A suspension type fixing device for graphite piece surface coating and a coating equipment

Abstract

The utility model provides a kind of for graphite piece surface coating's suspension type fixing device and coating equipment, suspension type fixing device includes: airflow flow piece, induction coil, wherein airflow flow piece includes upper airflow orifice plate and lower airflow orifice plate;Airflow flow piece's inside is equipped with accommodating cavity;Induction coil is around and is arranged in the outside of airflow flow piece;Upper airflow flow channel is provided on the side wall of airflow flow piece in the upper side of the graphite piece to be coated coating, lower airflow flow channel is provided on the side wall of airflow flow piece in the lower side of the graphite piece to be coated coating, upper airflow orifice is equipped on upper airflow orifice plate, lower airflow orifice is equipped on lower airflow orifice plate, after upper airflow flow channel and lower airflow flow channel ventilation, and after induction coil power on, the graphite piece to be coated coating is suspended in accommodating cavity, to improve existing airflow distribution uneven, coating thickness uneven, the continuity of coating is poorer technical problem.

Description

Technical Field

[0001] This utility model relates to the field of graphite part processing technology, and in particular to a suspended fixing device and coating equipment for coating the surface of graphite parts. Background Technology

[0002] In silicon carbide crystal growth and epitaxial growth apparatus, graphite components, as core components, must withstand high temperatures (above 2000℃), high vacuum, and corrosive gas environments. Therefore, surface coating with high-temperature resistant coatings such as silicon carbide (SiC) and tantalum carbide (TaC) is a key means to improve their service performance. However, existing coating equipment has significant drawbacks: graphite components are mostly fixed in contact, such as being placed directly on a stage or supported or clamped by metal supports. This results in a "shadowing effect" at the contact points due to obstructed gas deposition, disrupting the continuity of the coating. This localized coating loss not only accelerates component wear, but the peeled coating fragments can also become heterogeneous nucleation centers for crystal growth, easily leading to fatal defects such as microtubes and dislocations, resulting in a decrease in crystal yield.

[0003] Meanwhile, existing coating equipment generally employs a single-sided or top-concentrated air intake structure, resulting in a significant concentration gradient of reactant gases on the graphite part surface. This leads to a difference in coating thickness exceeding ±10% in both the axial and radial directions. This thickness inhomogeneity causes a mismatch in the component's thermal expansion coefficient, generating accumulated internal stress during high-temperature cycling, ultimately leading to component deformation or even cracking, severely disrupting the temperature field stability of crystal growth. Furthermore, the bonding strength between the coating and the graphite part in traditional processes is generally below 35N. Uneven airflow distribution results in micropores and impurity aggregation at the deposition interface, making it prone to bulging and peeling during long-term high-temperature service. This not only contaminates the crystal growth environment but also compromises the airtightness of the equipment, forcing production to be interrupted for maintenance. Utility Model Content

[0004] In view of the shortcomings of the prior art, the present invention provides a suspended fixing device and coating equipment for coating the surface of graphite parts, so as to improve the technical problems of uneven airflow distribution and poor coating continuity in the existing technology.

[0005] This utility model provides a suspended fixing device for coating the surface of graphite parts, comprising: an airflow component and an induction coil, wherein the airflow component includes an upper airflow perforation plate and a lower airflow perforation plate.

[0006] The inner side of the airflow passage is provided with a receiving cavity for accommodating the graphite part to be coated, and the receiving cavity is used to introduce the reaction gas; the induction coil is used to pass an alternating current to generate electromagnetic levitation force, and the induction coil is arranged around the outer side of the airflow passage.

[0007] The system includes an upper airflow channel on the side wall of the airflow channel on the upper side of the graphite part to be coated, a lower airflow channel on the side wall of the airflow channel on the lower side of the graphite part to be coated, an upper airflow perforation plate on the inner side wall of the airflow channel at the upper airflow channel, and a lower airflow perforation plate on the inner side wall of the airflow channel at the lower airflow channel. The upper airflow perforation plate has an upper airflow hole connecting the upper airflow channel and the receiving cavity, and the lower airflow perforation plate has a lower airflow hole connecting the lower airflow channel and the receiving cavity. After the upper and lower airflow channels are ventilated and the induction coil is energized, the graphite part to be coated is suspended in the receiving cavity.

