Chemical-erosion-resistant silicon carbide boat and method thereof

Abstract

The invention relates to the technical field of silicon carbide crystal boats, and provides a chemical-erosion-resistant silicon carbide crystal which comprises a first bottom support and a second bottom support, and is characterized in that a connecting piece is arranged between the first bottom support and the second bottom support and comprises an insertion block fixedly connected to one end of the second bottom support; an assembling groove in sliding fit with the inserting block is formed in the end, close to the second bottom support, of the first bottom support, a plurality of first screw holes distributed at equal intervals in the length direction of the inserting block are formed in the inserting block, and a first positioning screw in threaded fit with any first screw hole is inserted into the outer side of the first bottom support; the opposite sides of the first bottom support and the second bottom support are rotationally connected with side support parts, and the bottom ends of the first bottom support and the second bottom support are provided with adjusting pieces used for adjusting the included angles between the side support parts and the corresponding first bottom support and the second bottom support. According to the invention, the distance between the first bottom support and the second bottom support can be adjusted, so that the loading of wafers with different sizes can be met.

Description

Technical Field

[0001] The present invention relates to the technical field of silicon carbide boats, and specifically, to a silicon carbide boat resistant to chemical erosion and its method. Background Art

[0002] Silicon carbide (SiC) boats are important high-temperature resistant accessories used in the photovoltaic and semiconductor industries to load wafers for high-temperature treatment. Due to the high-temperature resistance, chemical corrosion resistance, and good thermal stability of silicon carbide materials, they are widely used in heat treatment processes such as diffusion, oxidation, chemical vapor deposition (CVD), and annealing;

[0003] For example, the "Preparation method of a silicon carbide ceramic boat" disclosed in Chinese Patent (Publication No.: CN115466123B), which includes seven steps: preparation of mixed powder, isostatic pressing forming, curing sintering purification, first impregnation, first reaction sintering, second impregnation, and second reaction sintering. By this method, a silicon carbide ceramic boat with high purity, high density, and excellent high-temperature bending strength can be prepared;

[0004] Another example is the "Preparation method of a large-size silicon carbide ceramic boat" disclosed in Chinese Patent (Publication No.: CN117756544B), which consists of the following steps: preparation of fiber aerogel, preparation of coated silicon powder, isostatic pressing forming, first sintering, impregnation, and second sintering. By this method, while improving the fracture toughness, room-temperature bending strength, and high-temperature bending strength of the large-size silicon carbide ceramic boat, high purity and high density can be ensured, and the polishability and thermal conductivity can be improved;

[0005] However, although such silicon carbide boats have high-temperature resistance and high bending strength, silicon carbide boats are prone to being eroded by acids, alkalis, and various chemical substances during service. Therefore, it is necessary to modify their materials to improve their chemical erosion resistance. The current production methods of silicon carbide boats face the following challenges:

[0006] Complexity of material modification technology: There are various existing modification methods, but it is still challenging to select a suitable modification technology to improve the chemical erosion resistance of silicon carbide. Different chemical environments require different modification strategies;

[0007] Uniformity of modification effect: Ensuring the uniformity of the modification effect is an important challenge during the modification process. If the modification treatment is uneven, it may cause local fragility of the boat during use, thus affecting its overall performance;

[0008] Maintenance of high-temperature resistance: The modification treatment may affect the high-temperature resistance of the silicon carbide boat. How to maintain its high-temperature stability while enhancing the chemical erosion resistance is a key issue;

[0009] Control of production cost: Modification usually requires additional investment in equipment and materials. How to control production cost on the premise of ensuring performance is also an important factor to be considered;

[0010] Difficulty in material sintering: The sintering process of silicon carbide is complex and usually requires long-time treatment at high temperature, resulting in low production efficiency;

[0011] Great processing difficulty: Due to the high hardness of silicon carbide, traditional machining methods are time-consuming and prone to wear of machining tools, increasing production costs;

[0012] Lack of design flexibility: Traditional production methods are restricted in design, difficult to quickly respond to changes in market demand, and unable to achieve personalized and small-batch production; Therefore, a new production method is urgently needed to improve the production efficiency and flexibility of silicon carbide boats, reduce production costs, and improve product quality;

[0013] High usage cost: Although there are integrated silicon carbide boats in the existing technology, during use, a silicon carbide boat can only match wafers of one size, and for wafers of different sizes, silicon carbide boats of corresponding sizes need to be produced. This makes it necessary to prepare silicon carbide boats of multiple sizes during the production of some small-scale wafers of multiple sizes, greatly increasing the usage cost. In view of this, the present invention proposes a chemically resistant silicon carbide boat and its method. Summary of the Invention

[0014] The present invention proposes a chemically resistant silicon carbide boat and its method, which solves the problem that the silicon carbide boat in the existing technology cannot match wafers of multiple sizes.

