A vacuum sintering furnace and firing process for silicon carbide ceramic production

Abstract

The present invention relates to the technical field of sintering equipment, and in particular to a vacuum sintering furnace and a firing process for producing silicon carbide ceramics. The vacuum sintering furnace for producing silicon carbide ceramics comprises a furnace body, a heating source, a support ring and a driving member. The support ring is located between a first heating sleeve and a second heating sleeve. After the support ring moves into a heating chamber, a sealing cover is used to seal a feeding port, and an exhaust pump is started to extract gas in the heating chamber, so that the heating chamber is in a relatively vacuum environment, reducing the influence of oxygen in the air on a silicon carbide ceramic embryo. When the first heating sleeve and the second heating sleeve are started, the driving member drives the support to rotate around its own axis. During the rotation, it is ensured that the silicon carbide ceramic is evenly heated in a stable state, reducing the probability of deformation of the silicon carbide ceramic.

Description

Technical Field

[0001] The invention relates to the technical field of sintering equipment, and in particular to a vacuum sintering furnace and a firing process for producing silicon carbide ceramics. Background Art

[0002] Under existing technical conditions, when using a vacuum sintering furnace to sinter silicon carbide ceramics, the air in the furnace must be evacuated to effectively prevent the silicon carbide ceramics from being oxidized during the high-temperature sintering process. Once the silicon carbide ceramics are oxidized, the performance and quality of the ceramics will be damaged. However, although this vacuum environment ensures oxidation resistance, the heat transfer method in the sintering furnace becomes extremely limited, and the heating of the ceramics mainly depends on the thermal radiation and heat transfer of the graphite rods. As a heat source, when the heat of the graphite rod diffuses to the surrounding space, it is difficult to ensure that the heat is evenly covered to every position of the ceramic body due to factors such as the radiation angle, distance, and the shape and placement of the ceramics themselves. This easily leads to uneven heating of the silicon carbide ceramics during the sintering process, and there are obvious temperature differences in different parts. At high temperatures, this uneven heating will directly cause an imbalance in the internal stress of the ceramics, which will lead to distortion during the heating process. Summary of the invention

[0003] The invention provides a vacuum sintering furnace and a firing process for producing silicon carbide ceramics, so as to solve the problem that the existing vacuum sintering furnace easily affects the quality of finished products when sintering silicon carbide ceramics.

[0004] A vacuum sintering furnace and firing process for producing silicon carbide ceramics of the present invention adopt the following technical scheme:

[0005] A vacuum sintering furnace for producing silicon carbide ceramics comprises a furnace body, a heating source, a supporting ring and a driving member.

[0006] The furnace body has a heating chamber inside, and is provided with a feeding port connecting the heating chamber and the external environment on the furnace body, and is provided with a sealing cover on the furnace body, and the sealing cover is used to block the feeding port; the furnace body is provided with an exhaust port connecting the heating chamber and the external environment, and is connected to an exhaust pump at the exhaust port, and the exhaust pump is used to extract the gas in the heating chamber; the heating source includes a first heating sleeve and a second heating sleeve, and the first heating sleeve and the second heating sleeve are coaxially arranged in the heating chamber; the support ring is arranged between the first heating sleeve and the second heating sleeve, and a plurality of placement tables are provided on the support ring, and silicon carbide ceramics can be placed on the placement tables; the driving member is used to drive the support to rotate at a uniform speed around its own axis.

[0007] Furthermore, a support platform is fixedly provided in the heating chamber, and a support plate is slidably provided on the support platform; the driving component includes an air inlet pipe, a driving blade and a driving roller, the air inlet pipe runs through the furnace body, and an inert gas bottle is connected to one end of the air inlet pipe outside the furnace body; the driving blade is rotatably connected to the support plate, and the gas entering the heating chamber through the air inlet pipe can act on the driving blade; the driving roller is coaxially connected to the driving blade, and the driving roller abuts against the support ring.