[0008] In one embodiment of the present invention, both the upper airflow passage and the lower airflow passage extend along the axial direction and pass through the airflow passage component;

[0009] And / or, the airflow passage is annular.

[0010] In one embodiment of this utility model, the ratio of the cross-sectional dimension of the upper airflow channel to the cross-sectional dimension of the lower airflow channel is 1:1 to 1:2.

[0011] In one embodiment of this utility model, the channel axis of the upper airflow hole is inclined, and the channel axis of the lower airflow hole is vertically upward.

[0012] In one embodiment of this utility model, the angle between the channel axis of the upper airflow hole and the radial direction is 10°-30° downwards.

[0013] In one embodiment of this utility model, the ratio of the opening size of the upper airflow hole to the opening size of the lower airflow hole is 1:1-1:2;

[0014] And / or, the ratio of the area of ​​the upper airflow orifice plate to the area of ​​the lower airflow orifice plate is 1:1 to 1:2.

[0015] In one embodiment of this utility model, the number of airflow holes on the upper airflow hole plate is 10-36 and they are evenly distributed;

[0016] And / or, the number of upper and lower airflow holes on the lower airflow orifice plate is 10-36 and they are evenly distributed.

[0017] In one embodiment of this utility model, the operating frequency of the induction coil is 10-100kHz.

[0018] In one embodiment of this utility model, a cooling element is provided between the induction coil and the airflow passage element, and the cooling element is used to introduce coolant, wherein:

[0019] The radial distance between the inner wall of the cooling component and the graphite part to be coated is 5-20 mm.

[0020] And / or, the cooling element is a hollow quartz tube or stainless steel tube arranged in a surrounding manner.

[0021] This utility model also provides a coating device, including the above-mentioned suspended fixing device for coating the surface of graphite parts.

[0022] The beneficial effects of this utility model are as follows: The suspended fixing device for coating graphite parts proposed in this utility model suspends the graphite part to be coated under the combined action of an alternating electric field and airflow by ventilating the upper and lower airflow channels of the airflow channel and energizing the induction coil. Compared with the contact fixing method of the prior art, this utility model adopts a suspended fixing method for graphite parts. This improves the "shadow effect" caused by obstructed gas deposition during the coating process, improves the local coating gaps, and improves the continuity of the coating. Furthermore, the upper and lower airflow channels ventilate on the upper and lower sides of the graphite part to be coated, respectively. Compared with the single-sided air intake or top concentrated air intake, this improves the uneven airflow distribution and the formation of a significant concentration gradient of reactive gases on the surface of the graphite part, thereby improving the uneven coating thickness of the graphite part. This achieves non-contact coating of graphite parts, improves coating uniformity, and provides high-performance graphite parts for fields such as silicon carbide crystal growth. Attached Figure Description

[0023] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0024] In the attached diagram:

[0025] Figure 1 This is a front sectional view of a suspended fixing device provided in an embodiment of the present invention;

[0026] Figure 2 Provided for an embodiment of this utility model Figure 1 A front sectional view of the airflow component in the middle section;

[0027] Figure 3 A schematic diagram illustrating the force analysis of a graphite component in a suspended fixing device according to an embodiment of the present invention;

[0028] Figure 4 Provided for an embodiment of this utility model Figure 2 A side sectional view of the airflow component.

[0029] The attached figures are labeled as follows:

[0030] 100. Induction coil; 200. Cooling component; 300. Airflow component; 301. Upper airflow channel; 302. Upper airflow perforated plate; 303. Lower airflow perforated plate; 304. Lower airflow channel; 305. Upper airflow hole; 306. Lower airflow hole; 400. Graphite part to be coated; 500. Receiving cavity. Detailed Implementation

[0031] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0032] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. The drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0033] In the following description, numerous details are explored to provide a more thorough explanation of embodiments of the present invention. However, it will be apparent to those skilled in the art that embodiments of the present invention may be practiced without these specific details. In other embodiments, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring embodiments of the present invention.