[0015] The technical solution of the present invention is as follows: A chemically resistant silicon carbide boat, including a first bottom support and a second bottom support, characterized in that a connecting member is provided between the first bottom support and the second bottom support. The connecting member includes an insertion block fixedly connected to one end of the second bottom support. An assembly groove slidably matched with the insertion block is opened at one end of the first bottom support close to the second bottom support. A plurality of first screw holes are opened on the insertion block at equal intervals along the length direction of the insertion block. A positioning screw rod one threadedly matched with any one of the first screw holes is inserted on the outer side of the first bottom support. Side support parts are rotatably connected to the sides of the first bottom support and the second bottom support opposite to each other. An adjusting member for adjusting the included angle between the side support part and the corresponding first bottom support and second bottom support is provided at the bottom ends of the first bottom support and the second bottom support.

[0016] Preferably, the cross-section of the first bottom support is a U-shaped structure, and a plurality of first slots are opened along the length direction at the top of the first bottom support. Two first ear seats are integrally formed at both ends of the first bottom support, and a second ear seat is integrally formed in the middle of the first bottom support.

[0017] Preferably, the cross-section of the second base is a U-shaped structure, and a number of slot two corresponding to the slots one by one are provided at the top of the second base. Two ear seats three are integrally formed at both ends of the second base, and an ear seat four is integrally formed in the middle of the second base.

[0018] Preferably, the side support part includes three side plates arranged at equal intervals. The side plates arranged at both ends are rotatably connected to the corresponding ear seats one and ear seats three through pin shafts. The side plate arranged in the middle is rotatably connected to the corresponding ear seats two and ear seats four through pin shafts. A support plate is integrally formed at the top of the three side plates, and a number of slot three corresponding to the slots one by one are provided on the support plate.

[0019] Preferably, the adjusting part includes a movable block. Installation grooves for sliding cooperation with the movable block are provided at the bottom ends of the first base and the second base. A plurality of screw holes two are provided in the movable block along the length direction. Positioning screws two threadedly engaged with the corresponding screw holes two are inserted on the outside of the first base and the second base. One end of the movable block is rotatably connected to a connecting rod, and the other end of the connecting rod far from the movable block is rotatably connected to a hinge seat, and the hinge seat is fixedly connected to the corresponding side support part.

[0020] The present invention also provides a preparation method of a silicon carbide boat resistant to chemical erosion, including the following steps:

[0021] S1: Material preparation: Select high-purity silicon carbide powder with a particle size of 1μm - 50μm, then add 5% - 8% binder to the high-purity silicon carbide powder, and then add 5% - 15% sintering aid to obtain a mixture;

[0022] S2: Mixing and drying: Add the mixture in S1 to a ball mill for dry mixing for 2 - 4 hours to ensure uniform dispersion, and then dehydrate in a vacuum drying oven at 60°C for 12 - 14 hours to obtain dry mixed powder;

[0023] S3: Laser sintering: Perform 3D printing on the mixed powder in S2 through a selective laser sintering rapid prototyping machine to respectively obtain green bodies of the first base, the second base, the connecting piece, the side support part and the adjusting part. The specific implementation process of a single green body is as follows:

[0024] A. Uniformly spread the mixed powder in S2 on the sintering platform through a powder spreading device to form a powder layer with a thickness of 50μm - 100μm;

[0025] B. Preheat the sintering platform to remove moisture and gas in the powder layer, and the preheating temperature is 100 - 150°C;

[0026] C. According to the pre-designed three-dimensional model, under the control of a computer, a laser beam scans the powder layer along a predetermined path at a scanning speed of 200 - 800 mm / s and a scanning spacing of 0.05 - 0.15 mm. The energy of the laser beam rapidly raises the temperature of the powder particle surface and partially melts it, bonding it together with the surrounding powder particles. Among them, the laser power ranges from 100 - 400 W;

[0027] D. After completing the sintering of one layer of powder, the sintering platform descends by the thickness of one powder layer, then powder is re-laid and the next layer of sintering is carried out. This cycle repeats until the entire three-dimensional model is completely sintered and formed;

[0028] E. After sintering is completed, let the sintered part cool naturally to room temperature;

[0029] S4: Post-treatment: The sintered part in S3 is subjected to debinding to remove the binder, then heat treatment is carried out to improve the density and strength of the sintered part, and finally a surface modifier is deposited on the surface of the sintered part by chemical vapor deposition to finally obtain a modified silicon carbide boat fitting;

[0030] S5: Inspection and assembly: The silicon carbide boat fitting in S4 is inspected for appearance, dimensions, density, and strength, and meets the relevant standards of the photovoltaic and semiconductor industries, and then assembled into a complete silicon carbide boat.