[0008] Furthermore, the driving blades include a first blade and a second blade, and there is an overlapping area between the first blade and the second blade. The more silicon carbide ceramics are placed on the placement table, the smaller the overlapping area between the first blade and the second blade.

[0009] Furthermore, a support block is fixedly arranged on the support plate, a sliding frame is connected to the support block, and the sliding frame is slidably connected to the support block up and down; a rotating shaft is rotatably arranged on the sliding frame, and the rotating shaft is coaxially fixedly connected to the driving roller; the rotating shaft is coaxially fixedly connected to the first fan blade; an adjusting screw is coaxially arranged on the rotating shaft, the second fan blade is coaxially slidingly connected to the first fan blade, the second fan blade is spirally connected to the adjusting screw, an adjusting gear sleeve is coaxially fixedly arranged on the adjusting screw, an adjusting tooth plate is arranged on the support block, the adjusting tooth plate has a first state of engaging the adjusting gear sleeve and a second state of disengaging the adjusting gear sleeve, and when the silicon carbide ceramic is placed on the placing table, the adjusting tooth plate is in the first state, and the sliding frame slides on the support block.

[0010] Furthermore, a locking member is provided on the support block, and the locking member is used to lock the position of the sliding frame on the support block.

[0011] Furthermore, the locking member includes a locking screw and a locking bolt; a vertical sliding groove is arranged on the support block, the locking screw is fixedly connected to the sliding frame, the locking screw is slidingly arranged along the sliding groove, the locking bolt is spirally connected to the locking screw, and the locking bolt can abut against the side wall of the support block.

[0012] Furthermore, a return spring is arranged between the sliding frame and the supporting block, and the return spring is arranged vertically.

[0013] Furthermore, a plurality of support rods are arranged on the support ring, the plurality of support rods are evenly distributed along the circumferential direction of the support ring, and the support rods extend along the axial direction of the support ring; a connecting rod is fixedly arranged on each of the placement platforms, and one end of the connecting rod is rotatably connected to the support rod.

[0014] Furthermore, a plurality of the support rings are provided, the plurality of the support rings are coaxially arranged at intervals, and the plurality of the support rings are fixedly connected to the plurality of the support rods at the same time.

[0015] A vacuum sintering process for producing silicon carbide ceramics, using a vacuum sintering furnace for producing silicon carbide ceramics, comprises the following steps:

[0016] S1, unblocking the feeding port by the blocking cover;

[0017] S2, moving the support ring to the outside of the heating chamber, and placing the silicon carbide ceramic on the placement table;

[0018] S3, moving the support ring into the heating chamber, and sealing the feeding port with the sealing cover;

[0019] S4, starting the vacuum pump and the heating source;

[0020] S5, driving the support to rotate around its own axis.

[0021] The beneficial effects of the present invention are as follows: a vacuum sintering furnace and firing process for producing silicon carbide ceramics of the present invention, wherein the vacuum sintering furnace for producing silicon carbide ceramics comprises a furnace body, a heating source, a support ring and a driving member. When sintering silicon carbide ceramics, firstly, the sealing cover is unblocked from the feed port, the support ring in the heating chamber is moved to the outside of the heating chamber, the silicon carbide ceramics to be sintered are placed on a placement table, and then the support ring is moved into the heating chamber. By setting the positions of the first heating sleeve and the second heating sleeve, the support ring is located between the first heating sleeve and the second heating sleeve. After the support ring is moved into the heating chamber, the sealing cover is used to seal the feed port, and the vacuum pump is started to extract the gas in the heating chamber, so that the heating chamber is in a relatively vacuum environment, reducing the influence of oxygen in the air on the silicon carbide ceramic embryo. When the first heating sleeve and the second heating sleeve are started, the driving member drives the support to rotate around its own axis. During the rotation process, it is ensured that the silicon carbide ceramics are evenly heated in a stable state, and the probability of deformation of the silicon carbide ceramics is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0023] Figure 1 A schematic diagram of the structure of a vacuum sintering furnace for producing silicon carbide ceramics provided in an embodiment of the present invention;

