Processing method of integrated heat shield

Abstract

This invention belongs to the technical field of single-crystal furnace thermal insulation devices, specifically relating to a processing method for an integrated heat shield. Through a step-by-step process involving the prefabrication and assembly of a core mold, a truncated conical insulation ring, and a lower splicing ring; the formation of an inner hard shell layer; the composite winding of the insulation felt layer; the composite formation of the outer hard shell layer; local reinforcement with annular protrusions; top and bottom edge sealing; and overall carbonization, the integrated composite molding of the various functional layers of the heat shield is achieved. This invention employs a resin adhesive system composed of phenolic resin, fiber powder, and methylcellulose. Through pre-impregnation of carbon fiber plates, reinforcement bonding with PAN-based carbon fiber soft felt, and tension binding of fiber filaments, the interlayer bonding strength and structural integrity are improved. Finally, a high-temperature carbonization process at 2000℃ is used to form a graphite crystal structure, resulting in a seamless, integrated heat shield product.

Description

Technical Field

[0001] This invention belongs to the technical field of single crystal furnace thermal insulation device, specifically relating to a processing method for an integrated thermal screen. Background Technology

[0002] In the pulling process of semiconductor silicon single crystal, germanium single crystal and sapphire single crystal, the heat shield is a key heat preservation component of the single crystal furnace hot field system. Its main function is to reduce the heat loss of the melt in the crucible to the outside radiation, reduce the energy consumption of single crystal growth, and at the same time stabilize the temperature distribution of the crystal growth interface by controlling the thermal field gradient, thereby ensuring the crystal quality and yield of the single crystal material.

[0003] In existing technologies, single-crystal furnace heat shields generally adopt a split structure design, that is, the outer heat shield liner, inner heat shield liner, heat shield insulation felt, and bottom ring carbon carbon component are formed by 3D weaving and vapor deposition. The components are usually formed by 3D weaving and vapor deposition of carbon carbon components, and then assembled into a cylindrical heat shield by stacking.

[0004] However, the split structure has the following technical drawbacks in practical applications:

[0005] Each component has a complex manufacturing process, a long production cycle, and high production costs;

[0006] Heat leakage and insulation performance degradation at seams: There are unavoidable physical seams between the split panels, which form thermal short-circuit channels under high-temperature conditions. Since the in-plane thermal conductivity of carbon / carbon composite materials is much lower than that through the thickness direction, direct contact at the seams causes heat to dissipate rapidly along the seams, significantly reducing the overall insulation efficiency of the heat shield and increasing the energy consumption cost of single crystal pulling; at the same time, silicon vapor or oxidizing gases can easily penetrate at the seams, accelerating material erosion.

[0007] Insufficient interlayer bonding strength: In the existing technology, when carbon carbon boards or carbon cloth boards are laid directly, due to the high rigidity and insufficient toughness of the materials themselves, it is difficult to bond tightly with the underlying materials, which easily creates interlayer gaps, resulting in low interlayer bonding strength and the risk of interlayer delamination during long-term use.

[0008] Poor overall structural integrity: Due to differences in thermal expansion coefficients and assembly constraints, stress concentration occurs at the joints of the various panels of the split heat shield. After long-term operation, cracks, loosening or deformation are likely to occur. Structural damage will change the local heat conduction characteristics, leading to distortion of the thermal field temperature gradient, which will affect the control of dislocation density and oxygen content in single crystal growth.

[0009] Therefore, there is an urgent need for an integrated heat shield processing method with good structural integrity, no risk of heat leakage at seams, and high interlayer bonding strength, in order to overcome the inherent technical defects of split structures and meet the stringent requirements of large-size single crystal growth for thermal field stability and energy saving. Summary of the Invention

[0010] To address the shortcomings of existing split-type heat shields, this invention provides a processing method for an integrated heat shield, employing a combination of step-by-step prefabrication and assembly with overall composite molding to achieve the overall molding of each functional layer of the heat shield.

