Reaction sintered silicon carbide tub-gelcast mold making and method

Abstract

This application relates to a preparation mold and method for gel casting of reaction-bonded silicon carbide barrels, belonging to the field of silicon carbide product technology. It includes an inner cylinder, an outer tube, and an outer cylinder. The outer tube is sleeved outside the inner cylinder. One end of the inner cylinder extends out of the outer tube and is connected to a first base plate. The outer tube abuts against the surface of the first base plate. A first molding cavity is formed between the inner wall of the outer tube and the outer wall of the inner cylinder. The first molding cavity is used for pouring paraffin wax and forming the inner barrel mold. The inner diameter of the outer cylinder is larger than the diameter of the inner barrel mold. A second base plate is provided on the inner wall of one end of the outer cylinder. After the inner barrel mold is inserted into the outer cylinder, it abuts against the second base plate. A second molding cavity is formed between the inner wall of the outer cylinder and the outer wall of the inner barrel mold. The second molding cavity is used for pouring gel-based sauce and forming the silicon carbide barrel blank. This application has the effect of improving the removal efficiency of the inner mold and the forming quality of the inner wall of the silicon carbide barrel blank in the gel casting process.

Description

Technical Field

[0001] This application relates to the field of silicon carbide product technology, and in particular to a preparation mold and method for reaction sintering silicon carbide barrel gel injection molding. Background Technology

[0002] Silicon carbide is an inorganic material that is smelted at high temperatures in an electric resistance furnace from raw materials such as quartz sand, petroleum coke, and sawdust. Ceramic lined barrels made primarily from silicon carbide are widely used in the grinding field, typically as grinding barrels. In addition, non-metallic ceramic liners are essential core components for the production of granular polycrystalline silicon. Due to their large size, complex structure, low metal impurity content, thin walls, and high height, ceramic lined barrels made primarily from silicon carbide have extremely important applications in the production of granular polycrystalline silicon and in the new energy industry.

[0003] Among related technologies, a method for manufacturing silicon carbide barrels is described. This method employs slip casting or isostatic pressing to form the unglazed silicon carbide ceramic barrel. After the unglazed barrel is formed, it undergoes drying, sintering, and finishing processes. Slip casting is difficult to use for products like silicon carbide barrels that require high wall thickness, while isostatic pressing requires large isostatic presses, resulting in high production costs. Therefore, new colloidal molding methods, such as gel casting, have become effective methods for preparing highly reliable ceramic components with complex shapes.

[0004] Regarding the aforementioned technologies, the inventors discovered that in the existing gel injection molding process, the molding of the silicon carbide barrel blank needs to be carried out between a cylindrical outer mold and a cylindrical inner mold. The inner mold is located inside the silicon carbide barrel blank. After the silicon carbide barrel blank is formed, it is difficult to remove the inner mold, resulting in low demolding efficiency. Furthermore, the removal of the inner mold can easily damage the inner wall of the silicon carbide barrel blank, affecting the molding quality. Therefore, improvements are needed. Summary of the Invention

[0005] In order to improve the efficiency of removing the inner mold in the gel casting process and improve the forming quality of the inner wall of the silicon carbide barrel blank, this application provides a mold and method for preparing a reaction sintering silicon carbide barrel gel casting mold.

[0006] Firstly, the preparation mold for a reaction-bonded silicon carbide barrel gel casting provided in this application adopts the following technical solution:

[0007] A mold for preparing a reaction-sintered silicon carbide barrel gel casting mold includes an inner cylinder, an outer tube, and an outer cylinder. The outer tube is sleeved outside the inner cylinder. One end of the inner cylinder extends out of the outer tube and is connected to a first base plate. The outer tube abuts against the surface of the first base plate. A first molding cavity is formed between the inner wall of the outer tube and the outer wall of the inner cylinder. The first molding cavity is used to pour paraffin wax and form an inner barrel mold. The inner diameter of the outer cylinder is larger than the diameter of the inner barrel mold. A second base plate is provided on the inner wall of one end of the outer cylinder. After the inner barrel mold is inserted into the outer cylinder, it abuts against the second base plate. A second molding cavity is formed between the inner wall of the outer cylinder and the outer wall of the inner barrel mold. The second molding cavity is used to pour gel slurry and form a silicon carbide barrel blank.

