeline of the system. A sample support mechanism is fixed to the furnace chamber chassis. An induction heating component and a measuring component are fixed to the side flanges of the furnace chamber.

[0004] In the aforementioned technical solution, due to the poor thermal conductivity (porosity > 40%) of silicon carbide synthetic powder, a significant temperature gradient is formed when heat is transferred from the crucible wall to the center in a traditional graphite crucible. Experimental data shows that in crucibles with a diameter > 600 mm, the temperature in the central region is 200-300 °C lower than that in the edge region, resulting in insufficient reaction in the central part, leading to black core phenomenon (unreacted silicon carbide mixture) and hard agglomeration (locally overcooled areas), while the edge region suffers from silicon carbide graphitization due to overheating. Summary of the Invention

[0005] The purpose of this invention is to provide a silicon carbide raw material synthesis furnace, which aims to solve the problem of uneven temperature at the edge and center of the crucible in the existing ultra-high vacuum silicon carbide raw material synthesis furnace system, resulting in insufficient silicon carbide reaction.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a silicon carbide raw material synthesis furnace, comprising: a body and a crucible located inside the body, wherein a vertically arranged column is provided inside the body, a rotating shaft is coaxially arranged inside the column, the rotating shaft can rotate inside the column, an end face gear is provided on the rotating shaft, a third gear meshes on the end face gear, a horizontal column is provided on the third gear, the horizontal column is arranged perpendicular to the rotating shaft, a fixing member is provided at the end of the horizontal column away from the rotating shaft, the fixing member is used to fix the crucible, and a drive structure for driving the rotating shaft to rotate forward and backward is provided on the body.

[0007] A further technical solution of the present invention is that the fixing member includes a fixing ring fixed to one end of the horizontal column, and a rotating ring is rotatably arranged inside the fixing ring, and the crucible can be installed on the rotating ring.

[0008] A further technical solution of the present invention is that a support plate is provided on the column, the support plate is located below the horizontal column, a first ratchet is provided on the side of the support plate away from the column, and a second ratchet is provided on the rotating ring to mesh with the first ratchet, and the horizontal column can drive the rotating ring to move in a telescopic manner.

[0009] A further technical solution of the present invention is that the horizontal column includes a sleeve and a sliding column, a fixing ring is disposed at one end of the sliding column, a sliding cavity is disposed inside the sleeve, there is a gap between the inner wall of the sliding cavity and the sliding column, and the opening is slidably sealed with the sliding column, and a piston is slidably sealed inside the sliding cavity of the sliding column.

[0010] A further technical solution of the present invention is that the cross-sections of the piston and the sliding cavity are both polygons with adapted shapes.

[0011] A further technical solution of the present invention is that the driving structure includes a forward and reverse motor disposed at the bottom of the main body, the output end of the forward and reverse motor extends into the interior of the main body and is connected to a first gear, the first gear meshes with a second gear, and a locking pin is disposed on the second gear extending into the interior of the inner liner, the locking pin being able to connect with a rotating shaft.

[0012] A further technical solution of the present invention is that the body is provided with an inner liner, the outer side of the inner liner is provided with a heating element, the inner liner is detachably provided with a base, the upright is mounted on the base and the rotating shaft is provided with a slot adapted to the upright, when the upright is installed in the inner liner, the positioning of the base can make the upright snap into the slot.

[0013] A further technical solution of the present invention is that multiple horizontal columns are provided, all uniformly arranged in a vertical array on the column, and the number of support plates is adapted to the number of horizontal columns.

[0014] A further technical solution of the present invention is that the first ratchet teeth are arranged in a ring array with the transverse column as the axis.

[0015] A further technical solution of the present invention is that a sealing strip is provided inside the gap. The sealing strip is in the shape of a ring, with one end sealed and fixed at the connection between the piston and the slide, and the other end sealed and fixed at one end of the sleeve opening, for sealing the opening of the sleeve and the slide.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] 1. The first transmission structure enables the crucible to swing repeatedly, thereby turning the raw materials inside the crucible and making the raw materials heat more evenly.

[0018] 2. By setting a second transmission structure, the crucible can rotate while it is repeatedly oscillating, making the material turn over more evenly.

[0019] 3. The second transmission structure can also vibrate the crucible, causing it to shake and shake off all the raw materials adhering to the inner wall of the crucible, thus avoiding the problem of graphitization. Attached Figure Description

[0020] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0021] Figure 1 This is a schematic diagram of a specific embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram of an isometric sectional view of a specific embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of the installation structure of the crucible rack in a specific embodiment of the present invention;

[0024] Figure 4 This is an isometric sectional view of the crucible holder in a specific embodiment of the present invention;

[0025] Figure 5 This is a schematic diagram of the second transmission structure in a specific embodiment of the present invention;

[0026] Figure 6 This is a schematic diagram of the installation structure of the second gear and the first gear in a specific embodiment of the present invention;

[0027] Figure 7 This is a schematic diagram of the first transmission structure in a specific embodiment of the present invention;

[0028] Figure 8 for Figure 4 A magnified schematic diagram of the structure at point A in the middle.