[0011] The technical solution of the present invention is as follows:

[0012] A method for manufacturing an integrated heat shield, wherein the heat shield is used in the hot zone of a single crystal furnace, characterized by comprising the following steps:

[0013] S1. Prefabrication and assembly of the core mold, truncated cone insulation ring, and lower splicing ring: Prefabricate a core mold matching the crucible shape; cut carbon carbon plates to the dimensions of the truncated cone shape, wrap them around the cone mold, apply resin adhesive between layers, and then cure and carbonize the entire assembly together with the cone mold; subsequently, machine to prefabricate a truncated cone insulation ring conforming to the design dimensions; wrap carbon felt around a cylindrical mold, apply resin adhesive between layers to form a ring-shaped blank, and then cure and carbonize the entire assembly together with the cylindrical mold; subsequently, remove the ring-shaped blank, attach carbon carbon plates to the outer surface of the ring-shaped blank, and prefabricate a lower splicing ring conforming to the design dimensions; fit the truncated cone insulation ring onto the core mold, the truncated cone insulation ring being truncated cone-shaped with an upper port diameter larger than the lower port diameter; fit the lower splicing ring onto the core mold and position it below the truncated cone insulation ring, the truncated cone insulation ring and the lower splicing ring together forming the inner support skeleton of the heat shield.

[0014] By prefabricating the truncated conical insulation ring and the lower splicing ring separately, independent quality control and precision machining of each component can be achieved. The truncated conical cylindrical structure of the insulation ring matches the shape of the crucible cone, forming a gradual thermal field gradient. The lower splicing ring adopts a composite structure of carbon felt wrapped around the outside and carbon carbon plate attached, which not only ensures the insulation performance but also enhances the strength of the bottom structure. The two together form a complete inner support skeleton, providing a stable forming foundation for the subsequent laying of each layer.

[0015] S2, Inner wall hard shell layer forming: Inner wall forming material is laid on the outer surface of the core mold, the truncated cone insulation ring and the lower splicing ring. The inner wall forming material is one or more of carbon fiber cloth, carbon fiber winding layer, carbon carbon plate or carbon cloth plate. After the inner wall forming material is impregnated with resin adhesive, it is cured together with the core mold to form an inner wall hard shell layer preform.

[0016] The inner hard shell layer is laid close to the outer surface of the truncated cone insulation ring and the lower splicing ring, forming the inner bearing structure of the heat shield. This protects the inner insulation layer from direct radiation from the high-temperature melt, while also providing an bonding interface with the outer insulation layer, thus achieving the inner layer support of the hard-soft-hard composite structure.

[0017] S3, Composite winding of thermal insulation felt layer: A resin adhesive is applied to the outer surface of the prefabricated inner hard shell layer, and carbon felt is wound around it circumferentially. A resin adhesive is applied between the layers, and the whole is cured again to form a thermal insulation felt layer. The carbon felt is one or more of the following: adhesive-based carbon felt, polyacrylonitrile-based carbon felt, or asphalt-based soft felt. A ring-shaped carbon board is bonded to the bottom of the thermal insulation felt layer.

[0018] As the core thermal insulation layer of the heat shield, the thermal insulation felt layer is made of soft carbon felt spirally wound around the circumference to form a continuous thermal insulation layer, which completely eliminates the physical seams caused by the cutting and splicing of traditional split panels, and solves the problem of heat leakage and gas penetration at the source. Resin adhesive is applied between the layers to ensure tight bonding between the layers, and a ring carbon board is bonded to the bottom to enhance the structural strength and thermal insulation performance of the bottom area.

[0019] S4, outer hard shell layer composite molding: a resin adhesive is applied to the outer surface of the insulation felt layer and wrapped with one or more combinations of carbon carbon board or carbon cloth board, and then cured as a whole to form an outer hard shell layer.

[0020] The outer hard shell layer serves as the external load-bearing structure of the heat shield, utilizing the flexible buffering effect of the middle insulation felt layer to absorb the expansion stress during the thermal cycle, while providing mechanical protection and structural support.

[0021] S5, Local reinforcement of annular protrusions: Carbon felt is wrapped around the top sidewall of the outer hard shell layer, and resin adhesive is applied between the layers to form annular protrusions; the carbon felt is one or more of the following: adhesive-based carbon felt, polyacrylonitrile-based carbon felt, or asphalt-based soft felt.

[0022] The annular protrusion serves as a localized reinforcement structure at the top of the heat shield. It is filled with soft carbon felt to form a localized insulation reinforcement zone, enhancing the insulation performance and structural strength of the top area. It also facilitates installation in conjunction with other components of the single crystal furnace.

[0023] S6, Top and bottom edge sealing treatment: Cover the top end face of the inner hard shell layer, the thermal insulation felt layer, the outer hard shell layer, and the local thermal insulation reinforcement layer with an annular carbon carbon plate to form a top seal; cover the bottom end face of the lower splicing ring, the inner hard shell layer, the thermal insulation felt layer, and the outer hard shell layer with a bottom carbon carbon plate, which extends to the side and is bonded and fixed to the thermal insulation felt layer by resin adhesive; drill a hole at the position where the outer hard shell layer and the bottom carbon carbon plate overlap, the hole penetrating the outer hard shell layer and the bottom carbon carbon plate and extending into the thermal insulation felt layer, and insert carbon carbon screws for fixation.