[0008] By adopting the above technical solution, after the inner cylinder and outer tube are assembled and fixed, molten paraffin wax is added into the first molding cavity. After the paraffin wax cools and solidifies, a paraffin inner barrel mold is formed. After the formed paraffin inner barrel mold is combined with the outer cylinder, silicon carbide gel slurry is injected into the second molding cavity. After cooling, a silicon carbide barrel blank is formed. When it is necessary to demold the inner wall of the silicon carbide barrel blank, water is simply injected into the paraffin inner barrel mold. The water solubility of paraffin wax allows the inner barrel mold to melt, thus enabling the rapid removal of the inner mold while ensuring the molding quality of the inner wall of the silicon carbide barrel blank. This method has high practicality and convenience, and the removed paraffin inner barrel mold can be reused, resulting in high economic benefits.

[0009] Preferably, a guide fluid is provided at the end of the inner cylinder away from the first chassis, and the diameter of the guide fluid gradually decreases from the end closer to the inner cylinder toward the end farther away from the inner cylinder.

[0010] By adopting the above technical solution, during the casting of colloidal paraffin, the paraffin colloid is poured onto the surface of the guide fluid, and the paraffin colloid flows into the first molding cavity along the inclined surface of the guide fluid. This can effectively improve the efficiency and convenience of paraffin injection, and also effectively reduce the probability of resource waste caused by paraffin not being aligned with the first molding cavity.

[0011] Preferably, the outer tube includes a first splice tube and a second splice tube, which are spliced ​​together and fitted onto the outside of the inner cylinder. The outer walls of the first splice tube and the second splice tube are provided with a fixing structure for fixing the first splice tube and the second splice tube.

[0012] By adopting the above technical solution, the outer tube is set as a combination of splicing pipe one and splicing pipe two. The outer tube can be easily disassembled and assembled through the fixed structure, which facilitates the quick removal of the outer mold from the molded paraffin inner barrel mold, and has high convenience.

[0013] Preferably, a guide ring is detachably provided at one end of the outer cylinder away from the second chassis. The guide ring has an injection groove extending through it along the thickness direction. The injection groove is connected to the second molding cavity. A guide surface is provided on the inner wall of the injection groove. The guide surface is used to allow the gel injection material to enter the second molding cavity.

[0014] By adopting the above technical solution, setting a guide ring, and opening an injection groove on the guide ring, the slurry can flow along the direction of the guide surface when the silicon carbide gel slurry is poured, so that the slurry can be more accurately poured into the second molding cavity, thereby improving the accuracy of slurry pouring and effectively saving raw materials.

[0015] Preferably, the end wall of the second chassis located inside the outer cylinder is provided with a snap-fit ​​ring, and the inner cylinder mold is sleeved on the outer wall of the snap-fit ​​ring after being inserted into the outer cylinder. The bottom wall of the second chassis is provided with a flow hole through the thickness direction, the snap-fit ​​ring is provided in the circumferential direction of the flow hole, and the inner wall of the snap-fit ​​ring is provided with a flow groove through the thickness direction.

[0016] By adopting the above technical solution, a snap-fit ​​ring is set on the surface of the second chassis for the inner paraffin barrel mold to be nested, which plays a stabilizing role for the inner paraffin barrel mold. This allows the inner paraffin barrel mold and the outer barrel to maintain a coaxial state, so that the wall thickness of the cast silicon carbide barrel blank can be kept consistent throughout, thereby improving the molding quality and having high convenience and practicality. The opening of the flow hole and flow groove facilitates the flow of molten paraffin out of the outer barrel.

[0017] Preferably, the inner wall of the outer cylinder is provided with a slide rail, the slide rail is provided along the length of the outer cylinder, a demolding strip is slidably connected in the slide rail, the demolding strip is connected to the side wall of the second base facing the slide rail, the demolding strip drives the second base to be slidably connected to the inner wall of the outer cylinder, a demolding handle is provided at one end of the demolding strip extending out of the slide rail, and a stop plate is provided on the outer wall of the outer cylinder.

[0018] By adopting the above technical solution, when it is necessary to remove the outer mold of the formed silicon carbide barrel blank, the worker needs to step on the stop plate with his foot and pull the demolding handle with his hand, so that the second base plate can slide along the length of the slide under the action of the demolding strip. At this time, the bottom wall of the silicon carbide barrel blank is resisted by the second base plate and will also slide along the length of the slide, thereby separating from the inside of the outer cylinder, realizing the rapid removal of the outer mold of the silicon carbide barrel blank, which has high convenience.

