Tantalum carbide coated carbon fiber yarn product and preparation method thereof

Abstract

The invention relates to a tantalum carbide coated carbon fiber yarn product and a preparation method thereof, a high-purity and high-strength tantalum carbide coated carbon fiber yarn is prepared by using a CVD (Chemical Vapor Deposition) process, and the tantalum carbide coated carbon fiber yarn has the characteristics of high strength, corrosion resistance, high temperature resistance, softness, weaving capability and the like, and is suitable for replacing the existing carbon felt, aluminum silicate fiber felt and the like to be used as a heat preservation and heat insulation sealing material in the semiconductor industry.

Description

Technical Field

[0001] The present invention belongs to the technical field of ceramic coating materials, and particularly relates to a tantalum carbide-coated carbon fiber wire product and a preparation method thereof. Background Art

[0002] Tantalum carbide is a ceramic material with superconductivity. It has a golden yellow appearance and has the advantages of high hardness (2100HV0.05), high melting point (3880 °C), corrosion resistance, and non-stickiness. It is a newly emerging ceramic material in recent years. Powdery tantalum carbide is widely used in the smelting process of special alloys. Tantalum carbide ceramics have broad application prospects in the fields of semiconductors, chemical engineering, metallurgy, mold processing, aerospace, nuclear industry, etc., and are excellent shielding and wear-resistant materials. However, its poor ductility, fragility, and high processing cost limit its wide use.

[0003] Common heat insulation materials in the semiconductor industry include carbon felt, aluminum silicate fiber felt, asbestos, rock wool, glass fiber, porous carbon, etc.; among them, asbestos has been banned by the state due to the strong carcinogenicity of dust during the production process, and the maximum use temperature of aluminum silicate fiber felt, rock wool, and glass fiber will not exceed 1500 °C, making it difficult to meet the requirements of the semiconductor industry; carbon felt and porous carbon will be corroded by the atmosphere in the crystal growth furnace, with a short service life and carbon elements will pollute the products.

[0004] Limited by the particularity of carbon fiber, common coating methods such as brushing, spraying, and in-situ methods are difficult to coat carbon fiber, and the coating effect is very unsatisfactory. Moreover, after coating, the fiber loses its original soft and bendable characteristics, and multiple strands of fiber are bonded into a whole and cannot be used continuously. For example, CN107176604B discloses a method for in-situ generating a nanocarbonide coating on the surface of carbon materials. An oxide sol or gel is prepared by the sol-gel method, uniformly coated on the surface of the carbon material, and after drying and sintering processes, it is then subjected to vacuum high-temperature treatment to achieve in-situ reduction-carbonization reaction. The preparation process is complex and time-consuming. Summary of the Invention

[0005] In view of the defects of the prior art, the present invention provides a tantalum carbide-coated carbon fiber wire product, including a wire core and a tantalum carbide layer, in the shape of a wire. It is characterized in that the wire core is a bendable carbon fiber wire with a diameter of 0.1-22 microns; the tantalum carbide wraps the outer layer of the wire core to form a dense protective layer, and the thickness of the tantalum carbide layer does not exceed 2 microns.

[0006] The present invention also provides a preparation method for a tantalum carbide-coated carbon fiber wire product, including the following steps:

[0007] ① Pretreatment of carbon fiber wire: Put the carbon fiber wire into a high-temperature furnace and heat-treat it under the protection of an inert gas; after heat-treatment, take out the carbon fiber wire and rinse it in absolute ethanol; after the rinsing is completed, put the carbon fiber wire into a deposition furnace for use;

[0008] ② Preparation of tantalum carbide layer: Start the CVD reactor, with the reaction temperature at 500 - 800 °C and the reaction pressure at 200 - 600 Pa, to prepare tantalum carbide-coated carbon fiber filaments.

[0009] ③ After the CVD process is completed, start the purging process, use an inert gas for purging, naturally cool to room temperature, and take out the product.

[0010] Furthermore, tantalum carbide layer is prepared by reacting tantalum ethoxide with methane.

[0011] Preferably, the diameter of the carbon fiber filaments is 0.1 - 22 microns.

[0012] Furthermore, the inert gas includes helium or argon.

[0013] Furthermore, the heat treatment temperature is 1200 °C and the time is 30 min.

[0014] Furthermore, a rotating gas distributor is also provided at the center inside the CVD reactor. The rotating gas distributor is provided with ventilation holes. The carbon fiber filaments are evenly wound around the rotating gas distributor. When depositing, the gas blown out from the ventilation holes makes the carbon fiber filaments suspended.

[0015] Beneficial effects: The tantalum carbide-coated carbon fiber filaments prepared by the present invention greatly improve the corrosion resistance and high-temperature resistance of the carbon fiber filaments, extend the service life of the carbon fiber filaments, effectively prevent carbon element pollution to the product, and can achieve the expected effect at a relatively low cost without changing the original excellent strength of the carbon fiber filaments.

[0016] The tantalum carbide-coated carbon fiber filaments prepared by the present invention still maintain the soft physical properties of the fibers, do not become hard, and can continue to be processed by processes such as winding and weaving.