[0024] The purpose of step S6 above is to: seal the top to prevent heat loss from the top and ensure the integrity between the layers; and seal the bottom edge by extending to the side through the bottom carbon carbon plate and using a double fixing process of "adhesion + screw" to form a reliable overall anchor for the bottom splicing ring, the thermal insulation felt layer and the outer hard shell layer, effectively resisting high temperature load and thermal stress cycle, and preventing the bottom from cracking and peeling.

[0025] S7, Overall Carbonization: The composite-molded heat shield blank is placed in a carbonization furnace and heated to 2000℃ in an inert atmosphere for high-temperature carbonization treatment to remove non-carbon elements and form graphite crystals. Finally, the core mold is removed to obtain the integrated heat shield finished product.

[0026] This step involves the simultaneous carbonization and shrinkage of the introduced resin binder to form a uniform carbonaceous bonding phase. This results in a seamless integral carbon / carbon composite material structure consisting of the inner hard shell layer, the insulation felt layer, the outer hard shell layer, the truncated conical insulation ring, and the lower splicing ring. At the same time, it eliminates non-carbon elements to form graphite crystals, thereby improving the material's high-temperature resistance and thermal stability.

[0027] Furthermore, the resin adhesive is a mixture of phenolic resin, fiber powder, and methylcellulose. The phenolic resin serves as the matrix to provide adhesive strength, the fiber powder (such as carbon fiber powder) acts as a reinforcing phase to improve interlayer bonding strength and toughness, and the methylcellulose acts as a thickener to improve the resin's brushability and permeability. This mixture forms a carbonaceous bonding phase after high-temperature carbonization, which has a better match with the thermal expansion coefficient of the carbon / carbon composite material, reducing the risk of cracking and delamination during the carbonization process.

[0028] Furthermore, in step S3, the insulation felt layer is spirally wound in the circumferential direction, and the amount of interlayer resin adhesive applied is 0.2 kg / m², to ensure that the interlayer bonding is tight and there are no gaps, thereby achieving a balance between interlayer bonding strength and carbonization stability.

[0029] Furthermore, before laying, the carbon carbon board or carbon cloth board described in step S2 or S4 is pre-impregnated with phenolic resin to allow the resin to fully penetrate into the material, improving the toughness and plasticity of the carbon carbon board or carbon cloth board, facilitating bonding and molding on the core mold surface, and reducing the risk of cracks and breakage during the laying process. Then, after the carbon carbon board or carbon cloth board is wound, a layer of polyacrylonitrile-based carbon fiber soft felt is wound around its outer surface. The polyacrylonitrile-based carbon fiber soft felt serves as a transition layer, filling the microscopic unevenness on the surface of the carbon carbon board or carbon fiber cloth and improving the interlayer bonding strength. Finally, fibers are wound around the polyacrylonitrile-based carbon fiber soft felt and a tension of 50-100N is applied. The tension applies a compressive force to the carbon carbon board or carbon fiber cloth, making it tightly bonded to the underlying material, eliminating interlayer gaps, and fixing the position of the carbon carbon board or carbon cloth board to prevent displacement or loosening in subsequent processes.

[0030] Compared with the prior art, the integrated heat shield processing method provided by the present invention has the following beneficial effects:

[0031] (1) Eliminate seam defects and achieve seamless integral molding: The layered composite winding process is adopted. The inner hard shell layer, the heat insulation felt layer, the outer hard shell layer, the truncated cone heat insulation ring, and the lower splicing ring are composite molded on the mold in one step. Each functional layer forms a continuous whole through resin bonding and winding tension, which completely eliminates the physical seams and assembly gaps caused by traditional split plate cutting and splicing, and solves the problem of heat leakage and gas penetration from the source.

[0032] (2) Improve interlayer bonding strength and prevent delamination failure: Through the pre-impregnation treatment of carbon carbon board, the reinforcement bonding of PAN-based carbon fiber soft felt and the tension binding process of fiber filament, a dual combination of chemical bonding and mechanical interlocking is formed between the flexible thermal insulation felt layer and the rigid hard shell layer. After carbonization, the interlayer shear strength is significantly improved, avoiding the risk of interlayer delamination during long-term use and ensuring the integrity of the "hard-soft-hard" composite structure.