[0031] Preferably, the binder is selected from any one of polycaprolactam, polyethylene, and polypropylene, and the sintering aid is boron nitride, aluminum, or other non-oxidizing aids.

[0032] Preferably, the working environment of the selective laser sintering rapid prototyping machine is controlled in a high-temperature and low-oxygen atmosphere to improve the sintering effect of silicon carbide.

[0033] Preferably, in S4, the specific implementation process of the debinding treatment is as follows:

[0034] (1). Place the sintered part in S3 in a nitrogen environment and heat it to 550 - 600 °C, keep it warm for 3 - 4 hours to remove the binder;

[0035] (2). Then soak the sintered part in acetone and perform ultrasonic cleaning to remove the residual organic matter and complete debinding.

[0036] Preferably, in S4, the specific implementation process of the heat treatment is as follows:

[0037] (1). Bury the debound sintered part in silicon powder so that the silicon powder completely buries the sintered part;

[0038] (2) Then, it is placed in a vacuum furnace and heated to 1500 - 2200 °C. The silicon melt infiltrates into the porous sintered part and reacts with free carbon to form silicon carbide, filling the pores to increase the density of the sintered part. Among them, the heating rate is 10 - 15 °C / min, the heat preservation time is 3 - 4 hours, and after cooling with the furnace, it is taken out to obtain a silicon carbide crystal boat.

[0039] The working principle and beneficial effects of the present invention are as follows:

[0040] 1. When in use, by matching the insertion block with the assembly groove, and then adjusting the assembly length of the insertion block and the assembly groove, after determining the assembly length of the insertion block, the positioning of the insertion block is achieved through the threaded cooperation of the first positioning screw and the corresponding first screw hole. In this way, the adjustment of the distance between the first bottom bracket and the second bottom bracket can be realized, so as to meet the loading of wafers of different sizes, greatly improving the versatility of the silicon carbide crystal boat and thus reducing the use cost;

[0041] 2. Through the modification treatment of the raw materials of the silicon carbide crystal boat of the present invention, the chemical erosion resistance of the silicon carbide crystal boat can be significantly improved, its service life can be extended, and the stability and reliability in a harsh chemical environment can be ensured;

[0042] 3. Utilizing the 3D printing technology, the sintering and forming of silicon carbide materials can be realized at a relatively low temperature, shortening the production cycle, improving the production efficiency. The 3D printing technology can directly form complex structures, reducing subsequent processing procedures, material loss and processing costs;

[0043] 4. Through the 3D printing technology, multiple accessories of the silicon carbide crystal boat can be formed at one time, quickly assembled and adjusted to match wafers of corresponding sizes, so as to realize the loading of wafers of different sizes, greatly improving the versatility of the silicon carbide crystal boat and thus reducing the use cost.

[0044] 5. Through the 3D printing technology, the design scheme can be quickly adjusted to meet the personalized needs of different customers for the silicon carbide crystal boat, supporting small-batch production;

[0045] 6. The 3D printing technology adopted by the present invention can reduce the generation of waste and energy consumption, meeting the concept of sustainable development. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0047] Figure 1 It is a schematic structural diagram of a chemically erosion-resistant silicon carbide crystal boat of the present invention;

[0048] Figure 2 It is a schematic structural diagram of the connecting piece of the present invention;

[0049] Figure 3Schematic diagram of the first bottom bracket of the present invention;

[0050] Figure 4 Schematic diagram of the second bottom bracket of the present invention;

[0051] Figure 5 Schematic diagram of the side support part of the present invention;

[0052] Figure 6 Schematic diagram of the adjusting part of the present invention;

[0053] Figure 7 Table of relative densities of each silicon carbide boat in Test Example 1 of the present invention;

[0054] Figure 8 Bar chart of mass loss rate of each silicon carbide boat in an acidic environment in Test Example 2 of the present invention;

[0055] Figure 9 Bar chart of mass loss rate of each silicon carbide boat in an alkaline environment in Test Example 2 of the present invention;

[0056] Figure 10 Table of deformation amounts of each silicon carbide boat in the thermal shock experiment in Test Example 4 of the present invention.

[0057] In the figure: 1. First bottom bracket; 11. Slot 1; 12. Ear seat 1; 13. Ear seat 2; 2. Second bottom bracket; 21. Slot 2; 22. Ear seat 3; 23. Ear seat 4; 3. Connecting piece; 31. Insert block; 32. Assembly groove; 33. Positioning screw 1; 34. Screw hole 1; 4. Side support part; 41. Side plate; 42. Support plate; 43. Slot 3; 5. Adjusting part; 51. Movable block; 52. Installation groove; 53. Positioning screw 2; 54. Screw hole 2; 55. Connecting rod; 56. Hinge seat. Detailed implementation manners

[0058] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present invention.