[0034] Please see Figure 1-4 This utility model provides a suspended fixing device and coating equipment for coating the surface of graphite parts. This is achieved by ventilating the upper airflow channel 301 and lower airflow channel 304 of the airflow passage 300, and energizing the induction coil 100. For specific implementation details, please refer to... Figure 3 (P1, P2, and P3 all represent pressure). The gas velocity (i.e., high-speed airflow) entering the upper airflow channel 301 is greater than the gas velocity (i.e., low-speed airflow) entering the lower airflow channel 304. According to Bernoulli's principle (Venturi effect), the pressure is lower where the airflow velocity is higher, and higher where the airflow velocity is lower. Therefore, P3 > P2 > P1. The airflow direction is as follows: Figure 3As shown by the middle arrow, the upper airflow channel 301 acts as a "suction cup," while the lower airflow channel 304 acts as an "air cushion," causing the graphite component to generate an upward force F. 浮 When the induction coil 100 is energized, it causes the graphite component to generate an upward force F. 抗 F 抗 +F 浮 =G, thereby enabling the graphite part 400 to be coated, placed in the receiving cavity 500, to be suspended under the combined action of alternating electric field and airflow. Compared with the contact fixing method of the prior art, the present invention adopts a graphite part suspension fixing method. In this way, during the coating process, the "shadow effect" caused by obstructed gas deposition is improved, the local coating is missing, and the continuity of the coating is disrupted. In addition, the upper airflow channel 301 and the lower airflow channel 304 respectively ventilate the upper and lower sides of the graphite part 400 to be coated. Compared with the single-sided air intake or top concentrated air intake method, the uneven airflow distribution is improved, the obvious concentration gradient of the reactive gas on the surface of the graphite part is improved, and the uneven coating thickness of the graphite part is improved. This realizes non-contact coating of graphite parts, improves coating uniformity, and provides high-performance graphite parts for fields such as silicon carbide crystal growth.

[0035] Please see Figure 1-2 The suspended fixing device includes: an airflow passage 300 and an induction coil 100, wherein the airflow passage 300 includes an upper airflow perforation plate 302 and a lower airflow perforation plate 303.

[0036] Please see Figure 1-2 The airflow passage 300 has an inner cavity 500 for accommodating the graphite part 400 to be coated. The cavity 500 is used to introduce the reaction gas, and the axis of the cavity 500 can extend in the horizontal direction. The induction coil 100 is used to introduce alternating current to generate electromagnetic levitation force. The induction coil 100 is arranged around the outer side of the airflow passage 300.

[0037] Please see Figure 1-4An upper airflow channel 301 is provided on the side wall of the airflow channel 300 on the upper side of the graphite part 400 to be coated, and a lower airflow channel 304 is provided on the side wall of the airflow channel 300 on the lower side of the graphite part 400 to be coated. An upper airflow perforation plate 302 is provided on the inner side wall of the airflow channel 300 at the upper airflow channel 301, and a lower airflow perforation plate 303 is provided on the inner side wall of the airflow channel 304. An upper airflow hole 305 is provided on the upper airflow perforation plate 302 to connect the upper airflow channel 301 and the receiving cavity 500, and a lower airflow hole 306 is provided on the lower airflow perforation plate 303 to connect the lower airflow channel 304 and the receiving cavity 500. After the upper airflow channel 301 and the lower airflow channel 304 are ventilated, and after the induction coil 100 is energized, the graphite part 400 to be coated is suspended in the receiving cavity 500.

[0038] In this embodiment, the combined effect of the alternating electric field and airflow achieves stable levitation of the graphite component within the receiving cavity 500 through dynamic force balance. The specific mechanism is as follows:

[0039] Please see Figure 3 From the perspective of force generation, the alternating electric field is the fundamental driving force for levitation. That is, when an alternating current of 10-100kHz is passed through the surrounding induction coil 100, an alternating electric field is generated, causing the graphite component to generate an upward electromagnetic levitation force F due to its antimagnetic properties. 抗 This provides the core upward force source for it to break free from contact; the role of airflow is reflected in the fine adjustment and balance of force. The flow velocity of the gas entering the upper airflow channel 301 (i.e., high-speed airflow) is greater than the flow velocity of the gas entering the lower airflow channel 304 (i.e., low-speed airflow). After the upper airflow channel 301 is ventilated, the gas enters the receiving cavity 500 through the upper airflow hole 305 of the upper airflow orifice plate 302. After the lower airflow channel 304 is ventilated, the gas enters the receiving cavity 500 through the lower airflow hole 306 of the lower airflow orifice plate 303. According to Bernoulli's principle (Venturi effect), where the airflow velocity is high, the pressure is low, and where the airflow velocity is low, the pressure is high. Therefore, P3 > P2 > P1. The airflow direction is as follows: Figure 3 As shown by the middle arrow, the upper airflow channel 301 acts as a "suction cup," while the lower airflow channel 304 acts as an "air cushion," causing the graphite component to generate an upward force F. 浮 From the perspective of balance logic, in the vertical direction, the electromagnetic levitation force F 抗 with force F 浮 Together they counteract the gravitational forces G and F of the graphite component. 抗 +F 浮=G, thereby preventing the graphite part from shifting in the vertical direction, and thus enabling the graphite part 400 to be coated in the cavity 500 to be suspended under the combined action of alternating electric field and airflow, realizing non-contact coating of graphite parts, improving coating uniformity, and providing high-performance graphite parts for fields such as silicon carbide crystal growth.