[0033] (3) Bottom reinforcement connection to solve mechanical weakness: By extending the bottom carbon plate to the side and using the "adhesive + screw" double fixing process, the bottom splicing ring, the heat insulation felt layer and the outer hard shell layer are reliably anchored as a whole. After carbonization, this connection method forms a synergistic effect of carbon bond phase and mechanical fastening, effectively resisting high temperature load and thermal stress cycle, and preventing bottom cracking and peeling.

[0034] (4) Optimize the performance of the resin adhesive and improve carbonization stability: A mixture of phenolic resin, fiber powder and methyl cellulose is used as the resin adhesive, which improves the shrinkage characteristics and thermal expansion coefficient matching of single phenolic resin, reduces the risk of cracks and delamination during carbonization, and improves the overall structural stability of the heat shield. Attached Figure Description

[0035] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0036] The processing method of the present invention will be described in detail below with reference to specific embodiments.

[0037] Example 1: This example is for processing an integrated heat shield in a 37-inch monocrystalline silicon growth furnace, using a mixture of phenolic resin, fiber powder and methylcellulose as the resin binder system.

[0038] S1, prefabrication and assembly of core mold, truncated cone insulation ring and lower splicing ring:

[0039] A detachable metal core mold is prepared, the shape of which matches the shape of the crucible in a 37-inch single-crystal silicon growth furnace.

[0040] Prefabrication of the truncated cone insulation ring: A 2mm thick carbon fiber plate is used, cut to the dimensions of a truncated cone. The cut carbon fiber plate is laid circumferentially on a truncated cone-shaped metal mold, with phenolic resin adhesive applied between layers at a rate of 0.15 kg / m². The prefabricated body, along with the mold, is placed in a hot air circulating oven for curing. The curing process involves holding at 90℃ for 1 hour, 110℃ for 1 hour, and 150℃ for 1 hour. After curing, the prefabricated body is placed in a carbonization furnace for high-temperature carbonization at 2000℃ under an inert atmosphere. After cooling, it is machined according to the design dimensions to obtain the finished truncated cone insulation ring with an upper diameter larger than the lower diameter.

[0041] Pre-fabrication of the lower splicing ring: Adhesive-based carbon felt is wound circumferentially around a cylindrical metal mold to form a ring-shaped blank. Phenolic resin adhesive is applied between layers at a rate of 0.2 kg / m². The wound blank, along with the mold, is placed in a hot air circulating oven for curing. The curing process involves holding at 90℃ for 1 hour, 110℃ for 1 hour, and 150℃ for 1 hour. After curing, the blank is placed in a carbonization furnace for high-temperature carbonization at 2000℃ under an inert atmosphere. After cooling, the ring-shaped blank is removed, and a 3 mm thick carbon fiber plate is bonded to its outer surface to form the finished lower splicing ring.

[0042] The prefabricated truncated cone insulation ring is fitted onto the upper section of the core mold, and the lower splicing ring is fitted onto the lower section of the core mold and located below the truncated cone insulation ring. The truncated cone insulation ring and the lower splicing ring cooperate to form the inner support skeleton of the heat shield.

[0043] S2, Inner wall hard shell layer forming:

[0044] Inner wall molding material is laid on the outer surfaces of the core mold, the truncated cone insulation ring, and the lower splicing ring. In this embodiment, T300 carbon fiber cloth with pre-impregnated phenolic resin is used as the inner wall molding material, and two layers are laid. First, the first layer of carbon fiber cloth is laid circumferentially on the surface of the core mold, the truncated cone insulation ring, and the lower splicing ring, and is rolled back and forth three times with a soft rubber roller to remove air bubbles and distribute the resin evenly. Then, the second layer of carbon fiber cloth is laid circumferentially, and is also rolled back and forth three times with a soft rubber roller. After the laying is completed, the entire core mold is placed in a hot air circulating oven for curing treatment. The curing process is to keep it at 90°C for 1 hour, at 110°C for 1 hour, and at 150°C for 1 hour to form a prefabricated inner wall hard shell layer with a thickness of about 3 mm.