[0059] The present invention provides a silicon carbide boat resistant to chemical erosion, which includes a first bottom support 1 and a second bottom support 2. It is characterized in that a connecting member 3 is arranged between the first bottom support 1 and the second bottom support 2. The connecting member 3 includes an insertion block 31 fixedly connected to one end of the second bottom support 2. An assembly groove 32 slidably matched with the insertion block 31 is formed at one end of the first bottom support 1 close to the second bottom support 2. A plurality of first screw holes 34 are formed in the insertion block 31 at equal intervals along the length direction of the insertion block 31. A positioning screw 33 threadedly matched with any one of the first screw holes 34 is inserted on the outer side of the first bottom support 1. Side support parts 4 are rotatably connected to the sides of the first bottom support 1 and the second bottom support 2 opposite to each other. An adjusting member 5 for adjusting the included angle between the side support part 4 and the corresponding first bottom support 1 and second bottom support 2 is arranged at the bottom ends of the first bottom support 1 and the second bottom support 2.

[0060] By matching the insertion block 31 with the assembly groove 32, then adjusting the assembly length of the insertion block 31 and the assembly groove 32, and after determining the assembly length of the insertion block 31, the positioning of the insertion block 31 is realized through the threaded cooperation of the positioning screw 33 and the corresponding first screw hole 34. In this way, the adjustment of the distance between the first bottom support 1 and the second bottom support 2 can be realized, so as to meet the loading of wafers of different sizes.

[0061] Furthermore, the cross-section of the first bottom support 1 is a U-shaped structure, and a plurality of first slots 11 are formed at the top of the first bottom support 1 along the length direction. Two ear seats 12 are integrally formed at both ends of the first bottom support 1, and an ear seat 13 is integrally formed in the middle of the first bottom support 1; the cross-section of the second bottom support 2 is a U-shaped structure, and a plurality of second slots 21 corresponding to the first slots 11 one by one are formed at the top of the second bottom support 2. Two ear seats 22 are integrally formed at both ends of the second bottom support 2, and an ear seat 23 is integrally formed in the middle of the second bottom support 2; the first slots 11 and the second slots 21 can limit the loading of the bottom of the wafer, so that the wafers are neatly arranged along the first slots 11 and the second slots 21.

[0062] Furthermore, the side support part 4 includes three side plates 41 arranged at equal intervals. The side plates 41 arranged at both ends are rotatably connected to the corresponding ear seats 12 and ear seats 22 through pins. The side plate 41 arranged in the middle is rotatably connected to the corresponding ear seats 13 and ear seats 23 through pins. A support plate 42 is integrally formed at the top ends of the three side plates 41. A plurality of third slots 43 corresponding to the first slots 11 one by one are formed on the support plate 42. The third slots 43 at the top of the support plate 42 can support the top of the wafer. In this way, the wafer can be supported at three points in cooperation with the first slots 11 and the second slots 21, so as to ensure the stability of the wafer.

[0063] Further, the adjusting member 5 includes a movable block 51. Installation grooves 52 that are slidably engaged with the movable block 51 are provided at the bottom ends of the first base 1 and the second base 2. A plurality of second screw holes 54 are provided in the movable block 51 along the length direction. Positioning screws two 53 that are threadedly engaged with the corresponding second screw holes 54 are inserted on the outer sides of the first base 1 and the second base 2. One end of the movable block 51 is rotatably connected to a connecting rod 55. The end of the connecting rod 55 away from the movable block 51 is rotatably connected to a hinge seat 56. The hinge seat 56 is fixedly connected to the corresponding side support portion 4.

[0064] Working principle: During use, by mating the insertion block 31 with the assembly groove 32 and then adjusting the assembly length of the insertion block 31 and the assembly groove 32, after determining the assembly length of the insertion block 31, the positioning of the insertion block 31 is achieved through the threaded engagement of the positioning screw one 33 and the corresponding first screw hole 34. In this way, the adjustment of the distance between the first base 1 and the second base 2 can be realized, so as to meet the loading of wafers of different sizes.

[0065] Then, by mating the movable block 51 with the installation groove 52 and connecting the two ends of the connecting rod 55 to the hinge seat 56 and the movable block 51 respectively through pin shafts, and moving the insertion block 31 to make it slide in the installation groove 52, the connecting rod 55 can be made to drive the side support portion 4 to rotate, thus realizing the adjustment of the angle between the side support portion 4 and the first base 1 and the second base 2, making the side support portion 4 match the wafers of the corresponding size. Finally, the positioning is carried out through the threaded engagement of the positioning screw two 53 and the corresponding second screw hole 54, so as to ensure stability during use. The whole structure can be flexibly adjusted according to the wafer size, enabling the silicon carbide boat to be adapted to the loading of multiple sizes, and greatly reducing the use cost of the silicon carbide boat.