[0029] In the diagram: 1. Body; 11. Outer shell; 12. Inner liner; 13. Reaction chamber; 14. Heating element; 2. Crucible rack; 21. Base; 22. Column; 23. Support plate; 24. Horizontal column; 241. Sleeve; 242. Sliding column; 243. Sliding cavity; 244. Piston; 245. Gap; 25. Fixing component; 251. Fixing ring; 252. Rotating ring; 3. Drive structure; 31. Forward and reverse motor; 32. First gear; 33. Second gear; 34. Locking pin; 4. First transmission structure; 41. Rotating shaft; 42. Slot; 43. End face gear; 44. Third gear; 5. Second transmission structure; 51. First ratchet; 52. Second ratchet; 6. Crucible; 7. Sealing strip. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Please see Figures 1-8 The present invention provides the following technical solution: a silicon carbide raw material synthesis furnace, including a body 1, a crucible rack 2, a drive structure 3, a first transmission structure 4, and a second transmission structure 5.

[0032] The crucible holder 2 is located inside the main body 1, and the drive structure 3 is located on the main body 1. It works in conjunction with the first transmission structure 4 to drive the crucible 6 to rotate in both directions, thereby allowing the raw materials inside the crucible 6 to be turned in one direction. The second transmission structure 5 works in conjunction with the first transmission structure 4 to enable the crucible 6 to rotate on its own axis. This allows the crucible 6 to rotate on its own axis while being turned in one direction, thereby improving the turning effect of the raw materials and making the raw materials inside the crucible 6 heated more evenly and fully. In addition, the second transmission structure 5 can cause the crucible 6 to vibrate, which can also shake off some of the raw materials adhering to the inner wall of the crucible 6 when turning the raw materials, thereby improving the reaction effect of the raw materials.

[0033] Please see Figure 1 and Figure 2 The main body 1 includes an outer shell 11, and an inner liner 12 is provided inside the outer shell 11. The inner liner 12 can divide the interior of the outer shell 11 into two semi-circular reaction chambers 13. There are two crucible racks 2, which are respectively arranged inside the two reaction chambers 13. A heating element 14 is provided between the outer shell 11 and the inner liner 12 and between the two inner liners 12 for heating the raw materials. The heating element 14 is an electric heating element.

[0034] Please see Figures 3-5The crucible rack 2 includes a base 21, the shape of which corresponds to the cross-sectional shape of the inner liner 12, so that the base 21 can be placed stably at the bottom of the inner liner 12 and is also easy to remove from the inner liner 12. An upwardly extending column 22 is provided on the base 21, and multiple horizontal columns 24 are mirrored on the left and right sides of the column 22. The multiple horizontal columns 24 are evenly arranged in a vertical array. A fixing member 25 is provided at the end of the horizontal column 24 away from the column 22. The fixing member 25 is used to fix the crucible 6.

[0035] By setting up the crucible rack 2, multiple crucibles 6 can be placed inside the inner liner 12, so that multiple crucibles 6 can be heated simultaneously. Furthermore, the horizontal columns 24 are arranged longitudinally, so that the distance between multiple crucibles 6 and the heating element 14 is equal, thereby enabling uniform heating of multiple crucibles 6 and avoiding the problem of uneven heating among multiple crucibles 6.

[0036] Please see Figure 2 and Figure 6 The drive structure 3 includes a forward and reverse motor 31 located at the bottom of the main body 1. The output end of the forward and reverse motor 31 extends into the interior of the main body 1 and is connected to a first gear 32. A second gear 33 meshes with both sides of the first gear 32. A locking pin 34 extending into the interior of the inner liner 12 is provided on the second gear 33. The locking pin 34 can be connected to the first transmission structure 4, thereby driving the crucible 6 to swing left and right.

[0037] When in use, the forward and reverse motor 31 is started, which drives the first gear 32 to rotate in both directions. At the same time, the second gear 33 rotates in both directions, and the second gear 33 drives the locking pin 34 to rotate in both directions. Thus, the crucible 6 can be driven to swing repeatedly through the first transmission structure 4.

[0038] Please see Figure 4 and Figure 7 The first transmission structure 4 includes a rotating shaft 41 that rotates inside the column 22. A slot 42 is provided at the bottom of the rotating shaft 41. A locking pin 34 can be inserted into the slot 42. The cross-sections of the locking pin 34 and the slot 42 are polygons that can be adapted to each other, so that the rotating shaft 41 can be driven to rotate when the locking pin 34 rotates. An end face gear 43 is provided on the rotating shaft 41. The number of end face gears 43 is adapted to the crucible 6. A third gear 44 meshes with the end face gear 43. A cavity is provided inside the column 22 to allow the end face gear 43 and the third gear 44 to mesh. The third gear 44 is connected to the horizontal column 24, so that the third gear 44 can drive the horizontal column 24 to rotate when it rotates.