[0017] The tantalum carbide coating obtained by this method has a high purity, no impurities, does not cause secondary pollution, and has a lower cost compared with other methods. Brief Description of the Drawings

[0018] Figure 1 It is a cross-sectional schematic view of the tantalum carbide-coated carbon fiber filaments of the present invention. 1 represents the core; 2 represents the tantalum carbide layer.

[0019] Figure 2 It is a surface electron microscope image of the tantalum carbide-coated carbon fiber filaments prepared in Example 1.

[0020] Figure 3 It is a metallographic image of the tantalum carbide-coated carbon fiber filaments prepared in Example 1.

[0021] Figure 4 It is an appearance morphology image of the tantalum carbide-coated carbon fiber filaments after heat test in Comparative Test 1. Detailed Implementation Modes

[0022] The present invention will be specifically described through some embodiments for a full understanding. However, the present invention can be implemented in many other ways different from those described herein. Those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific implementations disclosed below. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0023] The present invention adopts the CVD method. After adjusting the process, tantalum carbide-coated carbon fiber filaments similar to enameled copper wires can be prepared without changing the characteristics of the carbon fiber filaments, providing a protective effect for coating the carbon fiber filaments.

[0024] As Figure 1 shown, a tantalum carbide-coated carbon fiber filament product includes a wire core 1 and a tantalum carbide layer 2, in the shape of a silk thread. The wire core 1 is a bendable carbon fiber filament with a diameter of 0.1 - 22 microns; the tantalum carbide wraps around the outer layer of the wire core to form a dense protective layer, and the thickness of the tantalum carbide layer 2 does not exceed 2 microns. The tantalum carbide-coated carbon fiber filaments of the present invention still maintain the soft physical properties of the fibers, do not become hard, and can continue to be wound, braided into ropes, threads, nets, etc.

[0025] The preparation method of the above-mentioned tantalum carbide-coated carbon fiber filament product includes the following steps:

[0026] ① Pretreatment of carbon fiber filaments: Put the carbon fiber filaments into a high-temperature furnace and heat-treat them under the protection of an inert gas; take out the carbon fiber filaments after heat-treatment and rinse them in absolute ethanol; after the rinsing is completed, put the carbon fiber filaments into a deposition furnace for use;

[0027] ② Preparation of the tantalum carbide layer: Start the CVD process, with a reaction temperature of 500 - 800 °C and a reaction pressure of 200 - 600 Pa, to prepare tantalum carbide-coated carbon fiber filaments;

[0028] ③ After the CVD process is completed, start the purging process, use an inert gas for purging, naturally cool to room temperature, and take out the product. The purpose of purging is to prevent the carbon fiber filaments from sticking together and can also remove other impurities in the deposition furnace.

[0029] Further, the diameter of the carbon fiber filaments is 0.1 - 22 microns.

[0030] Further, the inert gas includes helium or argon.

[0031] Further, the heat-treatment temperature is 1200 °C and the time is 30 min.

[0032] The purpose of step ① is to remove residual organic matter and inorganic salts on the surface of carbon fiber filaments and improve fiber purity. The inert gas can be an inert gas that does not chemically react with the reactants, such as argon or neon or a mixed gas of argon and neon, etc.

[0033] Furthermore, to ensure that each carbon fiber filament can be uniformly deposited and not be deposited as a single entity due to adhesion, the carbon fiber filaments can be evenly wound around a rotating gas distributor. During deposition, the rotating gas distributor blows out gas to suspend the carbon fiber filaments, and CVD deposition is carried out in the air.

[0034] The present invention significantly improves the resistance of carbon fiber filaments to the corrosion of the atmosphere in the crystal growth furnace at a relatively low cost, reduces the influence of carbon elements on the crystal, improves the yield rate of the crystal, and reduces costs and increases efficiency for enterprises; and compared with other methods, the fibers prepared by the present invention still maintain a soft state, can be woven into a net, wound into a rope, and maintain the extremely high tensile strength of the carbon fiber filaments.

[0035] To further explain the technical solution of the present invention, the following will elaborate on the present invention through specific embodiments. In industrial production, considering the economic cost, argon is used as the inert gas for protection in the embodiments, and it can also be extended to other inert gases that do not participate in chemical reactions. The following embodiments will help researchers in the field to further understand the present invention, but do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, several adjustments and improvements can be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0036] The following test equipment uses general equipment if not otherwise specified, which does not affect the determination of the final result: the electron microscope is Thermo Fisher Apero2.

[0037] Example 1

[0038] The chemical vapor deposition equipment is a quartz reaction chamber. The materials and reagents used are as follows: T300 carbon fiber filaments, ethanol (AR), deionized water, high-purity methane (99.999%), high-purity tantalum ethoxide (99.999%), high-purity argon (99.999%); the implementation steps are as follows:

[0039] 1. Rinse the carbon fiber filaments twice in deionized water and then dry them in an oven.

[0040] 2. Take out the carbon fiber filaments and put them into a high-temperature furnace, and heat-treat them for 30 minutes under the protection of an inert gas at 1200°C. After heat treatment, rinse the fibers with absolute ethanol and then air-dry them naturally.