[0024] Figure 2 A schematic diagram of the structure of a vacuum sintering furnace for producing silicon carbide ceramics provided in an embodiment of the present invention after sectioning;

[0025] Figure 3 A schematic diagram of the structure of a vacuum sintering furnace for producing silicon carbide ceramics provided in an embodiment of the present invention with the sealing cover hidden;

[0026] Figure 4 A cross-sectional view of a vacuum sintering furnace for producing silicon carbide ceramics provided in an embodiment of the present invention;

[0027] Figure 5 A schematic diagram of the structure of a support ring, a support rod and a support table in a vacuum sintering furnace for producing silicon carbide ceramics provided in an embodiment of the present invention;

[0028] Figure 6 for Figure 5 A partial enlarged view of the middle A;

[0029] Figure 7 A front view of a support ring, a support rod and a support table in a vacuum sintering furnace for producing silicon carbide ceramics provided by an embodiment of the present invention;

[0030] Figure 8 for Figure 7 Cross-sectional view in the BB direction;

[0031] Fig. 9 for Figure 8 A partial enlarged view of point C in the middle.

[0032] In the figure: 110, furnace body; 111, heating chamber; 120, sealing cover; 130, exhaust port; 140, first heating sleeve; 150, second heating sleeve; 160, support ring; 210, support table; 220, air inlet pipe; 230, first fan blade; 231, first blade sleeve; 232, first blade; 240, second fan blade; 241, second blade sleeve; 242, second blade; 250, support block; 260, sliding frame; 270, rotating shaft; 280, driving roller; 290, adjusting screw; 310, adjusting tooth plate; 320, adjusting tooth sleeve; 330, reset spring; 340, support rod; 350, connecting rod; 360, placing table; 370, insulation sleeve. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] The serial numbers assigned to the components herein, such as "first", "second", etc., are only used to distinguish the objects described and do not have any order or technical meaning. The "connection" and "coupling" mentioned in this application, unless otherwise specified, include direct and indirect connections (couplings). In the description of the present invention, it should be understood that the orientation or position relationship indicated by the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc. are based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0035] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0036] like Figures 1 to 9 As shown, an embodiment of the present invention provides a vacuum sintering furnace for producing silicon carbide ceramics, which includes a furnace body 110, a heating source, a support ring 160 and a driving member.

[0037] The furnace body 110 is hollow inside, and the hollow chamber inside the furnace body 110 is a heating chamber 111; the profile of the heating chamber 111 is slightly cylindrical, and the furnace body 110 is placed horizontally on the ground so that the axis of the heating chamber 111 is in a horizontal state. A feeding port connecting the heating chamber 111 and the external environment is provided at the end of the axis of the furnace body 110, and a sealing cover 120 is provided on the furnace body 110. The sealing cover 120 is used to seal the feeding port. In the initial state, the sealing cover 120 is in a state of sealing the feeding port. When it is necessary to feed silicon carbide ceramics into the heating chamber 111 through the feeding port, the staff can unblock the feeding port by the sealing cover 120. Specifically, the sealing plate is hinged to the outer wall of the furnace body 110, and a plurality of sealing bolts are provided on the sealing cover 120. The plurality of sealing bolts are evenly distributed around the circumferential direction of the sealing cover 120. A plurality of spiral holes are provided at the end of the furnace body 110, and each sealing bolt can pass through a bolt hole. The sealing cover 120 is used to seal the feeding port by using a plurality of sealing bolts to ensure that the sealing cover 120 can completely seal the feeding port. The furnace body 110 is provided with an exhaust port 130 connecting the heating chamber 111 and the external environment. The exhaust port 130 is connected to an exhaust pump, which is used to extract the gas in the heating chamber 111. In this embodiment, the exhaust pump is a vacuum pump, which can extract the heating chamber 111 into a relatively vacuum environment.