[0019] Preferably, the demolding handle includes a fixed plate and a rotating plate. The fixed plate is connected to the end wall of the demolding strip extending out of the slide. A limiting groove is formed on the bottom wall of the end of the fixed plate extending out of the outer cylinder. The rotating plate is hinged to the inner wall of the limiting groove. After the rotating plate rotates, it abuts against the outer wall of the outer cylinder. The outer wall of the outer cylinder is provided with a locking member for fixing the outer cylinder and the rotating plate.

[0020] By adopting the above technical solution, when there is no need to remove the outer mold of the silicon carbide barrel blank, the rotating plate can be rotated to abut against the outer wall of the outer cylinder. The rotating plate is fixed to the outer wall of the outer cylinder by the locking device, making the outer cylinder easy to move and transport. When demolding is required, the locking device is released, the rotating plate is rotated, and after the rotating plate rotates and abuts against the inner wall of the limiting groove, it will be limited by the fixed plate. Thus, when the operator lifts the rotating plate, the fixed plate and the rotating plate interact to form a stable support, so as to quickly remove the silicon carbide barrel blank. It has high convenience and practicality.

[0021] Secondly, the preparation method of reaction-sintered silicon carbide barrel gel casting provided in this application adopts the following technical solution:

[0022] A method for preparing a reaction-bonded silicon carbide barrel gel casting includes the following steps:

[0023] The outer tube is fitted onto the outer wall of the inner cylinder body, and the outer tube is fixed to the inner cylinder body;

[0024] After the paraffin wax is heated to a molten state, it is poured into the first molding cavity and left to cool and solidify.

[0025] After the paraffin wax cools and solidifies into a paraffin wax inner barrel mold, the outer tube and inner cylinder are removed to complete the demolding of the inner barrel mold;

[0026] Insert the inner barrel mold into the outer barrel and fix the inner barrel mold and the outer barrel;

[0027] The silicon carbide gel grout is prepared, and after ball mixing and vacuum degassing, the prepared gel grout is injected into the second molding cavity and left to cool and solidify.

[0028] After the slurry solidifies and forms a silicon carbide barrel blank, a certain amount of water is introduced into the inner barrel mold to remove the inner membrane.

[0029] The silicon carbide barrel blank is dried.

[0030] The silicon carbide barrel blank is machined.

[0031] The silicon carbide barrel blank is sintered;

[0032] The preparation of silicon carbide ceramic silicon carbide barrels was completed.

[0033] By adopting the above technical solution, after the molten paraffin wax is poured into the first molding cavity and cooled and solidified, a high-strength paraffin wax inner barrel mold can be obtained. Then, by combining this paraffin wax inner barrel mold with the outer barrel, a high-density silicon carbide barrel blank can be obtained through gel injection molding. When demolding the paraffin wax inner barrel mold, water only needs to be injected into the paraffin wax inner barrel mold. The water solubility of paraffin wax can easily solve the problem of difficult demolding of silicon carbide ceramic inner mold, which helps to improve demolding efficiency and effectively protect the molding quality of the inner wall of silicon carbide barrel.

[0034] Preferably, the step of inserting the inner barrel mold into the outer barrel and fixing the inner barrel mold to the outer barrel includes:

[0035] PVP colloid is coated on the outer surface of the inner barrel mold, and aluminum foil is wrapped around the PVP colloid.

[0036] The inner barrel mold is inserted into the outer barrel, and the inner barrel mold and the outer barrel are fixed together.

[0037] By adopting the above technical solution, PVP colloid is relatively stable at room temperature and pressure. When it is coated on the outer wall of the inner barrel mold, it forms a protective film, which can isolate the paraffin inner barrel mold from the slurry during the casting of silicon carbide gel grout. This helps to improve the molding quality of the silicon carbide barrel blank. In addition, PVP colloid is very soluble in water. When removing the inner mold, the water introduced will also dissolve the PVP colloid, which has high convenience and practicality.

[0038] Preferably, the prepared silicon carbide gel grout, after ball mixing and vacuum degassing, comprises:

[0039] A catalyst, initiator, and densifying additive are added to the silicon carbide gel grout. The prepared gel grout is then injected into the second molding cavity and allowed to cool and solidify.

[0040] By adopting the above technical solution, adding catalysts, initiators and densifying additives to the silicon carbide gel slurry can increase the densification degree of the finished silicon carbide barrel during sintering, thereby effectively improving the molding quality of the silicon carbide barrel.