[0041] 3. Place the carbon fiber filaments air-dried in Step 2 into the deposition furnace, start the deposition process with a deposition temperature of 500 °C and a vacuum degree of 400 Pa. After depositing for 30 minutes, stop the deposition process and start the purging process. In this embodiment, tantalum carbide layer is prepared by reacting tantalum ethoxide with methane, and the gas volume ratio of the two is 1:1 - 2. Other tantalum alkoxides such as tantalum methoxide can also be used to react with methane to prepare the tantalum carbide layer. The rotation speed of the rotating gas distributor is set at 60 rpm.

[0042] 4. After ten minutes, stop the purging process and cut off the power supply to let it cool down naturally. After cooling to room temperature, take out the product.

[0043] The prepared tantalum carbide-coated carbon fiber filaments were detected using a metallurgical microscope, and the detection results are as Figure 3 shown. It shows that the diameter of the product after being made is 11 microns, the fiber thickness distribution is uniform, the coating is complete, the carbon fiber filaments remain soft, and the whole presents yellow. According to GB / T3362 - 2017, the tensile strength of the fiber was tested, and the test result was 4.1 GPa, which is the same as that of the carbon fiber filaments before deposition.

[0044] Figure 2 Figure 12 is the morphology of the tantalum carbide layer 1 observed using SEM. It can be seen that there are a large number of grains densely arranged in the coating, with a relatively dense microstructure and non-connected voids, forming an effective protection for the carbon fiber filaments. After being tested by the instrument, the diameter of the tantalum carbide grains is about 1 micron.

[0045] Comparative Test 1

[0046] According to Example 1, prepare the tantalum carbide-coated carbon fiber filament products. At the same time, purchase a little aluminosilicate fiber felt and glass fiber on the market, place them in a graphite crucible respectively, and heat them to 1700 °C in a corundum tube furnace and keep it warm for 10 minutes.

[0047] After testing, it can be found that the surface of the carbon fiber filaments of the present invention becomes dark yellow. As Figure 4 shown, it can still be observed under an electron magnifier that the carbon fiber filaments maintain their original structure, while the glass fiber and aluminosilicate fiber have melted and become white residues at the bottom of the crucible.

[0048] Comparative Test 2

[0049] Prepare the tantalum carbide-coated carbon fiber filaments according to the steps of Example 1. At the same time, purchase a little carbon felt on the market and place them together in a crystal growth furnace, and start the crystal growth process.

[0050] After the process is completed, take out the sample and find that the carbon felt has completely disappeared without leaving a trace of residue, while the tantalum carbide-coated carbon fiber filaments prepared by the present invention are still intact as before.

[0051] The above embodiments and diagrams do not limit the product form and style of the present invention. Any appropriate changes or modifications made by those of ordinary skill in the art, such as changes in parameters like reaction temperature, vaporization temperature, gas flow rate, etc., should be regarded as not departing from the patent scope of the present invention.

Claims

1. A tantalum carbide-coated carbon fiber wire product, comprising a wire core and a tantalum carbide layer, in the shape of a silk thread, characterized in that, The wire core is a bendable carbon fiber filament with a diameter ranging from 0.1 to 22 microns; tantalum carbide wraps the outer layer of the wire core, and the thickness of the tantalum carbide layer does not exceed 2 microns.

2. A method for preparing a tantalum carbide-coated carbon fiber filament product, characterized in that, Using the CVD process to prepare a tantalum carbide coating on the surface of the carbon fiber filament, obtaining a tantalum carbide layer-coated carbon fiber filament, including the following steps: ① Pretreatment of carbon fiber filament: Place the carbon fiber filament in a high-temperature furnace and heat-treat it under the protection of an inert gas; after heat-treatment, take out the carbon fiber filament and rinse it in absolute ethanol; after the rinsing is completed, place the carbon fiber filament in a deposition furnace for standby; ② Preparation of tantalum carbide layer: Start the CVD reaction furnace, with a reaction temperature of 500 - 800 °C and a reaction pressure of 200 - 600 Pa, to prepare tantalum carbide-coated carbon fiber filament; ③ After the CVD process is completed, start the purging process, use an inert gas for purging, and naturally cool down to room temperature, then take out the product.

3. The preparation method according to claim 2, wherein The diameter of the carbon fiber filament ranges from 0.1 to 22 microns.

4. The preparation method according to claim 2, characterized in that, Tantalum ethoxide and methane are used to react to prepare the tantalum carbide layer.

5. The preparation method according to claim 2, characterized in that, The heat-treatment temperature is 1200 °C and the time is 30 min.

6. The preparation method according to claim 2, characterized in that, A rotating gas distributor is also provided in the center of the CVD reaction furnace. The rotating gas distributor has ventilation holes. The carbon fiber filaments are evenly coiled around the rotating gas distributor, and the gas blown out from the ventilation holes during deposition makes the carbon fiber filaments suspended.

7. The preparation method according to claim 6, characterized in that, The rotation speed of the rotating gas distributor is set at 60 rpm.

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