[0038] The heating source includes a first heating sleeve 140 and a second heating sleeve 150. The first heating sleeve 140 and the second heating sleeve 150 are coaxially arranged in the heating chamber 111. The diameter of the first heating sleeve 140 is greater than the diameter of the second heating sleeve 150. The first heating sleeve 140 and the second heating sleeve 150 are coaxially arranged at intervals. The first heating sleeve 140 and the second heating sleeve 150 can both generate heat, and the heat generation of the first heating sleeve 140 and the second heating sleeve 150 is the same. Specifically, one end of the first heating sleeve 140 and the second heating sleeve 150 are both connected to the positive pole of the power supply, and the other end of the first heating sleeve 140 and the second heating sleeve 150 are both connected to the negative pole of the power supply. The material of the first heating sleeve 140 and the second heating sleeve 150 is a carbon core material. After the first heating sleeve 140 and the second heating sleeve 150 are powered on, the first heating sleeve 140 and the second heating sleeve 150 start to generate heat at the same time. Further, the first heating sleeve 140 and the second heating sleeve 150 are both annular structures surrounded by multiple carbon rods.

[0039] The diameter of the support ring 160 is greater than the diameter of the second heating sleeve 150, and the diameter of the support ring 160 is smaller than the diameter of the first heating sleeve 140. The support ring 160 can be placed between the first heating sleeve 140 and the second heating sleeve 150. A plurality of placement tables 360 are provided on the support ring 160, and each placement table 360 ​​can place a silicon carbide ceramic. The support ring 160 can rotate between the first heating sleeve 140 and the second heating sleeve 150. When the support ring 160 rotates, the silicon carbide ceramic placed on the placement table 360 ​​will not separate from the placement table 360, so that the silicon carbide ceramic can be evenly heated by the first heating sleeve 140 and the second heating sleeve 150.

[0040] The driving member is used to drive the support ring 160 to rotate at a constant speed around its own axis. Specifically, when the number of silicon carbide ceramics placed on the placement table 360 ​​changes, the resistance of the support ring 160 during rotation changes. At this time, the driving member can maintain the rotation speed of the support ring 160 constant, ensuring that the silicon carbide ceramics on the placement table 360 ​​are in a stable state. At the same time, it ensures that the silicon carbide ceramics on the placement table 360 ​​can be evenly heated.

[0041] A vacuum sintering furnace for producing silicon carbide ceramics of the present invention, when sintering silicon carbide ceramics, firstly, the blocking cover 120 is unblocked from the feeding port, the support ring 160 in the heating chamber 111 is moved to the outside of the heating chamber 111, the silicon carbide ceramics to be sintered are placed on the placement table 360, and then the support ring 160 is moved into the heating chamber 111, and the positions of the first heating sleeve 140 and the second heating sleeve 150 are set so that the support ring 160 is between the first heating sleeve 140 and the second heating sleeve 150. After the support ring 160 moves into the heating chamber 111, the sealing cover 120 is used to seal the feed port, and the vacuum pump is started to extract the gas in the heating chamber 111, so that the heating chamber 111 is in a relatively vacuum environment, reducing the influence of oxygen in the air on the silicon carbide ceramic blank. When the first heating sleeve 140 and the second heating sleeve 150 are started, the driving member drives the support ring 160 to rotate around its own axis. During the rotation process, it is ensured that the silicon carbide ceramic is evenly heated in a stable state, reducing the probability of deformation of the silicon carbide ceramic.

