Carbon fiber composite, method of manufacture, screening method and use

Abstract

This invention discloses carbon fiber composite materials, their preparation methods, screening methods, and applications. The carbon fiber composite material has a bending transmittance of 1-2.1 MPa, where bending transmittance = transmittance at 260 nm wavelength × upper surface bending strength. This application achieves a balance between material density, interfacial bonding, and microstructure through raw material proportioning and a gradient carbonization-graphitization process, thereby controlling its bending transmittance within the range of 1-2.1 MPa and significantly improving its service life.

Description

Technical Field

[0001] This invention relates to the field of carbon fiber technology, and more specifically, to carbon fiber composite materials, preparation methods, screening methods, and applications. Background Technology

[0002] Carbon fiber composites are widely used in semiconductor manufacturing due to their excellent properties such as lightweight, high strength, high temperature resistance, and chemical stability, especially as a key consumable in wafer fabrication. In SiC (silicon carbide) crystal growth processes, the high-temperature environment reaches over 2000℃, accompanied by the strong corrosive effect of silicon vapor, placing extremely high demands on material performance. Current technologies improve the mechanical properties of carbon fiber composites by optimizing fiber arrangement and interfacial bonding strength, and enhance corrosion resistance through surface treatment techniques such as chemical vapor deposition. However, in practical applications, the material still faces two technical bottlenecks: firstly, the inherent brittleness of carbon fibers leads to insufficient toughness, making them prone to microcracks under thermal shock conditions; secondly, silicon vapor penetration erodes the interfacial bonding zone between the matrix resin and the fibers, causing a sharp decline in material performance. These problems often lead to premature failure of existing carbon fiber composites in the extreme conditions of SiC crystal growth furnaces due to thermal stress cracking and surface spalling, significantly shortening their service life.

[0003] In view of this, the present invention is proposed. Summary of the Invention

[0004] The purpose of this invention is to provide carbon fiber composite materials, preparation methods, screening methods, and applications, which are beneficial for extending the service life of carbon fiber composite materials used in consumables for silicon carbide crystal growth.

[0005] This invention is implemented as follows: In a first aspect, the present invention provides a carbon fiber composite material, wherein the bending transmittance of the carbon fiber composite material is 1-2.1 MPa, wherein the bending transmittance = transmittance at a wavelength of 260 nm × bending strength of the upper surface.

[0006] In an optional embodiment, the flexural strength of the carbon fiber composite material is 1-1.1 MPa.

[0007] In an optional embodiment, the flexural strength of the carbon fiber composite material is 1.4-1.5 MPa.

[0008] In an optional embodiment, the flexural strength of the carbon fiber composite material is 1.9-2.1 MPa.

[0009] In a second aspect, the present invention provides a method for preparing carbon fiber composite material according to any one of the foregoing embodiments, comprising: cold pressing a mixture of raw materials to obtain a composite molding material; The composite molding material is subjected to heat treatment, carbonization, and graphitization in sequence to obtain the carbon fiber composite material.

[0010] In an optional embodiment, the raw material mixture comprises, by weight, the following components: 1 part pitch coke powder, 1-1.2 parts pitch-based carbon fiber powder, 0.15-0.25 parts PEG6000 powder, 0.15-0.25 parts graphene microsheets, and 0.1-0.3 parts phenolic resin.

[0011] In an optional embodiment, the cold pressing pressure is 15-30 MPa and the temperature is 18-30°C; And / or, the heat treatment includes heating the composite molding material to 148-152°C at 4-6°C / min and holding it at that temperature for 9-11 hours, and then cooling it to 18-30°C; And / or, the carbonization includes: using an inert gas as a protective gas, first heating the heat-treated composite molding material to 313-317℃ at 0.3-0.5℃ / min and holding it at that temperature for 2-4 hours; then heating it to 378-382℃ at 0.5-0.7℃ / min and holding it at that temperature for 2-4 hours; and finally heating it to 1100-1200℃ at 0.3-0.5℃ / min and holding it at that temperature for 9-11 hours to obtain a crude product; And / or, the graphitization includes: using an inert gas as a protective gas, heating the carbonized composite molding material to 2350-2450℃ at a rate of 0.8-1.2℃ / min and holding the temperature at that temperature for 40-44h.