[0066] Embodiment 1:

[0067] This embodiment provides a preparation method for a silicon carbide boat resistant to chemical erosion, including the following steps:

[0068] S1: Material preparation: Select high-purity silicon carbide powder with a particle size of 1 μm, then incorporate 5% polycaprolactam into the high-purity silicon carbide powder, and then add 5% boron nitride to obtain a mixture.

[0069] S2: Mixing and drying: Add the mixture in S1 to a ball mill and dry-mix for 2 hours to ensure uniform dispersion, and then dehydrate in a vacuum drying oven at 60 °C for 12 hours to obtain dry mixed powder.

[0070] S3: 3D print the mixed powder in S2 through a selective laser sintering rapid prototyping machine to respectively manufacture the blanks of the first base 1, the second base 2, the connecting member 3, the side support portion 4, and the adjusting member 5. The specific implementation process of a single blank is as follows:

[0071] A. Spread the mixed powder in S2 evenly on the sintering platform through a powder spreading device to form a powder layer with a thickness of 50 μm;

[0072] B. Preheat the sintering platform to remove moisture and gas in the powder layer, and the preheating temperature is 100 °C;

[0073] C. According to a pre-designed three-dimensional model, under the control of a computer, the laser beam scans the powder layer along a predetermined path. The scanning speed is 200 mm / s, the scanning spacing is 0.05 mm, and the energy of the laser beam rapidly raises the temperature of the powder particle surface and partially melts it, bonding it together with the surrounding powder particles. Among them, the laser power range is 100 W;

[0074] D. After completing the sintering of one layer of powder, the sintering platform descends by the thickness of a powder layer, then repowders and conducts the sintering of the next layer, and so on in a cycle until the entire three-dimensional model is completely sintered and formed;

[0075] E. After sintering is completed, let the sintered part cool naturally to room temperature;

[0076] S4: Post-treatment: Debind the sintered part in S3 to remove polycaprolactam, then conduct heat treatment to improve the density and strength of the sintered part, and finally deposit silicon nitride on the sintered part by chemical vapor deposition to obtain a modified silicon carbide boat fitting;

[0077] S5: Inspection and assembly: Inspect the appearance, dimensions, density, and strength of the silicon carbide boat fitting in S4, and meet the relevant standards of the photovoltaic and semiconductor industries, and then assemble them into a complete silicon carbide boat.

[0078] Through the modification treatment of the raw materials of the silicon carbide boat, the present invention can significantly improve the chemical erosion resistance of the silicon carbide boat, extend its service life, and ensure stability and reliability in a harsh chemical environment.

[0079] Example 2:

[0080] This example provides a preparation method for a chemically erosion-resistant silicon carbide boat, including the following steps:

[0081] S1: Material preparation: Select high-purity silicon carbide powder with a particle size of 30 μm, then incorporate 7% polycaprolactam into the high-purity silicon carbide powder, and then add 10% boron nitride to obtain a mixture;

[0082] S2: Mixing and drying: Add the mixture in S1 to a ball mill for dry mixing for 3 hours to ensure uniform dispersion, and then dehydrate it in a vacuum drying oven at 60 °C for 13 hours to obtain a dry mixed powder;

[0083] S3: Laser sintering: The mixed powder in S2 is subjected to 3D printing by a selective laser sintering rapid prototyping machine to prepare green bodies of the first base 1, the second base 2, the connecting member 3, the side support portion 4, and the adjusting member 5 respectively. The specific implementation process of a single green body is as follows:

[0084] A. The mixed powder in S2 is evenly spread on the sintering platform through a powder spreading device to form a powder layer with a thickness of 75 μm.

[0085] B. The sintering platform is preheated to remove moisture and gas in the powder layer, and the preheating temperature is 130 °C.

[0086] C. According to the pre-designed three-dimensional model, under the control of a computer, a laser beam scans the powder layer along a predetermined path. The scanning speed is 600 mm / s, the scanning pitch is 0.1 mm, and the energy of the laser beam causes the surface of the powder particles to rapidly heat up and partially melt, bonding with the surrounding powder particles. Among them, the laser power range is 250 W.

[0087] D. After completing the sintering of one layer of powder, the sintering platform descends by the thickness of a powder layer, and then powder is re-spread and the next layer is sintered. This process is repeated until the entire three-dimensional model is completely sintered and formed.

[0088] E. After sintering is completed, the sintered part is allowed to cool naturally to room temperature.