[0040] Please see Figure 4 Both the upper airflow channel 301 and the lower airflow channel 304 can extend axially and penetrate the airflow component 300, including but not limited to axially penetrating holes or grooves, to facilitate gas flow and thus form a stable airflow. The airflow component 300 can adopt various shapes readily conceived by those skilled in the art, including but not limited to squares, rectangles, etc.; in this embodiment, the airflow component 300 is annular, so that the gas introduced into the receiving cavity 500 along the upper airflow channel 301 and the lower airflow channel 304 can form a stable airflow on the surface of the graphite component, allowing the graphite component to be stably suspended within the receiving cavity 500; and the gas introduced into the receiving cavity 500 can surround the graphite component, thereby improving the uneven airflow distribution, and further improving the uneven coating thickness of the graphite component, improving coating uniformity, and providing high-performance graphite components for fields such as silicon carbide crystal growth.

[0041] The ratio of the cross-sectional dimensions of the upper airflow channel 301 to the lower airflow channel 304 can be 1:1-2. This allows the ratio to be adjusted according to actual usage requirements, thereby regulating F. 浮 The size of the airflow is adjusted to ensure symmetrical airflow distribution and further guarantee uniform force.

[0042] Please see Figure 4 The axis of the upper airflow hole 305 can be inclined, while the axis of the lower airflow hole 306 is vertically upward. This arrangement can better achieve force balance, ensure uniform airflow distribution, and allow the graphite part to be stably suspended within the receiving cavity 500. The angle α between the axis of the upper airflow hole 305 and the radial direction is 10°-30° downward, such as 10°, 15°, 20°, 27°, 30°, etc.; the flow velocity of the gas introduced into the upper airflow channel 301 can be 10-20 m / s (i.e., Figure 3 Medium to high speed airflow), such as 10 m / s, 15 m / s, 20 m / s, etc.; the flow velocity of the gas introduced into the lower airflow channel 304 can be 0-15 m / s (that is... Figure 3(Low-to-medium speed airflow), such as 1 m / s, 10 m / s, 15 m / s, etc.; the ratio of the opening size of the upper airflow hole 305 to the opening size of the lower airflow hole 306 can be 1:1-1:2. In specific implementation, the opening size of the upper airflow hole 305 can be 1-10 mm, and the opening size of the lower airflow hole 306 can be 1-8 mm; the ratio of the area of ​​the upper airflow hole 305 plate 302 to the area of ​​the lower airflow hole 306 plate 303 can be 1:1-1:2; the number of upper airflow holes 305 on the upper airflow hole 305 plate 302 can be 10-36 and evenly distributed, such as 10, 15, 20, 35, 36, etc.; the lower airflow hole 306 plate 302... The number of upper and lower airflow holes 306 can be 10-36 and evenly distributed, such as 10, 17, 26, 33, 36, etc. This allows for adjustment of the following parameters according to actual usage requirements: the angle α between the channel axis and radial direction of the upper airflow hole 305; the gas velocity in the upper airflow channel 301; the gas velocity in the lower airflow channel 304; the ratio of the opening size of the upper airflow hole 305 to the opening size of the lower airflow hole 306; the ratio of the area of ​​the upper airflow orifice plate 302 to the area of ​​the lower airflow orifice plate 303; the number of upper airflow holes 305 on the upper airflow orifice plate 302; and the number of upper and lower airflow holes 306 on the lower airflow orifice plate 303. This allows for adjustment of F. 浮 The size of the container ensures symmetrical airflow distribution, further guaranteeing uniform force and enabling the graphite component to be stably suspended within the 500-degree cavity.