[0042] In one embodiment, a support platform 210 is fixedly disposed in the heating chamber 111, the support platform 210 is disposed horizontally, the support platform 210 extends along the axial direction of the heating chamber 111, the support platform 210 is fixedly connected to the first heating sleeve 140, the support platform 210 is disposed at the lower side of the heating chamber 111, and the support platform 210 is used to support the support ring 160. Specifically, a guide rail along the length direction of the support platform 210 is disposed on the upper end surface, a support plate is slidably disposed on the upper end surface of the support platform 210, the support plate is slidably disposed along the guide rail, and the support plate can be detached from the guide rail, so that the support plate can be detached from the heating chamber 111. The driving member includes an air inlet pipe 220, a driving blade and a driving roller 280. The air inlet pipe 220 runs through the furnace body 110. One end of the air inlet pipe 220 outside the furnace body 110 is connected to an inert gas bottle. The inert gas bottle can be any one or more of helium, neon, argon, krypton, xenon, and radon. The inert gas stored in the inert gas bottle can be transported to the inside of the heating chamber 111 through the air inlet pipe 220. The driving blade is rotatably connected to the support plate, and the axial direction of the driving blade is parallel to the extension direction of the guide rail. The gas entering the heating chamber 111 through the air inlet pipe 220 can act on the driving blade, so that the driving blade rotates on the support plate. The driving roller 280 is coaxially connected to the driving blade, and the driving roller 280 is rotatably connected to the support plate. The driving roller 280 abuts against the support ring 160. When the driving roller 280 rotates, the support ring 160 rotates synchronously in the heating chamber 111.

[0043] In one embodiment, the driving blade includes a first blade 230 and a second blade 240, the first blade 230 and the second blade 240 are coaxially arranged, and there is an overlapping area between the first blade 230 and the second blade 240. In the initial state, the silicon carbide ceramic is not placed on the placement table 360, and the overlapping area between the first blade 230 and the second blade 240 is in the maximum state, then the area of ​​the complete driving blade composed of the first blade 230 and the second blade 240 is in the minimum state, and the air inlet pipe 220 enters the heating chamber 111. The gas blowing drives the fan blades to rotate at a first speed. As the number of silicon carbide ceramics placed on the placement table 360 ​​gradually increases, the resistance to the rotation of the rotating ring gradually increases, the overlapping area between the first fan blade 230 and the second fan blade 240 gradually decreases, and the area of ​​the complete driving fan blade formed by the first fan blade 230 and the second fan blade 240 gradually increases, then the wind receiving area of ​​the driving fan blade increases, and the gas blowing driving fan blade entering the heating chamber 111 at the air inlet pipe 220 still rotates at the first speed, thereby ensuring that the rotation speed of the support ring 160 remains constant.

[0044] In one embodiment, a support block 250 is fixedly provided on the support plate, the support block 250 is provided on the upper end surface of the support plate, a sliding frame 260 is connected to the support block 250, the sliding frame 260 is connected to the support block 250 for sliding up and down movement, a rotating shaft 270 is rotatably provided on the sliding frame 260, the extension direction of the rotating shaft 270 is parallel to the extension direction of the support platform 210, and the rotating shaft 270 is coaxially fixedly connected to the driving roller 280. In this embodiment, the first fan blade 230 includes a first blade sleeve 231 and a first blade 232, the first blade sleeve 231 is a circular sleeve, the first blade 232 is a straight plate, a plurality of first blades 232 are provided, the plurality of first blades 232 are evenly distributed around the circumferential direction of the first blade sleeve 231, and the first blade 232 is arranged along the radial direction of the first blade sleeve 231; the second fan blade 240 includes a second blade sleeve 241 and a second blade 242, the second blade sleeve 241 is a circular sleeve, the outer diameter of the second blade sleeve 241 is equal to the inner diameter of the first blade sleeve 231, the second blade 242 is a straight plate, a plurality of second blades 242 are provided, the plurality of second blades 242 are evenly distributed around the circumferential direction of the second blade sleeve 241, and the second blade 242 is arranged along the radial direction of the second blade sleeve 241. The rotating shaft 270 is coaxially fixedly connected with the first blade sleeve 231. The first blade sleeve 231 is provided with a plurality of limiting grooves, each of which penetrates the side wall of the first blade sleeve 231. The extension direction of each limiting groove is the axis direction of the first blade sleeve 231. When the second blade sleeve 241 is inserted into the first blade sleeve 231, the second blade 242 is in the limiting groove. When the first fan blade 230 rotates, the second fan blade 240 rotates synchronously with the first fan blade 230. The rotating shaft 270 is coaxially provided with an adjusting screw 290. The adjusting screw 290 is sleeved on the outer side of the rotating shaft 270. The adjusting screw 290 can rotate on the rotating shaft 270. The inner side wall of the second blade sleeve 241 is provided with a thread groove. The second blade sleeve 241 is threadedly connected with the adjusting screw 290. The adjusting gear sleeve 320 is coaxially fixedly provided on the adjusting screw 290. When the adjusting gear sleeve 320 rotates, it can drive the adjusting screw 290 to rotate synchronously. An adjusting tooth plate 310 is provided on the support block 250, and the adjusting tooth plate 310 has a first state of engaging with the adjusting tooth sleeve 320 and a second state of disengaging from the adjusting tooth sleeve 320. When the silicon carbide ceramic is placed on the placement table 360, the squeezing force of the support ring 160 on the driving roller 280 gradually increases. At this time, the adjusting tooth plate 310 is in the first state, and the support ring 160 squeezes the sliding frame 260 through the driving roller 280 to slide on the support block 250, so that the adjusting tooth plate 310 and the adjusting tooth sleeve 320 produce relative movement, so that the adjusting tooth sleeve 320 rotates. When the adjusting tooth sleeve 320 rotates, it drives the adjusting screw 290 to rotate, thereby driving the first blade sleeve 231 and the second blade sleeve 241 to move relative to each other, thereby changing the overlapping area between the first blade 232 and the second blade 242.