[0012] Thirdly, the present invention provides a consumable for silicon carbide crystal growth, comprising the carbon fiber composite material described in any one of the foregoing embodiments.

[0013] Fourthly, the present invention provides a screening method for carbon fiber composite materials used in the preparation of consumables for silicon carbide crystal growth, wherein the carbon fiber composite material has a bending transmittance of 1-2.1 MPa, wherein the bending transmittance = transmittance at a wavelength of 260 nm × bending strength of the upper surface.

[0014] The present invention has the following beneficial effects: This application achieves a balance between material density, interfacial bonding, and microstructure through raw material ratio and gradient carbonization-graphitization process, thereby controlling its bending permeability within the range of 1-2.1 MPa and significantly improving its service life. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a SEM image of the carbon fiber composite material prepared in Example 1 of this application. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0018] This invention provides a carbon fiber composite material with a bending transmittance of 1-2.1 MPa, such as 1 MPa, 1.1 MPa, 1.2 MPa, 1.3 MPa, 1.4 MPa, 1.5 MPa, 1.6 MPa, 1.7 MPa, 1.8 MPa, 1.9 MPa, 2.0 MPa, and 2.1 MPa, wherein the bending transmittance = transmittance at a wavelength of 260 nm × bending strength of the upper surface.

[0019] The transmittance of carbon fiber composites at a wavelength of 260 nm characterizes the degree to which ultraviolet radiation penetrates the carbon fiber composite components. Excessive ultraviolet radiation penetration can disrupt the furnace temperature field, induce crystal defects, and reduce wafer quality. Furthermore, it can accelerate material aging, cracking, and surface peeling, shortening the lifespan of consumables. Therefore, carbon fiber composites need to maintain low transmittance in relevant wavelength bands to stabilize the furnace process environment, delay material aging, avoid impurity contamination, and ensure crystal growth quality and the lifespan of carbon fiber composite consumables. Silicon carbide crystal growth consumables are subjected to repeated thermal expansion and contraction and uneven local stress during use, causing the surface of the carbon fiber composite component to continuously bear bending tensile stress. This, to a certain extent, improves the bending strength of the upper surface, which helps to suppress the formation and gradual propagation of microcracks on the material surface, thus extending its service life.

[0020] In an optional embodiment, the transmittance of the carbon fiber composite material at a wavelength of 260 nm is 0.05-0.1.

[0021] In an optional embodiment, the transmittance of the carbon fiber composite material at a wavelength of 260 nm is less than 0.05.

[0022] In an optional embodiment, the transmittance of the carbon fiber composite material at a wavelength of 260 nm is greater than 0.1.

[0023] In an optional embodiment, the upper surface flexural strength of the carbon fiber composite material is 12-25 MPa.

[0024] In an optional embodiment, the upper surface flexural strength of the carbon fiber composite material is less than 12 MPa.

[0025] In an optional embodiment, the upper surface flexural strength of the carbon fiber composite material is greater than 25 MPa.

[0026] In an optional embodiment, the flexural strength of the carbon fiber composite material is 1-2.1 MPa.

[0027] In an optional embodiment, the flexural strength of the carbon fiber composite material is 1-1.1 MPa.

[0028] In an optional embodiment, the flexural strength of the carbon fiber composite material is 1.4-1.5 MPa.

[0029] In an optional embodiment, the flexural strength of the carbon fiber composite material is 1.9-2.1 MPa.

[0030] The present invention also provides a method for preparing the carbon fiber composite material according to any one of the foregoing embodiments, comprising: cold pressing a mixture of raw materials to obtain a composite molding material; The composite molding material is subjected to heat treatment, carbonization, and graphitization in sequence to obtain the carbon fiber composite material.

[0031] The method described in this application can prepare carbon fiber composite materials with a bending permeability of 1-2.1 MPa, which can be applied to consumables for silicon carbide crystal growth and have a long service life.