[0041] In summary, this application includes at least one of the following beneficial technical effects:

[0042] 1. After assembling and fixing the inner cylinder and outer tube, melted paraffin wax is added into the first molding cavity. After the paraffin wax cools and solidifies, a paraffin wax inner barrel mold is formed. After assembling the formed paraffin wax inner barrel mold with the outer cylinder, silicon carbide gel slurry is injected into the second molding cavity. After cooling, a silicon carbide barrel blank is formed. When it is necessary to demold the inner wall of the silicon carbide barrel blank, water is simply injected into the paraffin wax inner barrel mold. The water solubility of paraffin wax melts the inner barrel mold, thus enabling the rapid removal of the inner mold while ensuring the molding quality of the inner wall of the silicon carbide barrel blank. This method has high practicality and convenience. Furthermore, the removed paraffin wax inner barrel mold can be reused, resulting in high economic benefits.

[0043] 2. During the casting of colloidal paraffin, the paraffin colloid is poured onto the surface of the guide fluid, and the paraffin colloid will flow into the first molding cavity along the inclined surface of the guide fluid. This can effectively improve the efficiency and convenience of paraffin injection, and at the same time, effectively reduce the probability of resource waste caused by paraffin not being aligned with the first molding cavity. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the connection structure between the inner cylinder and the outer tube in Embodiment 1 of this application.

[0045] Figure 2 This is a schematic diagram of the connection structure between the inner barrel mold and the outer barrel in Embodiment 1 of this application.

[0046] Figure 3 This is an exploded structural diagram of the inner cylinder and outer tube of Embodiment 1 of this application.

[0047] Figure 4 This is a schematic diagram of the fixed structure of Embodiment 2 of this application.

[0048] Figure 5 This is a schematic diagram of the connection structure between the inner cylinder mold and the outer cylinder in Embodiment 3 of this application.

[0049] Figure 6 yes Figure 5 A magnified view of a portion of point A in the middle.

[0050] Explanation of reference numerals in the attached drawings: 1. Inner cylinder; 11. First base plate; 111. Connecting hole; 12. Fluid guide; 2. Outer pipe; 21. Splicing pipe one; 22. Splicing pipe two; 23. Fixing structure; 231. Fixing block; 2311. Fixing hole; 232. Combination block one; 2321. Embedding block; 233. Combination block two; 2331. Embedding groove; 234. Fixing sleeve; 3. Outer cylinder; 31. Second base plate; 311. Snap ring; 312. Flow hole; 313. Flow groove; 32. Fluid guide ring; 321. Injection tank; 322. Fluid guide surface; 33. Slide rail; 34. Demolding strip; 35. Demolding handle; 351. Fixing plate; 3511. Limiting groove; 352. Rotating plate; 36. Stop plate; 37. Locking element; 4. First molding cavity; 5. Inner barrel mold; 6. Second molding cavity. Detailed Implementation

[0051] The following is in conjunction with the appendix Figure 1-6 This application will be described in further detail.

[0052] This application discloses a preparation mold for gel casting of reaction sintered silicon carbide barrels. In this application, the preparation mold is described in detail using the preparation of a silicon carbide barrel with a diameter of 500 mm and an inner diameter of 450 mm as an example.

[0053] Example 1:

[0054] Reference Figure 1 and Figure 2 It includes an inner cylinder 1, an outer tube 2 and an outer cylinder 3. The inner cylinder 1 has a diameter of 430 mm. One end of the inner cylinder 1 is integrally formed with a first base 11. The diameter of the first base 11 is larger than the diameter of the inner cylinder 1. The outer tube 2 is sleeved on the outside of the inner cylinder 1. The inner diameter of the outer tube 2 is set to 450 mm. The outer tube 2 abuts against the surface of the first base 11.

[0055] Reference Figure 1 and Figure 3 The first base 11 has a plurality of connecting holes 111 through it along the thickness direction. The plurality of connecting holes 111 are evenly distributed along the circumferential direction of the first base 11. After the inner cylinder 1 and the outer tube 2 are assembled, the screws are passed through the connecting holes 111 to fix the inner cylinder 1 and the outer tube 2, thereby making the inner cylinder 1 and the outer tube 2 coaxial.

[0056] Reference Figure 1 and Figure 2A first molding cavity 4 is formed between the inner wall of the outer tube 2 and the outer wall of the inner cylinder 1. A guide fluid 12 is integrally formed at the end of the inner cylinder 1 away from the first base plate 11. The diameter of the guide fluid 12 gradually decreases from the end closer to the inner cylinder 1 to the end farther away from the inner cylinder 1. The diameter of the smaller end of the guide fluid 12 is 200mm. By pouring the paraffin colloid through the inclined surface of the guide fluid 12, the paraffin can flow accurately into the first molding cavity 4, thereby reducing the waste of paraffin and improving the preparation efficiency and convenience. In the specific operation, the operator pours molten paraffin into the first molding cavity 4. After the paraffin cools, the paraffin inner barrel mold 5 is formed. Since the inner cylinder 1 and the outer tube 2 are in a coaxial fixed state, the wall thickness of the formed paraffin inner barrel mold 5 is consistent throughout, resulting in high strength and quality.