[0045] In one of the embodiments, a locking member is provided on the support block 250, and the locking member is used to lock the position of the sliding frame 260 on the support block 250. Specifically, in order to avoid shaking when the support ring 160 rotates, after all silicon carbide ceramics to be sintered are placed on the placement table 360, the locking member is used to lock the position of the sliding frame 260 on the support block 250, thereby stabilizing the axial position of the support ring 160, thereby improving the stability of the support ring 160 when rotating.

[0046] In one embodiment, the locking member includes a locking screw and a locking bolt; a vertical slide groove is provided on the support block 250, the locking screw is horizontally provided, the extension direction of the locking screw is perpendicular to the extension direction of the rotating shaft 270 of the guide rail, the locking screw is fixedly connected to the sliding frame 260, the locking screw is slidably arranged up and down along the slide groove, the locking bolt is threadedly connected to the locking screw, and in the process of placing the silicon carbide ceramics to be sintered on the placement table 360, the locking bolt is in a state of not abutting the side wall of the support block 250, and the locking screw and the locking bolt are in a state of not hindering the sliding frame 260 from sliding on the support block 250. After all the silicon carbide ceramics to be sintered are placed on the placement table 360, the locking bolt is rotated at this time, and the locking bolt gradually abuts against the side wall of the support block 250, thereby limiting the sliding frame 260 from sliding on the support block 250.

[0047] In one of the embodiments, a return spring 330 is arranged between the sliding frame 260 and the support block 250. The return spring 330 is arranged vertically, and the upper end of the return spring 330 is fixedly connected to the sliding frame 260, and the lower end of the return spring 330 is fixedly connected to the support block 250. When the silicon carbide ceramic is not placed on the placement table 360, the length of the return spring 330 is at its longest state. As the silicon carbide ceramic is gradually placed on the placement table 360, the length of the return spring 330 gradually decreases. After the silicon carbide ceramic is sintered, the support ring 160 is taken out of the heating chamber 111, and the locking bolt is rotated in the opposite direction. The locking bolt gradually disengages from the side wall of the support block 250, thereby releasing the restriction on the sliding frame 260 to slide on the support block 250. When the silicon carbide ceramic is gradually removed from the placement table 360, the return spring 330 begins to gradually reset, so that the support block 250 gradually returns to its initial state.

[0048] In one embodiment, a plurality of support rods 340 are provided on the support ring 160, and the plurality of support rods 340 are evenly distributed along the circumferential direction of the support ring 160, and the support rods 340 extend along the axial direction of the support ring 160. A connecting rod 350 is fixedly provided on each placement platform 360, and one end of the connecting rod 350 is rotatably connected to the support rod 340. On any one of the support rods 340, the plurality of connecting rods 350 are evenly distributed along the length of the support rod 340. When the support ring 160 rotates, the connecting rod 350 rotates on the support rod 340, so that the silicon carbide ceramics on the placement platform 360 are in a stable state.