[0045] S3, composite winding of thermal insulation felt layer:

[0046] A resin adhesive is uniformly applied to the outer surface of the inner hard shell prefabricated layer. The resin adhesive is a mixture of phenolic resin, carbon fiber powder, and methylcellulose in a mass ratio of 100:5:2, with a coating amount of 0.2 kg / m². Adhesive-based carbon felt is spirally wound circumferentially, with a layer of resin adhesive applied after each layer of felt is wound, for a total of 8 layers, each approximately 5 mm thick. A ring-shaped carbon fiber plate, pre-impregnated with phenolic resin, is bonded to the corresponding position at the bottom of the insulation felt layer. After winding, the entire core mold is placed in a hot air circulating oven for curing. The curing process involves holding at 90°C for 1 hour, 110°C for 1 hour, and 150°C for 1 hour, forming an insulation felt layer approximately 40 mm thick.

[0047] S4, outer hard shell composite molding:

[0048] A resin adhesive is uniformly applied to the outer surface of the insulation felt layer. The resin adhesive is a mixture of phenolic resin, carbon fiber powder, and methylcellulose, with a mass ratio of 100:5:2. Prepreg carbon carbon board is used as the outer wall molding material. The prepreg carbon carbon board is pre-dried at 40°C for 8 hours to improve its toughness and plasticity. After drying, the prepreg carbon carbon board is cut according to the shape of the insulation felt layer and laid circumferentially on the outer surface of the insulation felt layer, with resin adhesive applied between layers. After laying, a 2mm thick layer of polyacrylonitrile-based carbon fiber soft felt is wrapped around the outer surface of the carbon carbon board. Then, fibers are wound around the PAN-based carbon fiber soft felt using a winding machine and a tension of 80N is applied to tighten and fix the carbon carbon board. Finally, the entire core mold is placed in a hot air circulating oven for curing treatment. The curing process is 90°C for 1 hour, 110°C for 1 hour, and 150°C for 1 hour, forming an outer wall hard shell layer with a thickness of about 5mm.

[0049] S5, localized reinforcement with annular protrusion:

[0050] Adhesive-based carbon felt is wound around the top sidewall of the outer hard shell layer, and a resin adhesive is applied between the layers. The resin adhesive is a mixture of phenolic resin, carbon fiber powder, and methylcellulose in a mass ratio of 100:5:2, and is wound in three layers to form annular protrusions. After winding, the entire mandrel is placed in a hot air circulating oven for curing treatment. The curing process involves holding at 90℃ for 1 hour, at 110℃ for 1 hour, and at 150℃ for 1 hour.

[0051] S6, top and bottom edge sealing:

[0052] Cut the top annular carbon fiber plate and the bottom carbon fiber plate. Apply resin adhesive evenly to the top end face of each layer, covering the top annular carbon fiber plate to form a top seal. Apply resin adhesive to the bottom end face, covering the bottom carbon fiber plate. The bottom carbon fiber plate extends 50mm to the side to form a flange edge, which is simultaneously bonded and fixed to the lower end face of the outer hard shell layer and the bottom of the insulation felt layer using resin adhesive. Drill holes at the overlap position of the outer hard shell layer and the bottom carbon fiber plate, penetrating both layers and extending approximately 10mm into the insulation felt layer. Insert carbon fiber screws for mechanical fixation, forming a heat shield blank with dual anchoring of mechanical connection and chemical bonding.

[0053] S7, overall carbonization:

[0054] The composite preform formed by steps S1-S6, along with the metal core mold, is integrally placed into a carbonization furnace for high-temperature carbonization under an inert atmosphere. The carbonization process is as follows: the temperature is increased from room temperature to 800°C at a rate of 5°C / min and held for 2 hours; then increased to 2000°C at a rate of 3°C / min and held for 3 hours; finally, it is cooled in the furnace to below 150°C before being removed from the furnace. At this point, the resin binder introduced in each step of S1-S6 has simultaneously carbonized and shrunk, forming a uniform carbonaceous bonding phase. This results in a seamless integral carbon / carbon composite material structure consisting of the inner hard shell layer, the insulation felt layer, the outer hard shell layer, the truncated conical insulation ring, and the lower splicing ring. After removing from the furnace, the core mold is removed, yielding the integrated heat shield product.

[0055] The integrated heat shield prepared in this embodiment, after testing, has an interlaminar shear strength of over 15 MPa and a thermal conductivity of less than 0.15 W / (m·K). After continuous operation at 1600℃ for 500 hours, there is no delamination or cracking. Its thermal insulation performance is more than 20% higher than that of traditional split heat shields.