[0057] Reference Figure 2 and Figure 3 The outer tube 2 includes a first splicing tube 21 and a second splicing tube 22. In this embodiment, both the first splicing tube 21 and the second splicing tube 22 are semi-cylinders. After being spliced ​​together, they form a complete cylinder. The first splicing tube 21 and the second splicing tube 22 are fitted onto the outside of the inner cylinder 1. The outer walls of the first splicing tube 21 and the second splicing tube 22 are provided with a fixing structure 23 to fix the first splicing tube 21 and the second splicing tube 22. When the assembly of the first splicing tube 21 and the second splicing tube 22 is released through the fixing structure 23, the outer mold of the inner cylinder mold 5 can be quickly removed, improving work efficiency.

[0058] Reference Figure 1 and Figure 3 The fixing structure 23 includes several fixing blocks 231, which are integrally formed on the sidewalls of the contact surfaces of the first splice pipe 21 and the second splice pipe 22. The fixing blocks 231 on the sidewalls of the first splice pipe 21 and the second splice pipe 22 are evenly distributed along their length direction. The corresponding fixing blocks 231 on the first splice pipe 21 and the second splice pipe 22 are provided with fixing holes 2311 through them along the thickness direction so that screws can be inserted, thereby quickly fixing the first splice pipe 21 and the second splice pipe 22. The fixing structure 23 of this application has the advantages of simple structure and convenient installation, and can effectively improve the removal efficiency of the outer mold of the inner barrel mold 5, and has high convenience and practicality.

[0059] Reference Figure 1 and Figure 2After the inner barrel mold 5 is demolded, it is inserted into the outer barrel 3. The inner diameter of the outer barrel 3 is set to 500mm. A second base plate 31 is provided on the inner wall of one end of the outer barrel 3. The second base plate 31 has a flow hole 312 through it along the thickness direction. After keeping the inner barrel mold 5 and the outer barrel 3 coaxially set, the outer wall of the inner barrel mold 5 and the inner wall of the outer barrel 3 form a second molding cavity 6. The workers inject gel slurry into the second molding cavity 6. After it solidifies, a silicon carbide barrel blank with a diameter of 500mm and an inner diameter of 450mm is formed. Water is injected into the inner barrel mold 5, which allows the paraffin to dissolve in the water and flow out through the flow hole 312, thereby completing the rapid removal of the inner mold of the silicon carbide barrel blank and effectively improving the problem of difficult removal of the inner mold of silicon carbide ceramic.

[0060] The implementation principle of the preparation mold for the reaction sintering silicon carbide barrel gel injection molding in Embodiment 1 of this application is as follows: After the inner cylinder 1 and the outer tube 2 are assembled, molten paraffin wax is added into the first molding cavity 4. After the paraffin wax cools and solidifies, a paraffin inner barrel mold 5 is formed. After separating the inner barrel mold 5 from the inner cylinder 1 and the outer tube 2, it is combined with the outer cylinder 3. Silicon carbide gel injection material is injected into the second molding cavity 6. After cooling, it is formed into a silicon carbide barrel blank. Water is injected into the paraffin inner barrel mold 5. By utilizing the water solubility of paraffin wax, the inner barrel mold 5 can be melted. Thus, the inner mold can be quickly removed while ensuring the molding quality of the inner wall of the silicon carbide barrel blank. It has high practicality and convenience, and improves the problem of difficult removal of silicon carbide ceramic inner molds.

[0061] Example 2:

[0062] The difference between Embodiment 2 and Embodiment 1 of this application is as follows:

[0063] Reference Figure 4 The fixing structure 23 includes a first assembly block 232, a second assembly block 233, and a fixing sleeve 234. The first assembly block 232 is integrally formed on the side wall of the first splicing pipe 21 near the second splicing pipe 22. The second assembly block 233 is integrally formed on the side wall of the second splicing pipe 22 near the first splicing pipe 21. The side wall of the first assembly block 232 facing the second assembly block 233 has an insert block 2321 integrally formed. The side wall of the second assembly block 233 has an insert groove 2331 for inserting the insert block 2321. When the first splicing pipe 21 and the second splicing pipe 22 are spliced, the insert block 2321 is inserted into the insert groove 2331. At this time, the fixing sleeve 234 can be fitted on the outer wall of the first assembly block 232 and the second assembly block 233 to fix the first assembly block 232 and the second assembly block 233. Thus, the first splicing pipe 21 and the second splicing pipe 22 can be fixed.