[0032] In an optional embodiment, the raw material mixture comprises the following components by weight: One part of pitch coke powder; Pitch coke serves as a carbon source skeleton, forming a rigid support network for carbon fiber composites. In subsequent heat treatment, it forms a uniformly distributed microporous / mesoporous structure, which is beneficial for the densification and stress release of carbon fiber composites. If there is too little pitch coke powder, the matrix support will be insufficient and the bending strength of the upper surface will decrease; if there is too much, the pore connectivity will increase and silicon vapor will easily penetrate, reducing the transmittance at a wavelength of 260nm. Both of these will cause the bending transmittance to exceed the reasonable range, accelerate thermal shock cracking and interface corrosion, and significantly shorten the service life of carbon fiber composites.

[0033] 1-1.2 parts of pitch-based carbon fiber powder, for example 1.00 parts, 1.02 parts, 1.04 parts, 1.06 parts, 1.08 parts, 1.10 parts, 1.12 parts, 1.14 parts, 1.16 parts, 1.18 parts, and 1.20 parts; Pitch-based carbon fiber powder is beneficial to improving the flexural strength of the upper surface. At the same time, it fuses in situ with pitch coke / resin residue at high temperature, reducing interface pores and debonding defects, improving the overall density of the material, and helping to achieve a bending penetration of 1-2.1 MPa.

[0034] PEG6000 powder, 0.15-0.25 parts, for example 0.15 parts, 0.16 parts, 0.17 parts, 0.18 parts, 0.19 parts, 0.20 parts, 0.21 parts, 0.22 parts, 0.23 parts, 0.24 parts, 0.25 parts; PEG6000 powder can regulate the uniformity of cold-pressed green bodies and the stress release behavior in the early stage of heat treatment, which is beneficial to the composite molding material without macroscopic cracks and component segregation.

[0035] The graphene microflakes are 0.15-0.25 parts, for example, 0.15 parts, 0.16 parts, 0.17 parts, 0.18 parts, 0.19 parts, 0.20 parts, 0.21 parts, 0.22 parts, 0.23 parts, 0.24 parts, and 0.25 parts. On the one hand, the graphene microflakes significantly reduce light scattering centers and improve the transmittance at a wavelength of 260nm through layer bridging and defect passivation. On the other hand, they can inhibit the propagation of microcracks, which is beneficial to improving the bending strength of the upper surface and thus affecting the bending transmittance.

[0036] The phenolic resin content is 0.1-0.3 parts, for example, 0.10 parts, 0.12 parts, 0.14 parts, 0.16 parts, 0.18 parts, 0.20 parts, 0.22 parts, 0.24 parts, 0.26 parts, 0.28 parts, and 0.30 parts. The pyrolytic carbon of the phenolic resin forms continuous, low-defect carbon bridges between the fiber / coke particles, which helps to simultaneously improve density and interfacial bonding, thereby increasing the transmittance at 260nm wavelength and the flexural strength of the upper surface. When the phenolic resin content is less than 0.1 parts, the interfacial bonding is weak, resulting in poor transmittance and flexural strength; when it is more than 0.3 parts, the pyrolytic shrinkage stress is too large, inducing microcracks, which in turn deteriorates both the transmittance at 260nm wavelength and the flexural strength, shortening the service life.

[0037] In optional embodiments, the cold pressing pressure is 15-30 MPa, for example 15 MPa, 17 MPa, 19 MPa, 21 MPa, 23 MPa, 25 MPa, 27 MPa, 29 MPa, or 30 MPa; the temperature is 18-30℃, for example 18℃, 19℃, 20℃, 21℃, 22℃, 23℃, 24℃, 25℃, 26℃, 27℃, 28℃, 29℃, or 30℃. Too low a pressure in the cold pressing step results in a porous green body, weakening its flexural strength; too high a pressure induces microcracks, damaging the interface integrity. Room temperature pressing helps ensure a uniform spatial distribution of PEG and resin components, laying the foundation for the subsequent formation of continuous carbon bridges. The combination of pressure and temperature helps optimize the transmittance at 260nm wavelength and the flexural strength of the upper surface.