[0089] S4: Post-treatment: The sintered part in S3 is subjected to degreasing treatment to remove polycaprolactam, and then heat treatment is carried out to improve the density and strength of the sintered part. Finally, silicon nitride is deposited on the surface of the sintered part by chemical vapor deposition to obtain a modified silicon carbide boat fitting.

[0090] S5: Inspection and assembly: The silicon carbide boat fitting in S4 is inspected for appearance, dimensions, density, and strength, and meets the relevant standards of the photovoltaic and semiconductor industries, and then assembled into a complete silicon carbide boat.

[0091] Example 3:

[0092] This example proposes a preparation method of a silicon carbide boat resistant to chemical erosion, including the following steps:

[0093] S1: Material preparation: Select high-purity silicon carbide powder with a particle size of 50 μm, then incorporate 8% polycaprolactam into the high-purity silicon carbide powder, and then add 15% boron nitride to obtain a mixture.

[0094] S2: Mixing and drying: The mixture in S1 is added to a ball mill and dry-mixed for 4 hours to ensure uniform dispersion, and then dehydrated in a vacuum drying oven at 60 °C for 14 hours to obtain a dry mixed powder.

[0095] S3: Laser sintering: The mixed powder in S2 is subjected to 3D printing by a selective laser sintering rapid prototyping machine to obtain green bodies of the first base 1, the second base 2, the connecting member 3, the side support portion 4, and the adjusting member 5 respectively. The specific implementation process of a single green body is as follows:

[0096] A. The mixed powder in S2 is evenly spread on the sintering platform by a powder spreading device to form a powder layer with a thickness of 100 μm;

[0097] B. The sintering platform is preheated to remove moisture and gas in the powder layer, and the preheating temperature is 150 °C;

[0098] C. According to the pre-designed three-dimensional model, under the control of a computer, a laser beam scans the powder layer along a predetermined path. The scanning speed is 800 mm / s, the scanning pitch is 0.15 mm, and the energy of the laser beam rapidly raises the temperature of the powder particle surface and partially melts it, bonding it to the surrounding powder particles. Among them, the laser power range is 400 W;

[0099] D. After sintering one layer of powder, the sintering platform descends by the thickness of a powder layer, then powder is re-spread and the next layer of sintering is carried out. This cycle is repeated until the entire three-dimensional model is completely sintered and formed;

[0100] E. After sintering is completed, the sintered part is allowed to cool naturally to room temperature;

[0101] S4: Post-treatment: The sintered part in S3 is subjected to degreasing treatment to remove polycaprolactam, then heat treatment is carried out to improve the density and strength of the sintered part, and finally silicon nitride is deposited on the surface of the sintered part by chemical vapor deposition to finally obtain a modified silicon carbide crystal boat;

[0102] S5: Inspection and assembly: The silicon carbide crystal boat fittings in S4 are inspected for appearance, dimensions, density, and strength, and meet the relevant standards of the photovoltaic and semiconductor industries, and then assembled into a complete silicon carbide crystal boat.

[0103] Example 4:

[0104] This example proposes a preparation method of a chemically resistant silicon carbide crystal boat. Its preparation steps are basically the same as those of Example 1, and the only difference is that: during the post-treatment process, alumina is deposited on the surface of the sintered part by chemical vapor deposition to finally obtain a modified silicon carbide crystal boat.

[0105] Comparative Example 1:

[0106] This comparative example proposes a preparation method of a silicon carbide crystal boat. Its preparation steps are basically the same as those of Example 1, and the only difference is that: a sintered part of the silicon carbide crystal boat is obtained by means of static pressure forming and solidification sintering.

[0107] Comparative Example 2:

[0108] This comparative example presents a method for preparing a silicon carbide boat, and its preparation steps are basically the same as those of Example 1, with the only difference being that no chemical modification treatment is performed during the post-treatment process.

[0109] Test Example 1:

[0110] In this test example, the relative densities of the silicon carbide boats prepared in Example 1, Example 2, Example 3, and Comparative Example 1 were measured by the Archimedes method respectively. The specific test results are as Figure 7 shown;

[0111] As can be seen from Figure 7 , the compactness of the silicon carbide boat formed by 3D printing is higher than that of the traditional static pressure forming method. Therefore, the 3D printing process can effectively improve the compactness of the silicon carbide boat to meet the usage requirements under high temperature, high pressure, and corrosive environments;

[0112] As can be seen from Figure 7 , during the 3D printing process, the smaller the particle size of silicon carbide, the greater the compactness of the finally prepared silicon carbide boat.