[0043] The operating frequency of the induction coil 100 is 10-100kHz, such as 10kHz, 50kHz, 80kHz, 90kHz, 100kHz, etc. This allows the operating frequency of the induction coil 100 to be adjusted according to actual usage requirements, thereby regulating F. 抗 The size of the component further ensures the uniformity of force, enabling the graphite component to be stably suspended within the 500-degree cavity.

[0044] Please see Figure 1 A cooling element 200 is provided between the induction coil 100 and the airflow passage 300. The cooling element 200 is used to introduce coolant, which includes but is not limited to cooling water. The radial distance between the inner sidewall of the cooling element 200 and the graphite part 400 to be coated can be 5-20mm, such as 5mm, 8mm, 15mm, 17mm, 20mm, etc. The specific distance can be adjusted according to the actual use requirements to facilitate the cooling of the graphite part. The cooling element 200 can adopt various structural forms that are easy for those skilled in the art to conceive of, including but not limited to a hollow quartz tube or stainless steel tube arranged in a ring.

[0045] This utility model also provides a coating device, including the aforementioned suspended fixing device for coating the surface of graphite parts. The structure of the suspended fixing device is the same as above, and will not be described again here.

[0046] The present invention provides the following embodiments:

[0047] Example 1 (Graphite ring coated with TaC coating for silicon carbide crystal growth)

[0048] In this embodiment, the graphite part to be coated is a graphite ring in a silicon carbide crystal growth device, with dimensions of 203 mm inner diameter, 210 mm outer diameter, and a mass of 1128 g. A TaC coating with a thickness of 50 μm ± 5 μm needs to be coated on its inner and outer surfaces to improve its corrosion resistance.

[0049] The induction coil 100 is a copper coil (with a high-temperature resistant coating on the surface), and the coil parameters are as follows:

[0050] Number of coil turns N = 400 turns; current frequency f = 20 kHz; coil radius R = 0.1 mm;

[0051] The parameters of the airflow component 300 are as follows:

[0052] "Upper": The angle α between the channel axis of the upper airflow hole 305 and the radial direction is 30° downwards; the orifice diameter is 2mm, the number of orifice holes is 24, the orifice area is 80mm2, and the gas flow velocity is 5m / s.

[0053] "Down": The channel axis of the downflow orifice 306 is vertically upward; the orifice diameter is 3mm, the number of orifice openings is 24, the orifice area is 200mm2, and the gas flow velocity is 2m / s.

[0054] Coating effect: The coating thickness uniformity reaches 50μm±3μm, the surface roughness Ra=0.8μm, and the bonding force between the coating and the graphite substrate (scratch test) reaches more than 60N, which is much higher than the 35N of the traditional coating process.

[0055] Example 2 (Preparation of SiC coating by CVD method)

[0056] In this embodiment, the graphite part to be coated is a crucible (size Φ200×400mm, weight approximately 2100g);

[0057] Induction coil 100: 50-turn copper coil, 50kHz / 200A alternating current;

[0058] Airflow parameters: The gas flow rate in the upper airflow channel 301 is 12 m / s, and the gas flow rate in the lower airflow channel 304 is 6 m / s.

[0059] Process conditions: SiCl4 / CH4 / H2 = 80 / 50 / 800 sccm, reaction at 1550℃ / 80mbar for 6 hours;

[0060] Coating result: The coating thickness is 80±3μm, and there are no masking defects on the surface compared with the traditional coating process.

[0061] The coated graphite parts prepared in this embodiment are systematically optimized to fully meet the core requirements of silicon carbide crystal growth and epitaxial devices. In the crystal growth stage, the uniform SiC coating (thickness deviation ≤ ±3 μm) on the surface of the crucible significantly improves the consistency of thermal conduction, reducing the radial temperature difference from 15℃ in the traditional process to ≤ 5℃. This homogenization of the thermal field ensures the synchronous volatilization of silicon carbide raw material powder, forming a stable axial concentration gradient, which improves the mass transfer efficiency by 40%. This directly contributes to the uniformity of large-size crystal thickness (fluctuation narrowed to ±2%) and microtube defect density ≤ 3 cm³. -2 Low-defect crystal production.