[0039] When the locking post 34 rotates, the locking groove 42 drives the rotating shaft 41 to rotate, which in turn drives the end face gear 43 to rotate. When the end face gear 43 rotates, it drives the third gear 44 to rotate, which in turn drives the horizontal column 24 to rotate. Since a fixing part 25 is provided at one end of the horizontal column 24, and the crucible 6 is installed on the fixing part 25, when the horizontal column 24 rotates, it can drive the crucible 6 to swing left and right, thereby turning over the raw materials in the crucible 6 and improving the reaction effect.

[0040] Please see Figure 5 and Figure 7 The fixing member 25 includes a fixing ring 251 fixed to one end of the horizontal column 24. The fixing ring 251 is circular. A rotating ring 252 is rotatably arranged inside the fixing ring 251. The fixing ring 251 and the rotating ring 252 are coaxially arranged, so that the fixing ring 251 and the rotating ring 252 can rotate relative to each other. The middle part of the rotating ring 252 can be used to place the crucible 6. The outer diameter of the crucible 6 is slightly smaller than the inner diameter of the rotating ring 252. A flange is provided at the edge of the opening of the crucible 6. The outer diameter of the flange is larger than the inner diameter of the rotating ring 252. The pot body of the crucible 6 passes through the interior of the rotating ring 252, so that the opening of the crucible 6 can rest on the rotating ring 252, thereby realizing the installation of the crucible 6.

[0041] Please see Figure 5 The second transmission structure 5 can be used to drive the rotating ring 252 to rotate. The second transmission structure 5 includes a support plate 23 set on the column 22. The number of support plates 23 corresponds to the number of horizontal columns 24, and each support plate 23 is located below the corresponding horizontal column 24. A first ratchet 51 is provided on the side of the support plate 23 away from the column 22. The rotating ring 252 extends downward and is provided with a second ratchet 52 around its periphery. The first ratchet 51 and the second ratchet 52 mesh with each other. When the horizontal column 24 drives the rotating ring 252 to swing, it simultaneously drives the second ratchet 52 to swing around the horizontal column 24 as the axis. The first ratchet 51 is arranged in a ring array around the horizontal column 24 as the axis, so that the first ratchet 51 and the second ratchet 52 always remain meshed when the rotating ring 252 swings.

[0042] Please see Figure 7 and Figure 8 The horizontal column 24 is composed of a sleeve 241 and a sliding column 242. The fixing ring 251 is connected to one end of the sliding column 242. A sliding cavity 243 is provided inside the sleeve 241. There is a gap 245 between the middle part of the sliding cavity 243 and the sliding column 242. The open end of the sliding cavity 243 is in contact with the outer surface of the sliding column 242 and slides relative to it. A piston 244 is provided inside the sliding cavity 243. The sliding cavity 243 is polygonal, and the piston 244 is polygonal to match the sliding cavity 243.

[0043] Since both piston 244 and sliding cavity 243 are polygonal and slide in a sealed manner, when sleeve 241 rotates, piston 244 drives sliding column 242 to rotate. When sliding column 242 drives fixed ring 251 and rotating ring 252 to rotate, the first ratchet 51 and the second ratchet 52 engage in mutual movement. When sliding column 242 rotates clockwise, the horizontal surfaces of the first ratchet 51 and the second ratchet 52 contact each other, causing the first ratchet 51 to push the second ratchet 52 to move, which in turn causes the second ratchet 52 to drive the rotating ring 252 to rotate on the fixed ring 251. Simultaneously, this causes the crucible 6 to rotate. When sliding column 242 rotates counterclockwise, the inclined surfaces of the first ratchet 51 and the second ratchet 52 contact each other. Due to the friction between the rotating ring 252 and the fixed ring 251, the rotation... The inclined plane allows the rotating ring 252 to move away from the support plate 23, causing the piston 244 to slide inside the sliding cavity 243 and compress the gas inside the gap 245. When the first ratchet 51 passes the second ratchet 52, the compressed gas pushes the piston 244 to reset, causing the first ratchet 51 to pass the second ratchet 52 and re-engage. This prevents the rotating ring 252 from rotating relative to the fixed ring 251 when the sliding column 242 reverses. Therefore, when the sliding column 242 repeatedly reverses, the rotating ring 252 will still rotate in the same direction. This allows the crucible 6 to rotate in a specified direction while repeatedly oscillating, thus achieving the purpose of multi-directional tumbling of the raw materials inside the crucible 6 and making the raw materials more evenly heated.