[0038] And / or, the heat treatment includes heating the composite molding material to 148-152°C at a rate of 4-6°C / min and holding it at that temperature for 9-11 hours, then cooling it to 18-30°C. This condition avoids bubbling or residue and allows the composite molding material to undergo appropriate cross-linking to form an initial internal carbon network, improving the density of the matrix and the interfacial bonding force. This is beneficial for reducing the transmittance at a wavelength of 260nm, enhancing the surface load-bearing capacity, suppressing interfacial debonding and bending failure during service, and thus extending the service life.

[0039] For example, the heating rate in the heat treatment step can be 4.0℃ / min, 4.2℃ / min, 4.4℃ / min, 4.6℃ / min, 4.8℃ / min, 5.0℃ / min, 5.2℃ / min, 5.4℃ / min, 5.6℃ / min, 5.8℃ / min, or 6.0℃ / min.

[0040] For example, the isothermal temperature in the heat treatment step can be 148℃, 148.5℃, 149℃, 149.5℃, 150℃, 150.5℃, 151℃, 151.5℃, or 152℃.

[0041] For example, the isothermal time in the heat treatment step can be 9.0 h, 9.2 h, 9.4 h, 9.6 h, 9.8 h, 10.0 h, 10.2 h, 10.4 h, 10.6 h, 10.8 h, or 11.0 h.

[0042] For example, the cooling temperature in the heat treatment step can be 18°C, 19°C, 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, or 30°C.

[0043] And / or, the carbonization includes: using an inert gas as a protective gas, first heating the heat-treated composite molding material to 313-317℃ at 0.3-0.5℃ / min and holding it at that temperature for 2-4 hours; then heating it to 378-382℃ at 0.5-0.7℃ / min and holding it at that temperature for 2-4 hours; and finally heating it to 1100-1200℃ at 0.3-0.5℃ / min and holding it at that temperature for 9-11 hours to obtain a crude product; the carbonization process is carried out in three stages, which helps to reduce open pores and microcracks, balances density and stress release capability, simultaneously improves the bending stiffness and UV shielding of the upper surface, and inhibits silicon vapor erosion along defect channels.

[0044] For example, the first heating rate in the carbonization step can be 0.30℃ / min, 0.32℃ / min, 0.34℃ / min, 0.36℃ / min, 0.38℃ / min, 0.40℃ / min, 0.42℃ / min, 0.44℃ / min, 0.46℃ / min, 0.48℃ / min, or 0.50℃ / min.

[0045] For example, the first stage of the isothermal temperature in the carbonization step can be 313℃, 313.5℃, 314℃, 314.5℃, 315℃, 315.5℃, 316℃, 316.5℃, or 317℃.

[0046] For example, the first isothermal time in the carbonization step can be 2 h, 2.2 h, 2.4 h, 2.6 h, 2.8 h, 3.0 h, 3.2 h, 3.4 h, 3.6 h, 3.8 h, or 4 h.

[0047] For example, the second heating rate in the carbonization step can be 0.50℃ / min, 0.52℃ / min, 0.54℃ / min, 0.56℃ / min, 0.58℃ / min, 0.60℃ / min, 0.62℃ / min, 0.64℃ / min, 0.66℃ / min, 0.68℃ / min, or 0.70℃ / min.

[0048] For example, the second stage of isothermal temperature in the carbonization step can be 378℃, 378.5℃, 379℃, 379.5℃, 380℃, 380.5℃, 381℃, 381.5℃, or 382℃.

[0049] For example, the second isothermal time in the carbonization step can be 2 h, 2.2 h, 2.4 h, 2.6 h, 2.8 h, 3.0 h, 3.2 h, 3.4 h, 3.6 h, 3.8 h, or 4 h.

[0050] For example, the heating rate in the third stage of the carbonization step can be 0.30℃ / min, 0.32℃ / min, 0.34℃ / min, 0.36℃ / min, 0.38℃ / min, 0.40℃ / min, 0.42℃ / min, 0.44℃ / min, 0.46℃ / min, 0.48℃ / min, or 0.50℃ / min.