[0113] Test Example 2:

[0114] In this test example, the chemical corrosion resistance tests of the silicon carbide boats prepared in Example 1, Comparative Example 1, and Comparative Example 2 were carried out respectively. The specific experimental steps are as follows:

[0115] First, the silicon carbide boats prepared in Example 1, Comparative Example 1, and Comparative Example 2 were respectively immersed in boiling concentrated sulfuric acid (98%, 300 °C) for 24 hours, and then the mass loss rate of each silicon carbide boat was detected. The calculation formula is as follows:

[0116] The specific test results are as Figure 8 shown;

[0117] Second, the silicon carbide boats prepared in Example 1, Comparative Example 1, and Comparative Example 2 were respectively immersed in an 80 °C 40% KOH solution for 48 hours, and then the mass loss rate of each silicon carbide boat was detected. The calculation formula is as follows:

[0118] The specific test results are as Figure 9 shown;

[0119] As can be seen from Figure 8 and Figure 9It can be seen that the mass loss rate of the 3D printed silicon carbide boat-shaped crystal in acidic and alkaline environments is lower than that of the traditional static pressure forming method. Therefore, the 3D printed silicon carbide boat-shaped crystal has better chemical corrosion resistance;

[0120] From Figure 8 and Figure 9 it can be seen that by chemically modifying the silicon carbide boat-shaped crystal by depositing a silicon nitride coating on its surface, the mass loss rate of the silicon carbide boat-shaped crystal is further reduced, which can effectively improve the chemical corrosion resistance of the silicon carbide boat-shaped crystal.

[0121] Test Example Three:

[0122] In this test example, the silicon carbide boat-shaped crystals prepared in Example 1 and Comparative Example 1 were respectively subjected to thermal shock tests: the silicon carbide boat-shaped crystals prepared in Example 1 and Comparative Example 1 were cycled 50 times between 1600 °C (N2 protection) and room temperature water quenching, and then the deformation amounts of each silicon carbide boat-shaped crystal were respectively detected, including the relative deformation rate and the warpage degree. The calculation formulas are as follows:

[0123] ΔL = L 热震后 -L 初始 , where Linitial is the initial length before the thermal shock experiment, and Lafter thermal shock is the measured length after cooling to room temperature after the thermal shock experiment. The specific test results Figure 10 are shown;

[0124] where h is the vertical height difference between the highest point of warpage and the reference plane, and L is the reference length of the boat-shaped crystal. The specific test results Figure 10 are shown;

[0125] From Figure 10 it can be seen that the deformation amount of the 3D printed silicon carbide boat-shaped crystal after the thermal shock experiment is significantly smaller than that of the traditional static pressure formed silicon carbide boat-shaped crystal. Therefore, the 3D printed silicon carbide boat-shaped crystal has better high temperature resistance.

[0126] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A silicon carbide boat resistant to chemical erosion, comprising a first base (1) and a second base (2), characterized in that, A connecting member (3) is provided between the first base (1) and the second base (2). The connecting member (3) includes an insertion block (31) fixedly connected to one end of the second base (2). An assembly groove (32) slidably engaged with the insertion block (31) is formed at one end of the first base (1) close to the second base (2). A plurality of first screw holes (34) are formed in the insertion block (31) and are equidistantly distributed along the length direction of the insertion block (31). A positioning screw rod one (33) threadedly engaged with any one of the first screw holes (34) is inserted on the outer side of the first base (1). Side support parts (4) are rotatably connected to the sides of the first base (1) and the second base (2) facing away from each other. An adjusting member (5) for adjusting the included angle between the side support part (4) and the corresponding first base (1) and second base (2) is provided at the bottom ends of the first base (1) and the second base (2).

2. A silicon carbide boat resistant to chemical erosion according to claim 1, wherein, The cross-section of the first base (1) is a U-shaped structure, and a plurality of first slots (11) are formed in the top of the first base (1) along the length direction. Two ear seats one (12) are integrally formed at both ends of the first base (1). An ear seat two (13) is integrally formed in the middle of the first base (1).

3. The silicon carbide boat resistant to chemical erosion according to claim 2, characterized in that, The cross-section of the second base (2) is a U-shaped structure, and a plurality of second slots (21) corresponding to the first slots (11) one by one are formed in the top of the second base (2). Two ear seats three (22) are integrally formed at both ends of the second base (2). An ear seat four (23) is integrally formed in the middle of the second base (2).

4. A silicon carbide boat resistant to chemical erosion according to claim 3, characterized in that, The side support part (4) includes three side plates (41) arranged at equal intervals. The side plates (41) arranged at both ends are rotatably connected to the corresponding ear seats one (12) and ear seats three (22) through pins. The side plate (41) arranged in the middle is rotatably connected to the corresponding ear seats two (13) and ear seats four (23) through pins. A support plate (42) is integrally formed at the top ends of the three side plates (41). A plurality of third slots (43) corresponding to the first slots (11) one by one are formed in the support plate (42).