[0064] The implementation principle of the preparation mold for the reaction sintering silicon carbide barrel gel injection molding in Embodiment 2 of this application is as follows: After splicing pipe one 21 and splicing pipe two 22 are connected, the splicing of assembly block one 232 and assembly block two 233 can be realized simultaneously. Only by putting a fixing sleeve 234 on the outside of assembly block one 232 and assembly block two 233, the fixing structure 23 can quickly fix splicing pipe one 21 and splicing pipe two 22. Compared with the fixing structure 23 in Embodiment 1, the fixing structure 23 in Embodiment 2 is more convenient to operate.

[0065] Example 3:

[0066] The difference between Embodiment 3 and Embodiment 1 of this application is as follows:

[0067] Reference Figure 5 The second base plate 31 is slidably connected to the inner wall of the outer cylinder 3. The end wall of the second base plate 31 located inside the outer cylinder 3 is integrally formed with a snap ring 311. The snap ring 311 is arranged along the circumferential direction of the flow hole 312. The diameter of the snap ring 311 is 430mm, so that the inner cylinder mold 5 inserted into the outer cylinder 3 can be stably nested in the outer wall of the snap ring 311, so that the outer cylinder 3 and the inner cylinder mold 5 can maintain a stable coaxial state. The inner wall of the snap ring 311 is provided with a plurality of flow grooves 313 through the thickness direction. The plurality of flow grooves 313 are evenly distributed along the circumferential direction of the snap ring 311, so that after the paraffin dissolves in water, the paraffin water solution can flow out of the interior of the outer cylinder 3 through the flow grooves 313 and the flow hole 312.

[0068] Reference Figure 5 and Figure 6 The inner wall of the outer cylinder 3 has two parallel slides 33, which are opened along the length of the outer cylinder 3. A demolding strip 34 is slidably connected in the slides 33. The side wall of the demolding strip 34 is connected to the side wall of the second base plate 31 by adhesive, so that the second base plate 31 can slide inside the outer cylinder 3. A demolding handle 35 is provided at one end of the demolding strip 34 that extends out of the slides 33. A stop plate 36 is integrally formed on the outer wall of the outer cylinder 3. When it is necessary to remove the silicon carbide barrel blank from the outer cylinder 3, the worker needs to step on the stop plate 36 with his foot and pull the demolding handle 35, which can drive the second base plate 31 to slide towards the outside of the outer cylinder 3. Under the abutment of the second base plate 31, the silicon carbide barrel blank can also be separated from the inside of the outer cylinder 3, so as to improve the convenience of demolding.

[0069] Reference Figure 5 and Figure 6The demolding handle 35 includes a fixed plate 351 and a rotating plate 352. The fixed plate 351 is integrally formed and connected to the end wall of the demolding strip 34 extending out of the slide rail 33. The fixed plate 351 is set at a 90° angle to the demolding strip 34, and when the demolding strip 34 is not sliding, the bottom wall of the fixed plate 351 abuts against the end wall of the outer cylinder 3. One end of the fixed plate 351 extends out of the outer cylinder 3, and a limiting groove 3511 is formed on the bottom wall of the end of the fixed plate 351 extending out of the outer cylinder 3. The rotating plate 352 is hinged to the top wall of the limiting groove 3511. During demolding, the fixed plate 351... The fixed plate 351 and the rotating plate 352 abut against each other, so that the fixed plate 351 and the rotating plate 352 are in the same plane, which makes it easy for the workers to lift the rotating plate 352 and pull out the silicon carbide barrel blank. When demolding is not required, the rotating plate 352 is simply rotated to abut against the side wall of the outer cylinder 3. The rotating plate 352 is connected to the outer cylinder 3 by the locking member 37 provided on the side wall of the outer cylinder 3, which can keep the rotating plate 352 stable so that it can be carried or transported. In this embodiment, the locking member 37 is a screw.

[0070] Reference Figure 5 and Figure 6 A guide ring 32 is provided at one end of the outer cylinder 3 away from the second base plate 31. Two annular grooves are opened on the bottom wall of the guide ring 32, both of which are opened along the circumferential direction of the guide ring 32, so as to allow the inner barrel mold 5 and the end wall of the outer cylinder 3 to be inserted. An injection groove 321 is opened through the guide ring 32 along the thickness direction. The injection groove 321 is located between the two annular grooves and is connected to the second molding cavity 6. A guide surface 322 is opened on the inner wall of the injection groove 321 so that the gel injection material can enter the second molding cavity 6 along the guide surface 322, thereby improving the casting accuracy and reducing the waste of raw materials.