[0049] In one embodiment, a plurality of support rings 160 are provided, and the plurality of support rings 160 are coaxially spaced and fixedly connected to a plurality of support rods 340 at the same time. Furthermore, in order to improve the stable rotation of the support ring 160 in the heating chamber 111, a plurality of support blocks 250 are provided on the support plate, and a sliding frame 260 is slidably provided on each support block 250, and a driving roller 280 is rotatably provided on each sliding frame 260. On the same support ring 160, there are two driving rollers 280 that abut against the support ring 160, thereby ensuring that the support ring 160 is in a stable state during rotation.

[0050] In one of the embodiments, when the silicon carbide ceramic is not placed on the placement table 360, the support ring 160 and the first heating sleeve 140 are not in the same axis state, and the closed ring formed by the connecting lines between the multiple placement tables 360 and the first heating sleeve 140 are not in the same axis state. After the silicon carbide ceramic is placed on the placement table 360, the axis height of the support ring 160 decreases, and the axis of the closed ring formed by the connecting lines between the multiple placement tables 360 gradually approaches the axis of the first heating sleeve 140, thereby increasing the uniformity of heating between the silicon carbide ceramic and the first heating sleeve 140 and the second heating sleeve 150.

[0051] In one embodiment, a heat preservation sleeve 370 is disposed inside the furnace body 110 , and the heat preservation sleeve 370 is disposed outside the first heating sleeve 140 . The heat preservation sleeve 370 can reduce the loss of heat in the heating chamber 111 to the external environment.

[0052] A vacuum firing process for producing silicon carbide ceramics, using a vacuum sintering furnace for producing silicon carbide ceramics, comprises the following steps:

[0053] S1, unblocking the feeding port by the blocking cover 120. In the initial state, the blocking cover 120 is in a state of blocking the feeding port to prevent impurities in the external environment from entering the heating chamber 111.

[0054] S2, move the support ring 160 to the outside of the heating chamber 111, and place the silicon carbide ceramic on the placement table 360. To facilitate the placement of the silicon carbide ceramic on the placement table 360, if the support ring 160 is in the heating chamber 111, the space in the heating chamber 111 is limited, and it is not convenient for the staff to place the silicon carbide ceramic. Therefore, when the silicon carbide ceramic needs to be sintered, the support ring 160 is moved to the outside of the heating chamber 111, and then the silicon carbide ceramic blank is placed on the placement table 360.

[0055] S3, moving the support ring 160 into the heating chamber 111, and sealing the feeding port with the blocking cover 120. When sintering silicon carbide ceramics, in order to ensure that the heating chamber 111 is in a relatively closed environment, the blocking cover 120 is used to seal the feeding port.

[0056] S4, start the vacuum pump and the heating source. Before starting the heating source, first start the vacuum pump to draw the heating chamber 111 into a relative vacuum state to prevent the air in the heating chamber 111 from oxidizing the silicon carbide ceramic body. When the air pressure in the heating chamber 111 is close to the vacuum state, start the heating source so that the first heating sleeve 140 and the second heating sleeve 150 are heated up at the same time.