[0051] For example, the third stage of the carbonization process can be at a constant temperature of 1100℃, 1110℃, 1120℃, 1130℃, 1140℃, 1150℃, 1160℃, 1170℃, 1180℃, 1190℃, or 1200℃.

[0052] For example, the third isothermal time in the carbonization step can be 9 h, 9.2 h, 9.4 h, 9.6 h, 9.8 h, 10 h, 10.2 h, 10.4 h, 10.6 h, 10.8 h, or 11 h.

[0053] And / or, the graphitization includes: using an inert gas as a protective gas, heating the carbonized composite molding material to 2350-2450℃ at a rate of 0.8-1.2℃ / min and holding it at that temperature for 40-44 hours. The graphitization step highly orders the carbon structure of the prepared carbon fiber composite material, enhancing its high-temperature strength, thermal conductivity, and chemical inertness. It promotes the fusion of graphene and carbon fiber lattice, balances the surface thermal stress distribution, keeps the bendability within a reasonable range, and helps extend the service life under extreme operating conditions.

[0054] For example, the heating rate in the graphitization step can be 0.80℃ / min, 0.84℃ / min, 0.88℃ / min, 0.92℃ / min, 0.96℃ / min, 1.00℃ / min, 1.04℃ / min, 1.08℃ / min, 1.12℃ / min, 1.16℃ / min, or 1.20℃ / min.

[0055] For example, the isothermal temperature in the graphitization step can be 2350℃, 2360℃, 2370℃, 2380℃, 2390℃, 2400℃, 2410℃, 2420℃, 2430℃, 2440℃, or 2450℃.

[0056] For example, the isothermal time in the graphitization step can be 40.0 h, 40.4 h, 40.8 h, 41.2 h, 41.6 h, 42.0 h, 42.4 h, 42.8 h, 43.2 h, 43.6 h, or 44.0 h.

[0057] The present invention also provides a consumable for silicon carbide crystal growth, comprising the carbon fiber composite material described in any of the foregoing embodiments.

[0058] The present invention also provides a screening method for carbon fiber composite materials for preparing consumables for silicon carbide crystal growth, wherein the bending transmittance of the carbon fiber composite material is 1-2.1 MPa, wherein the bending transmittance = transmittance at a wavelength of 260 nm × bending strength of the upper surface.

[0059] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0060] Example 1 This embodiment provides a method for preparing carbon fiber composite materials, specifically including the following steps: For the ingredients, weigh out 1 part of pitch coke powder (Hebei Deri New Material Technology Co., Ltd.), 1 part of pitch-based carbon fiber powder (Jiangxi Shuobang New Material Co., Ltd., carbon content 92-99%), 0.25 parts of PEG6000 powder, 0.15 parts of graphene micro flakes (CAS No.: 1034343-98-0) and 0.3 parts of phenolic resin (Jinan Shengquan Group Co., Ltd., carbon-containing and carbon-grade resin). Mix the weighed raw materials evenly to obtain a raw material mixture. Cold pressing molding involves cold pressing the raw material mixture at 18℃ and 30MPa for 4 minutes to obtain a composite molding material. Heat treatment: The composite molding material is placed in an oven and heated to 148°C at a rate of 4°C / min, held at that temperature for 11 hours, and then cooled to 18°C. Carbonization involves transferring the heat-treated molding material to a carbonization furnace. Using argon as a protective gas, the heat-treated composite molding material is first heated to 317℃ at a rate of 0.5℃ / min and held at that temperature for 2 hours; then heated to 382℃ at a rate of 0.7℃ / min and held at that temperature for 2 hours; finally, heated to 1100℃ at a rate of 0.3℃ / min and held at that temperature for 9 hours to obtain the crude product. Graphitization: The crude material is transferred to a graphitization furnace, and argon is used as a protective gas. The carbonized composite molding material is heated to 2450℃ at a rate of 0.8℃ / min and held at that temperature for 40 hours to obtain carbon fiber composite material. SEM images are shown below. Figure 1 As shown.