[0071] The implementation principle of the preparation mold for the reaction sintering silicon carbide barrel gel injection molding in Embodiment 3 of this application is as follows: When it is necessary to remove the outer mold of the formed silicon carbide barrel blank, the worker needs to step on the stop plate 36 with his foot and pull the demolding handle 35 with his hand, so that the second base plate 31 can slide along the length direction of the slide 33 under the action of the demolding strip 34. At this time, the bottom wall of the silicon carbide barrel blank is resisted by the second base plate 31 and will also slide along the length direction of the slide 33, thereby separating from the inside of the outer cylinder 3, realizing the rapid removal of the outer mold of the silicon carbide barrel blank.

[0072] This application also provides a method for preparing reaction-sintered silicon carbide barrel gel casting, comprising the following steps:

[0073] S1: An inner cylinder 1 with a diameter of D430mm is prepared by welding stainless steel, and the first chassis 11 is coaxially welded to the bottom wall of the inner cylinder 1. An outer tube 2 with an inner diameter of 450mm is sleeved on the outer wall of the inner cylinder 1 and the outer tube 2 is fixed to the inner cylinder 1.

[0074] S2: After heating the paraffin wax to 80℃ and melting it, pour it into the first molding cavity 4 and wait for it to cool and solidify to obtain a paraffin wax inner barrel mold 5 with a diameter of D450mm;

[0075] S3: After the paraffin wax cools and solidifies into the inner barrel mold 5, remove the outer tube 2 and the inner cylinder 1 to complete the demolding of the inner barrel mold 5.

[0076] S4: Coat the outer surface of the inner barrel mold 5 with PVP colloid, and wrap the PVP colloid with aluminum foil.

[0077] S5: An outer cylinder 3 with an inner diameter of 500mm is prepared by welding stainless steel, and a second base plate 31 is set at one end of the inner cylinder. The inner cylinder mold 5 is inserted into the outer cylinder 3, and the inner cylinder mold 5 and the outer cylinder 3 are coaxial and then fixed.

[0078] S6: Prepare silicon carbide gel grout. After ball mixing, vacuum degassing, addition of catalyst, initiator and densifying additive, the prepared gel grout is injected into the second molding cavity 6 and waits for cooling and molding.

[0079] S7: After the slurry solidifies and forms a silicon carbide barrel blank, a certain amount of water is introduced into the inner barrel mold 5 for removing the inner membrane.

[0080] S8: Dry the above-mentioned silicon carbide barrel blank;

[0081] S9: Machining the above-mentioned silicon carbide barrel blank;

[0082] S10: The above silicon carbide barrel blank is reacted and sintered at 1700-1720℃;

[0083] S11: Complete the preparation of silicon carbide ceramic silicon carbide barrel.

[0084] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A mold for reaction sintered silicon carbide tub-gelcast, characterized by: The device includes an inner cylinder (1), an outer tube (2), and an outer cylinder (3). The outer tube (2) is fitted outside the inner cylinder (1). One end of the inner cylinder (1) extends out of the outer tube (2) and is connected to a first base plate (11). The outer tube (2) abuts against the surface of the first base plate (11). A first molding cavity (4) is formed between the inner wall of the outer tube (2) and the outer wall of the inner cylinder (1). The first molding cavity (4) is used to pour paraffin wax and form an inner barrel mold (5). The inner diameter of the outer cylinder (3) is larger than the diameter of the inner barrel mold (5). A second base plate (31) is provided on the inner wall of one end of the outer cylinder (3). The inner barrel mold (5) is inserted into the outer cylinder (3) and abuts against the second base plate (31). A second molding cavity (6) is formed between the inner wall of the outer cylinder (3) and the outer wall of the inner barrel mold (5). The second molding cavity (6) is used to pour gel grout and form a silicon carbide barrel blank. A guide ring (32) is detachably provided at one end of the outer cylinder (3) away from the second chassis (31). The guide ring (32) has an injection groove (321) extending through it along the thickness direction. The injection groove (321) is connected to the second molding cavity (6). A guide surface (322) is provided on the inner wall of the injection groove (321). The guide surface (322) is used to allow the gel injection material to enter the second molding cavity (6). The second chassis (31) is provided with a snap ring (311) on the end wall inside the outer cylinder (3). After the inner cylinder mold (5) is inserted into the outer cylinder (3), it is sleeved on the outer wall of the snap ring (311). The bottom wall of the second chassis (31) is provided with a flow hole (312) through the thickness direction. The snap ring (311) is provided along the circumferential direction of the flow hole (312). The inner wall of the snap ring (311) is provided with a flow groove (313) through the thickness direction. The inner wall of the outer cylinder (3) is provided with a slide (33), which is opened along the length of the outer cylinder (3). A demolding strip (34) is slidably connected in the slide (33). The demolding strip (34) is connected to the side wall of the second base (31) facing the slide (33). The demolding strip (34) drives the second base (31) to slide and connect to the inner wall of the outer cylinder (3). A demolding handle (35) is provided at one end of the demolding strip (34) that extends out of the slide (33). A stop plate (36) is provided on the outer wall of the outer cylinder (3).