[0062] For epitaxial growth processes, for example, the consistent thermal conductivity of the TaC-coated seed crystal cap (axial temperature difference ≤2℃) combined with the precise temperature control system of the device's heater reduces the epitaxial growth rate fluctuation to ±1.5%, and its surface flatness (flatness ≤5μm / 150mm) further promotes the formation of laminar flow distribution of reactive gases, reduces turbulence intensity by 60%, and improves the uniformity of epitaxial layer thickness from ±5% to ±1.5%, providing silicon carbide power devices with a defect density of less than 0.5cm². -2 High-quality substrate.

[0063] In terms of device reliability, for example, high-adhesion coatings (≥60N) endow graphite components with excellent thermal shock resistance. A typical example is the WC-coated sealing ring, which improves wear resistance by more than three times, increases high-temperature cycle life from 50 cycles to 150 cycles, reduces annual maintenance frequency by 60%, and lowers maintenance costs per unit by 500,000 yuan. Simultaneously, the ultra-strong adhesion between the coating and the substrate (peeling rate <0.1%) inhibits impurity release at the source, and, in conjunction with the vacuum system, stably suppresses the partial pressure of impurities (O2, H2O, etc.) in the growth chamber to 1×10⁻⁶. -8 Below Pa; the matching coefficient of thermal expansion due to uniform coating (Δα < 0.5 × 10⁻⁶) -6 / K), effectively avoiding thermal stress deformation and ensuring the airtightness of the device (leakage rate <1×10). -9 Pa·m 3 / s), enabling a significant leap in the cleanliness of the crystal growth environment.

[0064] This invention achieves a system-level breakthrough in terms of raw material volatility stability, material transport efficiency, defect suppression, and device durability through a four-pronged mechanism of thermal field homogenization, flow field laminarization, interface enhancement, and environmental purification, providing a fundamental guarantee for the manufacturing of high-performance silicon carbide crystals.

[0065] In typical applications of this invention, the suspended fixing device utilizes the synergistic effect of airflow suspension and alternating electric field to coat high-performance coatings onto the surface of graphite parts using chemical vapor deposition (CVD) and physical vapor transport (PVT) methods. For the CVD process, taking SiC coating as an example, the reactive gas (such as a mixture of SiCl4 and CH4) is delivered to the suspended graphite surface via a symmetrically distributed annular airflow path, where a gas-phase chemical reaction occurs at a high temperature of 1550-1600℃, generating SiC which is then uniformly deposited to form a dense coating. For the PVT process, taking TaC coating deposition as an example, gaseous raw materials (such as a mixture of sublimated TaCl5 and C3H8) are transported to the graphite surface via the airflow path, where solid-phase crystallization achieves coating growth. In both processes, the non-contact suspension design effectively eliminates airflow dead zones, ensuring uniform coverage of the reactants in three-dimensional space.

[0066] The coatings used on graphite components in this invention can include high-temperature protective materials such as SiC, TaC, and WC, with the selection tailored to the functional requirements of the components: SiC coatings, due to their lattice constant difference of less than 1% with silicon carbide crystals and excellent compatibility with raw materials, are particularly suitable for components that directly contact molten raw materials, such as crucibles and raw material tanks, and can suppress heterogeneous nucleation; TaC coatings, with their ultra-high melting point of 3880℃ and hardness of 1800-2100HV, possess both high-temperature stability and corrosion resistance, and are specifically used for components subjected to extreme heat loads, such as seed crystal caps and heater covers; WC coatings, with their excellent wear resistance and oxidation resistance (3 times longer lifespan than traditional coatings), are suitable for components that require frequent disassembly, such as crucible caps and sealing rings, significantly reducing maintenance frequency. All coatings exhibit uniformity in thickness deviation ≤ ±3μm and adhesion force ≥ 60N in the suspended airflow field, fundamentally avoiding the risk of high-temperature peeling.

[0067] In summary, this utility model relates to a suspension fixing device and coating equipment for coating graphite parts, specifically an apparatus for coating high-performance coatings on graphite surfaces. Through the synergistic effect of airflow suspension (Venturi effect) and alternating electric field (electromagnetic suspension), it achieves a non-contact state around the graphite parts during the coating process, while ensuring uniform distribution of reactant gases or gaseous raw materials on the graphite surface. This solves the core problems of "contact defects" and "uneven airflow" in traditional coating processes, significantly improving the coating thickness consistency, surface uniformity, and smoothness. It provides high-performance coated graphite components for silicon carbide crystal growth and epitaxial growth devices, and is particularly suitable for processes involving the preparation of high-temperature and corrosion-resistant coatings such as silicon carbide and tantalum carbide using physical vapor transport (PVT) and chemical vapor deposition (CVD) methods, significantly improving component performance. The suspended fixing device for coating the surface of graphite parts provided by this utility model can provide graphite parts coated with various crystals such as silicon carbide or gemstones. It is used to protect critical graphite parts from corrosion by gas components generated in the crystal growth atmosphere (such as silicon-rich gas generated by the high-temperature decomposition of raw materials during the growth of silicon carbide crystals), thereby improving the service life of critical graphite parts and crystal quality.