[0044] When the slide column 242 reverses, the gas inside the gap 245 is compressed. When the first ratchet 51 disengages from the inclined surface on the second ratchet 52, the gas pressure instantly pushes the piston 244 back to its original position. The instantaneous return of the piston 244 impacts the bottom of the slide cavity 243, causing the slide column 242 to vibrate. The slide column 242 can transmit the vibration to the crucible 6 through the rotating ring 252 and the fixed ring 251, shaking off the raw material adhering to the crucible 6 and preventing the raw material adhering to the crucible 6 from graphitizing due to prolonged high temperature.

[0045] Since the sleeve 241 and the sliding column 242 are slidably connected, prolonged friction will cause wear on both the sliding column 242 and the sleeve 241, leading to gas leakage inside the gap 245. Therefore, a sealing strip 7 is provided inside the gap 245. The sealing strip 7 is annular, with one end sealed and fixed at the connection between the piston 244 and the sliding column 242, and the other end sealed and fixed at one end of the opening of the sleeve 241, to achieve a seal between the opening of the sleeve 241 and the sliding column 242, preventing gas leakage from between the sleeve 241 and the sliding column 242. Alternatively, the piston 244, the sealing strip 7, and the sleeve 241 constitute a sealed cavity. When the piston 244 slides inside the sleeve 241, it can compress this cavity, thereby resetting the second ratchet 52.

Claims

1. A silicon carbide raw material synthesis furnace, including: The body (1) and the crucible (6) located inside the body (1) are characterized in that the body (1) has a vertically arranged column (22) inside, a rotating shaft (41) is coaxially arranged inside the column (22), the rotating shaft (41) can rotate inside the column (22), an end face gear (43) is arranged on the rotating shaft (41), a third gear (44) meshes on the end face gear (43), a horizontal column (24) is arranged on the third gear (44), the horizontal column (24) is arranged perpendicular to the rotating shaft (41), a fixing member (25) is arranged at the end of the horizontal column (24) away from the rotating shaft (41), the fixing member (25) is used to fix the crucible (6), and the body (1) is provided with a drive structure (3) for driving the rotating shaft (41) to rotate in both directions. The fixing member (25) includes a fixing ring (251) fixed to one end of the cross column (24), and a rotating ring (252) is rotatably arranged inside the fixing ring (251), and the crucible (6) can be installed on the rotating ring (252); The column (22) is provided with a support plate (23), which is located below the horizontal column (24). The side of the support plate (23) away from the column (22) is provided with a first ratchet (51), and the rotating ring (252) is provided with a second ratchet (52) that meshes with the first ratchet (51). The horizontal column (24) can drive the rotating ring (252) to extend and retract. The horizontal column (24) includes a sleeve (241) and a sliding column (242). A fixing ring (251) is disposed at one end of the sliding column (242). A sliding cavity (243) is provided inside the sleeve (241). There is a gap (245) between the inner wall of the sliding cavity (243) and the sliding column (242), and the opening is slidably sealed with the sliding column (242). A piston (244) is slidably sealed inside the sliding cavity (243) of the sliding column (242). The drive structure (3) includes a forward and reverse motor (31) located at the bottom of the body (1). The output end of the forward and reverse motor (31) extends into the interior of the body (1) and is connected to a first gear (32). The first gear (32) meshes with a second gear (33). A locking pin (34) extending into the interior of the inner liner (12) is provided on the second gear (33). The locking pin (34) can be connected to the rotating shaft (41). The main body (1) is provided with an inner liner (12), and a heating element (14) is provided on the outside of the inner liner (12). The inner liner (12) is detachably provided with a base (21). The column (22) is installed on the base (21). The pivot (41) is provided with a slot (42) that is compatible with the locking column (34). When the column (22) is installed in the inner liner (12), the locking column (34) can be locked into the slot (42) by the positioning of the base (21).

2. The silicon carbide raw material synthesis furnace according to claim 1, characterized in that: The cross-sections of the piston (244) and the sliding cavity (243) are both polygonal shapes that are adapted to each other.

3. The silicon carbide raw material synthesis furnace according to claim 1, characterized in that: Multiple horizontal columns (24) are provided, all arranged in a uniform array along the vertical direction on the column (22), and the number of support plates (23) is matched with the number of horizontal columns (24).

4. The silicon carbide raw material synthesis furnace according to claim 1, characterized in that: The first ratchet (51) is arranged in a ring array with the transverse column (24) as the axis.

5. The silicon carbide raw material synthesis furnace according to claim 1, characterized in that: The gap (245) is provided with a sealing strip (7). The sealing strip (7) is in the shape of a ring. One end of the sealing strip (7) is fixed at the connection between the piston (244) and the slide (242), and the other end is fixed at one end of the opening of the sleeve (241) to seal the opening of the sleeve (241) and the slide (242).

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