[0061] Example 2 This embodiment provides a method for preparing carbon fiber composite materials, specifically including the following steps: For the ingredients, weigh out 1 part of pitch coke powder (Hebei Deri New Material Technology Co., Ltd.), 1.1 parts of pitch-based carbon fiber powder (Jiangxi Shuobang New Material Co., Ltd., carbon content 92-99%), 0.20 parts of PEG6000 powder, 0.20 parts of graphene micro flakes (CAS No.: 1034343-98-0) and 0.2 parts of phenolic resin (Jinan Shengquan Group Co., Ltd., carbon-containing and carbon-grade resin). Mix the weighed raw materials evenly to obtain a raw material mixture. Cold pressing molding involves cold pressing the raw material mixture at 25℃ and 25MPa for 4 minutes to obtain a composite molding material. Heat treatment: The composite molding material is placed in an oven and heated to 150°C at a rate of 5°C / min, held at the temperature for 10 hours, and then cooled to 25°C. Carbonization involves transferring the heat-treated molding material to a carbonization furnace. Using argon as a protective gas, the heat-treated composite molding material is first heated to 315℃ at a rate of 0.4℃ / min and held at that temperature for 3 hours; then heated to 380℃ at a rate of 0.6℃ / min and held at that temperature for 3 hours; finally, heated to 1150℃ at a rate of 0.4℃ / min and held at that temperature for 10 hours to obtain the crude product. Graphitization involves transferring the crude material to a graphitization furnace, using argon as a protective gas, and heating the carbonized composite molding material to 2400℃ at a rate of 1℃ / min and holding it at that temperature for 42 hours to obtain carbon fiber composite materials.

[0062] Example 3 This embodiment provides a method for preparing carbon fiber composite materials, specifically including the following steps: For the ingredients, weigh out 1 part of pitch coke powder (Hebei Deri New Material Technology Co., Ltd.), 1.2 parts of pitch-based carbon fiber powder (Jiangxi Shuobang New Material Co., Ltd., carbon content 92-99%), 0.15 parts of PEG6000 powder, 0.25 parts of graphene micro flakes (CAS No.: 1034343-98-0) and 0.1 parts of phenolic resin (Jinan Shengquan Group Co., Ltd., carbon-containing and carbon-grade resin). Mix the weighed raw materials evenly to obtain a raw material mixture. Cold pressing molding involves cold pressing the raw material mixture at 30℃ and 15MPa for 4 minutes to obtain a composite molding material. Heat treatment: The composite molding material is placed in an oven and heated to 152°C at a rate of 6°C / min, held at that temperature for 9 hours, and then cooled to 30°C. Carbonization involves transferring the heat-treated molding material to a carbonization furnace. Using argon as a protective gas, the heat-treated composite molding material is first heated to 313℃ at a rate of 0.3℃ / min and held at that temperature for 4 hours; then heated to 378℃ at a rate of 0.5℃ / min and held at that temperature for 4 hours; finally, heated to 1200℃ at a rate of 0.5℃ / min and held at that temperature for 11 hours to obtain the crude product. Graphitization involves transferring the crude material to a graphitization furnace, using argon as a protective gas, and heating the carbonized composite molding material to 2350℃ at a rate of 1.2℃ / min and holding it at that temperature for 44 hours to obtain carbon fiber composite material.

[0063] Comparative Example 1 This comparative example provides a method for preparing carbon fiber composite material, which differs from Example 2 only in that graphene microsheets are not added in the batching step.

[0064] Comparative Example 2 This comparative example provides a method for preparing carbon fiber composite material, which differs from Example 2 only in that PEG6000 powder is not added in the batching step.

[0065] Comparative Example 3 This comparative example provides a method for preparing carbon fiber composite material, which differs from Example 2 only in that 0.3 parts by weight of graphene micro flakes are weighed in the batching step.

[0066] Comparative Example 4 This comparative example provides a method for preparing carbon fiber composite material, which differs from Example 2 only in that 0.3 parts by weight of PEG6000 powder are weighed in the batching step.

[0067] Test Example 1 The transmittance and upper surface flexural strength of the carbon fiber composite materials prepared in the above embodiments and comparative examples were tested at a wavelength of 260 nm. The test methods and test conditions are as follows, and the flexural transmittance was calculated based on the test results. The calculation results are shown in Table 1.