2. The mold for preparing a reaction-sintered silicon carbide barrel gel casting according to claim 1, characterized in that: A guide fluid (12) is provided at the end of the inner cylinder (1) away from the first chassis (11), and the diameter of the guide fluid (12) gradually decreases from the end close to the inner cylinder (1) toward the end away from the inner cylinder (1).

3. The mold for preparing a reaction-sintered silicon carbide barrel gel casting according to claim 1, characterized in that: The outer tube (2) includes a splicing tube one (21) and a splicing tube two (22). The splicing tube one (21) and the splicing tube two (22) are spliced ​​together and then fitted onto the outside of the inner cylinder (1). The outer walls of the splicing tube one (21) and the splicing tube two (22) are provided with a fixing structure (23), which is used to fix the splicing tube one (21) and the splicing tube two (22).

4. The mold for preparing a reaction-sintered silicon carbide barrel gel casting according to claim 1, characterized in that: The demolding handle (35) includes a fixed plate (351) and a rotating plate (352). The fixed plate (351) is connected to the end wall of the demolding strip (34) extending out of the slide (33). A limiting groove (3511) is provided on the bottom wall of the fixed plate (351) extending out of the outer cylinder (3). The rotating plate (352) is hinged to the inner wall of the limiting groove (3511). After the rotating plate (352) rotates, it abuts against the outer wall of the outer cylinder (3). The outer wall of the outer cylinder (3) is provided with a locking member (37) for fixing the outer cylinder (3) and the rotating plate (352).

5. A method for preparing a mold for gel casting of a reaction-sintered silicon carbide barrel according to any one of claims 1-4, characterized in that, Includes the following steps: The outer tube (2) is fitted onto the outer wall of the inner cylinder (1), and the outer tube (2) is fixed to the inner cylinder (1); After the paraffin wax is heated to a molten state, it is poured into the first molding cavity (4) and left to cool and solidify. After the paraffin wax cools and solidifies into a paraffin wax inner barrel mold (5), the outer tube (2) and the inner cylinder (1) are removed to complete the demolding of the inner barrel mold (5); Insert the inner barrel mold (5) into the outer barrel (3) and fix the inner barrel mold (5) and the outer barrel (3); After preparing silicon carbide gel grout, it is ball-mixed and vacuum defoamed. The prepared gel grout is then injected into the second molding cavity (6) and left to cool and solidify. After the slurry solidifies and forms a silicon carbide barrel blank, a certain amount of water is introduced into the inner barrel mold (5) for removing the inner membrane; The silicon carbide barrel blank is dried. The silicon carbide barrel blank is machined. The silicon carbide barrel blank is sintered; The preparation of silicon carbide ceramic silicon carbide barrels was completed.

6. The method for preparing a mold for preparing a reaction-sintered silicon carbide barrel gel casting according to claim 5, characterized in that: The step of inserting the inner barrel mold (5) into the outer barrel (3) and fixing the inner barrel mold (5) and the outer barrel (3) includes: PVP colloid is coated on the outer surface of the inner barrel mold (5), and aluminum foil is wrapped around the PVP colloid. Insert the inner barrel mold (5) into the outer barrel (3) and fix the inner barrel mold (5) and the outer barrel (3).

7. The method for preparing a mold for preparing a reaction-sintered silicon carbide barrel gel casting according to claim 5, characterized in that: The prepared silicon carbide gel grout, after ball mixing and vacuum defoaming, includes: A catalyst, an initiator, and a densifying additive are added to the silicon carbide gel grout. The prepared gel grout is then injected into the second molding cavity (6) and left to cool and solidify.

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