5. A silicon carbide boat resistant to chemical erosion according to claim 1, characterized in that, The adjusting member (5) includes a movable block (51). Installation grooves (52) slidably engaged with the movable block (51) are formed at the bottom ends of the first base (1) and the second base (2). A plurality of second screw holes (54) are formed in the movable block (51) along the length direction. Positioning screw rods two (53) threadedly engaged with the corresponding second screw holes (54) are inserted on the outer sides of the first base (1) and the second base (2). One end of the movable block (51) is rotatably connected to a connecting rod (55). The end of the connecting rod (55) away from the movable block (51) is rotatably connected to a hinge seat (56). The hinge seat (56) is fixedly connected to the corresponding side support part (4).

6. A method for preparing a chemically resistant silicon carbide boat according to claim 1, characterized in that, Including the following steps: S1: Material preparation: Select high-purity silicon carbide powder with a particle size of 1 μm - 50 μm, then add 5% - 8% of a binder to the high-purity silicon carbide powder, and then add 5% - 15% of a sintering aid to obtain a mixture; S2: Mixing and drying: Add the mixture in S1 into a ball mill and dry-mix for 2 - 4 hours to ensure uniform dispersion, and then dehydrate in a vacuum drying oven at 60 °C for 12 - 14 hours to obtain a dried mixed powder; S3: Laser sintering: Use a selective laser sintering rapid prototyping machine to perform 3D printing on the mixed powder in S2 to separately produce green bodies of the first base (1), the second base (2), the connecting piece (3), the side support part (4), and the adjusting piece (5). The specific implementation process of a single green body is as follows: A. Evenly spread the mixed powder in S2 on the sintering platform through a powder spreading device to form a powder layer with a thickness of 50 μm - 100 μm; B. Preheat the sintering platform to remove moisture and gas in the powder layer, and the preheating temperature is 100 - 150 °C; C. According to the pre-designed three-dimensional model, under the control of a computer, the laser beam scans the powder layer along a predetermined path. The scanning speed is 200 - 800 mm / s, the scanning pitch is 0.05 - 0.15 mm, and the energy of the laser beam causes the surface of the powder particles to rapidly heat up and partially melt, bonding with the surrounding powder particles. Among them, the laser power range is 100 - 400 W; D. After completing the sintering of one layer of powder, the sintering platform descends by the thickness of a powder layer, and then powder is re-spread and the next layer of sintering is carried out. This cycle repeats until the three-dimensional model is completely sintered and formed; E. After sintering is completed, let the sintered part cool naturally to room temperature; S4: Post-treatment: Subject the sintered part in S3 to a debinding treatment to remove the binder, and then perform heat treatment to improve the density and strength of the sintered part. Then, deposit a surface modifier on the surface of the sintered part through chemical vapor deposition to finally obtain a modified silicon carbide boat fitting; S5: Inspection and assembly: Inspect the appearance, dimensions, density, and strength of the silicon carbide boat fitting in S4, and meet the relevant standards of the photovoltaic and semiconductor industries, and then assemble them into a complete silicon carbide boat.

7. The preparation method of a silicon carbide boat resistant to chemical erosion according to claim 6, characterized in that, The binder is selected from any one of polycaprolactam, polyethylene, and polypropylene, and the sintering aid is boron nitride, aluminum, or other non-oxidizing aids.

8. The preparation method of a chemically resistant silicon carbide boat according to claim 7, characterized in that, The working environment of the selective laser sintering rapid prototyping machine is controlled in a high-temperature and low-oxygen atmosphere to improve the sintering effect of silicon carbide.

9. The preparation method of a silicon carbide boat resistant to chemical erosion according to claim 6, characterized in that, In S4, the specific implementation process of the debinding treatment is as follows: (1). Place the sintered part in S3 in a nitrogen environment and heat it to 550 - 600 °C, and keep it warm for 3 - 4 hours to remove the binder; (2). Then soak the sintered part in acetone and perform ultrasonic cleaning to remove the residual organic matter to complete debinding.

10. The preparation method of a chemically resistant silicon carbide boat according to claim 9, characterized in that, In S4, the specific implementation process of the heat treatment is as follows: (1). Bury the debound sintered part in silicon powder so that the silicon powder completely buries the sintered part; (2). Then place it in a vacuum furnace and heat it to 1500 - 2200 °C. The silicon melt penetrates into the porous sintered part and reacts with free carbon to form silicon carbide, filling the pores to increase the density of the sintered part. Among them, the heating rate is 10 - 15 °C / min, the holding time is 3 - 4 hours, and it is taken out after cooling with the furnace to obtain a silicon carbide boat.

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