Claims

1. A method for processing an integrated heat shield, wherein the heat shield is used in the hot zone of a single crystal furnace, characterized in that... Includes the following steps: S1. Prefabrication and assembly of the core mold, truncated cone insulation ring, and lower splicing ring: Prefabricate a core mold matching the crucible shape; cut carbon carbon plates to the unfolded dimensions of a truncated cone shape, wrap them around a cone mold, apply resin adhesive between layers, and then cure and carbonize the entire assembly together with the cone mold; subsequently, machine to prefabricate a truncated cone insulation ring conforming to the design dimensions; wrap carbon felt around a cylindrical mold, apply resin adhesive between layers to form a ring-shaped blank, and then cure and carbonize the entire assembly together with the cylindrical mold; subsequently, remove the ring-shaped blank, attach carbon carbon plates to the outer surface of the ring-shaped blank, and prefabricate a lower splicing ring conforming to the design dimensions; fit the truncated cone insulation ring onto the core mold, the truncated cone insulation ring being truncated cone-shaped with an upper port diameter larger than the lower port diameter; fit the lower splicing ring onto the core mold and position it below the truncated cone insulation ring, the truncated cone insulation ring and the lower splicing ring together forming the inner support skeleton of the heat shield; S2, Inner wall hard shell layer forming: Inner wall forming material is laid on the outer surface of the core mold, the truncated cone insulation ring and the lower splicing ring. The inner wall forming material is one or more of carbon fiber cloth, carbon fiber winding layer, carbon carbon plate or carbon cloth plate. After the inner wall forming material is impregnated with resin adhesive, it is cured together with the core mold to form an inner wall hard shell layer preform. S3, Composite winding of thermal insulation felt layer: A resin adhesive is applied to the outer surface of the prefabricated inner hard shell layer, and carbon felt is wound around it circumferentially. A resin adhesive is applied between the layers, and the whole is cured again to form a thermal insulation felt layer. The carbon felt is one or more of the following: adhesive-based carbon felt, polyacrylonitrile-based carbon felt, or asphalt-based soft felt. A ring-shaped carbon board is bonded to the bottom of the thermal insulation felt layer. S4, outer hard shell layer composite molding: the outer surface of the insulation felt layer is coated with resin adhesive and wrapped with one or more combinations of carbon carbon board or carbon cloth board, and then cured as a whole to form an outer hard shell layer. S5, Local reinforcement of annular protrusion: Carbon felt is wrapped around the top sidewall of the outer hard shell layer, and resin adhesive is applied between the layers to form annular protrusion; the carbon felt is one or more of the following: adhesive-based carbon felt, polyacrylonitrile-based carbon felt, or asphalt-based soft felt. S6, Top and bottom edge sealing treatment: A ring-shaped carbon fiber plate is covered on the top end face of the inner hard shell layer, the thermal insulation felt layer, the outer hard shell layer, and the local thermal insulation reinforcement layer to form a top seal; a bottom carbon fiber plate is covered on the bottom end face of the lower splicing ring, the inner hard shell layer, the thermal insulation felt layer, and the outer hard shell layer, and the bottom carbon fiber plate extends to the side and is bonded and fixed to the thermal insulation felt layer by resin adhesive; a hole is drilled at the position where the outer hard shell layer and the bottom carbon fiber plate overlap, the hole penetrates the outer hard shell layer and the bottom carbon fiber plate and extends into the thermal insulation felt layer, and carbon fiber screws are inserted for fixation; S7, Overall Carbonization: The composite-molded heat shield blank is placed in a carbonization furnace and heated to 2000℃ in an inert atmosphere for high-temperature carbonization treatment to remove non-carbon elements and form graphite crystals. Finally, the core mold is removed to obtain the integrated heat shield finished product.

2. The processing method of the integrated heat shield as described in claim 1, characterized in that: The resin adhesive is a mixture of phenolic resin, fiber powder, and methylcellulose.

3. The processing method of the integrated heat shield as described in claim 2, characterized in that: In step S3, the insulation felt layer is spirally wound in the circumferential direction, and the amount of resin adhesive applied between the layers is 0.2 kg / m², to ensure that the layers are tightly bonded and without any gaps.

4. The processing method of the integrated heat shield as described in claim 1, characterized in that: Before laying, the carbon carbon board or carbon cloth board described in step S2 or S4 is pre-impregnated with phenolic resin. After the carbon carbon board or carbon cloth board is wound, a layer of polyacrylonitrile-based carbon fiber soft felt is wound on its outer surface. Finally, fiber filaments are wound around the polyacrylonitrile-based carbon fiber soft felt and a tension of 50 to 100 N is applied.

Images