[0068] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

Claims

1. A suspended fixing device for coating the surface of graphite parts, characterized in that, include: An airflow passage (300) is provided on the inner side of which is a receiving cavity (500) for accommodating a graphite part (400) to be coated, and the receiving cavity (500) is used to introduce a reaction gas. An induction coil (100) is used to pass an alternating current to generate an electromagnetic levitation force. The induction coil (100) is arranged around the outside of the airflow passage (300). Among them, an upper airflow passage (301) is provided on the side wall of the airflow passage (300) on the upper side of the graphite part (400) to be coated, and a lower airflow passage (304) is provided on the side wall of the airflow passage (300) on the lower side of the graphite part (400) to be coated. An upper airflow perforated plate (302) is provided on the inner side wall of the airflow passage (300) at the upper airflow passage (301), and a lower airflow perforated plate (303) is provided on the inner side wall of the airflow passage (300) at the lower airflow passage (304). The upper airflow perforation plate (302) is provided with an upper airflow hole (305) connecting the upper airflow passage (301) and the receiving cavity (500), and the lower airflow perforation plate (303) is provided with a lower airflow hole (306) connecting the lower airflow passage (304) and the receiving cavity (500). After the upper airflow passage (301) and the lower airflow passage (304) are ventilated, and after the induction coil (100) is energized, the graphite part (400) to be coated is suspended in the receiving cavity (500).

2. The suspension fixing device for coating the surface of graphite parts according to claim 1, characterized in that, Both the upper airflow passage (301) and the lower airflow passage (304) extend along the axial direction and pass through the airflow passage (300); And / or, the airflow passage (300) is annular.

3. The suspension fixing device for coating the surface of graphite parts according to claim 1, characterized in that, The ratio of the cross-sectional dimensions of the upper airflow channel (301) to the cross-sectional dimensions of the lower airflow channel (304) is 1:1 to 1:

2.

4. The suspension fixing device for coating the surface of graphite parts according to any one of claims 1-3, characterized in that, The channel axis of the upper airflow hole (305) is inclined, and the channel axis of the lower airflow hole (306) is vertically upward.

5. The suspension fixing device for coating the surface of graphite parts according to claim 4, characterized in that, The angle between the channel axis of the upper airflow hole (305) and the radial direction is 10°-30° downwards.

6. The suspension fixing device for coating the surface of graphite parts according to claim 4, characterized in that, The ratio of the opening size of the upper airflow hole (305) to the opening size of the lower airflow hole (306) is 1:1 to 1:2; And / or, the ratio of the area of ​​the upper airflow perforated plate (302) to the area of ​​the lower airflow perforated plate (303) is 1:1 to 1:

2.

7. The suspension fixing device for coating the surface of graphite parts according to claim 4, characterized in that, The number of upper airflow holes (305) on the upper airflow perforation plate (302) is 10-36 and they are evenly distributed; And / or, the number of the lower airflow holes (306) on the lower airflow perforation plate (303) is 10-36 and they are evenly distributed.

8. The suspension fixing device for coating the surface of graphite parts according to claim 4, characterized in that, The operating frequency of the induction coil (100) is 10-100kHz.

9. The suspension fixing device for coating the surface of graphite parts according to claim 4, characterized in that, A cooling element (200) is provided between the induction coil (100) and the airflow passage (300), the cooling element (200) being used to introduce coolant, wherein: The radial distance between the inner wall of the cooling component (200) and the graphite component (400) to be coated is 5-20 mm. And / or, the cooling element (200) is a circumferentially arranged and hollow quartz tube or stainless steel tube.

10. A coating apparatus, characterized in that, Includes the suspended fixing device for coating the surface of graphite parts as described in any one of claims 1-9.

Images