[0057] S5, driving the support ring 160 to rotate around its own axis. When the support ring rotates, the position of the silicon carbide ceramic changes in the heating chamber 111, so that the silicon carbide ceramic can be evenly heated.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A vacuum sintering furnace for producing silicon carbide ceramics, characterized in that: include: A furnace body, wherein a heating chamber is provided inside the furnace body, a feeding port communicating with the heating chamber and the external environment is provided on the furnace body, a blocking cover is provided on the furnace body, and the blocking cover is used to block the feeding port; an exhaust port communicating with the heating chamber and the external environment is provided on the furnace body, and an exhaust pump is connected to the exhaust port, and the exhaust pump is used to extract gas from the heating chamber; A heating source, the heating source comprising a first heating sleeve and a second heating sleeve, the first heating sleeve and the second heating sleeve being coaxially disposed in the heating chamber; A support ring, the support ring is arranged between the first heating sleeve and the second heating sleeve, and a plurality of placement tables are arranged on the support ring, and silicon carbide ceramics can be placed on the placement tables; A driving member, the driving member is used to drive the support to rotate at a constant speed around its own axis; A support platform is fixedly provided in the heating chamber, and a support plate is slidably provided on the support platform; the driving member comprises an air inlet pipe, a driving blade and a driving roller, the air inlet pipe runs through the furnace body, and an end of the air inlet pipe outside the furnace body is connected to an inert gas bottle; the driving blade is rotatably connected to the support plate, and the gas entering the heating chamber through the air inlet pipe can act on the driving blade; the driving roller is coaxially connected to the driving blade, and the driving roller abuts against the support ring; The driving blade comprises a first blade and a second blade, the first blade and the second blade have an overlapping area, and the more silicon carbide ceramics are placed on the placement table, the smaller the overlapping area between the first blade and the second blade is; A support block is fixedly arranged on the support plate, and a sliding frame is connected to the support block, and the sliding frame is slidably connected to the support block up and down; a rotating shaft is rotatably arranged on the sliding frame, and the rotating shaft is coaxially and fixedly connected to the driving roller; the rotating shaft is coaxially and fixedly connected to the first fan blade; an adjusting screw is coaxially arranged on the rotating shaft, and the second fan blade is coaxially and slidably connected to the first fan blade, and the second fan blade is spirally connected to the adjusting screw, and an adjusting gear sleeve is coaxially fixedly arranged on the adjusting screw, and an adjusting tooth plate is arranged on the support block, and the adjusting tooth plate has a first state of engaging the adjusting gear sleeve and a second state of disengaging the adjusting gear sleeve, and when the silicon carbide ceramic is placed on the placing table, the adjusting tooth plate is in the first state, and the sliding frame slides on the support block.

2. The vacuum sintering furnace for producing silicon carbide ceramics according to claim 1, characterized in that: The support block is provided with a locking member, and the locking member is used to lock the position of the sliding frame on the support block.

3. The vacuum sintering furnace for producing silicon carbide ceramics according to claim 2, characterized in that: The locking member includes a locking screw and a locking bolt; a vertical sliding groove is arranged on the support block, the locking screw is fixedly connected to the sliding frame, the locking screw is slidably arranged along the sliding groove, the locking bolt is spirally connected to the locking screw, and the locking bolt can abut against the side wall of the support block.

4. The vacuum sintering furnace for producing silicon carbide ceramics according to claim 3, characterized in that: A return spring is arranged between the sliding frame and the supporting block, and the return spring is arranged vertically.

5. The vacuum sintering furnace for producing silicon carbide ceramics according to claim 1, characterized in that: A plurality of support rods are arranged on the support ring, and the plurality of support rods are evenly distributed along the circumferential direction of the support ring, and the support rods extend along the axial direction of the support ring; a connecting rod is fixedly arranged on each of the placement platforms, and one end of the connecting rod is rotatably connected to the support rod.

6. The vacuum sintering furnace for producing silicon carbide ceramics according to claim 5, characterized in that: The support rings are provided in plurality, the plurality of support rings are coaxially arranged at intervals, and the plurality of support rings are fixedly connected to the plurality of support rods at the same time.

7. A vacuum sintering process for producing silicon carbide ceramics, using the vacuum sintering furnace for producing silicon carbide ceramics as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: S1, unblocking the feeding port by the blocking cover; S2, moving the support ring to the outside of the heating chamber, and placing the silicon carbide ceramic on the placement table; S3, moving the support ring into the heating chamber, and sealing the feeding port with the sealing cover; S4, starting the vacuum pump and the heating source; S5, driving the support to rotate around its own axis.

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