[0068] Test methods and conditions: Transmittance at 260nm wavelength was measured using a UV-Vis-NIR spectrophotometer, model Shimadzu UV-3600i Plus (Japan), with a sample thickness of 2mm.

[0069] The bending strength of the upper surface shall be in accordance with JB / T8133.7.

[0070] Bending transmittance = transmittance at 260nm wavelength × bending strength of upper surface.

[0071] Test Example 2 A self-developed thermal cycling accelerated aging method was used to conduct simulated service life tests for crystal growth. The specific steps included: (1) Test the initial upper surface flexural strength of the specimen according to JB / T8133.7; (2) The sample was placed in a high-temperature graphitization furnace and heated to 2450°C at 5°C / min under the protection of high-purity argon. After being kept at the temperature for 50 hours, it was cooled to room temperature with the furnace. This was recorded as one thermal cycle. (3) After each thermal cycle, take out the sample and test the bending strength of its upper surface according to JB / T8133.7; (4) The surface bending strength retention rate ≥70% is taken as the acceptable service standard. The maximum number of cycles required for each sample to meet this standard is calculated. Surface bending strength retention rate = Surface bending strength after N cycles / Initial surface bending strength. The number of samples is 5, and the average value is taken as the “simulated service life of crystal growth” of the material.

[0072] Table 1

[0073] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A carbon fiber composite material, characterized in that, The bending transmittance of the carbon fiber composite material is 1-2.1 MPa, where bending transmittance = transmittance at a wavelength of 260 nm × bending strength of the upper surface.

2. The carbon fiber composite material according to claim 1, characterized in that, The bending permeability of the carbon fiber composite material is 1-1.1 MPa.

3. The carbon fiber composite material according to claim 1, characterized in that, The bending permeability of the carbon fiber composite material is 1.4-1.5 MPa.

4. The carbon fiber composite material according to claim 1, characterized in that, The bending permeability of the carbon fiber composite material is 1.9-2.1 MPa.

5. A method for preparing the carbon fiber composite material according to any one of claims 1-4, characterized in that, include: The raw material mixture is cold-pressed to obtain a composite molding material; The composite molding material is subjected to heat treatment, carbonization, and graphitization in sequence to obtain the carbon fiber composite material.

6. The method for preparing carbon fiber composite material according to claim 5, characterized in that, The raw material mixture comprises, by weight, the following components: 1 part pitch coke powder, 1-1.2 parts pitch-based carbon fiber powder, 0.15-0.25 parts PEG6000 powder, 0.15-0.25 parts graphene microsheets, and 0.1-0.3 parts phenolic resin.

7. The method for preparing carbon fiber composite material according to claim 5, characterized in that, The cold pressing pressure is 15-30 MPa, and the temperature is 18-30℃; And / or, the heat treatment includes heating the composite molding material to 148-152°C at a rate of 4-6°C / min and holding it at that temperature for 9-11 hours, and then cooling it to 18-30°C.

8. The method for preparing carbon fiber composite material according to claim 5, characterized in that, The carbonization process includes: using an inert gas as a protective gas, first heating the heat-treated composite molding material to 313-317℃ at a rate of 0.3-0.5℃ / min and holding it at that temperature for 2-4 hours; then heating it to 378-382℃ at a rate of 0.5-0.7℃ / min and holding it at that temperature for 2-4 hours; and finally heating it to 1100-1200℃ at a rate of 0.3-0.5℃ / min and holding it at that temperature for 9-11 hours to obtain a crude product. And / or, the graphitization includes: using an inert gas as a protective gas, heating the carbonized composite molding material to 2350-2450℃ at a rate of 0.8-1.2℃ / min and holding the temperature at that temperature for 40-44h.

9. A consumable for silicon carbide crystal growth, characterized in that, Includes the carbon fiber composite material according to any one of claims 1-4.

10. A method for screening carbon fiber composite materials for preparing consumables for silicon carbide crystal growth, characterized in that, The bending transmittance of the carbon fiber composite material is 1-2.1 MPa, where bending transmittance = transmittance at a wavelength of 260 nm × bending strength of the upper surface.

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